Lazy brake question.

[Frogland]

Why do my brakes scream when i haven't driven for a few days,do they need copper grease on the back of the pads or is it something else ?

[mmgemini]

I wouldn't recomend any type of grease on the back of any disc pad.

Try fitting anti-squeal shims.

I'm assuming that the calliper pistons are working correctly.

[western]

a smear of copaslip grease & anti squeal shims should cure it, always works for my 110, no ill effects from the copaslip grease.

[ThreeSheds]

Does anyone know the definitive answer on which grease to use on brake components?

I was told 30 years ago that copper grease was not to be used anywhere near brakes because (like most other greases) it rots the seals and goes runny when it gets hot. I was further told that the only grease that should be used on brake components is 'red rubber grease' - also known as 'brake grease' - which has neither of these problems. I have stuck to this advice ever since, but everyone seems to use copper grease nowadays and I am wondering if I was told wrong?

WRT the original post, the only real way of discerning what's causing the squeal is to strip them and have a look - then even if you don't see anything wrong you may well find, after a good clean and application of a THIN smear of (in my case) brake grease to the back of the pads and the points where they contact the calliper, that your squeal will have gone. Hope so anyway!

Either way you should have a look - a friend of mine told me a couple of days ago that her brakes had suddenly started making an awful noise and would hardly stop the car - investigation showed that the pads had finally given up the ghost and lost all of their friction material. "Were there no warning signs?" I asked, and she relied that they had been making funny noises for a few weeks... So now instead of new pads she has had to get new discs fitted too...

Roger

[mmgemini]

Roger.

No I don't think you're wrong. I was taught during my apprentiship that NO grease to anywhere near brake linings. I've always managed to keep to that.

Where squealing brakes are concerned, in the 1960's 'bus companies fitted "anti-squeal" bands to the brake drums. That didn't work.....

Where drums are concerned dust in the drum can cause squealing, which is why drums should be removed on a regular basis.

Discs are slightly different. As I said earlier I keep the shims in my garage. I don't fit them when I renew the pads but if the pads start to squeal then it's easy enough, apart from the struggle with the wheel, to put the shims in.

[Ratty43]

Given that coppaslip is designed to work at temperatures up to 1100 degrees C it's not likely it's going to melt on the back of a brake pad, it's also formulated for high pressure areas so is ideal for that application. Given it's widespread use on brake pads throughout the automotive industry I would have thought that any problems would have been brought up years ago by the mainstream manufacturers. I've always used it, never had a problem with brake squeal or anything else while using it.

[Mo Murphy]

I think copper grease has come a long since Mike did his apprenticeship many moons ago I put a film of copper grease on the back of my pads and have never had squealing or grease contamination. However if there is no friction material left on the pad nothing is going to stop it squealing

Mo

[mmgemini]

True Mo.

Ratty it's still a grease onto pad material. I wondr what my discs temperature is when the discs are white ??? Yes I can get brake fade with the old DS11 pads.

I see no reason whatever to cover the pad with any grease. Use tank tape but not grease.

It's a bit like when I had my Imp rally car. Margarer would glaze the shoes on the VG95 shoes because she wkes. Discs are the same. They need a good hammering once in a while to get the pistons out of the calliper.

[Disty]

What pads do you guys use generally? What is the usual culprit of poor braking performance; pads, calipers, lines or master cylinder?

[Ratty43]

I suspect that the brake fluid would be boiling long before the grease melted, and wouldn't tape melt a lot earlier too? Once the fluid was boiling the pressure on the pads would be reduced and thus the friction and temperature would drop, still far below the grease's melting point. This is all hypothesis on my part so I'd be interested if someone could support or dispell this idea.

[mmgemini]

Some pad manufactures use tank tape on the back of the pads....

Yes I too have said that other things could be the problem including sticky pistons.

Disty it can be caused by a lot on things. Including not using the brakes hard enough, one of my problems at times.

I use either Apex or Brakeworld pads.

Not had a problemwith fluid boiling but the fluid gets changed on a regular basis and IIRC it's Lockheed fluid.

In the case of the firts poster it could be rust on the discs.