The pressure differential valve is the device that alerts you if you have a leak in one of your brake circuits. The valve contains a specially shaped piston in the middle of a cylinder. Each side of the piston is exposed to the pressure in one of the two brake circuits. As long as the pressure in both circuits is the same, the piston will stay centered in its cylinder. But if one side develops a leak, the pressure will drop in that circuit, forcing the piston off-center. This closes a switch, which turns on a light in the instrument panel of the car.
This setup #1, #2 is a pressure differential valve and switch on 1976 cars. It senses that there is different pressure in one set of lines vs the other. e.g. brake failure
The purpose of the switch (item 2) in the brake line manifold/valve (item 1). When this switch detects enough of a pressure difference between the redundant front circuits, it latches on, and that turns on the dash light. It stays on until you reset it manually.
You can easily reset the switch by pressing the little plastic plunger between the electrical terminals of switch #2. The plunger may be covered by a rubber boot, and the whole thing may be covered in stealthy grease and dirt.
I was more curious to see innards of the unit, so I was able to find one from FAQ member. I bought ¼” pipe plugs (x3) and plugged 3 ports and connected 4th port to a grease gun. After a few strokes of grease gun and rotating spool end a few times was able to get the piston out.
This upgrade is to compliment a pre-existing Volvo/320i vented system (-or whatever it is you Tii fellas do..) that can be added to the front with relative ease.
In an effort to replicate the placement of the calipers in a rear conversion at the stock(ish) 3 and 9 O'clock positions as compared to the front calipers, I worked with Todd21 who had formulated a plan based on the work of others, combined with his own ideas.[/b][/b]
Here is the stock location of the front calipers which we are attempting ot replicate:
His concern, which as it worked out was OUR concern, is that the calipers in other designs were hung off the bottom, necessitating that the calipers be removed in order to get the bleeder vertical when... bleeding.
This led to a rather gutsy design and ultimately a fine product. Although the final products for Todd an I are slightly different, I will cover the reasons. The biggest being that we live four hours apart, and once I returned home and discovered the need to a rethink, reworking from afar was impossible.. so it evolved.
OK, so, for reference, here is a bone stock swing arm and bone stock assembly..
As you may have guessed, the stopper in anyone's design looking to get the caliper in the correct position, is the location of the rear shock boss. In this design, the stock shock boss is removed and thus relocated. (This is the gutsy part!!)
Here is the drawing for the adaptor plate, indicating the placement of the new shock boss.
This exact design worked well on Todd's car, with I.E. Stage II 235 LB. springs, 15X7 et 25 wheels and stock shocks. Where my Eibach progressive springs, 15X7 e25 wheels combined with Bilstein Sports (larger body to the shock), required a different shock boss location to provide clearance for the shock body and inner lip of the rim. As well, the lower shock boss location in my final offered more travel to prevent shock bottoming.. even with sports. The reason being, while Bilstein's have more aggressive dampening rates, they also have longer compressed length than the OEM shocks.
As you can see, my design became a two part plan..
I was able to get the mounting location in an almost identical parallel to the original boss location. This totally eliminated the issue I was having with bottoming.
In hindsight, I will say that had I the ability to redesign based on the original drawing, I could have extended the shock boss to get the wheel clearance and the drop needed to have it all come together with just the plate. So going forward, I recommend this be the route anyone following this method use.
Once again, refer to Todd's original drawing, and extend the boss (test fit the plate with the shock and wheel installed to measure the appropriate boss dimension). See the next pic for a visual...
So without further ado, lets dig in to this..
Here is the parts list:
Donor car info:
· Rabbit Mk1 (A1/Typ 17, 1974-1984)
· Golf Mk2 (A2/Typ 19E, 1985-1992)
· Golf Mk4 (A4/Typ 1J, 1998-Present)
2) VW Calipers (rear) from MK4, 2000 to 2006 Golf, Beetle, or Jetta (with lines)
2) VW Carrier Brackets (rear) from MK2, 1985 to 1989 Golf or Jetta
2) VW Rotors (front) from MK1 (74-84 Rabbit) (239x12mm)
2) Reduced OD hubs from 2002 (existing hubs can be modified at a shop, or on the car if you're clever..)
2) Adapter plates (see drawing)
6) M10x25 Socket Head Cap Screw
2) M10x20 Flat Head Cap Screw
1) Proportioning valve for rear brakes
1) 3’ section of 3/16” steel brake line
Start by jacking the rear of the car and placing jack stands under it to allow for safe work. This should be done on a flat hard surface it at all possible. All typical safety precautions should be taken to prevent the car from falling during the conversion. Very little, if any work will require getting under the car, but always err on the safe side. While we love our cars they can be replaced, we cannot.
