Excessive rotor heat - Ford Mustang Forum
 
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post #1 of 6 (permalink) Old 2 Weeks Ago Thread Starter
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Excessive rotor heat

I have a 2000 mustang. The other day the front right brake began to smoke, so I got home and pulled the wheel and checked it out. I greased the slide pins and put it back together and it was fine for about a week and then started doing it again.
This time I replaced the caliper, brakes, and guide pins figuring that would certainly fix it. Got it all done and test drove it only to find out the rotor was almost twice as hot as the other side when I parked it (over 400*)!
Any idea what it could be? I also noticed after new caliper was on, that it was very hard to spin the rotor by hand (almost impossible). I know that can't be right. So what is wrong?

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post #2 of 6 (permalink) Old 2 Weeks Ago
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It sounds like you have a flexible brake line that is keeping pressure on the caliper pistons.

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post #3 of 6 (permalink) Old 2 Weeks Ago
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You might have better luck getting an answer if you get the moderator of this forum to move your thread to the 4.6 "1996-2004" forum,since this is the "1979-1995" forum.Since you're already here though,did you try spinning the rotor without the caliper installed?? Maybe its not the caliper sticking thats causing the binding and subsequent heat.I would remove the wheel and caliper, reinstall a couple lug nuts to hold the rotor in place then try spinning the rotor to see if it spins freely or not.If it doesn't,the bearing hub assembly is the source of the binding and subsequent heat and will need to be replaced.If it does spin freely,you could have got a defective caliper,if its a remanufactured unit.However,I have read numerous threads related to your symptoms that stated a couple possible causes.One- installing the pads on the wrong side,Two- a internally damaged brake line.From age and/
or prior brake work where the owner twisted
or kinked the brake line or allowed the caliper to hang by the brake line instead of using a ziptie or wire to hang it.This couldve damaged the line internally,which couldn't be seen from the outside.When it occurs,there is plenty of fluid pressure through the line (when the brake pedal is down) to make it past the damaged section of the line,but when the pedal is released,the pressure isnt high enough to make it back through the damaged section,so this keeps the caliper pistons from releasing properly and the brakes drag or lock up completely.One test that was mentioned was to jack the front of the car up,so that both wheels are off the ground,spin both wheels to make sure they spin freely,then press the brake pedal a few times,release then try spinning both wheels again.If the wheel you're not having trouble with spins freely,but the trouble wheel is locked up or dragging,wait awhile then check the wheel again and see if it spins freely again.If it is spinning now,thats usually an indication the line may be damaged internally,because over time the pressure/
fluid will gradually work its way past the damaged section of line and back towards the master cylinder and the caliper pistons will compress back into their normal position,releasing the pads from the rotor.If your test shows the results above,replace the brake line,preferably with a stainless replacement that youll never have to worry about again.

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post #4 of 6 (permalink) Old 2 Weeks Ago Thread Starter
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Quote:
Originally Posted by wbrockstar View Post
You might have better luck getting an answer if you get the moderator of this forum to move your thread to the 4.6 "1996-2004" forum,since this is the "1979-1995" forum.Since you're already here though,did you try spinning the rotor without the caliper installed?? Maybe its not the caliper sticking thats causing the binding and subsequent heat.I would remove the wheel and caliper, reinstall a couple lug nuts to hold the rotor in place then try spinning the rotor to see if it spins freely or not.If it doesn't,the bearing hub assembly is the source of the binding and subsequent heat and will need to be replaced.If it does spin freely,you could have got a defective caliper,if its a remanufactured unit.However,I have read numerous threads related to your symptoms that stated a couple possible causes.One- installing the pads on the wrong side,Two- a internally damaged brake line.From age and/
or prior brake work where the owner twisted
or kinked the brake line or allowed the caliper to hang by the brake line instead of using a ziptie or wire to hang it.This couldve damaged the line internally,which couldn't be seen from the outside.When it occurs,there is plenty of fluid pressure through the line (when the brake pedal is down) to make it past the damaged section of the line,but when the pedal is released,the pressure isnt high enough to make it back through the damaged section,so this keeps the caliper pistons from releasing properly and the brakes drag or lock up completely.One test that was mentioned was to jack the front of the car up,so that both wheels are off the ground,spin both wheels to make sure they spin freely,then press the brake pedal a few times,release then try spinning both wheels again.If the wheel you're not having trouble with spins freely,but the trouble wheel is locked up or dragging,wait awhile then check the wheel again and see if it spins freely again.If it is spinning now,thats usually an indication the line may be damaged internally,because over time the pressure/
fluid will gradually work its way past the damaged section of line and back towards the master cylinder and the caliper pistons will compress back into their normal position,releasing the pads from the rotor.If your test shows the results above,replace the brake line,preferably with a stainless replacement that youll never have to worry about again.
Thanks for the info! The rotor does spin freely without the caliper mounted. Once the caliper is mounted, it's almost impossible to spin by hand. I'm beginning to think it's the brake line because for one, I've had the car for 8 years now and never replaced the lines and I don't know when the last owner did, if ever. Plus, I may have twisted the line the last time I replaced the pads thinking nothing of it. Caliper may have accidentally fallen while working on the pads too. The combination of age and carelessness is most likely the cause. Anyhow, it's going to the shop on friday. I'm going let someone else figure it out for me. If it is the line that's bad, I'll tell them to replace the other side as well. If I knew for SURE it was the line, I would buy the stainless steel ones and have them put them on but I don't know exactly what the problem is. Like you said earlier, it could be the hub assembly too but I don't recall hearing any noises from it when spinning the rotor though.... I'll let you know Friday what the problem was.
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post #5 of 6 (permalink) Old 2 Weeks Ago Thread Starter
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So, I took the car to the shop today and told them what the problem was. The mechanic said it could be a bad brake hose. I said well if that's the case go ahead and replace both sides then. An hour later he comes out and says he put ONE new brake line on and said the rotor still seems to be getting hot after he test drove it but said it should be "ok" because it doesn't pull to one side during braking. He never pulled either of the calipers off to inspect anything like I assumed he would. He went on to say it could be a bad caliper I bought.

So, I spent $101 dollars for them to install ONE brake hose and still have the same problem! He said it could also be brake fluid burning off that I smell. (********). I drove home, got out my infrared temp gun and pointed at the bad side and it read 450*, compared to 200* on the other side. I'm sorry but I don't think that's right. WHat should I do now? Buy another caliper from somewhere else?
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post #6 of 6 (permalink) Old 2 Weeks Ago
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I moved the thread to the proper forum.

Unfortunately I am not familiar with the 2000 Brake System but it sounds like your dragging front brake is fluid is not returning to the master cylinder. You already replaced the suspect components such as the caliper and greasing the pins and installing new pads.

The brake line was also replaced and the rotor spins freely without the caliper installed but is it warped? Check that. In fact swap the front rotors and see if that changes anything. Are there any kinks in the tubing?

In any case what I recommend is perform a complete flush of the brake system into a clean container for each wheel and then screen the 4 containers you purged through a coffee filter and see what debris flushed out each cylinder. Get a friend to help and take your time.

When I said I am not familiar with the 2000 brake system what I mean is I don't know if your master cylinder has individual ports going to each brake caliper, or if you have 2 ports feeding front and rear with a proportioning block splitting off to the respective left and right calipers. But what you have is a 19 year old master cylinder that may have the rubber seals deteriorating inside.

If all other actions do not correct the hanging brake I would replace the master. They run about $80 - 90 with the reservoir attached. The downside it you will need to bleed the system again.

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