Broken brakes?

[geebeemer]

The patient is a '97 S-10, 6 banger, ABS with 113k. When wet out, or early in the drive time, if I just press on the brakes I hear a funky squishy sound and one of the front calipers will hold, locking up, while the other is free to roll. Double pump it and both lock normally.

A genuine pita in traffic - but once she's warmed up, seems to do better.

My guess is I've got a master cylinder to replace this weekend, but I'm concerned that's a waste of cash if there's some secondary distribution block on the fritz, given the ABS setup.

Wutcha think?

[FC]

Could be that the calipers need to be re-built. That seems to happen more often than master cylinder failures. Ask Zach.

[zach]

Originally Posted by FC

Could be that the calipers need to be re-built. That seems to happen more often than master cylinder failures. Ask Zach.

Yes, all of my calipers have been replaced at least once, several of them twice over the last 6 or so years.

That said, pumping the brakes never did anything when my calipers were bad.

[geebeemer]

Hm, any outward indication on bad calipers? From a visual inspection there's no bluing of the rotors or grooving at all. And the brakes generally work fine on the 2nd pump.

Wish I could "write out" the sound!

[FC]

Originally Posted by geebeemer

Hm, any outward indication on bad calipers? From a visual inspection there's no bluing of the rotors or grooving at all. And the brakes generally work fine on the 2nd pump.

Wish I could "write out" the sound!

I skimmed and missed the 2nd pump thing. Yeah, I would say it does sound like the cylinder. I can't think of anything else right now.

[geebeemer]

Cool - thx guys!

Does this mean I should've posted this in the perseverators forum?

[Nick M3]

I guess I would want to know how the car is plumbed before I said "master cylinder." I mean, if the calipers are on the same cylinder (which they typically are), then I'm ambivalent about it.

Have you tried flushing the fluid out? It kind of sounds more like you've got either a blockage, or a big air bubble.

[geebeemer]

Comes out of the master cyl and goes straight into a rather complex assembly that must be the ABS - certainly not just your typ distribution block.

Wires & connectors, brake input/output lines, etc., comprise this secondary assembly - but the front and rear lines out of the master go into their own inputs on this secondary. *Looks* as though I'd be able to bleed them normally as it appears these are only balancing check valves of some sort - though likely will require the car to be running to work properly.

Will try for the purge and bleed option first - if nothing else, this will put new juice in the lines.

[misterlance]

Originally Posted by geebeemer

The patient is a '97 S-10, 6 banger, ABS with 113k. When wet out, or early in the drive time, if I just press on the brakes I hear a funky squishy sound and one of the front calipers will hold, locking up, while the other is free to roll. Double pump it and both lock normally.

A genuine pita in traffic - but once she's warmed up, seems to do better.

My guess is I've got a master cylinder to replace this weekend, but I'm concerned that's a waste of cash if there's some secondary distribution block on the fritz, given the ABS setup.

Wutcha think?

Sounds like you have a leak. Check the rear wheel cylinders on the drum brakes.

[geebeemer]

Originally Posted by misterlance

Sounds like you have a leak. Check the rear wheel cylinders on the drum brakes.

Well, the truck has had the issue as long as I've had it (8 months) - but will check for bloody kankles when I get home.