Remove the rear wheels, brake drums, and hubs exposing the brake shoe assembly. The components of the rear drum brake assembly will be completely removed, including the backing plate attached to the spindle tube flange. The cable for the parking brake can be left hanging loose. The hard brake line can be removed back to the connection with the flex line at the trailing arm.
Remove the shock absorber mounting nut and slide the shock absorber off the trailing arm mount. Using a grinder or port-a-band saw cut the shock absorber mount off the flange. This is required to allow clearance for the caliper piston. The flange can be relieved as required during final fit to minimize the amount of the flange removed.
Install the fabricated adapter plates (see drawing) to the spindle tube flange using two socket head cap screws (SHCS) in the front holes and two flat head socket cap screws (FHCS) in the rear holes. The FHCS are required to allow clearance for the carrier bracket. Loc-tite 242 (blue) should be applied to all fasteners. Here we are test fitting with an early prototype bracket..
The rear hubs will be reduced on the outside diameter to allow the brake disk to pass over it. Take a measurement of the inside diameter of the brake disk “top hat” and then turn down the outside of the hub to allow the two parts to mate. Once the hub and disk is installed, test fit the carrier bracket and caliper to insure proper fit. The carrier bracket may require the slot for the disk to be opened depending on the location of the disk and hub.
Once the hub and disk are installed and the carrier bracket and caliper are installed, you will then install the wheel and put the swing arm under load with a floor jack. Do this to gather your measurements for the length of the shock boss. Check for clearance at the inner wheel lip, the caliper and the spring. You can reuse the original knurled shock mounting stud in your design. We used rod stock. Counterbored to accept the stud, and tack welded it into place.
Then.... here's the tricky part, Todd ground the boss to a 21 degree angle on the bolt head end. His best attempts at getting measurements on the boss orientation put it at 21 degrees down from the horizontal and rotated around 11 degrees to get the proper position. Just put the bolt/boss in the bottom mount of the shock and take a look. If it doesn't look right grind the angle to suit you and then put in back in the shock and see if it looks correct.
Once the angles and clearances add up, tack it into place , remove the plate and fully weld. (The position on the drawing is for reference.)
Next, the brake line from the VW are of very good quality, and can be installed on the trialing arm. Straighten out the hard line to allow for it to be routed along the trailing arm similar to the original line. Attach the hard line end to the fitting on the trailing arm and then route the flex end to the caliper. The banjo mount on the caliper may require turning 90 degrees to create clearance with the inside of the rear wheels.
While you're at it, grind off that little rectangular nub from the body of the caliper. It got in my way later..
Install the shock to the new mounting location.
Install the proportional valve in the line to the rear brake calipers.
Bleed the system down. This will take some time since the system has been broken into in more than one location.
The parking brake cables can be attached to the calipers by extending the cable using a locking chain link or other means. The cables are not long enough to make the connection as is so I used a small chain link that I got a home depot to extend it. You must do a little grinding on it to get it to pass through the end of the cable..
(While it may not pretty, until we discover another means to accomplish this, it does work very well. Verified with over a year on the road.
Be sure to torque your hub nuts when finishing up...
Install the rear wheels and adjust the proportioning valve to achieve proper bias.[/b]
One of these days, I'm going to go test my 60 to 0 stopping distance, as a reference.. so watch for it.
I wanted to change the rear drums on my 2002 to disks. There are no problems with using drums for daily use, but in a race car i wanted to have a bit more maintenance and better consistency day after day. The rules for SCCA FSP class require the car to retain the parking brake. So one of the better ways was to go to the VW Disk conversion. Ireland Engineering sells the full kit that can easily be installed by anyone. What i installed was very similar, but i used an aluminum caliper.
Ireland Engineering Kit includes:
Custom Steel mounting bracket
VW Golf MKII Rear Caliper carrier (1985 to 1989 Golf or Jetta)
VW Golf MKII Rear Caliper (1985 to 1989 Golf or Jetta)
I used aluminum caliper from MKIV VW. (2000 to 2006 Golf, Beetle, or Jetta) Pros: aluminum, lighter weight, less corrosion, better reliability. Cons: Bleeding can only be done with caliper not mounted to the bracket since the bleeder is at the bottom after the installation.
VW Golf MKI Front Rotor (74-84 Rabbit) (239x12mm)
You will need to machine the edges of your hub to fit inside the new rotor or IE can do this for you.
Several Bolts and Several Spacer Washers
To start the installation you will need to remove the Drum, Hub, and backing plate with all the brake parts attached to it.
Mount the bracket to the control arm. Try to clean it before mounting. These parts were never designed to be precise but cleaning will make them a bit better for installation something that requires some precision like a caliper.
