89 Cav Non-ABS Master Cylinder Bleed - Maintenance and Repair Forum

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89 Cav Non-ABS Master Cylinder Bleed
Wednesday, August 03, 2011 7:59 AM
I have changed out the calipers and wheel cylinders on an 89 Cavalier (non-ABS) and did not plug the lines. I suspect that the master cylinder has gone low.

1) Is it definitely true that bleeding at the calipers and wheel cylinders is not enough, and that bleeding the master cylinder first is necessary?

2) Briefly, how would I bleed the master cylinder (while is in the car)? My manual makes reference to a front port and a rear port, but all I see are the four brake lines coming out of the master cylinder.


Thanks

Re: 89 Cav Non-ABS Master Cylinder Bleed
Friday, August 05, 2011 8:47 PM
Being your car is NON abs you would bleed the system as the normal right rear,left rear,right front,left front.The description you stated is ONLY if you removed the master cylinder itself.Being you removed the caliper lines,and wheel cylders you have ALOT of air that has got into the system.You will will just bleed the the wheels rr,lr,rf,lf in order.May sure your container has clean fluid u bleed into first this reduces the air going back into the line.I fill mine almost half up,on my bleeder,place hose on bleeder screw and open have helper push pedal BY HAND repetiviley (is that right) and until NO bubbles and soley clean fluid.Do this on each bleeder and refill the resevoir each time u do ONE wheel(almost draining it helps,but not empty)Having the car on jack stands and wheels off makes this about a 20 minute job.Just brake clean each bleeder (keeps things clean) afer each whl.By the time you get to the left front the pedal should be solid,and NO bubbles,or dirty fluid.To me it sounds like you u have a big air pocket and not bleeding it effectively.By having clean fluid in the catch cup,with a vac line going down into the fluid that is clean prevents air going back into the system,and while a hassle to keep dumping it and refill the cup with clean on each whl prevents the problem u have.You DO NOT have to bleed the master,being you did not disconnect the hard lines going to it.I hope this makes sense and you understand this simple process,and in under 30 min have good brake pressure.Not to mention adjusting the rear brakes to just touch the drums slight drag,for proper setting.You may have to drive it and back up hard several times to get the star wheel to set accordingly.Make sure the threads on the adjuster are the SAME on each wheel like 6 or 7 threads showing as a example.Ok sorry for the book just trying to be specific and not leave anything off.Ok



Re: 89 Cav Non-ABS Master Cylinder Bleed
Wednesday, August 17, 2011 3:41 AM
A belated thanks for your reply.

A front line WAS disconnected at the master cylinder, as the line had to be taken off and repaired after it broke at the connection with the hose.

I bled at the master cylinder line connections in the same manner as is done at the calipers/wheel cylinders, I think in this order: lower front, upper front, lower rear, upper rear. Then I did the wheels in the order specified by the manual for the car (RR, LF, LR, RF).

The brakes currently have excessive travel, and are spongy. But I believe at some point during the bleeding process, I had a good pedal. Will check for leaks, check that the rear drum adjusted, and re-bleed. I may have gotten careless at some point.
Re: 89 Cav Non-ABS Master Cylinder Bleed
Wednesday, August 17, 2011 8:21 PM
Cool glad it is all done.I wondered if you ever got it fixed.



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