R32 Abs Unit - Exploded View/photos Of It Pulled Apart

[Bozz]

I want to know whats inside them and see if it's part of the common cause of spongy brake pedals in R32's

Cheers

[Rowdyr32]

Braided lines and a master cylinder stopper will fix all your probs with some new fluided added.

Every car I drive feels like the brakes are spongy in comparison.

[Bozz]

Braided lines and a master cylinder stopper will fix all your probs with some new fluided added.

Every car I drive feels like the brakes are spongy in comparison.

Brakes used to be perfect. Bit well the moment you touch the pedal. Problems began after I fried the brakes on a track.

The pedal does nothing until about half travel.

I have braided brake lines, QFM A1RM pads, new discs, master cylinder to strut stopper.

I removed and drained the fluid from all four calipers, refitted, bled - no difference.

I rebuilt the master cylinder - no difference

I rebuilt the front calipers - no difference

I bled the system no less than 10 times including the ABS unit, in the order the manual recommended - no difference.

I lifted the car in the air, an assitant "drove" it while leaning on the brake pedal to trigger the ABS while I bled it - no difference

When I manually energize any of the three ABS servo solenoids and the fluid return motor, the pedal goes rock solid and can't be moved at all. This means the master cylinder is perfect and it's not firewall flex. It's ABS servo or the calipers have gone soft.

Hence I'd like a damaged/leaky ABS unit to investigate the problem. Somebody must have one, i've seen plenty of threads where people have replaced their leaky ones.

Cheers

Edited July 20, 2010 by Bozz

[Bozz]

Lets just say this isn't for the inexperienced, there are hundreds of parts inside. If you can rebuild automatic transmission valve bodies or an engine, you'll probably be able to do this job.

To reassemble it will require complete cleanliness and complete accuracy - a single speck of dirt, a missing check ball, seal or incorrect re-assembly could result in no brakes or brakes locking on and not releasing....

Next week i'll acid dip the parts, get all the replacement seals and reassemble it.

[THENIG]

Lets just say this isn't for the inexperienced, there are hundreds of parts inside. If you can rebuild automatic transmission valve bodies or an engine, you'll probably be able to do this job.

To reassemble it will require complete cleanliness and complete accuracy - a single speck of dirt, a missing check ball, seal or incorrect re-assembly could result in no brakes or brakes locking on and not releasing....

Next week i'll acid dip the parts, get all the replacement seals and reassemble it.

WOW!! Everybody I speak to won't go near it because they are too scared to get it wrong. Really interested in how you go with this, I am in exactly the same boat as you, had to remove my brake booster stopper because it was accentuating the ABS unit leaking. Before that nothing I did could get rid of the spongy brake pedal.

Read a thread about someone rebuilding the ABS unit with new o-rings, had a spare/leaky ABS unit lying around from the first time it started leaking, got all the sizes of the o-rings from the thread and tracked down a supplier that could supply the correct type that are ok for use with brake fluid, bought 3 complete sets just incase I wanted to fix the other one & sell it or needed some spares. 6 months later they are still sitting in the zip locked bags on my desk.

Can you please update thread with any further info you have?

Cheers

Rob

[THENIG]

P.S I think I have read somewhere that isopropyl alcohol is good at cleaning brake fluid.

[Kinks]

WOW!! Everybody I speak to won't go near it because they are too scared to get it wrong.

probably a wise move in many cases. brakes are a very simple pneumatic system, ABS is a very complex pneumatic system.

[Bozz]

Hey,

While its apart, I'm trying to draw a 3D exploded view of it in sketchup - there is absolutely no information on the interwebs about how this particular NipponDenso ABS unit operates.

I'm 90% sure the solenoids have three modes (build, maintain, release) instead of just two modes since there are three in/outlets (two at the top, one at the bottom) but I need to establish how to trigger them out of circuit. When time permits I'll hook up my digital storage CRO to two of the ABS solenoids and see how the ABS controller drives them. Google told me that some Toyota's use three mode solenoids but I can't find any pictures of them to see if the solenoids are the same or not. Then I'll be able to build a controller circuit to trigger and bleed the ABS modulator properly.

I dont think the ABS unit is difficult, just very time consuming and you have to triple check everything. I took photos at every step of disassembly so I shouldn't have dramas reassembling it. The only thing slowing me down now is lack of time

[djr81]

probably a wise move in many cases. brakes are a very simple pneumatic system, ABS is a very complex pneumatic system.

Hmm, when I went to school they were hydraulic.

[Bozz]

Hmm, when I went to school they were hydraulic.

