Rear brake trouble, 88' Pontiac 6000 STE

Reply

  #1  
Old 07-11-04, 04:33 PM
Canada AC
Visiting Guest
Posts: n/a
Question Rear brake trouble, 88' Pontiac 6000 STE

I changed the rear calipers on my 88' Pontiac 6000 STE because the old ones were shot, so I thought.

I've bled the brakes numerous times (almost a dozen times actually) and I still have a warning light on the dash and no rear brake movement, even with brand new calipers and pads. The front brakes work perfectly.

I've been told on some Pontiac models the master cylinder is at an angle and you have to jack the car up to bleed the rears properly. I even tried that, with no success.

I do get fluid flowing to the calipers and I even tried to bleed them with a little bit of pressure, rigging up a squeeze bottle to suck the fluid from the lines.

Is air my problem here, or is there something I'm missing?

Any suggestions would be appreciated!
 
Sponsored Links
  #2  
Old 07-11-04, 05:01 PM
Member
Join Date: Dec 2003
Location: Indiana
Posts: 312
That vehicle requires a special bleeding procedure for the rear brakes because of the ABS system. The accumulator for the ABS has to be fully charged to bleed them properly. Turn the ignition key on and you should hear the ABS pump/motor kick on - when it turns off, the accumulator should be charged. Leave the key on, and attach a hose to the bleeder screw and run it into a jar of clean fluid and very slightly depress the pedal (no pumping) for 10-15 seconds, until no air bubbles. You should have help on this, and be very, very careful. That fully charged accumulator runs at 2300+ psi.
 
  #3  
Old 07-11-04, 06:25 PM
Canada AC
Visiting Guest
Posts: n/a
Does it matter if the ABS has been disabled? The previous owner (my father in-law) was a dealership mechanic and disabled the ABS feature on the car because he didn't like the pedal "feel". It never gave me any trouble till now.
 
  #4  
Old 07-11-04, 07:47 PM
Member
Join Date: Dec 2003
Location: Indiana
Posts: 312
I guess my first reply may have been a little confusing concerning the ABS. Even though they are tied together electronically, the ABS and regular brake systems are still seperate entities. Failure (or disabling) of the ABS won't affect normal brake operation, but the hydraulics on that system are a little unique (or they were back then at least). The mas. cyl./hydraulic unit has no vacuum power assist, it is all electronically controlled. Without pump/motor and accumulator operation, you have no brakes, as it will transfer absolutely no hydraulic pressure. Why did you replace the calipers to begin with? If the brake operation was normal before, then the bleeding procedure should work. You should be able to hear the pump/motor engage when you turn the key on. It will shut off when the accumulator reaches full charge. If the pump/motor isn't working, the pedal will be hard as a rock with no travel, no matter how much air is in the system.
 
  #5  
Old 07-11-04, 10:35 PM
Canada AC
Visiting Guest
Posts: n/a
So would I have any brakes at all if the pump was shot? The reason I ask is because the front brakes are fine, responsive and tight. Does the pump only effect the back calipers?

This is starting to sound more like the pump/motor is shot and the rear calipers were fine. Which hurts to think about considering how expensive the rear calipers were.

PS- The pedal feels odd, but not solid/rock hard, it does have normal movement but near the floor it fades and goes hard. This is while the car is started and moving.
 
  #6  
Old 07-12-04, 09:33 AM
Member
Join Date: Dec 2003
Location: Indiana
Posts: 312
If the pedal has travel and is fading, the pump is working. Bleed the brakes as described and post back with the results.
 
  #7  
Old 07-12-04, 12:52 PM
Canada AC
Visiting Guest
Posts: n/a
You asked why I replaced the calipers in the first place, and I thought it might shed some light on the trouble I am having.

The rear calipers on the 6000 STE are the threaded type that require that special socket to TURN them back in. I didn't know that when I was changing the rear pads and I simply pressed them in. Actually, it wasn't simple, or easy. But I thought they were just old and hard to press back in. So without even thinking, I mashed the threads and ruined the calipers.

Could that be where I ended up with all the trouble I am having with the lines now?
 
  #8  
Old 07-12-04, 02:22 PM
Member
Join Date: Apr 2002
Location: Pittsburgh,Pa
Posts: 2,417
I doubt that is what is causing the bleeding problem,proceed as pmg said and then post back.
 
  #9  
Old 07-12-04, 03:59 PM
Member
Join Date: Dec 2003
Location: Indiana
Posts: 312
I also doubt that caused any problem beyond trashing the calipers. At this point, you simply need to bleed it per the recommended procedure and post back with the results. Really not much else we can help you with until you get that accomplished.
 
  #10  
Old 07-12-04, 04:12 PM
Canada AC
Visiting Guest
Posts: n/a
Thanks.

I was just curious if it was possible that I pushed up metal shavings into the lines by squeezing the rears closed.

If you don't think that is possible, then I will bleed them again according to your specs.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes