Ive got stock cobra brakes on my car, they stop great, but with the car in the air the wheel will only rotate 1/2 when you spin it. I too the caliper off and the wheel spins free, so it has to be in the caliper setup. I changed pads and lubed where the pads ride on the caliper bracket. My car is 80% track, drag, and this is slowing me down if the wheel wont spin free. I did a search and found nothing. Thanks.
Stock brake problem/ question
- Thread starter Naste95
- Start date
Calipers are hanging without a doubt. If its the fronts the pistons could be ceased, if the rears could be the same problem but try greasing the pins for the rear if thats where it is.
Bottom line replace calipers and you will have no issues especially if it the fronts
Bottom line replace calipers and you will have no issues especially if it the fronts
could be quite a few things. frozen slides so the caliper cannot move freely, bad brake hose, warped rotor, or the caliper could just be gone. there are many things you could eliminate as suspects before jumping right into buying a caliper. tough to explain these things over the internet but if i were there i could diagnose it in about 10mins.
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Ive got braided hoses, the wheel does shake when I stop, so the rotors aren't wraped, and I anti-seized the pins. The brakes are only 5-6 years old, and my car is a toy, doesnt get drove in the weather at all.
then take caliper off and try to compress the piston. if you cant get it try opening the bleeder and compressing. if it still wont go you need a new caliper.
Warped rotors will not cause this problem. They will make an intermitent scraping sounds as the high spots rub. Cobra front brakes really do not slide like other standard calipers because of the quick change setup we have from the factory. Its actually the pads that slide vs pins in a traditional setup. The pins not being greased will not cause that much resistance with our setup.
You say your brakes still work so you know its not the lines. If your running reman calipers they probably are the suspects.
You say your brakes still work so you know its not the lines. If your running reman calipers they probably are the suspects.
Warped rotor
5-6 years old? Your rotors are done.
80% track? Your rotors are done.
Look at it whis way.
When you have your rotors within an enclosed space of (hypothetically) 1mm open space on each side of the rotor.
When you spin the rotor and it stops,
A) Did the pads magically move by themselves and close the space on one side?
or
B) Did the rotor have a high spot that caused it to fill that 1mm space and come to a stop?
The answer is B)
Your rotors are warped.
You are correct but warped rotors would not stop the wheel after on 1/2 rotation. Plus you will be able to hear the pads hitting the high spot on the rotos when you spin it. It takes a significant amount of force to stop the entire wheel after only 1/2 rotation there no way in hell a warped rotors will do that. If your tracking your car i am sure the rotors are warped but that is not the only culprit in this situation the caliper is definetly hanging which is why the wheel only goes 1/2 rotation when you spin it.
Think about how ungodly warped your rotor would have to be to stop the wheel that quickly it just doesnt make sense.
Think about how ungodly warped your rotor would have to be to stop the wheel that quickly it just doesnt make sense.
Your advice is wrong.
This should have been all the clue you need:
That is a classic #1 case of warped rotors.
Not to sound dumb, but the pads should have slight contact with the rotors at all times. Not a lot, but if the pads were to fully lose contact then the pedal would feel like mush. But given the facts at hand, I'd say warped rotor as well.
thats kind of what it sound like. usually if a caliper is stuck the wheel wont move at all or it will be tough to move. it wont turn halfway then lock up. rotors can disort alot and bend out of shape enough to cause this.
Think what you want warped rotors will not prevent the wheel from stopping after 1/2 rotation under ANY condition. Yes the steering wheel shakes which means the rotors are warped you are a master tech actually not really.
READ THE POST
He wants to know why the wheel wont spin freely not why the wheel shakes. Warped rotors will slow the movement of the wheel if you spin it while in the air when the pad hits the high spots but it will not abruptly stop it after only 1/2 turn. 5+ years on rotors i am sure they are warped under even normal driving.
This means theres a bad caliper or incorrect adjustment in the front brake setup. If he had just put on all new stuff and this problem came about then i would say its bad adjustment/installed incorrectly. Otherwise from the way it is described the caliper is most likely bad. Is the warped rotor contributing to this problem absolutely but it is not the cause.
