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MG MGB Technical - locking caliper

The left front caliper on my 71 b locks up for no reason i can see. i don't drive it as much as i would like so i thought this might be a problem? i don't see a ring of rust on the piston. what else could it be? open for sug. Thanks, Don
dab donald a baker

As suggested elsewhere open the bleed nipple. If you get a spurt of fluid, or if you don't but the caliper releases anyway, then there is a blockage in that line. When this happens it is usually the flex hose which can develop flaps which act as one-way valves. Personally before shelling-out for new flex hoses I'd slacken the joint to the fixed line as well, and if that release the caliper as well then the problem isn't in the flex hose but in the line back towards the junction of the lines from the two calipers, but then I'm tight.

If it doesn't release the caliper then the problem is in the caliper itself. If you get unbalanced braking as well i.e. pulling to one side then it probably is the caliper. I have cleared this by removing the pads and working the pistons back and fore a few times, wrapping cord around the extended piston and pulling back and fore to polish them, but that was for someone who was even tighter than me.

Paul Hunt

Thanks Paul, i already replaced the caliper with one of the spares i have. it seams to work ok. i havent been on the road with it yet just drove it back and forth in the driveway. like i said it would do it only once in a while. Thanks again, Don Baker
dab donald a baker

I had this problem myself especially with infrequent use. Almost invariably the problem will be a partially seized piston. You may be able to free it off by taking out the pads and turning the piston to free it.Better to have a specialist refurbish both calipers butt even better to fit the Frontline 4-pot conversion along with ventilated discs. An excellent conversion
R.W. Homer

A routine of mine is whenever I get into any of my cars I always operate the brake and clutch pedal a number of times even if not running the engine. It's good practice to get into this habit. I have not had any issues with frozen calipers or cylinders.
Mike
MK Mike

I fixed mine permantley with stainless pistons. I got them from the MGOC.
Stan Best

Same problem with me, but i went to my local Advance Auto Parts store, and had a reconditioned one in my hand in 2 days for well under $50. Not worth the hassle of trying to repair it.
Gerry

' I have cleared this by removing the pads and working the pistons back and fore a few times, wrapping cord around the extended piston and pulling back and fore to polish them, but that was for someone who was even tighter than me.'

That made me laugh - I did this less than a year ago to my car, it was eating pads on one side of a caliper. I only just looked up the price of a new caliper - you are right Paul, this indeed does make me feel a bit tight given they are so cheap - but hey, it worked!
Still laughing over your description - wife agrees with you.......
mick

This thread was discussed between 20/03/2009 and 17/04/2009

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