Technical 100HP Brakes(Again)

[leegar30]

Has anyone else had a problem with the brakes rubbing all the time.I have noticed that I seem to have a constant squeak when travelling forwards and turning left and right.
I know about the groaning in reverse which my car also does to great effect but I'm not sure the two are related.When I took the car to the dealer a few months back they said the pads were badly glazed and they had cleaned them but this has had no effect!
I'm just a bit concerned that the discs will be damaged if the brakes are on slightly on all the time.The car has done 2400 miles now and doing a few hard stops and pulling the handbrake slightly to try and burn off any crud seems to have no effect.
Any ideas?

 

[HP]

Standard thing to do is to strip them, clean them down and apply a bit of brake grease (or copper slip) and rebuild. If the pads are glazed, give the faces a rub down with emery cloth - even do the same lightly on the discs.

 

[ScoobyChris]

Has anyone else had a problem with the brakes rubbing all the time.I have noticed that I seem to have a constant squeak when travelling forwards and turning left and right.

Does the noise go away when the brakes are applied? I think mine went through a phase where light braking made the brakes squeal but firmer braking stopped it. If it is the brakes being in contact with the disc, you'll be getting a huge amount of heat off them, lots of brake dust and also your economy will be suffering.

Chris

 

[The Panda Nut]

Does the noise go away when the brakes are applied? I think mine went through a phase where light braking made the brakes squeal but firmer braking stopped it. If it is the brakes being in contact with the disc, you'll be getting a huge amount of heat off them, lots of brake dust and also your economy will be suffering.

Chris

I eventually replaced the slider pins. I believe the rubber collar fitted - one on each side had gone soft and expanded just enoiugh to cause this. It was not easy locating the parts and I think I had to but a kit of stuff just to get some pins with the new rubber bits. Also make sure you only use top brand brake grease on the slides not copper based stuff as it just causes problems. Make sure you fit the pins in the correct positions as each caliper has one slide pin with a rubber collar and one without. If not in the right way round its my impression this too can cause issues.

 

[DaveMcT]

DO NOT USE ANYTHING OTHER THAN RED RUBBER GREASE ON BRAKE PIN SLIDERS.

Normal greases will rot the rubber seals. Some greases will cause the polymer bushes to expand and seize the sliding pins. Silicone grease is too slippery.
The brake slides are intended to stick and slip. The piston rubber seal should distort when brakes applied. When brake is released the piston seal pulls the piston back a fraction of a mm so there is no binding. When the grease is too slippery, the sliding pins move too easily and the brake will not release. Same issue applies on the piston seal. Red rubber grease only. The pins will move when the pads wear so they cannot be too tight (or too loose). Fitting new pins, bushes and seals make sense to avoid the brakes binding.

 

[koalar]

DO NOT USE ANYTHING OTHER THAN RED RUBBER GREASE ON BRAKE PIN SLIDERS.

Normal greases will rot the rubber seals. Some greases will cause the polymer bushes to expand and seize the sliding pins. Silicone grease is too slippery.
The brake slides are intended to stick and slip. The piston rubber seal should distort when brakes applied. When brake is released the piston seal pulls the piston back a fraction of a mm so there is no binding. When the grease is too slippery, the sliding pins move too easily and the brake will not release. Same issue applies on the piston seal. Red rubber grease only. The pins will move when the pads wear so they cannot be too tight (or too loose). Fitting new pins, bushes and seals make sense to avoid the brakes binding.

???

are you sure

its not what I would use here

 

[chris3234]

???

are you sure

its not what I would use here

Nothing wrong with red rubber grease

But no reason not to use silicone grease I've never once heard of it being too slippy for the seals on the slide pins

 

[koalar]

Nothing wrong with red rubber grease

But no reason not to use silicone grease I've never once heard of it being too slippy for the seals on the slide pins

I was joking, as it was being shouted

and it wasn't copper anti seize for a change

It seem you need this or that special grease for everything,

RRG is fine, although it was originally for assembly there so many blends now some are suitable for external weathered applications

on the Panda the slide pins are well protected. I would guess if the job was done in a garage 95 out 100 times they would use standard High temperature lithium axle grease as that's normally lying around and is what I would use

silicon grease is what supplied in the kits

 

[Mike1alike]

