E36 M3 brake all around, 25mm BMC, PEDAL STILL SPONGEY!!

[Wanganstyle]

dude, before you keep speculating, you need to listen to couple folks here: Flip the calipers! (swapping to other side)

Rule #1 with brakes: all bleeders MUST be facing up, or on top to be more clear.

bleed, then you can proceed, but you have a classic case of AIR in the rear lines, no reason to over complicate issue.

factory F/R bias based on the MC piston sizes internally, in the 25mm master with equal pistons (735iL were heavy in the ass) you have much more rear bias than stock MC, therefore if there is air in the rear lines, you get sponge bob

Edit: Also, when bleeding, make sure you close the valve before your friend's foot reaches the full stroke, if his/her foot on pedal bottoms out before you close the bleeder, some air will get in.

I cannot believe op has been driving around with giant air bubble on his wace kar e30 for months now.

It must be rad to be out braked by a KIA sportage

Flip those calipers upside up.

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[franky2fingaz]

unsafe... get some line locks so when you decide to switch you won't have to drain the whole rear

[E30stan]

dude, before you keep speculating, you need to listen to couple folks here: Flip the calipers! (swapping to other side)

Rule #1 with brakes: all bleeders MUST be facing up, or on top to be more clear.

bleed, then you can proceed, but you have a classic case of AIR in the rear lines, no reason to over complicate issue.

factory F/R bias based on the MC piston sizes internally, in the 25mm master with equal pistons (735iL were heavy in the ass) you have much more rear bias than stock MC, therefore if there is air in the rear lines, you get sponge bob

Edit: Also, when bleeding, make sure you close the valve before your friend's foot reaches the full stroke, if his/her foot on pedal bottoms out before you close the bleeder, some air will get in.

Thanks for chiming in here franky

Ill have to check on finding a 90 degree elbow in order to position the calipers properly, until then i guess the fronts are doing all the work.

When i bleed the brakes i usually have the pedal pumped up then held down, while the bleeder gets cracked open for a second then shut again. The tubing from the bleeder to the bottle is filled with fluid, and the bleeders have been antisezed to prevent air going past the threads.
I can imagine that the pedal might sink to the end of its stroke before the bleeder gets shut again, and this would not necessarily allow air to get back in the line. Unless there is absolutely no fluid in the line to begin with, in which case the air let in is negligible. Can you picture what I'm talking about?

Unless you simply mean that the bleeder should be opened for only a split second to prevent the pedal from reaching its full stroke as a precautionary method?

[franky2fingaz]

Unless you simply mean that the bleeder should be opened for only a split second to prevent the pedal from reaching its full stroke as a precautionary method?

yes.. but that's debatable, because some have a tendency to let off a bit when pedal hits floor as you close bleeder... the importing thing is you sort the calipers then you should be fine...

[Wanganstyle]

Why is it not possible to flip the calipers?

I've been trying to say this entire time; I made this mistake with a jap car back in 1999; bled it 4 times and drove it 1 day then realized I had installed the front calipers upside down.

Swapped left to right calipers to make nipples upside up. Bled once and problem solved

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[E30stan]

Why is it not possible to flip the calipers?

I've been trying to say this entire time; I made this mistake with a jap car back in 1999; bled it 4 times and drove it 1 day then realized I had installed the front calipers upside down.

Swapped left to right calipers to make nipples upside up. Bled once and problem solved

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Wangan,
I've said it before in an earlier post, if i put the calipers on the proper side then the brake line is directly in front of the bottom shock bolt. Unless i find an elbow like shown here

rear brake elbow by stanislavsmal, on Flickr
then I'm unable to route the brake line. You wouldn't happen to know where i can find that elbow, would you?

[Wanganstyle]

Wangan,
I've said it before in an earlier post, if i put the calipers on the proper side then the brake line is directly in front of the bottom shock bolt. Unless i find an elbow like shown here

rear brake elbow by stanislavsmal, on Flickr
then I'm unable to route the brake line. You wouldn't happen to know where i can find that elbow, would you?