Liquids, gasses, stop being so fussy

[THENIG]

probably a wise move in many cases. brakes are a very simple pneumatic system, ABS is a very complex pneumatic system.

Yeah fair enough, rightly so, all bar one bearing place I went to wouldn't even sell me the EPDM (?) o-rings after I told them I was going to attempt to rebuild my ABS with them. Guess people are too scared of litigation these days.

Sif I could somehow blame them if they failed, I think anyone attempting this knows the risks if they get it wrong, I def wouldn't be blaming a supplier for faulty, unqualified workmanship.

[MrStabby]

I tried rebuilding my ABS using the EPDM o ring list that was on this forum. I had a big fail with a lot of leakage. Most of the original seals have custom cross-sections (few are orings) and i very much doubt that it would be possible to get it properly sealed unless you can get the real seals. But - if you can get a set of proper seals please let us know!

[THENIG]

I tried rebuilding my ABS using the EPDM o ring list that was on this forum. I had a big fail with a lot of leakage. Most of the original seals have custom cross-sections (few are orings) and i very much doubt that it would be possible to get it properly sealed unless you can get the real seals. But - if you can get a set of proper seals please let us know!

Thats really disappointing to hear Adam, I was really hoping someone had a success rebuilding one of these. I really want to keep my ABS, no matter how crappy it is compared to modern day systems. Mine only seems to be leaking from the top, I wonder if I can leave the rest alone and just replace the o-rings in that area that have failed? I have no idea as to how the thing comes apart, was thinking about documenting it so I could put it back in the correct order but never got around to it. When you say you had 'lots of leakage', over what period of time and were you still able to stop the car? Or did you have no pedal whatsoever?

Cheers

Rob

[Bozz]

Once you pull the body apart, you seperate the high pressure seals between the solenoids and machined aluminium upper and lower bodies. You wont get it to seal again without replacing the seals. Unfortunately, the bottom seal shape appears to be made of unobtanium and you'll have no hope of getting it back together, sealed, without replacing it.

Work on a spare like I am.

Cheers

[MrStabby]

Thats really disappointing to hear Adam, I was really hoping someone had a success rebuilding one of these. I really want to keep my ABS, no matter how crappy it is compared to modern day systems. Mine only seems to be leaking from the top, I wonder if I can leave the rest alone and just replace the o-rings in that area that have failed? I have no idea as to how the thing comes apart, was thinking about documenting it so I could put it back in the correct order but never got around to it. When you say you had 'lots of leakage', over what period of time and were you still able to stop the car? Or did you have no pedal whatsoever?

I got pedal pressure but it leaked worse than when I pulled it apart. You might have better luck, but IMO some of the seals from the list arent quite the right size even if you leave the shape question aside, and IIRC there were a few missing from that list.

I checked it as soon as it was reinstalled and bled, and pumping the pedal hard was enough to see the telltale wetness. I bought another second hander that looked good, but it also has a small leak. I'm thinking that the ABS manufacturer might be the best place to get seals from, if they're still available. I would like to have another shot at rebuilding, but I lost motivation...

[GGG]

Hi

You seem the type of person that wants to do it for the challenge; if you need a back up plan I have one in good working order for sale.

Regards Taylor

0408 188 777

[DVS JEZ]

is it a consistent half way pedal feel? is it normal when it gets to half way?

try adjusting the brake pedal pushrod that goes into the master cylinder, i had to do this on my old s13 to get the pedal working correctly

[Bozz]

Hi

You seem the type of person that wants to do it for the challenge; if you need a back up plan I have one in good working order for sale.

Regards Taylor

0408 188 777

Bit late unfortunately - I picked one up in good working order for $25 a few weeks ago and it's in my car now.

Thanks for the offer

[Bozz]

is it a consistent half way pedal feel? is it normal when it gets to half way?

try adjusting the brake pedal pushrod that goes into the master cylinder, i had to do this on my old s13 to get the pedal working correctly

Hey,

That's exactly how it feels but in my case, it's not the pushrod:

When I manually energize any of the three ABS servo solenoids and the fluid return motor, the pedal goes rock solid and can't be moved at all. This means the master cylinder is perfect and it's not firewall flex. It's ABS servo or the calipers have gone soft

There is air in the system somewhere, I just can't figure out where. That's one of the reasons I'm pulling down the ABS unit and learning about how it works.

I've emailed NipponDenso to see if they'll give me any info on the unit although I dont think they'll reply.

Cheers

[ARTZ]

these guys in hallam may be able to help...Good luck, i wouldnt even of attempted it..

http://www.injectronics.com.au/