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

[E30stan]

You posted a thread for advice; Here is the advice you have been ignoring the entire time.

Your symptoms are (besides the Upside down calipers)

Bad master cylinder.

Seems you have been avoiding this advice all along and don't really wish the car fixed.
Nobody gives a rip about your feelings; there is an entire genre of music devoted to this; it's called EMO

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Cool story bro

[BenM]

Wanganstyle is spot on and you really should just change your MC. Who gives a shit if he was rude, grow some thicker skin dude.

Soft Pedal = Air in the lines or Bad MC
Hard Pedal = Bad Booster

Also, what is the thickness of your brake rotors?

[Wanganstyle]

Only one with a extremely high IQ will defend upside down brake calipers as being "bled right"

I think op is doomed here


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[E30stan]

Wanganstyle is spot on and you really should just change your MC. Who gives a shit if he was rude, grow some thicker skin dude.

Soft Pedal = Air in the lines or Bad MC
Hard Pedal = Bad Booster

Also, what is the thickness of your brake rotors?

Rotors are 22mm i believe.

[kristov]

Do you have ABS?

[E30stan]

Do you have ABS?

Yes, but its deactivated for some reason.

[rkettner]

how did you get e36 m3 brakes on the rear? as far as i know that is impossible. did you make an adapter?

[bimmerteck]

how did you get e36 m3 brakes on the rear? as far as i know that is impossible. did you make an adapter?

M coupe/roadster rear trailing arms allow e36 M brakes to bolt on.

[rkettner]

M coupe/roadster rear trailing arms allow e36 M brakes to bolt on.

that was not mentioned but yes, they do.

I would like to know how the ti trailing arms were modded maybe there was a slip up there.

[E30stan]

that was not mentioned but yes, they do.

I would like to know how the ti trailing arms were modded maybe there was a slip up there.

Here's how I got m3 brakes modified to fit the ti arms

http://www.318ti.org/forum/showthread.php?t=35983&page=3

Just for future reference, i once had to stop short and activated the abs. Ever since that happened the brakes are back to normal! Seems i had air in the lines going to the abs unit. Now The brakes grab right on top and im able to modulate the pressure fine. I dont even feel the need to change out the proportioning valve just yet.
Thanks for all your inputs gents:)

[E30stan]

So, to my chagrin, i still am working on fine tuning the brakes on the e30.
I installed a brand new ATE brake master cylinder.
I was unsuccessful in swapping the calipers to make the bleeder positioned upwards because when using 318ti trailing arms and e36 m3 rear calipers the brake line is directly in the way of the shock bolt.

A 90 degree elbow of some sort would allow for the brake lines to connect and therefore the bleeders would be pointed upwards, alas i have yet to find such an elbow. Which by the way, would realistically only relocate the bleeder screw about an inch upwards.
Ill have to snap some pictures to show everyone what I'm rambling about:)

Just to recap, i have rebuilt e36 m3 calipers all around.
A Wilwood proportioning valve that allows up to 57% pressure reduction to the rear.
A stock e30 brake booster.
I have even "tickled" the abs unit by grounding the black and black/white wires at the abs unit while key is in ignition, then a rebleed, to no avail.

Just to put it out there, I still feel safe driving the car; by no means would i intentionally put myself or other drivers at risk of not being able to stop in time.

My issue is the feedback from the pedal is less than inspiring. I'm becoming so desperate that i might just bring the car to a place with a GT1 that can properly tickle the abs into bleed mode and pay for a professional power bleeding.

Any thought Gents?

[kronus]

I'm still confused about what you're actually feeling from the pedal.

Is the throw too long? That is because your master cylinder doesn't move fluid as fast as the one typically used with the calipers you have.

Does it never firm up? Have you tried a pressure bleeder instead of a vacuum bleeder?

[Wanganstyle]

His rear brake calipers are installed upside down. Brake calipers installed upside down with bleed nipples pointing down will never ever bleed properly.

One could try to unbolt caliper and bleed it rightside up with a rotor (out of the car) and then reinstall it....upside down? ???




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[E30stan]

What is the difference between Girling brake boosters and ATE brake boosters?
Is there a different length shaft that interacts with the brake master cylinder or something?

[franky2fingaz]

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.