Why do my brakes pull when hot?

[BJM]

I just replaced both factory original rotors the other week because one cracked. I bought these new ceramic based pads to go with the new rotors. They stopped amazingly well right out of the box. These pads are amazing but I am worried they are too much for the brakes. In the past the standard parts counter pads would fade after a couple of stops.

I thought I should bed them in so I started doing hard stops followed by a short cool-down time and repeating. All of a sudden the car started pulling wildly to the left. After cooling over night it felt fine but acted up after some hard stops again. So I replaced the right hand caliper (they were both replaced 2 years ago). After warming up the brakes again it started pulling to the left again but not as badly so I replaced the left caliper too.

Now I get the same pulling but it can change from side to side after cooling down completely. In normal driving I can get one or two hards stops that feel fine before this starts to happen. These pads have no fade at all which I'm not used to. Am I seizing up the calipers when hot or am I boiling fluid? I am using DOT 3 fluid good to 425F which I am thinking may be the problem.

Any brake experts have an opinion? Should I be changing over to something better?

 

[Gbodynutt]

When you bleed the brakes after you replaced the calipers did the fluid flow out pretty good or was it kind of slow? Something you might try is after you get them hot and it starts pulling is jack the front end up and try spinning the wheels and see how much drag is on them, you may have a restriction in one of the hoses. Also did you clean all the contact patches on the spindal were the caliper rides and use a good brake lube for those areas?

 

[BJM]

Thanks for replying. I cleaned everything thoroughly, the calipers are fresh rebuilds. I had to bleed them alone but I rigged a hose to a vacuum pump and was able to watch the fluid drop in the master cylinder. Both sides seemed to be about the same. When the pulling starts, its only when the brakes are applied. There is no residual pull once the pedal is released. I have not actually lift the tires and spun them though.

Do brake lines clog up ever? I have never heard of anyone changing a line other than because it was rusted or damaged.

 

[turbofrank]

When the hoses age they tend to collapse on the inside. This
can cause the brakes to grab evenually until they won't release.

 

[87natl]

You beat me to it Frank. Notorious problem.

 

[Gbodynutt]

Like the others have said yes they can get blockages or collapse on the inside.

 

[BJM]

Let me make sure I know what you are saying. I am going by the terms in the manual, the pipes are the hard steel lines and the hoses are the flexible lines at each front wheel. Correct? I hate messing with flared lines. Is there ever a need to change the steel pipes?

 

[87natl]

The metal lines are far less likely to be your problem. When they corrode to the point that they are a problem, they will usually begin to leak.

The hoses should be easily replaceable by themselves.

 

[Slow91z]

I'd definitely think hoses could be the problem...My old truck did the same thing, but when I changed mine I couldn't get the hoses loose from the steel lines so I had to change both at the same time.

 

[BJM]

I think I figured it out. I went lapping yesterday. After a couple of laps the brakes started fading so I pulled in and let them cool down. Next time out they were fine and never faded. I think they pulling was an overheat of the pad during breakin. I think my track runs worked them in in short order.

Check out this turn I am doing about 65 mph here.