Looking for vented front brake parts

[baller908790]

Mike K is a local "guru". Next time we see one another I'll have him drive my car and give me feedback. He bought his 02 brand new in 1975 so he should know how the brakes should feel. The pads and shoes are the ones that the car had when I acquired it. I didn't change them as they had plenty of "meat" on them. Who knows what brand they are. What do you guys recommend for pads and shoes?

[Pierre]

There is obviously something wrong with your brakes. Do you have a soft pedal? Are you pressing hard but the car will just not stop? (You should be able to lock the front wheels if not all 4 if you press hard enough, even with some pretty sticky tires.) Do you get apull one way or the other? A 2002 brake pedal will feel like a modern car and better. It should be firm and very easy to modulate. Maybe you have worn suspension components, maybe your choice of pads is an issue, your rebuilt calipers may be defectice, you may have a bad master, clogged lines, worn wheel bearings or even tires may be part of your problem. A competent mechanic who is familiar with 2002s should be able to diagnose your problem.

[GoFaSSter]

Pierre amd mlytle,

I know this isn't the section to ask, but what do you think of using the rear drum brakes from the 320i?

[Pierre]

The answer to your question is not as straight forward as it may seem.

The E21 has a bigger master cylinder and bigger drums, so in effect, a stronger brake.

But it is designed to work with the E21 master which pumps more fluid to the rear.

So it's a question of proportioning the front to the rear. If you use a 2002 master, you will obviously send less brake fluid to the rear, to a "stronger" brake drum. If you have a tii, the rear wheel cylinder is bigger than a standard 2002 but still smaller that an E21. And you decide to go with an E21 master, you have a new problem. E21s have single lines to the front brakes. 2002s have 2 lines up front on each side.

On its own, I don't recommend it. 2002s do not need more braking in the back.

I have "heard" than an E21 rear setup works well with an E12 master and tii front brakes. An E12 has the same calipers up front as the tii but they have rear discs. It's just a rumor but I am doing it to my 69 as we speak. Tii struts, E12 vented calipers, E21 vented rotors and early E21 hubs, E12 master and E21 rear drums.

[GoFaSSter]

Thanks Pierre! Great explanation. I appreciate the insight.

[M3M3]

a pretty normal brake system for a regular 02 is change to volvo fronts, tii or e12 master (they are the same) and complete e21 250mm drums brakes.

this is the setup i have on my M2. perfect bias/balance/pedal pressure feel. works great.

it is well documented in the faq.

[baller908790]

Before I changed the master I wasn't getting any pedal pressure at all. Bought one from Ireland Engineering and bench bled it and installed it etc and I regained the pedal pressure. Maybe there is still air in the line for some reason. If I try and lock up the brakes in a non rainy condition I can only lock up the right rear wheel. In rainy conditions it seems as I can lock up all 4. I'll have my go one more time at adjusting the brakes and will borrow my cousins mity vac to flush the fluid. Thanks for your guys help. If the 02 brakes are supposed to feel like a modern cars it will be my mission over the winter while it is hibernating to restore the feel.

[M3M3]

i am not a fan of miti vac's or any other tool that "pulls" fluid through the system. more often than not they pull air in too. use a pressure bleeder instead.

[Pierre]

a pretty normal brake system for a regular 02 is change to volvo fronts, tii or e12 master (they are the same) and complete e21 250mm drums brakes.

this is the setup i have on my M2. perfect bias/balance/pedal pressure feel. works great.

it is well documented in the faq.

The E12 and the tii masters are not the same. The difference is in the proportioning of the front and rear brakes since the E12 has a discs in the back and the tii has drums. The early E12s (75 and 76) have the same front calipers as the tii. )E3s and E9s too) The later E12s (77 on) have a spacer added to the two-halves of that same caliper to accommodate a vented disc.

The tii master is shared with some NK cars and early E9 coupes that had rear drums. Later E9s with rear discs and E3s share the master with the E12, all of them has 4 wheel discs.

I am not saying that your suggested setup does not work. I just wanted to clarify the master cylinder compatibility.

