john_a

Was the pedal firm while you adjusted & bled? Did it just become an issue during the test drive? If the pedal is firm/higher AFTER you pump the pedal one or two times for each stop, you could have caliper piston knock back. Loose wheel bearings can let the rotor rock enough to knock the caliper pistons back, and that makes for a lot of extra travel on the initial apply to bring the piston back up to where it will press the pad against the rotor. That, or it could still be air bubbles.

Don't mess with the pedal rod until you fix your problem, and probably will not have any need to do so then. You can cause more serious problems if you remove too much of the pedal free travel and the m/c piston can't retract 100%. New pads & rotors are thicker than the old parts, but that added thickness does not have any impact on your pedal travel. Disc brakes do not work that way, they "self adjust" to where the piston pushes the pad against the rotor, then the caliper piston rubber seal causes the piston to retract just enough to not drag the brake when you are off the pedal. The piston does not move any more or less based on pad/rotor thickness, the piston only has to travel from the retracted position its seal pulled it to (this is a VERY small distance.) Only when there are other issues does caliper piston travel become excessive enought to cause pedal problems, and usually that means a somewhat softer pedal rather than an outright loose travel problem. Other issues meaning things like severe tapered pad wear, loose wheel bearings letting the rotor rock & kick back the piston, caliper flex (not an issue with 02 calipers.) Calipers are "self adjusting" for piston travel, but your rear drums are NOT, as the brake shoes are retracted by springs to the same position they are adjusted to, regardless of how much wear occurs. So as the drum & shoe wear, the travel from the retracted position to the apply position grows & the pedal sinks lower & lower. This is why so many people are telling you to adjust the rears, and if the drums/shoes are worn much at all you will have a lower pedal, even when you get them adjusted as best as possible. Adjusting the rears with the wheels off (and nothing else hold the drum tight against the hub) will not provide correct adjustment. If you do the adjustment properly, and can't get the pedal higher, then look again at the drum wear limits (have a shop measure them) and it might be time to replace them.

Sounds like rear adjustment, still... (can't really diagnose an issue from just what's posted.) You've bled all, probably enough since you have seen the right result coming out of the bleeders. "Not much pedal" meaning too much travel before it starts to get firm? As you've heard, the rear adjustment is critical to pedal travel. Worn drums/shoes won't be able to adjust close enough to prevent excess pedal travel (wear limit on rear drum is like 1 mm, IIRC?) When you adjust the rear brakes, you can't have the drum loose with the wheel off. If you have to have the wheel off during adjustment, you need to find enough large washers & lug nuts to clamp the brake drum in place while you set the adjustment.

Well, I'm going to point out the unintended consequences of SS hose(really teflon) and bigger brakes. SS braided over Teflon (or Kevlar, whatever..) help give a firmer pedal IF you are experiencing balloning with the stock rubber hoses. That's a big IF in there! Some folks will claim to be sensitive enough to detect the difference and feel it's worthwhile, others may not ever notice the difference that is truly attributable to the new hose. How much of the firmer pedal was really due to the new fluid change out & system bleed/adjust that was done at the same time? SS braid covered lines (Aeroquip-type hose) do offer a very slight improvement in apply pressure to the corners, but the tradeoff is they are much more delicate than the stock rubber hoses. They are NOT tougher & more resilant, they DO require much more scrutiny. Racecars are different, as those parts are inspected constantly, and cycled out before they fail. Stock brake hoses will outlast SS braided hoses, because the stock hoses are far less prone to develop leaks at the fittings (SS braid over Teflon usually does not pass the SAE whip test required for MVSS) So they are cool looking, they do offer some performance, but consider the added maintainence & expense as you decide. For the Big Brake conversion, consider this is worthwhile if you have problems shedding heat with the current setup. If not, AND you are able to apply enough torque with your brake pad of choice to modulate the pedal all the way to lock up, there's not much to gain, and definately some trade off. Bigger brakes can make make the car accelerate & decelerate SLOWER. Think about that -- Big brakes can make the car harder to stop, as the increase in mass rotating means there's more inertia to overcome. So if the stock brakes delivered enough torque, and shed enough heat, they will outperform larger brakes. Brakes bigger than needed are going to hurt performance 100% of the time, so be sure you need them. Lightness is a virtue for acceleration & braking. That said, I do have SS braided (teflon) hose + bigger brakes on my street cars, but I made the decision well aware of the tradeoffs. And I have replaced more damaged SS hose than stock rubber. The biggest improvement can be simply choosing a brake pad compound that suits your usage. Race pads are lousy for street use, and street pads suck on track, so don't try to find one setup that will work with both. I race on lightweight Hoosier tires with lightweight wheels & stock brakes, and for the track I'm on most often, I would loose performance with bigger brakes even if they were legal in my class. A heavier car, a different track, this might not be true.

