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MG MGB Technical - Brake Squeal Help!

Good Morning, I am hoping that someone can help with this as I am just about to pull the last few strands of hair out over it!

Before a long drive to France last year, I decided to replace the front brake calipers, discs and pads. There was an offer on at a specialist for a kit which consisted of new calipers, green stuff pads and drilled and slotted rotors (discs). I fitted it and all was fine for the first few hundered miles. Then the brakes started squealing. I stripped and re-lubricated everything and it was fine again for a few hundred miles then squeal again. I rang the suppliers who sent some 3M black (1mm thick) pads, each sticks to the back of the pads (over the whole surface). So I tried this and everything was fine for 2000 miles ish and then the squeal came back. On removing the pads, I found the cut outs in the pistons had worn through the tape. The problem with the tape was also that it made the brakes feel spongy (although they are well bled).

I have tried everything I can think of, chamfering the edges of the pads, using copper slip on the back of the pads, using mintex brake lube on the back of the pads, but still, after a few hundred miles - or even one hundred if I give the brakes some abuse!

I know the drilled and slotted rotors are not needed but hey, they look good! I am on the verge of dumping them and going back to standard discs.

Any advice on anything else I can try as purchasing new discs is a cost I really do not need right now (the postage is a fortune!)


CHris B

Well I have same problem, I installed Austin Princess calipers and cross-drilled discs and when are brakes hot music starts. Couldn’t find solution up to now.

Toni Kavcic

THese are mine, look great, sound naff!!! Someone did suggest to me that I should try increasing the bearing play slightly to see if that helped but it didnt!

As these only have a few thousand miles on them, I am really not wanting to replace them just to find out the problem is still there. I am tempted to put my old discs back on to try them for a while but they are quite scored and wont do the new pads much good!

C Briggs

Is it one side or both? I had repeated squeal from one rear brake until I swapped the shoes over, since then it has been fine.

Are the cut-outs facing the right way? Should be on the spindle side of the piston.
Paul Hunt

I have checked the cut outs and they are facing the right way.

As for sides, I cant tell exactly but it does seem to be both, I know the nearside does seem to exert more force as the car does slightly pull to the left under braking and the nearside wheel does lock up first. I have some additional brake hoses to try ( had new braided ones when i put the new discs bads and calipers on) and a good bleed to see if that makes a difference to the balance but I cant see how it can affect squeal.


C Briggs

I have feeling that is noise coming only from one side (LH) but am not shore. Will pay some more attention in coming days.

Chris - this may well be simply coincidental, but when I had greenstuff pads, with the backings, std discs, braided hoses, calipers cleaned, new piston seals, all working correctly, with copperslip on backs, with the cut outs the right way around, with new spring clips and pins, with less and less hair on top of my head and decreasing chances of an afterlife due to my language, they squealed all the time - very loud upon even mild braking. I changed to 'standard' minitex pads - no squeals at all, and no discernible negatives as regards braking. No fancy anti-squeal shims/pads on the back, just a smear of copperslip again. And a lot less dust on wheels. Explanation - I have none, as the backs of both types of pads seemed very similar, I did not expect my squeal to vanish, but it did. For whats its worth....

THanks for that mick, I wonder if any others had the same problems with the greenstuff pads?

Would it do any harm to try some shim roll, cut to the size of the pad backing and placed between the pad and the piston? Would it stay in place and would it cause any harm? If the squeal is caused by the backing on the pad, perhaps the shim would stop this...
C Briggs

Greenstuff pads squeal in many cases - change to Mintex.
Chris at Octarine Services

Thats two for Mintex then!
C Briggs

I put Greenstuff on mine and have never been able to elimintate squeal. Repeatedly, I have stripped down, clean everything, new copper slip. OK for about 20 miles then squeal starts again getting progressively worse.

Would be really interested to hear the feedback on those who go from Greenstuff to Mintex.

I have the same issue with Greenstuff pads on my V8 and they are driving me mad. I have the correct shims, plenty of copper slip but the squeal wont disappear.
I have put up with it for the last 3000 miles and have just ordered a set of Mintex pads.
PR Hughes

This might be worth trying
c cummins

An old hot-rodder trick is to drill 3-5 (or so) small holes in the
friction material (only) - not through the back plate - and then
insert thin #2 mechanical pencil leads in them.

The graphite in the lead adds a bit of dry lube between the
pad and disk and disrupts the vibratory harmonics (squeel).

I've tried it with varying results.
Daniel Wong

thanks for the comments, I am so fed up with it, I have just ordered some mintex pads - £15 delivered so hopefully with 10 mins a side and all will be ok.


C Briggs


The MGOC charged me £22 delivered with standard delivery. Just realised why I stopped using them years ago.
PR Hughes

But V8 pads are more expensive than MGB ones - it's always cheaper to let me know what you want so I can pop it in with a regular order - then you a) get it cheaper and b) can pick it up from me, especially if you live in Southend!
Chris at Octarine Services

Chris @ Octarine,

I didnt know you did things like this - otherwise I would have ordered from you, will remember in future.


C Briggs

Cheers Chris I will bear this in mind next time.
PR Hughes

This thread was discussed between 19/07/2009 and 23/07/2009

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