Brakes are and Have Been Weak- Lots Done

[m3f_zhp43867]

The brakes have been weak on my E36 M3 more or less since I got the car. It currently sits at 246,000 miles, and it was bought with 159k. In that time i have done new rotors and pads twice.



To eliminate variables:

- current setup is Zimmerman rotors with OEM Textar pads (about 20,000 miles on them).

- tires are Super Sports

- calipers have all been rebuilt in the last 20k miles (Centric Premium)

- lines were replaced yesterday with Goodridge SS lines

- brakes have been pressure bled with ATE countless times (including two times since line install)



I know what this should feel like, as I've had another E36 M3, and countless E46s to compare feel with.



The feeling the brakes currently give is a system with good hydraulic pressure and pedal feel (not spongy) and no bite whatsoever. It feels like I have installed the crappiest ceramic pads in the world.



At this point I am ready to buy some more aggressive pads (Ferrodo DS2500 or Carbotech AX6) but I fear this will not solve the issue. OEM rotors and pads, fresh calipers, lines and fluid should result in good brake feel and power.



Any thoughts on what could be causing my problem?

[m3f_bluptgm3]

Running brass caliper Bushings? I've see bound guide pins with bushings- If so need to 'hone' the bushings. I used a short strip of crocus cloth/emery paper and a large cotter pin in a drill motor to 'hone' the bushings.

Alternatively, if you are stock, are the caliper guide pins clean and ever so lightly greased?

Pagid, Textar, Ate should all be great pads. If disks/pads are worn the volume of fluid in the caliper can reduce braking effectiveness.


I tried Performance Friction Z-rated pads, worked great after a few stops (warm) and/or 80-plus degree days. Also worked great for intermediate track demonstration rides.


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[m3f_frbz]

How about the brake booster?

[m3f_Earthwormjlm]

Could your pedal be bent, so you're not applying full power until far along in travel?


Check the part number on the brake master cylinder, maybe its not the M3 part.

[m3f_Braymond141]

Same issue here, but I moved on to a full 996 4-pot Brembo setup. I'm going to do a new brake booster (even though original holds vacuum perfect).

[m3f_bluptgm3]

Same issue here, but I moved on to a full 996 4-pot Brembo setup. I'm going to do a new brake booster (even though original holds vacuum perfect).

Why?


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[m3f_bluptgm3]

Check the part number on the brake master cylinder, maybe its not the M3 part.

A fellow Club member did this, or her mechanic did.…


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[m3f_Nate047]

I would consider replacing the brake booster and check valve and probably put on a more aggressive pad as well. Stock pads suuuuuck.

[m3f_Braymond141]

I would consider replacing the brake booster and check valve and probably put on a more aggressive pad as well. Stock pads suuuuuck.

Zimmerman rotors with Textar pads have fantastic bite and street stopping power though. A set just went on my 98 M3 Sedan and it feels great.

[m3f_englishtom1596q]

Are the pads wearing correctly? Flat and on the whole rotor surface. As said earlier the bushing may be allowing the caliper to flex and not contacting the rotor properly. I haven't had it on the M3 but I have had it on other cars

[m3f_zhp43867]

How about the brake booster?

Same issue here, but I moved on to a full 996 4-pot Brembo setup. I'm going to do a new brake booster (even though original holds vacuum perfect).

This is what I'm doing. ATE boosters are NLA so I went with A-1 Cardone (only one I could find outside of $600+ BMW). aeronaut had good luck with this part on bf.c. I will install it later this week and report back.


More resources for anyone facing a soft pedal on the E36:


https://www.bimmerforums.com/forum/s...e-booster-HELP!


https://www.bimmerforums.com/forum/s...al-Feel-Issues


http://www.bimmerforums.com/forum/sh...dal-Feel-Issue


Pads are wearing normally fwiw. With new calipers and pins (yes- greased) nothing less than perfect should be expected IMO.

[m3f_zhp43867]

Update. Cardone booster installed and... it's not good. Near immediate vacuum failure. I'll let this post I found sum it up:

Replaced my Vacuum brake booster some 16 months ago with a remanufactured A1 Cardone #54-71405 unit from Rockauto. It crapped-out 11 months later...Rockauto sent me another via product warranty. Installed the replacement unit this past April....it totally failed witout prior warning yesterday morning :U



Called Rockauto and they agreed to refund my money in full if I return the defective unit...FOR THE RECORD......I LIKE ROCKAUT0, VERY DEPENDABLE COMPANY....TOO BAD THIS REMANUFACTURER SUCKS. I did notice this is the only vacuum booster rebuild they carry, also used to cary ACDELCO, but no more.



Purchased a new GM OEM #10242104 vacuum booster from Bob McGuire Parts a GM Wholesale Parts Distributor in NJ.



Part lists at $359.54 They quoted $266.06 last night and called me to confirm it qualifies for some kind of additional GM discount and will cost $235 + $12 shipping, and I should recieve it by tomorrow arty:



http://www.bobmaguireparts.com



I'll never be so stupid as to install another remanufactured vacuum booster again, when it takes me about 2 hours to remove the old and install the new...this will be my third time :rant:

$500 for a BMW booster and this should be resolved.

[m3f_Braymond141]

Update. Cardone booster installed and... it's not good. Near immediate vacuum failure. I'll let this post I found sum it up:


$500 for a BMW booster and this should be resolved.

Sorry to hear it didn't work. I'm anxious to know how the new one is.

[m3f_zhp43867]

BMW booster ending in 965 is NLA. ATE is also "NLA-" Pelican lists them as in stock but if you call they have none. My local part guy said SSF and WorldPac both showed NLA on ATE but found one (just one!) through another supplier so I suppose some are still out there.


If you look at RealOEM it says that booster ending in 963 supersedes 965, but when you search 963 the M3 is not a cross referenced application.


Anyway, one part getting complicated to find as these cars get old. Will post again when I get the ATE booster installed. The job is a pita and a half.

[m3f_zhp43867]

ATE booster did it! My brake feel has returned and is better than ever. Second time would have taken about two hours (as opposed to five) if the pressure bleeder didn't explode twice.


Hopefully those facing a similar problem can find an OEM booster.