Seized caliper piston?
Discussion
Hoping some of you grease monkeys can help, on my 2004 mk2.5 mx5 I noticed a grinding/ rubbing noise coming from my passenger rear corner. It sounded like something caught in the wheel or rubbing on the disc.
Upon inspection the disc wasn't to healthy and the pads were getting towards wanting changing so decided to kill 2 birds etc. I've stripped of the caliper, pads and disc ready for new.
Now here is the problem, I now cannot return the piston in order for the caliper to fit over the new pads. I now think the grinding / rubbing was the pads not fully releasing from the disc. I have tried using the correct piston compressor, I have taken the cap of the expansion tank and still FA movement. Is this a new caliper or am I missing something. Any DIY hacks / cheats would be great as I am trying to spend as little as possible. Thanks for your time and any help I receive.
Upon inspection the disc wasn't to healthy and the pads were getting towards wanting changing so decided to kill 2 birds etc. I've stripped of the caliper, pads and disc ready for new.
Now here is the problem, I now cannot return the piston in order for the caliper to fit over the new pads. I now think the grinding / rubbing was the pads not fully releasing from the disc. I have tried using the correct piston compressor, I have taken the cap of the expansion tank and still FA movement. Is this a new caliper or am I missing something. Any DIY hacks / cheats would be great as I am trying to spend as little as possible. Thanks for your time and any help I receive.
You need to wind the piston in. There should be a 14mm bolt on the back of the caliper, removed it and you'll find a 4 or 6mm internal hex screw, use it to retract the caliper. When all set, adjust the handbrake using the same screw: screw in until pads fully grip the disc, then back off half to 2/3 a turn.
Yes I used the correct piston compressor, the piston wasnt moving because I'm fick and hadn't undone the allen screw on the back of the caliper 
However I have now put on the new pads and disc and a new problem has arisen. When I try to slide the caliper back over the new pads the rear pad clears easily with the piston pushed back in, the problem is the 2 forks on the front of the caliper are catching on the front pad.
I can force it over but it then makes the front pad Bind on the disc. I'm not sure what is causing the problem. It is like the pad is to thick but I'm sure that isn't the case. Once again if someone can point me in the right direction it would be greatly appreciated as I am trying to get the car ready to sell.
Time is of the essence as my tax and insurance run out on this car at the end of the month so after that I can't use it. I do have another car but I really want to get this sorted pronto without paying someone else to do it. Thanks for any help that I receive.
However I have now put on the new pads and disc and a new problem has arisen. When I try to slide the caliper back over the new pads the rear pad clears easily with the piston pushed back in, the problem is the 2 forks on the front of the caliper are catching on the front pad.
I can force it over but it then makes the front pad Bind on the disc. I'm not sure what is causing the problem. It is like the pad is to thick but I'm sure that isn't the case. Once again if someone can point me in the right direction it would be greatly appreciated as I am trying to get the car ready to sell.
Time is of the essence as my tax and insurance run out on this car at the end of the month so after that I can't use it. I do have another car but I really want to get this sorted pronto without paying someone else to do it. Thanks for any help that I receive.
Berkshire bred said:
However I have now put on the new pads and disc and a new problem has arisen. When I try to slide the caliper back over the new pads the rear pad clears easily with the piston pushed back in, the problem is the 2 forks on the front of the caliper are catching on the front pad.
I can force it over but it then makes the front pad Bind on the disc. I'm not sure what is causing the problem. It is like the pad is to thick but I'm sure that isn't the case. Once again if someone can point me in the right direction it would be greatly appreciated as I am trying to get the car ready to sell.
Do the pads move nice and freely within the carriers? If you had to force them in then, then remove the sprung metal shims that the "ears" on the pad locate into, and remove every trace of corrosion from the carrier before refitting.I can force it over but it then makes the front pad Bind on the disc. I'm not sure what is causing the problem. It is like the pad is to thick but I'm sure that isn't the case. Once again if someone can point me in the right direction it would be greatly appreciated as I am trying to get the car ready to sell.
How bad is the binding, can you still turn the disc by hand?
I'm not keen to replace both rear calipers at the moment as like I say I just want it safe to sell without spending cash that wont increase the sale price. If I was keeping the car I probably wouldn't hesitate to replace them.
The binding is quite bad, I can just about move the disc. With the wheel on it turns easier but that is just down to more leverage. I wouldn't be happy to drive it any sort of distance at the moment.
The binding is quite bad, I can just about move the disc. With the wheel on it turns easier but that is just down to more leverage. I wouldn't be happy to drive it any sort of distance at the moment.
IF everything else is OK - piston pushed fully back, pads moving freely in the carriers, handbrake set properly, etc, it may be that the pads or the discs are slightly too thick.
If they are aftermarket components they may well not have been made from the manufacturers' drawings, so a little bit of guesswork has been used to determine the correct dimensions. Anti-squeal palliatives such as shims can add thickness - they may be used on aftermarket pads where they weren't used on OE.
As I said, IF everything else is OK, just lay a piece of abrasive paper on a flat surface & rub one of the pads on it to take a small amount off the friction face until it will fit without causing the brake to bind.
If they are aftermarket components they may well not have been made from the manufacturers' drawings, so a little bit of guesswork has been used to determine the correct dimensions. Anti-squeal palliatives such as shims can add thickness - they may be used on aftermarket pads where they weren't used on OE.
As I said, IF everything else is OK, just lay a piece of abrasive paper on a flat surface & rub one of the pads on it to take a small amount off the friction face until it will fit without causing the brake to bind.
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