Install the hub and tighten the castle nut properly.
Install the rotor over the modified hub and use a couple lug nuts to tighten it to the hub. All this has to be done prior to installation of calipers since and movement afterwards might cause the disk to rub on the caliper.
Now it's time to test fit the carrier. Use the washers to get it properly aligned to the rotor. Use lock tight after you have positioning all set
Now it is time to fit the caliper and the brake pads. These calipers are equipped with a parking brake mechanism that will require a special tool to push the piston back in place. This caliper can be loaned from your local Auto Parts Store or purchased on Amazon. It will allow you spin the piston as you apply the pressure.
At this time you might notice that the caliper protrudes about an inch away from the mounting face of the wheel. If your wheels do not have that much clearance at that spot you will most likely need to use a spacer.
Aluminum calipers have cooling fins that make that slightly larger then the cast iron calipers. You might have to shave them to get to fit them inside your wheels
Once all is in place, you will need to hook the parking brake over the mechanism of the caliper and do some adjustments on the cable side to get them to be tight
You will notice that the bleeder on the caliper is on the side. You will need to undo one of the bolt, swing the caliper and bleed it. You will not be able to use the "pump the pedal" method, but both push and pull vacuum tools work well in this situation.
p.s. if you find any of the information incorrect or you have something to add, feel free to modify the article.
This is my first post to this forum and first up, I'd like to thank all those that have come before me and shared their tips and tricks for everyone.
After recently completing the Girling Caliper/ Vented Rotor front brake upgrade to my 74' 2002, I decided to tackle the rear brakes as the shoes were pretty worn and I was at maximum adjustment. I'd read about the fun and games with getting that lower "M" shaped spring back on without losing an eye in the process and was a bit sceptical about tackling it myself! I scoured the internet (including this forum) and couldn't really find a super clear explanation so I set about trying to figure one out. I think I've come up with a pretty safe and easy way to get those springs on and I wanted to share what I learned on here. I actually took a lot of video of the job which I'll turn into a YouTube clip when I get a chance but until then, here is the basic explanation of what I did.
Large flat blade screw driver
3 x G clamps
Needle (long nose) Vice Grip pliers
40cm long piece of wood (about 4-5cm wide)
small block of wood (3 x 3cm) See pic.
Once you've removed the old shoes and cleaned up the drum backing plate, wheel cylinder, hub etc. Check everything is in good shape and the cylinder moves freely and the rubber seals are intact. Release both 10mm nuts on the handbrake cables at handbrake inside car. Turn the 17mm adjusting nuts on rear of backing plate to allow for shoes to be as close to the centre hub as possible.
Install new shoes by connecting the top spring between the shoes, attach the handbrake cable and position ends of shoes in the vertical slots in the wheel cylinder. Its a good idea to take a photo of the brake layout BEFORE removing the old shoes! Once the shoes and top spring are all in position, clamp the long piece of wood across the top of the brakes (covering the wheel cylinder) to the backing plate. This will hold the shoes in position while you're trying to manhandle the bottom spring on.
Here comes the tricky bit....
Take the big spring and position the LEFT hand end into the hole on the lower left shoe and position the middle of the spring in BEHIND the small central plate. Hold this in position while you clamp the small block of wood over the left hand end of the spring to secure this end in the shoe (see pic). Once the spring is firmly clamped in place, take the screwdriver in your left hand and poke it up behind the hub and onto the top of the small central plate and rest it on the spring. The idea is to apply upward pressure on the screwdriver to firmly hold the middle of the spring from jumping out from behind the central plate. (I used my foot to hold the screwdriver which then freed up both hands to work the Vice Grips)
Set the Vice Grips as tight as you can get them on the RH end of the spring which is kind of tucked in behind the right shoe at this point. You should be able to get a grip on the lower "U" part of the spring and then gently (and carefully) pull the spring out over the shoe and downwards until it drops into the hole. BINGO! Wasn't that hard was it!
Remove all the clamps and wood etc and check if everything seems to be in position. Slip drums back on and adjust the 17mm nuts on the back of the backing plate until drag is felt, then back it off a bit.
Road test the car and repeat the brake adjustment. Don't forget to do the handbrake!
I hope this info has helped and look out for the YouTube tutorial in the next few weeks.
The "big brakes" upgrade is probably the most-frequently asked question when it comes to upgrading an '02 for high-performance driving. In fact "big brakes" is really a misnomer because what we are really after here isn't necessarily a larger diameter brake rotor (although these upgrades below do give you a marginally larger rotor), but in fact rotors that are vented for better cooling.
