Master cylinder going bad?

[hemihead2]

<t>I have a recently increasing instance of calipers dragging once they warm up (I.e after a few hard stops). I've replaced all 4 of them so far and have even backed off the parking brake to the point it hardly functions. My problem is that my rear caliper will drag (I.E. The wheel gets hot and I can smell burning) but on a different day a front caliper will do the same thing. They all release given a cooling off period though. None have ever hung up completely- yet. At some point I have to think that the braking system itself is the culprit, no? My truck has 162k on it but I drive it daily and can take it anywhere. I've replaced everything as needed but the master cylinder currently has my attention. Has anyone else experienced this? All the rotors and pads have been replaced over the last 5k miles or so but it continues to jerk to one side or the other with a panic stop. Any ideas? Thanks!</t>

[Colibri]

I had to replace my master cylinder recently for dragging calipers, it’s pretty straight forward. If I remember correctly oem part was around 200 ish maybe? Make sure you bleed the system thoroughly though. And you’ll need to bench bleed the new master cylinder first.

[olyelr]

Have you ever changed/flushed the brake fluid?

[TwinStick]

I had to replace the calipers on mine when that started happening. No more issues. I did the PowerStop one click brake kit. 4 rotors, shiny red calipers & pads all the way around. Expensive but truck stops a LOT better than it did.

[waldo]

Might have a bad flex line on one or more wheels.

[hemihead2]

Bingo! I replaced the R brake hose and it fixed my problem instantly. I finally walked by the truck after I parked it amd heard the caliper releasing slowly and methodically... I'm assuming the master cylinder had pressure to force fluid in but the hose was occluded too much to let the pressure back out and allow the caliper pistons to retract. The inside pad and rotor was all eaten up. Just a FYI for anyone else having the same isssues.

[Bill2014]

Bingo! I replaced the R brake hose and it fixed my problem instantly. I finally walked by the truck after I parked it amd heard the caliper releasing slowly and methodically... I'm assuming the master cylinder had pressure to force fluid in but the hose was occluded too much to let the pressure back out and allow the caliper pistons to retract. The inside pad and rotor was all eaten up. Just a FYI for anyone else having the same isssues.

Waldo previously responded with the Flex hoses and beat me to it so I didn't respond...

Had a high mileage AWD Chevy van that I had a shop replace front rotors, calipers, and pads - with lifetime warranty. They did a fluid flush as part of the deal. After less than 1000 miles, I noticed that it would start to pull to the left as soon as I applied the brakes... After 2000 miles, not only did it pull left when braking, but started to pulse (warped rotor). So i took it back in to the shop and they replaced the driver side rotor and pads under warranty. Again, it worked great for about 1000 miles and then began to pull left again during braking. Soon the drivers side rotor warped and the pulsing started during braking. So back in the shop it went again. They wanted me to be happy, so they pulled the brakes all apart, inspected the calipers, installed all new clips, pads, and rotors on the front. The flex hoses weren't cracked, so they left them alone. Within a month it was pulling to the left during braking. I had one hard stop at a light that turned red and the driver side rotor warped AGAIN. I went back to the shop and told the entire history to one of the old time mechanics and he said "I know exactly what's happening and it's an easy fix."

He said: The flex hose on the passenger side is bad and nearly obstructed. When you push on the brakes, the driver side brake does most of the work to stop you because fluid is very slow to make it to the right wheel caliper. Fluid eventually makes it through the right side flex hose, so it only pulls to the left for 5-10 seconds until the pressure equalizes. Since the front driver wheel is doing most of the braking for you, (the rear brakes never do much by design), that rotor and pad heat up rapidly. This eventually glazes the pads and warps that rotor.

So - they replaced the front driver side pads and rotor and the passenger side flex hose. That solved the brake issues for the rest of it's life.

That one bad flex hose caused them to warranty 3 driver side rotors, 3 driver side sets of pads, 1 passenger rotor, and one passenger set of pads.