rear brake regulator

[deacon]

I have just installed new rotors, caliper, pads and stainless lines at all four wheels. I began the bleeding process and was able to get the front two ok. I can't seem to get any air or fluuid out of the rears. We pumped the brakes and bled for some time without any progress. I took a look at the shop manual and noticed that there is a rear brake regulator that restricts flow to the rear brakes under hard (nose down) braking. I have the car jacked up by the differential so I didn't think that should cause the regulator to engage, but I can't think of any other reason why we can't get air or fluid out of the rear.

Any suggestions? I figure someone on here must of run into this at some point. Thanks in advance for any feedback.

[So Cal Mark]

you have to disconnect the link to the rear axle and push it up as high as it will go to get fluid from the rear brakes. It's also possible that the center brake hose is collapsed, but that's not a common occurence

[deacon]

Thanks Mark. I will give the link a try. I have replaced the center hose with a new braidied metal one.

[MNspiderman]

you can jack it up by the pumpkin but you'd have to set it on two jack stands to level out the axle properly. It don't take much to set off the brake line regulator, at least on my car, Or just tear it out of there and install an adjustable proportion valve you you don't keep locking up your rear wheels when stopping hard. Or like mark said, disconnect it and push it up.

[kmead]

So you have the rear of the car supported on the differential housing and the front presumably on jack stands which has the body and rear suspension in a nearly normal attitude. So first a stupid question, did the rear brakes function before you decided to redo the system?

If they didn't then you may want to look at adjusting the torsion bar that engages the rear compensator as it may be keeping the rear brakes isolated.

Presuming they did work previously, I would start at the hose you installed that goes from the body to the rear axle. Loosen one end and see if it leaks fluid when you apply brake pressure. If it doesn't start moving upstream to the hard line connections to the compensator. When you loosen the connection from the master cylinder into the compensator, does that leak fluid when you apply brake pressure? Presuming it does leak at the connection and you have already adjusted the compensator (you might want to run it through its range of motion to ensure it isn't being blocked internally by some schmutz) you may need to also replace the compensator.

Some may suggest changing the plumbing to omit the compensator, but it is there for a reason as spinning out of control with rear wheels locked is never a fun thing. Ask GM about the X car...

[deacon]

Karl,

Don't know if the brakes worked before as this car was a shed find that had been sitting for 16 years. The pads and calipers were all stuck to rotors and in bad shape. I do know that the master is pumping fluid into the line to the rear. I plan on pulling the end of the new rear center hose to make sure that fluid is there. I have not investigated the compensator yet, but I assume that there is an issue of some kind. That will all be my Labor Day task as today the wife is requesting my presence......I will be leaving the compensator in the car and replacing it if needed. Thanks

[racydave]

Spinning out of control? Guess I should put mine back on a few thousand miles ago!

[deacon]

well I couldn't stand not knowing, so I disconnected the lever from the axle that engages the compensator. The rod attached tot he lever that goes into the compensator is frozen solid. It will not rotate. That would explain why the fluid is blocked to the rear calipers. When I disconnected the brake lines form the compensator there was fresh fluid coming out so it is blocked at the compensator. The compensator also looks like it has a lot of corrosion. I started to remove the compensator but will need to study it a bit to figure out how to remove the rod that goes into it. The compensator is in a tough spot to get to. More to follow......

[So Cal Mark]

you can replace the compensator, or bypass it with a hose. I haven't had one complaint of rear brake lockup from anyone that has bypassed the compensator

[deacon]

I may just bypass it for now and possibly install a newer style adjustable proportioning valve a bit later. There are so many things I want to get dialed in on the car and I need to have it on the ground and road to do so. Thanks for all of the suggestions and guidance.

[kmead]

I wouldn't do it, but if you do be very careful in the rain when its most likely to be a problem.

There are a variety of cars that use a mechanical "switch" to deal with this as well as rear proportioning valves. VW Sciroccos had two valves at the master cylinder.

Given the nature of the Fiat suspension (soft and with plenty of dive in the geometry) to unload the weight on the rear wheels under heavy braking and when you need this system (an emergency stop) you don't want the rear wheels locking.

[Hvnfn]

I haven't had the rear compensator out yet, but it is leaking at one of the ports... So, I am about to take it out and replace it or repair it, if possible. Are these compensators repairable? Is there much to them?

[acfiat]

Hello everyone.Can anybody please give me a simple explaination,on how to set up,or adjust a newly installed rear brake compensator.Also,could anyone explain how the compensator works.Thanks,Garry.

[baltobernie]

http://www.international-auto.com/fiat- ... a-beta.cfm

[acfiat]

Hi everyone.By simple explaination,I mean,has anyone actually installed one of these from scatch,and could post a step by step guide on how to adjust the compensator so it works like it should.Thanks,Garry.