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MG MGB Technical - right brake caliper not working

Yikes, the left front locked up! Seams the right front caliper failed to operate and clamp the rotor and the left front did the work of both. Is there a simple way to un-freeze the pistions short of disassembling the caliper?
Geoff Kimler

Open the bleeder nipple on the caliper, if the brake releases you have a brake hose that is deteriorating on the inside blocking the return flow.
John H

John, thanks for the quick reply. Hydraulic pressrue is not getting to the caliper to apply piston. Could there be something wrong at the master cylinder? The car is 1969 with the split system. Maybe the shuttle is frozen only allowing fluid to go to one side.
Geoff

It could be that the hose has collapsed and isn't allowing any fluid through...in either direction.
Dave O'Neill 2

I was thinking from your post that the left was frozen on. If the right isn't working first check to see if at least one of the two pistons moves when the pedal is pressed. If neither moves it is a problem in the hydraulics as it would be rare to have both pistons freeze at once. The split system is split front to rear not left to right. I don't believe the shuttle switch can completely block one line. If the pistons aren't frozen, it has to be in the hose or lines.
John H

Slacken the bleed nipple and see if the pistons will retract, if they do it's more than likely that the flexibles have given up the ghost.
allan

If you can push the pistons back by hand they aren't stuck, then try the pedal and see if either moves. If they don't then it is a problem in the hose or elsewhere in the pipe, slackening the upper hose union and trying again should reveal which. If you get fluid out of the upper union also slacken the lower hose union and see if you can get any fluid out of that, just in case something is blocking the passage in the caliper.
Paul Hunt 2

As others have stated most of the time it is the flexible hoses that fail. They can look perfectly fine on the outside but still be faulty. If this is the problem replace the hoses on BOTH sides while you are at it as the other one will eventually fail also.
Good luck
Mike
MK Mike

This thread was discussed between 11/12/2007 and 14/12/2007

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