About the squeaking breaks, the problem presented in the first post on this topic...
I had the exact same problem as OP described and I didn't pin it down to the brake pads. But seeing this topic, it does sound possible that the pads are making the squeaky noise. At mine the noise were now and then and it was worse on rainy days.
The pads are in permanent contact with the discs, that's how this system works and how it was made. But not pressing the brake pedal, there is no pressure on the discs, so no wearing of either discs or pads.
And I'd say that the squeaky noise comes from dirt caught between pads and disc, possible even pad-dust or maybe sand-dust of the roads. Recently my breaks started squeaking while I was slightly press the brake pedal. I thought maybe the pads are almost worn out and I checked them. They are half way through being worn, the friction material is 6 mm thick, on new pads it is 11 mm. I moved the pads inside out on the discs (put the inner out and the outer in) and I gently taped the calipers and a lot of dust came out.
Now there is no squeaky sound when I press the brake pedal and also, no squeaky sound while driving and slightly turn left or right, as there was, before.
I didn't apply any grease on the brakes, not this time, nor ever.

 

[koalar]

The pads are in permanent contact with the discs, that's how this system works and how it was made.

Is this true, I have read this also.

if you take the fact I sometimes on two or three cars I must have well over 50 years of car ownership and in practical terms I found this not to be the case unless there is something sticking, air in the system or hoses ballooning.

Rubber bending, metal expanding and contracting, bearings flexing and so on. Should mean a very small air gap, cooling the discs and greater fuel economy. At least thats what I observed on my cars

 

[Mike1alike]

Is this true, I have read this also.

Well... there is contact, that is for sure. And if you think how this system works, you'll see there is.
The pads are sitting on disc. And they are being held there by the caliper. To use the brakes, we push the pedal and consequently the caliper's piston pushes the pads onto the disc. And when we release the pedal, the piston is not being pushed anymore, but there is no piston pushing the other way, pushing pads away from the disc in such way that there to be no contact between pads and disc.
So there is contact, that is the normal state. But is no friction, or minimum amount of friction and that is due to what the pads are made of (the friction layer). When there is friction, like more than when you just use the brakes, there is heating, you can feel the wheels hot and that is a fault in the system, something forces friction when there should be no friction.

 

[koalar]

Well... there is contact, that is for sure. And if you think how this system works, you'll see there is.
The pads are sitting on disc. And they are being held there by the caliper. To use the brakes, we push the pedal and consequently the caliper's piston pushes the pads onto the disc. And when we release the pedal, the piston is not being pushed anymore, but there is no piston pushing the other way, pushing pads away from the disc in such way that there to be no contact between pads and disc.
So there is contact, that is the normal state. But is no friction, or minimum amount of friction and that is due to what the pads are made of (the friction layer). When there is friction, like more than when you just use the brakes, there is heating, you can feel the wheels hot and that is a fault in the system, something forces friction when there should be no friction.

here in ferodo instruction it ask for the brake retraction to be checked

Ferodo instruction on correct fitting of brake pads and caliper | techtalk.ie

Avoiding Noise Problems - Tips for Correct Assembly

www.techtalk.ie

here a nice animation watch the Black seal

in reality there is more movement than this the discs dont stay exactly true when being driven, cornered and so on

unlike the animation the pads can touch the disk and the gap be at the back

 

[Mike1alike]

That's just in theory. In practice, there are always minor differences.
One such difference is that the pads are not "glued" to caliper, so in reality you'll never have such retraction as in the video above.

 

[koalar]

That's just in theory. In practice, there are always minor differences.

in nearly a million miles the only time I have never heard any noise from the discs or pads

when something is seized
or the car is up in the air being worked on

out and about you occasionally hear one, its always a old transit van or similar never a newish car

 

[DaveMcT]

Noisy brakes = worn or damaged disc, wheel bearing or seized caliper.

Caveat - discs with surface rust after standing for a few days can make a rubbing noise until the rusty layer rubs off. Leave them standing for long periods and pitted rust can develop. But while it weakens the disc, rust pitting is rarely noisy.

 

[Mike1alike]

None of the above were causing the squeaky sounds in my case. The only thing I can say is that I didn't use grease on the caliper's slide pins. But the calipers were not seized, for sure. And still not using grease, the brakes are smooth and very quiet now.
The discs are not rusty and not worn nor damaged. I replaced them quite recently, no more than 25.000 kms ago, after I replaced the wheel bearings, so no problem with them either.

L.E. Actually, I think the squeaks were produced by the calipers not having grease on the slide pins. They could have been produced by that, for sure. And when I tapped the caliper with the hammer, a lot of dust came out, mainly from the upper part, from the slides. I will put grease onto them now.