Braking systems are basically heatsinks that suck kinetic energy out of a bunch of flying metal, plastic and glass, and convert it into heat: depositing it in the brake rotor itself. Then the rotor is supposed to shed it into the rushing, cool night air... Vented brakes simply allow this process to take place with more efficiency, in addition to having a higher basic mass which will by itself soak up more heat without failing.
Which option you choose to get your vented brakes will depend mostly on where you are starting. For tii owners, the best option is to use the brakes from the e12 early 5-series sedan or e24 6-series coupe. They will fit on the stock tii spindles and require no other modification of the car.
For non-tii '02s, really there are two major options. One is to go with all-BMW parts and buy a set of tii front struts. Then use the parts from an e12 sedan or e24 coupe as stated above. The other option is to just use the Girling Vented calipers from a mid-80s Volvo 240, and the rest of the parts from the e21 320i. This will save you some money if you are starting with a "regular" '02, and provide braking on par with the pure-BMW solution above.
Please note that Rob Torres, Jr. of 2002 Haus recommends the use of tii struts with their the larger spindles if you are running large-diameter (15"+) wheels, or else you will chew up wheel bearings at a rapid rate! Thanks to Rob for the tip!
Other options involve using racing brakes from people like Wildwood and the like. If you are considering operating at this level, the best advice is to find a vendor who will work with you to get the product installed on your car. Some vendors also sell other higher-end braking solutions such as lightweight aluminum calipers, and these kits will come with everything you need to adapt them to your car.
Because we are only worried about the DIY-type stuff at this point, here are the details for low-buck, big-bang brake upgrades:
Parts Required for tii upgrade:
New 1977 e21 Vented rotors
Used e21 hubs up through 1979 (junkyard)
New or Used e12/e24 up through 1981 calipers (I'd just buy already-rebuilt ones but you could get good used ones or rebuildable ones from a junkyard for less $$)
New brake hoses (unless yours are less than five years old, you might as well refresh/upgrade while its apart. Braided stainless ones will give you the best performance.)
New wheel bearings
Wheel bearing grease
New performance brake pads
Two pints of new brake fluid (might want to get a pressure bleeder too)
If you are upgrading to the "pure-BMW" solution from a standard '02, then you will obviously also need a set of tii struts in addition to the above.
Parts Required for non-tii upgrade:
New 1977(only) e21 Vented rotors
Used 1981-83 e21 Hubs (just get these from a junkyard: dont buy new like I did... ;p)
New or Used Girling Vented Calipers for a mid-80s Volvo 240 with VENTED brakes. (There are rumors of ATE Vented calipers also being available but the Girlings are far more available and that is probably for a good reason.)
New brake hoses (unless yours are less than five years old, you might as well refresh/upgrade while its apart. Braided stainless ones will give you the best performance.)
New wheel bearings
Wheel bearing grease
New performance brake pads
Two pints of new brake fluid (might want to get a pressure bleeder too)
Four 1" standard galvanized or stainless steel (why not, right?) washers
Be aware that certain 13" wheels will NOT fit over these upgraded calipers. In some circumstances, you can do a little grinding on the outside of the caliper to get them to fit, but you will need to start with a wheel with a good deal of offset amd should be as wide open inside as possible.
SAFELY raise the car and put it on jackstands. All the standard disclaimers apply. I don't want to get the FAQ sued because some e46 clownie wandered in here and decided to try this. (;p)
Basically, make sure the wheels are chocked behind them, its in gear, the e-brake is on (and working!), and your teeth are gritted. Put a floor jack under the middle of the front subframe with a block of wood between jack and subframe to protect and spread load. Raise the car and then put jackstands under the frame rails that are welded to the front floors. Again use some wood to buffer the stands and spread the load some.
Remove the road wheels, then remove the old brake lines and calipers. Theres not much to this, just some angry grunting with the aforementioned gritted teeth and possibly some flagrant cussing. Its also messy work, and you will need to drain the brake fluid, so get a pan or bucket too. Once you have the caliper removed, and the old brake lines (this part can be a nightmare in itself! Get out the vice grips and rhyming dictionary!), remove the cotter pin and big wheel nut, and then the old rotors and hubs (as a unit). Again, this is just dirty, messy but straightforward work.
Next is to clean the spindles, and inspect them for wear. IF you have a non-tii car and find that your spindles are shot/worn/etc., THIS might be a good time to think about upgrading to a tii strut-based setup (you didnt already order all the Volvo parts, did you!? - just something to think about before indeed placing that order.) If you have used hubs, you have to remove the old seals and bearings and clean them up. I bought new hubs like an idiot, which I immediately got filthy just by handling them. But, CLEAN them up so that you can put in the new clean bearings and grease.