You could test the circuit end-to-end (at the fuel pump [with the pump out of the circuit] to the fuse block, or wherever the fuel pump power first connects) with an ohmmeter. There should be very little resistance in the circuit. Agreed, checking the wiring harness with an ohmeter is recommended before blowing money on a fuel pump. But first, consider what else is powered by the same fuse. While the pump is the chief suspect, there are other consumers on that fuse, some of which have wiring in places it can get pinched (think of the park brake switch that is on the same fuse, the tach & other I/P lights are powered by the same fuse, so it _could_ even be wiring to sensors and ign coil underhood.) Do any of those circuits behave flakey? This is an 8 amp fuse IIRC, and the fact that it worked a bit better with the next bigger fuse points more to a pump on the way out, but STILL, check the wiring. Confirm the B+ voltage reading at the pump (duirng key on.) Then, with the fuse pulled out, find the VOLTAGE at the fuse terminals to see which side is HOT with key on so you will then know the opposite terminal is the one that feeds the pump & whatnot. Turn the ign key off, and go back to the pump and disconnect the B+ wire there. Using the OHM setting, check the resistance to GROUND from that end of the wire (wiggle everything you can touch to try and find an intermittent short to ground.) Note that the other power consumers that share this fuse can present a path to ground, so you will not see infinite resistance. You can disconnect the various sensors (fuel level, oil psi, water temp, etc..) if you wanted to be more thorough. But the idea is to check for shorts that would show up as much lower OHM readings. Then with long enough leads to reach up to the fuse terminal where that circuit starts, check the OHMs for the entire circuit end-to-end (wiggle everything along the wire to find intermittent OPEN circuit.) Good wiring should be well under 1 ohm over that length, but your meter & long leads can have an effect, so just look for something in that ball park. While this sounds like a lot of work, the pump is pricey$ and you want to be sure everything else is OK before replacing it. You can also have a pump pull high current (which blows fuse) when its motor is overloaded due to restricted input (dirty pickup screen) or a problem with the tank venting.

While it sounds good to weld up box sections on the trailing arms, blast them clean & use a rust preventive paint, there is a lot that can go wrong with this project. I'm not saying you personally are doomed, just speaking in general as there are many folks that have found trouble. The rear trailing arms will warp when you weld them, or they might even be crooked before you start. Unless you know they are straight & can use a fixture to hold them, you're inviting trouble. The factory manual shows the trailing arm checking fixture the dealers used back in the day. It only takes a very small amount of distortion to impact the alignment. I'm a user of POR15, but not enthusiastic.. It is very good for painting over rust (POR) where it gets a chemical bond to the substrate through conversion. It is not good at all painting over clean metal, there is almost no chemical bond, and also a very weak mechanical bond. You can improve the mechanical bond by roughing the surface (which you have with the blasting), and the chemical bond to un-rusted metal can be improved with a phosphoric acid based metal prep (PPG, Dupont, POR all has these). Still, POR15 will not adhere very well compared to a good epoxy primer, and you WILL have chips large & small as chassis parts are usually prone to stone impingement. I like to use DP90 epoxy primer, and whatever leftover PPG topcoat Iis on hand. I truly believe clean metal is better protected by a real automotive paint system than POR15. POR15 is fine on rusted metal, usually crap anywhere else. It does not bond well to clean metal, top coats don't bond well to it, uncoated it turns chalky appearance, and is prone to chip. The drain holes are on the bottom (duh!) near hub, make sure they are open, and enlarge them if possible. They are hidden near a weld, IIRC. Vent holes elsewhere are helpful, but good drains are mandatory. Cleaned up tii arms with PPG DCC paint system leftovers applied:

copied from a couple older posts: The 1979 joint is really the best bet, as it is exactly the same width as the 2002 part but is made for the larger diameter M10 bolts you need for the E21 diff. The later 320i cv joints will have the M10 bolts, but the joints are narrower, which does not help. If you use the 79 cv joint, and swap out the E21 diff's stub axles with modified 76 2002 diff stub axles (just need to machine a snap ring groove in the same place the E21 parts have it) then you're golden & won't need any spacers. If you buy the "good" kits, you get all new parts. That end cap thing is as weak as a paint can lid, and it is pretty easy to mess it up. That's why Lobro & BMW gave you new ones with every boot kit (along with detailed instructions.) They also include the stamped steel, bright yellow-zinc plated cap on the boot end. This allows you to really take everything down to just the outer race (the 'body' of the CV joint.) No need to try & save/paint the old dented boot attaching caps. If you do not take it all the way apart, any solvent you use to wash out will creep into the space between the steel boot cap and outer race, and can contaminate the new grease. To really clean it proper, you need it apart to wash off all trace of the solvent residue with detergent and hot water, but I know that's hardly ever going to happen with the shade tree job or the local rebuilder. Don't use hose clamps, use the correct Oetinker clamps that come with all kits. Borrow a clamp tool from Autozone if you need to. Don't hammer out the shaft while supporting only the outer race. Each blow impacts both races thru the balls, and that's gotta hurt.. You need to devise a way to support the inner race when you drive the shaft out (see the pics from the other thread for a sample of the tool to copy.) Don't assemble the parts dry Install joints per the Lobro instructions below. Note that the pictures are grouped 6 to a page, each of the 4 pages have their pictures read in sequence like this: 1-3-5 2-4-6 and so on.. just so you get the steps in the right order. The key thing is to support the inner race as remove the shaft (see pic 7, do not support by the outer race and hit the shaft, that can damage the joint.)

There's two versions of that fitting, and your description sounds like the early part (ridiculus nearly $50 price) vs the later $2 part. Might be easier to swap boosters if you can't cobble a part. Perhaps there is a way to find a grommet that can act as an adapter from the old style 3-wing hole (on booster) with the I.D. sized for the late $2 fitting. Copied from an old thread: BillWilliams wrote: We can get those but for some reason, we can not get the gasket that the connector goes into. http://www.bmwmobiletradition-online.com/bmw/showparts.do?model=ST12&mospid=47140&btnr=34_0813&hg=34&fg=25 Bill & blue7500, There were two versions of the booster vacuum connector, the part Bill points to (yikes! $$47.52 for 34 33 1 103 261) is only for the early cars pre-Model 73. If Max's catalog is loaded from the later ETK, I know it misses the distinction between the two versions, which can be a problem for unwitting customers. Early part: Usually round topped white plastic, and fits in a hole in the booster approx. 22 mm diameter with 3 keyed notches. The seal is like a gasket, rather than the grommet that fits in the later boosters. These early parts are almost always brittle by now, so if yours is not cracked or leaking, leave it alone! Seals are NLA and the connector might as well be, I can't see paying almost $50 for a plastic elbow connector. Later part: Usually square black plastic, with an ATE logo. Only $2.29 and is used on many BMW from Model73 2002s thru at least some E36. These fit into a grommet that fits in a plain round hole in the booster that is a bit over 18 mm diameter. You can still get 34 33 1 113 652 for the elbow connector, and the grommet is 34 33 1 113 653 (was $2.76, might be NLA from BMW) Which booster you have will determine the elbow you need. If you break an early part, it's almost worth it to switch to a later booster (or get a tii booster) for the parts availability. The late elbow is also found as an Opel part: BMW 34 33 1 113 652 OPEL 5 45 306 The late grommet is common with even more makes of cars: BMW 34 33 1 113 653 HANOMAG HENSCHEL 000 431 99 60 MERCEDES-BENZ 000 431 99 60 MERCEDES-BENZ 000 997 67 35 OPEL 5 45 351 OPEL 8983664 PORSCHE 911 355 921 00 VAG 861 612 175 VOLVO 3344990

A "regular" alignment on BMW 2002, where they really can only set front toe, should still be done as a thrust alignment. Three main types of service are done by shops: Four wheel alignment -- this measures AND adjusts front & rear alignment angles. Stock 2002 has no provisions for adjusting anything but front toe, so a four-wheel alignment is not possible. If you need anything more than front toe adjusted, it requires slotting/cutting mounting locations or bending trailing arms or struts. There are factory eccentric trailing arm bushings that allow very small adjustments, but those are a real pain to tweak once they're installed. Front wheel alignment -- this measures & adjust just the front. Nothing is measured on the rear. Thrust alignment -- only adjusts the front, but the rear is measured and that is used to determine the thrust axis (basically which way the rear wheels are pointed) and the front wheels are then set to have their straight ahead position based on the thrust axis determined by the rear axle. Thrust angle is the deviation of thrust axis from true centerline, zero thrust angle means the car tracks straight. So for a stock 2002 you won't get anything more paying for a four-wheel alignment than a thrust alignment, as they can't typically adjust anything in the rear. Either way, let them know you want ALL angles recorded even if they can only adjust front toe.

