1999 Corolla - Brakes Locking Up

[StephanieMitchell]

My brakes were fading, pedal going right to the floor.

Fine. Had a friend install an aftermarket master cylinder. Problem solved.

BUT... the brakes for all wheels except the front driver side would "lock up" somewhat and get hot while driving.

Slightly cracking open one of the lines coming off the master cyl would relieve the pressure for a while. After 30 minutes more driving, another mini-bleed would be required.

Checked the adjustment at the top of the pedal.

Replaced the aftermarket master cyl with a used one from a car with 80,000 km. NOW ONLY THE FRONT LEFT WHEEL LOCKS UP AND GETS HOT. Mini-bleeding it's line (the "front" one) helps for 30 minutes.

It is the weirdest thing I've ever seen.

Any suggestions?

My "backyard mechanic" brother says he is stumped.

 

[Donabed Kopoian]

First, do NOT bleed the brakes off lines connecting to the master cylinder, ever.

My first question is, do you have ABS?

If you have ABS, there may be air in the unit and the brakes will need to be power bled.

If you do not have ABS, bleed the brakes at the calipers starting from the shortest line and progressing to the longest line, make sure all air is removed.

If calipers are still sticking ... either the caliper itself is defective, or the brake master cylinder return spring is sticking.

Was the aftermarket cylinder a remanufactured unit? I often have seen remans that were DOA, so it wouldn't surprise me if it was defective and is causing the issue.

Also, check the front left caliper ... that one may be sticking.

 

[StephanieMitchell]

First, do NOT bleed the brakes off lines connecting to the master cylinder, ever.

My first question is, do you have ABS?

If you have ABS, there may be air in the unit and the brakes will need to be power bled.

If you do not have ABS, bleed the brakes at the calipers starting from the shortest line and progressing to the longest line, make sure all air is removed.

If calipers are still sticking ... either the caliper itself is defective, or the brake master cylinder return spring is sticking.

Was the aftermarket cylinder a remanufactured unit? I often have seen remans that were DOA, so it wouldn't surprise me if it was defective and is causing the issue.

Also, check the front left caliper ... that one may be sticking.

Sorry so slow to get back to you. And thanks for the detailed reply.

No ABS.

The brakes have been properly bled several times.

I should not have called it "bleeding" the brakes at the master cylinder, I should have called it "relieving the pressure" or something. Basically it is the technique I use to unlock the brake calipers so I can get home without having to smell cooking brake pads all the way home. :^)

Both front calipers and pads are only a few months old and when my mechanic friend pulled them off to take a look, they seemed to move smoothly and still looked quite new overall.

The first replacement master cylinder was an aftermarket unit from a local auto parts store. I blamed that master cylinder until I got a used OEM from a salvage yard and continued to have similar problems (ie, now its only the front left one sticking on).

The brake fluid in the car is pretty old, and I hear that it can pick up water. The brakes were bled, but we kept filling the reservoir with fluid from the same bottle of brake fluid we've had around here for several years.

So I am hoping that changing the brake fluid will help, but I doubt it, since the problem moved from 3 wheels to the other wheel (left front) when the master cylinder was replaced the second time. If the fluid quality was significant, I don't think the problem would "move" when the cylinder was replaced.

Thanks again for your reply!

 

[Donabed Kopoian]

I'd spend the money and get a new master cylinder. Sounds like the one you got from the junkyard has sat for a while and probably started to collect rust in the system.

And yeah, with brake fluid, mark the date that you opened the bottle on the cap. If it is more than a year old, chuck it and get another bottle. Old fluid will cause a spongy petal, but it won't make things stick unless it becomes so saturated with water, that components start to rust.