Pack the new bearings with grease. If you've never done this before, the `word "pack" pretty much covers it. Do not OVERpack them because this will interfere with torquing down the main wheel nut. You will want to retighten the main wheel nut in 100 miles anyway, and you can put a wrench on the main wheel nut to give it a good squish, then back off and tighten the nut as described a little more below.
Install the new bearings into the hub and install the new seal with a flat piece of wood. As I recall, the seals go in flush with the edge of the hub, but I'm not totally sure about that. Then install the hub onto the spindle. Put the outer bearing, washer, and nut on, then spin the hub and finger tighten the big wheel nut until the hub stops. Then back it off a smidge and then put in the cotter pin. Make sure there is veryvery little to no play in the assembly when you rack it up and down, and that it also spins freely when you spin it with your hand.
Put the new rotor on, and then slide the new (rebuilt, etc.) caliper over it with the new brake pads installed. Make sure that the bleeder nipples are facing up, otherwise the system will be impossible to bleed correctly. Next install your new hoses. Some of you Volvo upgraders might want to think about using a tii or for tii people, an e28 master cylinder at this point too. The theory is that a larger set of calipers will require more volume of fluid to move the pistons a given distance. If you have a larger master, this will supply that additional flow. In my case, I used a 528 master cylinder. Im not exactly sure what the deal is with the rear proportioning systems in these various MCs, but since I am going to use rear discs eventually, I havent let it keep me up nights yet. Most people, however, simply choose to use the rear brakes from a 320i.
Once you have the rear brakes sorted, then bleed the brakes. Start from the passenger rear, drivers rear, then pass front, then drivers front. Make sure you flush all the old fluid out of the system. Some like to use a different-colored fluid each time they change it so they can tell when the old stuff is gone and the new stuff has taken its place. IF you do this, just make sure the two fluids are compatible chemically or else you can have a bunch of new problems on your hands.
Once you've got it all back together, it usually takes about 500 miles for the brakes to fully "seat," so don't go out and "test" them right away (oh, officer! see, i just got this new carburetor and i was just trying to test it..... ;p). Other than that, enjoy the new stopping power!
I went to install front brake pads on my '73 2002 with stock brakes earlier this week. My current pads ended up still having plenty of life, but I thought I would post pictures to the extent that might help others.
My process followed from Haynes:
1. Parts/Tools - new brake pads, 1/8" flat head punch, small hammer, brake cleaner (note: depending on the condition of your retaining pins and anti-rattle spring, you could need replace them)
2. Jack up car and remove the front wheels
3. Extract the two retaining pins using your small hammer and 1/8 inch flat head punch to gently tap out the retaining pins and the anti-rattle spring. You tap on the small end of the pin located on the outer side of the caliper. See pic below of two pins and spring.
Before picture of caliper, two retaining pins, and anti-rattle spring:
4. Withdraw the pads by gripping ends with a pair of pliers or using a flat head screw driver. In the picture below, I have removed the pins, spring, and the outer brake pad.
5. Once the pads are out, brush any dust from the ends of the pistons
6. Here is a picture of the pins, spring, and pads out of my car (you can also see the tool kit you'll need - mentioned in step 1).
7. Inspect the thickness of your disc pad friction material. If it has worn to 2.00 mm or less than the pads should be replaced on both front bakes as an axle set. My pads were okay.
8. Clean your pins, pads, and anti-rattle spring with brake cleaner. This is also a good time to check your rotors for runout/wobble, cracks, thickness, or other problems.
9. If you need to install new pads, use a syphoning device (I had a turkey baster - see below picture) to withdraw some fluid out of your reservoir. When you compress your pistons some additional brake fluid will be displaced and it will ensure your fluid reservoir doesn't overflow. If installing new pads, after removing the brake fluid from the reservoir (remember brake fluid eats paint and causes rust, so be careful with it), use a flat peice of wood or metal to compress the caliper pistons into their cylinders in order to accept the new thicker depth pads.
10. Install your new pads, the spring, and the pins in the reverse order. Here is what mine looked like after cleaning up the pins and springs.
11. After you put your wheels back on and lower your car to the ground... remember to pump your foot brake hard a few times, test your brakes, and top back up the fluid reservoir. You're done.
The e21 rear drum brake upgrade is a cheap, effective way to improve rear braking, particularly to match a "big brake" upgrade up front. It involves simply pulling the required parts from a donor 320i and exchanging them for the 2002 parts. There are a couple of complications, but its an otherwise fairly straightforward job.
Tools and Parts Needed:
36mm socket and big breaker bar for big rear hub nuts. The SAE equivalent is approximately 1 7/16"
10, 13, 17, and 19mm sockets and/or box wrenches
11mm flare wrench for brake fittings
7 and/or 8mm combination wrenches for the bleed nipples
5mm allen wrench
BIG screwdriver or something to pry with
3-jaw gear puller for pulling the hubs
Brake cleaner (get a few cans!)