"it’s the best 2002 Turbo I’ve ever driven" Man, that's one sweet 2002 Turbo! Congrats for job well done, love that kick-out oil pan. Korman used to get them made by (Kevin?) at Aviad, but that one looks different. Do you know who made it?

Regular 2002 front wheel bearings are the same as a lot of VW rear sets. Same deal, where the sets are "standard" combinations of certain common cups & cones. The outer cup/cone set for the regular 02 is known as SET #1, that's how common it is. The inner cup/cone set for the regular 02 is known as SET #15 (or SET #8 if SKF, Timken, or CR brand, same exact size.) If you go in a store and ask for a bearing for a BMW, they might try to charge you more than if you asked for a plainer-sounding SET #1. The rear wheels on almost every 1975 thru 1991 Volkswagen and Audi Coupe,Fox, 80,90, 100, 4000, 5000 use the same two bearing sets. The VW/Audi hubs won't fit on your 2002, there is more to it than just the bearing sizes. Like the "hub" is often part of the rear brake drum on the VW, or the distance between the inner & outer likely won't match a BMW spindle.

SEARCH turned up old posts, was pretty sure I had replied to this question before. The tii front wheel bearings are not a BMW-specific part, they are available most anywhere as standard sets of cup/cone bearings. Standard bearings have numbers for a matched pair of cup & cone. The two numbers for inner cup & cone on a tii front hub = SET #6, and the outer = SET#2. No matter what brand & part number is on the box, somewhere the box should say S6 or A6 or SET 6 for the correct inner, likewise the outer will state "S2" etc.. These are the same fitment as used on diverse applications as: all 80-83 Ferrari, lots of Ford (inc. some Mustang, Falcon, early Truck/Van), many Chryslers. The bearings themselves will have the LMXXXXX series numbers on them. set 6 details (inner tii) LM67048 / LM67010 Cone bore=31.750 (1.2500") Cup OD=59.131 (2.3280") 36.5 kN load rating set 2 details (outer tii) LM11949 / LM11910 Cone bore=19.050 mm (0.750") Cup OD=45.237 (1.7810") 30.6 kN The seal is available, just not quite as generic as the standard bearings listed above. They can look it up by application, but the size should be 45x62x7 and some typical aftermarket part numbers could be 71-550154

Stefan got it right, the first link above shows the parts catalog page for the REAR suspension, and the four bolts (item #3) are the large diff mounting fasteners. BMW, in their infinite wisdom, hid the REAR swaybar parts in the diagrams for the FRONT suspension! http://www.bmwmobiletradition-online.com/bmw/showparts.do?model=2233&mospid=47141&btnr=31_0441&hg=31&fg=05&hl=16 Even looking at the picture it takes a bit of study to see that it shows both front & rear stabilizers, but you can see item 12 are the rear stab bar bracket screws. HEX BOLT M8X18 qty 4 07119913627 $0.31

I've seen heads where the aluminum was in bad shape, and corroded around the bolt, seizing it tight. Take a good look at the head when you get the bolts out, if the aluminum is shot around your stuck bolts, just replace it as it has turned to sponge & is not worth the cost of a new head gasket.

If that ultra-low compression piston is not sufficiently low enough CR, you can invert them with the rod passing through the big hole in what was the top. Skirts up! With the combustion pressures blowing right inside the "cup" formed by the upside-down piston, they will seal tight against the cylinder wall as the skirts expand and this will eliminate blow-by. Of course you will need a hi-temp red urethane bushing to seal around the rod where it passes through the new hole in the piston, but I've seen those on eBay from the regular leeches... We all know that's why Bilstein are so kewl, they're inverted!

Bosch catalog has the list of other applications for this part: 1 234 332 088 Rotor, distributor Supersedes 1 234 332 024, 1 234 332 030, 1 234 332 070, 1 234 332 072 Resistance [Ohm] 5 AUTO UNION 8920 315 20 00 000 KÄSSBOHRER 8 312 000 062 MERCEDES-BENZ 000 158 20 31 MWM 6 0690 40 8 0003 PORSCHE 616 602 221 00 PORSCHE 616 602 221 02 PUCH 700 1 09 019 2 VOLVO 238258 VOLVO 870619 VW 111 905 225 C

In the straight-ahead position, the steering linkage brings the center link to be closest to the trans, and most in your way. In lieu of actually removing the center link, just turning the steering wheel all the way (full lock) left or right makes the center link drop lower to provide clearance for trans R&R. Simple step that is worth a reminder. Swearing in your native tongue is easier, but more likely to offend those within earshot. Mix it up with yer skills from those Rosetta Stone training DVDs!

