suggestions please. I have A mk2 s with a unusually low brake pedal which pumps up hard . Usually indicating brakes needing adjustment. But its the front discs that are pumping up, appears pads retracting back to far i have some theorys but if someone else has already experienced this and rectified it you might save me a lot of time. please help if possible.

may i ask who bleed your brakes because thatsmore than likely the problem just bleed your breakes again and c how it goes because u prop have air in the lines.

I think that Old School would be right with bleeding brakes, he's a mechanic.
My thoughts would be that it could be uneven wear or warped disc's. or a jamed brake piston. if one is stuck then the other has to push out further to compensate.

Cheers

Aaron

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You may also want to check the clevis pin between the master cylinder and pedal for wear, this probably isn't your problem, but it wouldn't help. Your master/cyl may have a leak and there may be air in the system as suggested.

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Starlet Conversion:
http://www.ausmini.com/forums/viewtopic.php?t=15484

Thanks guys brakes I checked for air first but its not a spongey pedal. I also checked clevis pins. Apparently everthing has been replaced in this car. I was suspecting the breake and clutch master cylinders are the wrong way around!! Not shore if this would retract brake pads !! Or maybe there is A valve in booster that could cause this??

You would have to have the booster plumbed up to a breather rather than a vacum for it not to work, and then it would only be an issue when the motor is running. I doubt that the booster is the issue. Could be wrong though. As far as i am aware there isn't anything that would pull the pistons back, hence my train of thought of warped rotor's that would push the pistons back. Worth have a little look. The other thought i had of a seized piston would push the rotor off center and will cause it to warp and hence cause that issue. This is just a thought, so just check the rotor and the pistons are moving freely. worth a look see.

Cheers

Aaron

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I had this same problem, I found the seals had been contaminated by washing calipers with degreaser- it had swollen the dust seal rubbers so they were soft and sticky, they were flexing and pulling pistons back too far.
New seal kits fixed it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

It'll be the new seals & rubbers in the calipers. Being new they are "hanging on" to the pistons a litle, pulling the pads off the disc, just needs driving a bit to free up. Don't know why it happens, but does when new kits are installed. Happened to me a couple of times now and others I know.

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Steve

All these are great bits of advice and I would look into all of them, esp the clevis pin part as I've had near heartache with those.

But can I just say, start simple and work your way up. Bleed the brakes first. Bleed the whole system from back to front. If that does fix it, try adjusting your back shoes. If that's not it, have a look at your wheel cylinders or master cylinder.

It sounds alot like air in the system to me

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Lillee - 1969 Morris Mini K

Sorry guys definetly not a air problem I like the idea of sticky pistons I will be attempting this job again towards the end of the week. Note blocking off rear wheels does nothing this rules out rear brakes having problem . Blocking off front brakes though rectifies problem indicating something wrong there if it was A normal drum brake mini this would indicate either not adjusted shoes or wheel cylinder springs left off. But since there discs there is no adjusting. Front brakes been bled definetly no air!!

hey,
Iam having exactly the same problem, i have already put new seal etc in my cailpers and still have the problem. i was wondering do any of you have a tiny little hole in the lid of your master cylinder, has i replaced my master cylinder with one i had (cause i broke the other one by mistake) and its identical to the clucth one which has the little hole in the lid, i'm unsure if the old one had a hole in it because i threw it out.
Cheers
Rikki