Topics and replies.

Re: Brake squeal

Postby Gavin Brown » 24 Jul 2017 09:50

Angus,

I know you've tried copper spray, but have you tried this product from Wurth:

https://eshop.wurth.com.au/Anti-squeal- ... paignName=
Gavin Brown
 
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Re: Brake squeal

Postby Mike Howlett » 24 Jul 2017 09:53

Two comments. Firstly the Hoyle front suspension doesn't get rid of the kingpins. That for me is it's major weakness. Secondly I have been led to believe that drilled or grooved discs are more likely to squeal than solid ones. I could never see the point of them. Not only does the drilling or machining weaken the disc, but the holes and grooves will become blocked with dust and dirt, so why have them? Snake oil if you ask me!
Mike Howlett
 
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Re: Brake squeal

Postby Angus Munro » 24 Jul 2017 10:07

Hello Peter,
The car that I now have is delightfully 'in period'. As close to a Factory fresh car as can be realistically achieved with a 44 year old. It does have some sympathetic modification such as electronic ignition but I would not want to change it too much, lovely as the range of Hoyle products is.
Had the brakes been silent, as they should be, I wouldn't consider scrapping them for a different set up but I really am faced with a car that is simply unusable in its present form.
Thank you for the feedback regarding my 'old' RV8. I am really happy that the new owners are pleased with it, and the IRS, as was I.
Good to hear from you my friend. Love to Pauline.
Angus Munro
 
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Re: Brake squeal

Postby Angus Munro » 30 Jul 2017 09:56

When a highly competent chum recently looked at the problem of the squealing brakes he found that the complete front brake system was new, as it should be on a completely rebuilt car, but when he tried to chamfer the pads one of them was so hard that it would not be cut. He termed it a rouge pad.
The pads were then changed for a brand new set of Mintex but, the squeal is now even worse. It is really awful. Brake squeal seems to be a problem for everybody with a B or a BV8 if what I read on the internet is correct. As brake squeal didn't happen at conception, I had a brand new MGB Roadster in 1966, the only conclusion I can come to is that the pad compound has changed over the period. This quite understandably as the original compound contained asbestos apparently.

I hover on the point of changing the entire front brake system for a 4 pot, ventilated disc system but several of the kits available only work with 15" wheels. Frontline offer a kit that works with 14" wheels but not the standard BGTV8 ones.

It's all very frustrating.

I spoke with a leading person within the parts and workshop market on Friday. He told me that most MGBs and BV8s suffer from the problem and nobody really knows why. On one customers car they changed the callipers twice, the discs twice, and different pads as they went along, all without success.

On my own car, wearing through any glaze brought about by the one 'rouge' pad might take a long time. I could buy new discs, they are cheap enough, and find the softest pads that I can to see if that solves the problem. But, I don't want to get into a try - this - try - that situation. I would rather do the right thing once and get on with what I bought the car for, enjoying MG.

So, no real conclusions or answers yet but a fifty mile drive to the North Norfolk coast yesterday convinced me that a wonderful car and driving experience is being completely ruined until I do something and preferably get it right first time.

What to do? What to do???

Desperate in Norfolk.
Angus Munro
 
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Re: Brake squeal

Postby Tony Lake » 31 Jul 2017 08:43

Angus,
My brake set up is dimpled and grooved discs with EBC Green Stuff pads which squeal occasionally when reversing.. I believe my callipers are the original factory design. I am not a heavy braker.
I have rebuilt them a couple of times in the last 17 years when fitting new disc rotors and have always managed to salvage the whole assembly and reuse all the parts with a service seal kit.
The pistons are relieved for a small sector where they butt against the pad. This is counter intuitive, it would seem like good practice to apply the hydraulic load through a full 360 degrees.
The squeal is caused by a very high frequency vibration which I suspect is interrupted by the discontinuous perimeter of the piston.
I also recall that piston position in the calliper with respect to the relief is critical, but can't find a reference to it. I wonder if this is the key to the squeal problem, replacement parts book illustrations show pistons with a full 360 degree piston perimeter.
Tony Lake
 
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Re: Brake squeal

Postby Tony Lake » 31 Jul 2017 12:48

I've just found the assembly instruction for the piston. Extract from AUSTIN MORRIS PRODUCT TRAINING, Service School Cowley, part of a publication dated 1972.

" The cut-away portion of the piston must be located at the inner edge of the calliper, I.e, towards the hub."

In that position the hydraulic load will likely lead to a "toe-in" attitude as the pad makes first contact with the disc. That method of adjustment is also favoured when setting up bicycle brake callipers to get rid of squeal.
Tony Lake
 
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Re: Brake squeal

Postby Angus Munro » 31 Jul 2017 15:36

Tony, thank you very much for all of that.

I have just ordered a new set of EBC discs together with a new set of EBC Blackstuff pads and some 3M stick on Anti Squeal shim material. I am hoping that the Blackstuff pads, being softer, will be sound absorbing. I had Greenstuff pads on my RV8 which were OK...
It will be some time before these items can be fitted due to family visits and so on but, I will get back to you with the result. At the time of fitting I really do hope to see slots in the pistons and further, that they are out of position. Putting them in position will certainly add to my confidence.

Many thanks again Tony. That was really kind of you to go to that trouble and is very much appreciated.
Angus Munro
 
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Re: Brake squeal

Postby Nic Houslip » 14 Aug 2017 18:16

Angus. In the early 1970's I was responsible for a fleet of vehicles and in particular the boss's wife's car, a rather nice Alfa Romeo Berlina 1750 Saloon, which was frequently brought to me for squealing brakes. I tried everything but couldn't stop it. I took it to an independent Alfa mechanic [in Staines if I recall correctly] and mentioned it to him. I'll show you how to cure that he said, Jump in. We sped off down the road and after about 3 VERY heavy crash stops he said, it won't do it for about 1,500 miles now, so just repeat as necessary. No more complaints at all, and when her hubby started using the car it stopped. I am of the opinion that being too light on the brakes glazes the pads [and linings] and leaves a kind of film that squeaks as you are barking, braking occasionally a little harder to wear that film off is the best way to avoid it. It also removes the corrosion issue from discs that have rusted overnight in rain.
Nic Houslip
 
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Re: Brake squeal

Postby Peter R Mittler » 17 Aug 2017 12:34

David Macadam wrote:
> Angus,
> You mention you have fitted new pads recently. I recall there is a need to
> avoid glazing the disc surface which may be contributing to the brake
> squeal noise you have. Although you say you "are easy on your
> brakes" but that could be contributing to the glazing. I think it
> would be well worth adopting a much firmer style of braking for your next
> trip in the V8 and give the pads some real work and get the pad surfaces
> really hot with some hard braking. It may not be your usual style of
> driving but with due consideration for any drivers behind you I think it
> will help you.

New forum member here. I recently suffered from low speed brake squeal on my 1980 MGB with Green Stuff pads and relatively new roots. Then I took the B out on the track at Mosport on Canada for a spirited track day with VARAC (Vintage Automobile Racing Association of Canada). Low and behold, after track day, the squeal is gone. So the "wear off the glaze" theory may just be spot on.
Peter R Mittler
 
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Re: Brake squeal

Postby Anthony David Marchington » 21 Aug 2017 19:01

I have just replaced the front pads on my RV8 with new ones obtained from Clive Wheatley. I wish it was just a break "squeal"! It is a "howl" and only at low speeds and just before stopping. Most embarrassing. Any suggestions on a cure would be most welcome.
Anthony David Marchington
 
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