I don't like to mount the engines to a stand using the trans attaching holes. The top two trans attachment bolts are only M8 bolts! With the engine now held lengthwise, the mounting bolts are subject to a high load in single shear, think about those 8 mm bolt shanks when you are at the far end torquing down the main cap bolts. Plus, you have very poor access to the flywheel (which I like to have attached as I degree camshafts - makes it easier to rotate the valvetrain a precise amount.) And hanging the weight so far away from the upright makes the whole setup less steady. I've got lots of engine stands, and I just buy the simple 3-caster jobs with slotted attachment plates. I do not use any of the other attaching hardware pieces that come with the stand, I mount the main slotted plate directly to the RH engine mount bolt bosses with three M10 bolts. Note that the block is well reinforced in the area of the engine mount bolt boss (duh!) and the pictures in the factory shop manual shows this is how they do it. This pic shows an engine stand where I had to drill one hole in the slotted plate, just use the engine mount bracket to find the locations. Some other stands I've got in use had slots that _almsot_ lined up to the bolt holes as received, just needed a slight spot ground off in one slot to fit the pattern. NOTE you will find that ONE of the three RH engine mount bracket bolt hole bosses on the block is recessed just a bit, (think it's the forward-most one) and you have to stuff a couple washers between the slotted plate and block to keep it all in the same plane. Stronger, more compact, better balanced, better access to the parts I need to work with, with fewer parts to attach.

You did leave out one digit. I'd guess the actual number is this: 0 231 181 011 Bosch It is a good number for an original BMW 2002 distributor, but was used only for one month of production, and was discontinued long ago. So it was used on a standard 2002 only November 1974, then Bosch's catalog says "Superseded by 0 231 176 059" which is now noted as "Article to be discontinued." Even so, there's no assurance that the parts from the second number fit the original distributor number. Probably easier to just try the two likely distributor caps that might fit, pay attention to the alignment notch on the mating lip & the one the fits is it. For the points, as long as yours are not a left-hand set (like some tii) then again if they will fit, they are OK, same with rotor. Bosch was pretty good about having interchangable parts for these distributors, you could fit points with more or less tension by selecting different numbers. A Porsche point set offered more spring tension, resisited bounce better at the expense of quicker rubbing block wear. Can you find someone local with a box of used caps & rotors? They should have part numbers on them, once you find the correct fitting stuff.

Not entirely true there.. although this might seem like splitting hairs. There are now, and nearly always have been, lots of parts on vehicles that are common & can be found as the identical item from the same supplier, even though they are assembled into vehicles from different manufacturers. BMW may have their own Design Release Engineer that is responsible for it, and there certainly will be BMW technical specifications & math drawings for the part, but that actual part could have been developed entirely by the vendor who has the expertise. And BMW can specify a purchased part without retaining any exclusive rights. Now this is less common for more complicated parts that are vehicle specific or proprietary, but all parts on a car are still subject to being officially released for production. A BMW valve stem for a steel wheel has an official BMW part number, & there is a guy at BMW who is responsible for the part, but they could very well source the part from a supplier's existing standard offerings if it meets BMW's needs. The supplier may have developed the valve stem, and could retain rights to sell it elsewhere (even to other vehicle mfg's.) Now the kicker is that that valve stem maker would then be a BMW OEM. And if he decides on his own to design (or reverse-engineer) & produce any other part that could be sold to service any BMW, the aftermarket can & will likely still call that supplier a BMW OEM, even though the S14 crankshafts he's decided to produce were never supplied by him to BMW for production & don't have to meet any of the BMW specifications at all. He is still an "OEM to BMW" even though he only ever supplied valve stems for BMW production. Be careful when you hear part descriptions, it does occur that companies (esp. resellers) take advantage of any confusion when it makes their goods seem more 'legit' and can command a better price. Semantics, sure.. but the definitions in the marketplace do go this way. The second dirty secret of parts is that the very stringent control of manufacturing to the original specifications goes out the window after the production period ends. During production, the vehicle parts have to be top quality to protect the vehicle manufacturer's warranty costs, liability, and reputation. The vehicles as built have to perform & last, and there is great expense to continually produce exacting parts that can do that. After production run is over, there is a legal requirement to supply service parts for a period of ? years, but no real cost justification to keep the same standards, so quality almost always suffers. Service parts, even those sold by the vehicle's manufacturer, do not necessarily meet the same specifications as the same part made for production. I have seen engineering prints for German KolbenSchmidt pistons for service, where the tolerances on key features were twice as loose as the same part's production run spec. When your 2002 was in production, how expensive do you think it was to replace the stamping dies for fenders & other sheet metal as they wore? BMW ate the cost then, because they had to or the new cars would look like crap. You can still buy that 2002 fender from BMW today, but how's the quality now? They are under far less pressure to keep expensive quality processes in place after the model's production is over. Don't fool yourself that an offer of an "OEM" water pump must be the original, or even that the OE part you get at the BMW dealer for an older car has to be exactly as good as the stuff your car was built with. Sometimes stuff is better, but usually not where there's unjustified (to the beancounters) expense involved to keep it that way

