2000 Blazer Brake Problem

[CWF]

My wife's blazers brakes became very spongy. No lights came on to indicate a problem with the ABS. So I will do a brake job even though my mechanic said the pads looked like they had some life to them. My brother said I might have a problem with the rear calipers. He said I might need a special tool to screw them in, instead of just using a C-clamp. Anybody heard of such a thing?

Anyway, by the doing the brake job, new rotors, pads, and maybe calipers, I'm not sure this will explain the why of the air in the lines.

And with the job all done, can I just bleed the lines like I normally would have, or are there new rules to bleeding since it has 4 wheel ABS?

Thanks

[Chris Stewart]

I don't know which year they started but some caliper pistons "screw" back into position. They'll have a cross or 2 "grab holes" at the back of the pistons. Seems like clockwise put them back in the retracted position but that was a Ford.

The '97 Service manual shows ABS internal ports open during normal conditions and historically standard hydraulic brake bleeding is the standard procedure. Catch the old fluid to properly dispose of it.
A pal showed me that opening the bleeder and just letting gravity flow the air out works if the assistant isn't available. It's slower but works, just keep the master cylinder full...RRear then LRear then RFront then LFront.

[old_master]

The pistons just push back in, however, they WILL bind in the bore. It can happen right away, or it may take a week or so, but they WILL bind. Also, the caliper guide pins seize in the mounting brackets. When doing rear disc brakes on S&T series, replace the entire assembly. Most auto parts stores carry remanufactured loaded calipers with all of the hardware, the pads and the mounting brackets. Do yourself a favor and do the job right, once, and be done.

Bleeding ABS brakes requires a scan tool to bleed ONLY if the master cylinder runs dry.

[Chris Stewart]

Wow, sounds like you've been down that rocky road a few times OM...can ya'll guess what I'll do when the daughter's S10 needs rear discs done? :>]


Just thinking about the brakes just becoming spongy...it's possible the master cylinder may have a seal starting to leak. Taking it loose from the brake booster can confirm fluid leakage without taking any brake lines loose.
If it's dry AND the reservoir is full then a rubber brake line may be letting go. Check each one by removing a wheel 1 at a time and have someone gently apply some brakes while you watch for the rubber line swell.

Another trick is very gently apply some brakes while the engine is idling.
If it slowly goes to the floor, the master cylinder is shot and needs replacing.

[old_master]

Hi Chris,
Yes, been down that road, several times. I always give my customers the option of doing a good job, or doing it the right way. They always end up doing it the right way... some people are slow learners and have to come back to complete the "lesson" though.