New 320i wheel cylinders (optional but recommended)
Brake Drums from Donor e21 (you could opt for new ones if you feel like spending the extra $$)
Complete e21 backing plate assemblies with hardware - no need to remove the shoes or any other hardware from the backing plates. Pull them as a unit. (Optional also is a new brake shoes kit instead of the used ones.) The retaining pins are not found on the 2002, so make sure you keep the pins and the fork clips that hold the shoes to the backing plates (one per shoe = two per assembly, or two per backing plate). These pins go in from the backing plate through the shoe and are held on by the fork clip (which also acts as a spring). Again, keep these, or get a new brake harware set for either a 320i or a 318i. The 318i kit uses a small button-like retainer over a spring to hold the shoe to the backing plate.
Your first step will be a trip to the local boneyard for the parts (see list). Don't make the mistake of pulling the shoes and associated hardware from the plates before removing them. Since you are going to be putting a huge amount of removal torque on the main hub nuts, you will need to find a donor that is either sitting on the rear wheels or has working emergency brakes. If that doesn't work, try to wedge some spare wheels/tires under the donor wheel to keep it from turning.
Once the main nut is off or just loose, pull the road wheel and then use the 5mm allen wrench to remove the hold-down bolts on the 320i drum. Remove the drums (mark them left and right first) and then use the 3-jaw puller to remove the 320i hubs. The hubs themselves are useless to you (wrong splines for the '02 application) so don't bother "rescuing" them.
The backing plate bolts are 17mm, and it helps if you undo the e-brake cable at this point to get at them a little easier. Remove the rigid brake lines with the 11mm flare wrench. Use the big screwdriver to pry the backing plates away from the trailing arms. Congrats! Pay for the parts and head on home.
The same procedures apply to removing the same parts from your '02, and the reassembly procedure should be obvious at this point. In order to re-fit the 320i drums, you may need to loosen the e-brake cables under the rubber boot at the base of the parking brake lever between the front seats.
Reassemble and fill the system with new fluid. A pressure bleeder is a VERY handy tool and makes the bleeding process much easier. Bleed starting from the furthest corner from the master and close in from there. I (Rob) have personally found that the exact bleeding order isn't important, but your mileage may vary. If anything seems iffy, just bleed everything again.
That's it! The entire procedure took Marty about six hours, including removal from the '83 320iS and installation on his '73 2002.
I knew I needed new brake hoses when I tried to bleed my brakes and could not get any fluid to come out of the wheel cylinders because of the 40 year old swollen rubber lines. I knew my front hoses were replaced about 20 years ago because of the 9/94 date on them so I decided to replaced them for good measure.
I started with the front drivers side. After soaking the fittings with PB Blaster for a couple of weeks, I tried to remove the front hoses. The nuts on the line would not turn. I tried cleaning the outside of the lines, I tried heat, nothing seemed to work. I ended up rounding over the nuts with my flare nut wrench and had to cut them off with a Dremel, ruining the brake lines. Not fun but I was able to put new cunifer hard lines and braided hoses on the drivers side.
On to the passengers side. I really didn't want to have to cut the nuts off and replace the line that ran from the hose, along the firewall to the MC with the engine in the car. There had to be a better way. I remembered an article I had read about penetrating oil comparisons. PB Blaster, Liquid Wrench and Kroil were all good but a 50/50 mixture of ATF and acetone was much better. So I mixed some up and put that on everyday for about a week with a syringe and tube.
Trying to find a better way, I read online that the nut on the hard line is locking the hard line in place and the trick is to hold the nut still and turn the hose instead. I had to find a way to hold the nut without destroying it. Then I found a pair of small 4LW vise-grips specifically made to hold hex nuts. One jaw has a V that fits on two flats of the nut and the other jaw holds the opposing third flat. I was able to get a very good grip on the nut.
I found the vise-grip on Amazon and they are made for hex nuts 1/4 to 9/16.
Holding the vice-grip stationary, I had to exert extreme force to the 14mm wrench on the hose. With a loud snap. it broke loose with out damaging the line, nut or hose. I was then able to do the same for the other three nuts and remove the hoses.
New stainless steel braided hoses
The bleed nipple on top of the right caliper was also frozen and had been rounded in an effort to open it. A six point socket was not going to work. I needed to use a different vice-grip with teeth to lock down on the bleeder. I did not want to crush the bleeder and break it off so I put a 1/8" drill bit in the bleeder for strength.
With the bit out and my eye protection on and a fire extinguisher near by, I heated the bleeder red hot. Propane was not hot enough so I switched to Mapp gas which got the bleeder nice and red. BTW, I put my hand on the caliper and it was barely hot.
I tapped the bleeder with a hammer and then quenched it with a wet rag. I dropped the bit back in and then was able to unscrew it with the vice-grips.
Replaced with a new nipple, job done.
When I did the back hoses I soaked them with PB Blaster for about a week. I unbolted the center brackets for the sway bar and let it hang for room to turn the wrench. Once the 14mm wrench is on the hose, there is no room to turn it so I had to turn the nut on the line. For the other end of the hose, I put the 14mm wrench inside the trailing arm on the hose and then loosened the nut. Tight working space but I did not need to cut the hose to remove. I was able to remove the rear hoses by using my flare nut wrench. I think the fact they had 40 years of oily grime protecting them, they did not fuse together.
The beauty of the small 4LW vice-grips is that it has no teeth to mar the nut. The flat jaws hold three opposing flats of the nut putting equal pressure inward and will not deform the nut. Here is a picture holding an M6 nut that takes a 10mm wrench.
But the real trick to removing the nut is to hold it stationary with the hard line and turn the hose to break it loose. Once loose, I was able to used a flare wrench to remove the nut.
Contributed by felix_666 Saturday, 07 March 2009 I have written this article because I live in Australia and you cannot simply trade calipers for $50 a pop at your local BMW specialist centre – no such thing for 02’s. For that money you will get them rebuilt excluding the kits and providing the calipers are a straightforward job. I reckon if you paid someone to do the lot it would cost over $250, easily. If I took the mentality of: “its going to save your life!”, then I wouldn’t be nearly as close as I am to being finished because I would have spent every hour at work tying to pay for everything – boring.
PLEASE READ EVERYTHING, OR AT LEAST THE SECTION BEFORE COMMENCING WORK!
The usual disclaimer applies; I’m simply reporting some of my findings and this is by no means a bible for rebuilding brakes. You are accountable for your own work
Parts that i used
I will start with the calipers off the car and ready to work on, if you need assistance with this part of the DYI you are probably not up to rebuilding the brakes. You should be confident with the tools you are using and have no trouble getting the calipers off. Work on ONE caliper at a time, you’ll see why later.
There are two ways of rebuilding brakes, pulling them apart or leaving them together.[/b] I have pulled calipers apart to rebuild them in the past and continued to do so despite the idea being taboo. I can’t imagine rebuilding the brakes without splitting them, you simply cannot do the same job, especially if the brakes are 35 years old there is almost certainly going to be marks on the bores, cylinders etc. The reason people believe splitting the calipers is bad is because you supposedly can’t buy the “expandable/stretch” bolts or the small flat O-rings.
I bought both, the bolts from my local nut and bolt shop – they are allen screw cap bolts with a tensile rating of 12.9. The bloke from the store had a lot to say about these types of bolts but I’ll leave this for another time. And the flat O-rings from a brake service joint, the bloke there explained that these O-rings are used on old BMW’s, Merc’s and some other cars. Anyway, point is I bought them.
Prepare the calipers
Remove the pads.
Using a plastic/wooden something-a-rather pry off the rubber seals. If you insist on using a screwdriver be careful, you will easily scratch the pistons and need to replace them.
removing the old seals without scratching things
Removing the cylinders
This can be done via compressed air – compressed air with blocking plates and possibly using a flat edge and a hammer (the latter is for the more experienced and not recommended).
Before staring give the calipers are rough clean with break cleaner and compressed air.
There are two holes where the brake fluid enters; the holes correlate to the closest opposing cylinders. When ejecting pistons by air, cover the opposing one with something as they leave with considerable force. Don’t forget to make a note of where each piston comes from.
The key to this is making a good blocking plate. It needs to cover the cylinder and have a soft backing to provide a good seal, I used blue tack but something more rubbery like rubber tape adhesive might work well.
removing the pistons and protecting with wood
By applying air to one of these holes you will eject one piston and hopefully move the other. The manuals suggest clamping one piston while using the air to remove the other, but I find it better to remove both as far as possible, making it easier to remove the one that isn’t shot out by the air – you’ll see what I mean.
Once you have removed one piston you will need to apply your blocking plate to the opposing cylinder and fasten it with a clamp.
By applying air to the same inlet you will pop the other piston, but your plate has to be well fitted to prevent air from leaking out.
To remove the other two pistons carry out the same process as above.
Clamp with blocking plate
You can use a small compressor to supply the air, but it needs to be above 8 bar for seized pistons, and even still you will struggle. If possible take it to your local mechanic and get them to supply the air.
If your pistons refuse to move you can use the following VERY carefully to get them started.
This method is for the experienced only. If you have not used tools in this way you need to be really careful.
