Is the brake master bad?

[lostinthe202]

'95 legacy, 240k, 5spd.

 

This is a buddy's car. The front brakes have been dragging and it's kind of stumping me. The front calipers have been replaced, the brake fluid changed. The pins are free moving and the caliper brackets have been cleaned up so the pads move freely. The master cylinder is probably the original, but it does look cleaner then everything else so hard to say. My buddy has only had this car for a year or so and bought it with no maintenance history.

 

The problem is that the front brakes are dragging. Not enough to smoke and only occasionally enough to create a smell that can be detected at a stop with the window open. But after even short drives, both front wheels are borderline hot to the touch.

 

The interesting part, driving down the road the car feels sluggish (like the brakes are dragging...) if I reach down and pull the pedal up with my hand (or my foot) you can feel the brakes ease up and the car will roll like normal. This can be done from a stop on a slight incline, the car won't roll but if you pull up on the brake pedal it will.

 

Does this sound like a sticking master cylinder?

 

Thanks!!

 

Will-

[idosubaru]

i don't think that's the MC.

sounds more like pedal linkage or brake booster to me, but i've never seen that stuff have issues before so not sure what to say. i'd try greasing the pedal pivot point or checking out the rest of the linkage down there.

[lostinthe202]

hmm... alright, I'll give that shot. Thanks Gary

[OB99W]

For the brakes to release, the MC pistons have to come back far enough to uncover the ports. After 240,000 miles, it's possible that the pedal return spring has broken, weakened, etc. It could also be that the fluid got contaminated, causing the MC seals to swell and bind, not allowing the internal return springs to push the pistons back. Sometimes, the push rod is misadjusted.

[Fairtax4me]

I've had brake boosters get water inside and rust a little. Just enough to make the push rod stick.

 

You can grab one from a junk yard pretty easy. The master can be rebuilt pretty easily, but it's up to you if you want to do that much labor. Most people just replace them.

 

Make sure the pivot bushing is in place on the pedal as well as the push rod. Put some grease on them and work it around a couple times and see if that helps before you go ripping the master out.