+1 on the pressure bleeder. Every DIYer should have one.

[M3M3]

have you taken a tii and an e12 mc apart? i have not, but the info i have gathered indicates they both share the same 23.8mm bore, for both front and rear brake circuits. not the same part number, but same effect. if you have some evidence showing different bores or how the bias is changed otherwise, please share! :-)

for those that have not found this yet,

2002.Brake_Upgrades.pdf

[Pierre]

It's based on strong circumstancial evidence.

1. If they are the same, why do they have a different part number?

2. If two cars have the same front setup and different rears the chances that a rear drum and a rear disk would have identical pressure and volume demands are unlikely. The consistency across the board between cars that have 4 wheel discs and the same master, (E3, E9 and E12 and early E24) and the consistency between the cars that have a disc/drum set up tii, NK and early E9 does lead to that conclusion.

3. I have not dissassembled the 2 MC and compared them but looking at both on REALOEM, side to 2 side, I see several differences, the most significant being the absence of a pressure/proportioning valve on the E12 MC. The lack of a pressure valve may make the pedal feel spongy when using drum brakes since wheel cylinder can bleed down and calipers don't. The proportioning valve on the tii may restrict the volume/volume of fluid to the drums since wheel cylinders require less fluid than calipers. And both MCs are available for sale from the usual parts houses with a significant price difference. Autohauz has the E12 MC $60 cheaper than the tii MC.

4. I have spoken with mechanics dubbed " tii experts" about the topic. They will tell you that then have tried to save their customers money by installing a cheaper E12 master on their tiis. Customers have come back complaining that the brakes "don't feel right." The cars still stop fine but they "feel" there is something different and they don't like it. Replacing the MC with the proper tii master restores the correct "feel" of the brakes.

I am far from a purist. I have no problem trying things, swapping things and experimenting. Sometimes the resuts are better, sometimes worse. Sometimes I can't tell the difference but someone else might. And sometimes I like it better while someone else might not.

[Chamoix]

I put tii struts on my on my non tii '73 and went with the e21 calipers with spacers and Ireland vented rotors and the improvement was amazing. Now my stock brakes were not in the best of shape to begin with, but the car went from being downright scary to very firm and secure.

[M3M3]

i suspect you mean "E12" calipers, not "E21" calipers?

just for reference...i took off the extra "thing" on the rear brake outlet on a tii master cyl and looked at it. does not look like a proportioning or pressure limiting valve to me. looks like a pressure check valve. purpose to hold a slight pressure in the rear brake lines when the brakes are off to keep the shoes out. effectively does the same thing as keeping the drum brakes adjusted correctly.

but...i did not hydraulicly test the thing...could be totally wrong!

[Guest_anonymous]

i suspect you mean "E12" calipers, not "E21" calipers?

just for reference...i took off the extra "thing" on the rear brake outlet on a tii master cyl and looked at it. does not look like a proportioning or pressure limiting valve to me. looks like a pressure check valve. purpose to hold a slight pressure in the rear brake lines when the brakes are off to keep the shoes out. effectively does the same thing as keeping the drum brakes adjusted correctly.

but...i did not hydraulicly test the thing...could be totally wrong!

+1 Pre pressure check valve.

Girling BBK, e21 rears, e12 mc

Pedal feel is different w/o pre pressure valve. Need to have narrow tolerance on rear pad adjustment. Wilwood makes an inline pre pressure check valve. This setup is pretty well hammered in the forum. For those who do not have a tii mc and want the larger bore pedal feel which the tii mc has, the economical route is the e12 mc. But the sacrifice is a different feel of the pedal. To achieve that same feel with the e12 mc would add the cost of the wilwood pre pressure valve, cutting and flaring the brake lines and of course having bought the larger mc to resevoir elbow grommets.

The systems locks up. Did a panic stop in traffic. Laid a three foot patch of rubber. Smelled great.

OP. Tell dad its never going to feel like ABS. But you may also need some adjustment to a vital and crucial saftey system in your car.