Positively tap the pistons swapping sides constantly making sure you don’t cock the piston – giving them a couple of taps on each side will be enough. This will loosen them to allow you to use air again – gentle is the key.
flat head screw driver that could ruin your day if you don't take car
Put them back on the car
If your still stuck, a last resort is to put the calipers back on the car and push out the pistons by pumping the peddle, this is a fool proof method and the reason why you should work on one caliper at a time.
Splitting the halves
Using the appropriate torx head and breaker bar, split the caliper in a vice.
Cleaning the calipers
The best way to clean the external parts of the calipers was to use break cleaner and wire wheel brushes or the a like. This will give the outside a nice metallic finish. Bead blasting gives a similar (but better) finish; you just need to find someone who knows what there doing!
Cleaning the pistons and cylinders requires patience and elbow grease. You can use steel wool or the green scotch guard pads to remove any stains or super light marks. If you have light scratches or surface rust you can gently use 1200 grit sand paper – anything greater will be difficult to restore.
I use my Dremel and a copper brush piece (designed for cleaning soft metals like gold) to clean the sealing ring groove at the top.
clean and not so clean
While the caliper is now in half and cleaned you can paint it with some high temp paint. Make sure you mask up the appropriate areas. Follow the instructions on the can.
Installing the new kits
This is pretty straight forward, you just need to make sure you apply the caliper grease. The inner sealing rings just push in and feed the rest of it into the groove with your finger/thumb.
inserting the inner seal
The piston boot/rubber needs to be put on before you insert the piston into the bore. Simple apply a liberal amount of grease inside the boot and slide it over the top of the piston, keep pulling it down past the lip of the piston, and then wriggle the boot back up INTO the lip, not past the lip. This method makes easy work of getting the boot into the right spot – refer to the picture.
putting the boot over the piston - (i'll edit this soon so its clearer)
Using a small but even amount of grease on the piston it will enable it to easily slide back into the bore – make sure it goes in straight, to push it right in use a bit of wood.
Now with the piston at the bottom of the bore you can apply the snap rings to keep the boots in place as the new boots don’t have the metal ring running through them like the old ones.
This is pretty straight forward, put the new o-rings in and close the caliper haves together and put the bolts in by hand.
To tighten them there is an order and torque value of , refer to the picture.
Install your pads and fitting kit and your sorted.
Written by steve kupper Sunday, 08 March 2009
Use DOT 3 brake fluid. Use only brake fluid that has not been opened. Brake fluid absorbs moisture, moisture boils before brake fluid, boiling water does not stop 2002s.
Three pints should be on hand to change out the brake and clutch systems.
Three methods discussed.
1. Fill the reservoir, open the bleed screws and let the brake fluid leak everywhere overnight.
Old fashion way - need a partner or helper.
1. Protect the area around the reservoir, brake fluid removes paint, unpainted metal rusts.
2. Fill the reservoir with fresh brake fluid.
3 Start at the right rear. Get a big bottle with a hose to it. The hose needs to be the size that will fit tightly over the bleeder screw. Here is what I use.
The bottom of the jug should have some fluid in it. Keep the tube submersed in the old fluid to keep air from being sucked back into the system.
4. Put the closed end side of a 8mm or 7mm wrench on the bleeder screw then put the hose over the bleeder screw.
5. Ask your helper to get in the car, pump the brakes slowly five times and on the fifth time hold to the floor.
6. While the brakes are held, quickly release the bleed screw a bit and watch for bubbles. Quickly close (after counting one-thousand one one thousand two) the bleeder screw and tell the helper they can release the brake. Get this sequence absolutely correct. Pump, Hold, Release and close the bleeder screw, then and only then, release the brake pedal.
7. Repeat the process until you do not see any bubbles. Use a good light near your work so you can see the bubbles.
8. Keep checking the level of fluid and top off as needed.
9. Repeat the process on the driver's side rear.
10. Now move to the passenger's side front. Bleed in the same manner in the sequence of Upper, Inner and Outer (UIO)
11. Move to the driver's side and bleed like the passenger's side front.
12. Always checking the level of fluid in the reservoir and topping off as needed.
Power Bleeder method.
1. Same as the old fashion method but you need a power bleeder and the helper can go fix dinner.
2. Fill the reservoir.
3. Attach the power bleeder to the reservoir and pump to 10-15 psi.
4. Bleed as old fashion way, (no pumping the brake pedal with the power bleeder) keeping an eye on pressure and fluid in the reservoir.
Note: some folks fill the bleeder with fluid, I do not.
I guess there is another way but I do not know how to do that. That method uses a vacuum tool like a Mighty Vac
Brake fluid is nasty stuff, clean up real good and through away the rags or wash them good before you reuse.
Bleed your clutch while you are at it.