READ THE POST
He wants to know why the wheel wont spin freely not why the wheel shakes. Warped rotors will slow the movement of the wheel if you spin it while in the air when the pad hits the high spots but it will not abruptly stop it after only 1/2 turn. 5+ years on rotors i am sure they are warped under even normal driving.
This means theres a bad caliper or incorrect adjustment in the front brake setup. If he had just put on all new stuff and this problem came about then i would say its bad adjustment/installed incorrectly. Otherwise from the way it is described the caliper is most likely bad. Is the warped rotor contributing to this problem absolutely but it is not the cause.
if the caliper is seized with pressure against the rotor how are you going to spin the wheel at all? your not.
Calipers can be seized at any point in the piston bore which will not allow them to retract in as far as they should. The piston can still push outward but when it tries to retract when the pressure is reduced it is not possible. This will cause constant pressure (the amount will vary depending on the severity of the problem) on the brake rotors which will prevent the wheel from turning freely.
I have rebuilt at least 50 pairs of calipers and i have seen this happen under high heat conditions(BTW Road Racing fits in this category). The piston bore warps and it will not let the piston fully retract which causes what they call a hanging caliper and in turn prevents the wheels from moving freely.
I know he said the steering wheel shakes which you are correct in saying the rotors are bad but thats about as much depth as your haynes manual gave you so you dont know any better. Take it from someone who has the experience and has been there if you are road racing with 15 year old calipers and facing these problems the chances are that you messed the piston up and thats why he is fighting the wheel.
I'd be willing to bet the car is also slightly pulling to one side.
I have rebuilt at least 50 pairs of calipers and i have seen this happen under high heat conditions(BTW Road Racing fits in this category). The piston bore warps and it will not let the piston fully retract which causes what they call a hanging caliper and in turn prevents the wheels from moving freely.
I know he said the steering wheel shakes which you are correct in saying the rotors are bad but thats about as much depth as your haynes manual gave you so you dont know any better. Take it from someone who has the experience and has been there if you are road racing with 15 year old calipers and facing these problems the chances are that you messed the piston up and thats why he is fighting the wheel.
I'd be willing to bet the car is also slightly pulling to one side.
i do have the experience. i do quite a few brake jobs everyday and the only way to tell for sure is to pull the caliper off and try to compress it. if it compresses no problem everything is fine, if it only compresses with the bleeder open its usually the brake hose, if it doesnt compress at all its the piston. ive never seen a wheel spin freely then lock up due to a bad caliper unless its a combination of both severly warped rotors and a bad caliper.
I'm having the same problem. When the car was newer I could spin that tire around and it would not stop for a long time. The last 5 years I'm lucky if I get 1 revolution with a push and at a full force spin 3 times max. Last year I did new brembo rotors and pads and still have the same problem. I used caliper grease every where you would need it. I have been doing brakes since I was 12 years old. I'm now 45.
I have no problems with shake when the brakes are applied. My lines are stock and the calipers are stock.42000 fair weather miles.
PLEASE IF YOU FIGURE THIS OUT FOLLOW UP WITH THIS THREAD!!!!!!thank you.
I have no problems with shake when the brakes are applied. My lines are stock and the calipers are stock.42000 fair weather miles.
PLEASE IF YOU FIGURE THIS OUT FOLLOW UP WITH THIS THREAD!!!!!!thank you.
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Do the brake pads scrape against the rotors pretty firmly? if so, then your caliper's pistons might not be retracting/alleviating and the pistons may need servicing.
If the pads do not scrape with much resistance, then your hub/spindles will need to come off and either need greasing or you may need new bearings/hubs.
you don't want the wheel to be able to spin freely like that anyways. it should only spin around a couple times and then stop if it has the correct amount of pad pressure against the rotor.
Steering wheel shake = warped rotor.
The rotors are relatively inexpensive and they crack and warp under track conditions.
Tom
The rotors are relatively inexpensive and they crack and warp under track conditions.
Tom
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