Call summit performance or jegs?

Find a custom brake line place; I did this back in 1999 when I needed a clutch line ; phone book was the answer.


Whining about a situation you created for yourself and "upgrades" that don't work are just crappy excuses.

Don't be r3vtarded and kill a mini van of soccer kids.

Nipples of brakes are designed to face UP.

[franky2fingaz]

Call summit performance or jegs?

Find a custom brake line place; I did this back in 1999 when I needed a clutch line ; phone book was the answer.


Whining about a situation you created for yourself and "upgrades" that don't work are just crappy excuses.

Don't be r3vtarded and kill a mini van of soccer kids.

Nipples of brakes are designed to face UP.

lol.... chill.. it's unsafe but not deadly.. deadly is when an old shitty Beretta I drove hit a major broken-up highway expansion joint, master breaking off booster, that's scary... we all learning, still got front brakes...

[M3 euro ltw]

Interesting thread

First off:
E36 M3 master cylinders were 25 front and 25 rear. No stagger.

There is no comment I can find regarding whether you have E36 ABS system pump and computer or, retained E30 ABS pump and computer.

If your original car had a non-adjustable brake bias valve installed in conjunction with the ABS system you're currently using, I would retain that as well as the stagger or lack there of in the masters as the factory has calibrated the ABS computer to function properly with that mechanical bias. In other words if the original master was 24/24, then certainly using an E36 master of 25/25 won't mess things up. REALOEM seems to show a bias valve or control valve to the rear with or without ABS for 325s at least.

Math matters here.

I would pay attention to what the original factory mechanical bias was, usually its around 68% to the front for the cars, and strive very hard to retain that.

The LAST thing I would do is put in an adjustable bias valve. You're likely only to adjust things outside of where the ABS expects it to be, and thus increase your braking distances.

Poor man's ABS cycling can be achieved in a gravel patch or grassy area of you can do that.... brake hard several times to activate the ABS. I would not use a road shoulder as that is likely to be unsafe.

[Julien]

I've got the same issue :-/

e36 m3 fronts, flipped e36 rear calipers.

When bleeding (with pressure bleeder) I have removed the calipers and orientated them such that the bleed screw is on top. I also gutted my OEM proportioning valve as an attempt to fix this.

Crazy part is that my front brake system has some kind of track pad (carbotechs? shoots spark when you hit the brakes) so the front locks with any pedal input past the "spongey" part.

I think my next step is to swap the OEM rear 318ti back in and install some random autozone front pads I have laying around to see if that brings the brake system back in check and/or manually activate the ABS pump while I have the pressure bleeder on the system. Last step is new 25mm MC.

[BenM]

You guys using a 318ti rear trailing arms need this - http://www.300mm.de/294mm/294adapter.html

Allows you to properly use E36 M3 Calipers and Z4 294mm rotors.

[E30stan]

Update:
By the grace of God, my brakes are much better now!
Turns out mixing brake components, ie.. ate with girling is a no no...
Funny thing is that most late e30s were equipped with girling BMC and booster, and most places online say the 25 mm are BMC is a direct fit. Yea right.
I installed an ate BMC from an early model and now it's worlds better!

The rear calipers bleed fine without messing with the bleeders, so I don't want to hear it.

The 300de adapters are costly and still locate the e36 stuff flip flopped on the e30 chassis.
Here you can see the bleeders are still pointed downwards,

http://www.e30tech.com/forum/showthread.php?t=113858

For what it's worth, the 25 mm brake master cylinder is a great upgrade to improve pedal feel. Now I just have to play with setting the rear bias perfectly!
Cheers

[berlow94]

Sounds like your master just wasn't bled properly then, and this one is...


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[wazzu70]

Sounds like your master just wasn't bled properly then, and this one is...


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Thats my thoughts too.

[Julien]

i fixed my issue by going bigger MC.


also about the flipper rear calipers, it's not all that hard.. unscrew, flip up and stick something to mimic disc inside them, took all of 15 extra mins with a pressure bleeder