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Technical Area => Questions and Answers => MK II B roadsters ('67 to '74 1/2) => Topic started by: 1972MGB on October 20, 2007, 09:20:46 PM

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Title: 1972 MGB Brakes
Post by: 1972MGB on October 20, 2007, 09:20:46 PM
I've disassembled my front caliper assembly and when I put it back together, my brake pads have locked onto the disc.  All the manuals I have say the will "self adjust"....but I'm concerned they are generating a lot of heat and are wearing down my pads since they don't seem to back off the disc.  Anyone got a suggestion?
Title: Re: 1972 MGB Brakes
Post by: Art on October 23, 2007, 05:17:27 AM
The new pads can be tight, especially if combined with new rotors, but too tight will glaze the pads and cut the rotors. The brakes may even pull unevenly as a result. 

A common cause of this is the piston freezing in caliper and not being able to retract, so holds the pad against the rotor. Worm bores or pistons can cause this.  The pistons also need to be installed in the proper orientation - the cutaway section facing the hub.  If you reuse the same pistons when you put the calipers back together, you have to make sure the pistons and bores are not pitted or worn and that the seals fit properly or they will cock and jam.  Did you hone the caliper bores and thoroughly clean all the parts with solvent and then lube all seals and parts per the manual before reassembling?

What eever was done, my suggestion at this point would be to remove the pads and calipers (one side at a time to avoid popping the pistons) and use a C clamp to see if the piston retracts easily.  If it does not move or offers resistance, you may have to rebuild the calipers again, possibly sending them out to  a specialty shop, like Apple Hydraulics, for sleeving.  I hope that helps you.  Let me know what you find.  Good luck.   Art
Title: Re: 1972 MGB Brakes
Post by: Kimberly on October 28, 2008, 02:20:41 AM
I've disassembled my front caliper assembly and when I put it back together, my brake pads have locked onto the disc.  All the manuals I have say the will "self adjust"....but I'm concerned they are generating a lot of heat and are wearing down my pads since they don't seem to back off the disc.  Anyone got a suggestion?

Did you replace the rubber brake lines?  Rubber brake lines deteriorate internally and act like check valves preventing the flow of brake fluid back to the master cylinder causing the caliper to stick or lockup.

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