Yep, -6 can be considered 6/16 which of course = 3/8" same as -10 being 10/16 or 5/8" -6 is fine and the volume the pump pulls does not change, in fact the pump will have an easier time delivering the same fuel, just the velocity in the lines is reduced which means less of a vacuum will be there, less chance of cavitation

Sometimes, personal experience can give you an initial impression that something is good, but later on you find out it caused more harm than expected. Here's one place I would say to follow the recommendation of BMW & Mobil 1, who both say this is the wrong type of product for your gearbox. Do not use Hypoid gear lubes in your trans, it will shorten the life of the synchros by about one- half. Sulphur additives attack brass synchros, see the M1 product description shows it has it: "Mobil 1 Synthetic Gear Lubricant LS 75W-90 combines wax-free synthesized hydrocarbon base oils and a specially designed extreme-pressure, limited-slip, sulfur-phosphorous additive system to provide a significantly higher level of performance in rear axles and differentials versus conventional fluids. " "Not recommended for automatic, manual or semiautomatic transmissions for which engine oil or automatic transmission fluids are recommended" BMW 2002 trans falls in that category, both of those fluids are mentioned in the owner's manual as a substitute for the GL4 type that was more readily available back when these cars were produced. If you want a quieter trans fluid, use MT90 instead of Redline MTL, or find some other alternative that is not Hypoid Gear lube.

Sad story is that BMW Dealers often inflate the price over the actual BMWNA list price. Small parts get doubled or tripled when they think they can get away with it. The upside is that frequently they are willing to skip the gouging & sell parts based on the actual list price if you confront them on this. My local Dealers always give me a good discount off the actual list price, but they know I'm usually coming in with part numbers & some idea of current prices for most items. Check this link, you can verify the BMW retail pricing if you know the parts (and they also show your discounted price.) In this case, the BMW Dealer here shows the real list is only $1.57 and they sell for $1.26 http://www.trademotion.com/partlocator/index.cfm?action=searchCatalogOEM&siteid=26

I could likely be wrong, but I don't see how that ignition box would produce the cylinder-specific issue like this. With a single coil, that gets switched by the Pertronix, the ignition box itself can't tell one cylinder from another, right? Now the coil can react different according to the energy needed to fire each plug, and of course the cap & plug wires could make a repeatable cylinder miss, but the ignition box just gets "switched" from the trigger repeatedly, and should not see or react differently unless there was a problem with the trigger. Curious how did you check vacuum, what did you measure, from where, and at what RPM? Reason for asking, is that this sounds most like a mechanical issue where each carb's throttles are not moving in sync .. like could result from bent throttle shafts. Not using center pull linkage (like you would get with a correct pairing of DCOE 45 model #15 & 16), but having two of exact same DCOE where you must twist the shaft from the right side of each carb? Have you made certain with your linkage you're not pulling the throttle too hard against the stop @ WOT? If the throttle shaft get a twist in them, 2 & 4 can be open at idle while 1 & 3 are too far shut off (and subsequently not show as much difference when you kill their plug.) Was all your testing showing #1 & 3 weak done at idle? What happens with the same tests at partial open throttle? Check the aux venturi retaining screws did not fall out?

There is a hydraulic difference between circuit one, and circuit two (which also has to fill the rear wheel cylinders.) There _may_ be a mechanical advantage to using the primary circuit on the leading edge of the pads. OR it could be the other way around, but there would likely be one arrangement that is better,