Brake Problems

[Markb873]

Hello,

Got a '93 s10 blazer with the 4w abs. I am having two problems. My right front has developed a pounding in the wheel area when the brakes are applied I can sort of feel it in the pedal but more or less hear it. (It makes the dash and the door rattle.) New rotors with some improvement. Checking a few days later everything was still tight. The strange thing is occasionally it won't do it.

The second problem is slow pedal return. At night I can take my foot off the pedal look up in the mirror and watch the brake lights turn off. Their is vacuum going to the booster and the pedal seems to operate normal otherwise. I've seen with the hydro-assist systems a hydrolic problem in the booster cause the pedal to slowly rise but can a bad "basic" booster cause similar symptoms?

-Mark

[mike2004tct]

Originally Posted by Markb873

Hello,

Got a '93 s10 blazer with the 4w abs. I am having two problems. My right front has developed a pounding in the wheel area when the brakes are applied I can sort of feel it in the pedal but more or less hear it. (It makes the dash and the door rattle.) New rotors with some improvement. Checking a few days later everything was still tight. The strange thing is occasionally it won't do it.

The second problem is slow pedal return. At night I can take my foot off the pedal look up in the mirror and watch the brake lights turn off. Their is vacuum going to the booster and the pedal seems to operate normal otherwise. I've seen with the hydro-assist systems a hydrolic problem in the booster cause the pedal to slowly rise but can a bad "basic" booster cause similar symptoms?

-Mark

The booster is vacuum operated, and mainly used for applying pressure, not releasing.

I'd venture a guess as to a gummed up master cylinder. The spring inside the cylinder causes the pressure release to be slow (in your case). This might also be causing the pounding sound you hear. I'd also say, that if the master cylinder is gunked up, it's a pretty good chance that the calipers are also gunked with crud in the brake lines.

Check the fluid in the master. Is it black and grainy?

[Markb873]

Yeah, the brake fluid must be original. It looks like motor oil well past the change interval. I'm assuming everything has to be dismantled to clean it out right? I just can't run a bunch of fluid through the system correct?

[mike2004tct]

Originally Posted by Markb873

Yeah, the brake fluid must be original. It looks like motor oil well past the change interval. I'm assuming everything has to be dismantled to clean it out right? I just can't run a bunch of fluid through the system correct?

You probably could clean it out. . First, cyphon out the master, then fill with new fluid. Starting at the passenger side rear brake cylinder, open the bleeder, and pump the pedal until the master reservoir empties. Close the brake cylinder, then do the same on the driver side rear.
Close that, and move to the front passenger side, and lastly the driver side.

Once cleaned out, fill and bleed the system in the same order as above.
(Always start with the wheel farthest away from master cylinder, and finish up with the closest wheel to the master)

[Markb873]

Well I made it through the rear wheels but the both front bleeders broke off. I said screw it and filled it up and I'll do it again when it warms up. As of now the pedal is normal with the new fluid in the master. The vibration is better but that wheel was never bled so I assume it will go away then.

I will update when the time comes. Thanks again for the advice.

-Mark