Squealing front brakes

[Ulf]

My 230 had new front brake pads installed last october but due to an unusually long winter with loads of snow (what global warming???) I didn't have a chance to take it out for a spin which I usually do 3-4 times during its winter hibernation. The result is, that the front brakes are squealing a lot - I thought it would go away by itself, but so far it hasn't. The sound goes away when braking but re-appears soon after. Do I need to take them apart to clean them (or rather have someone do it for me as I'm not much of a handyman) or is there another solution?

A nice sunny weekend to all of you

Ulf

PS: Have searched for other threads for this, but nothing matched completely

[mdsalemi]

Ulf,

My 280SL never squeals, even after sitting all winter.

I think this has to do with the softness or composition of the brake pad material.  Change your pads, probably will go away.

I recall as a child, that this very same 280SL, when owned by my Uncle in it unrestored, original state, squealed quite loudly.  So did nearly every other W113 I recall as a child.  That, and a distinctive combination of exhaust "note" and engine noise let me know when one was approaching.  A "sound signature" all their own.

[graphic66]

I have found you have to fit the pads into the caliper by filing the edges down smooth so they move freely into the caliper. They always look very rough on the edges, I just smooth them down with a file. Also, the pistons have a small relief in the face that needs to be oriented in a certain position. The BBB shows a special alignment tool, Piston gauge 001 589 30 21 00 and a piston turning tool 000 589 36 37b 00 to get the pistons oriented correctly. I just installed them and turned them by hand to what looked like the correct position. The tool is shown on page 42-12/8 Fig. 42-12/19. I also put some anti seize compound on the edges of the brake pads where they touch the caliper and some anti squeal paste on the back of the pads. This is for Ate calipers, Girling, I believe don't have the same relief cutout on the piston. 

[RickM]

To add and agree, the pad compound is likely the main culprit. Many times a metallic component will create squealing. The pad may last longer, brake better in extended heavy braking scenarios (reduced fade) and create less dust but the price is often noise.

You may want to look into anti-squeal shims, paste/gel products designed to eliminate or reduce squeal and/or organic or ceramic pads.
Also, it may be worth your while to have the rotors resurfaced. I don't necessarily mean "turned", rather, resurfaced on a grinding type machine designed to remove any glaze that may have developed on the surface. Unfortunately with the low cost of rotors it's getting harder to find shops with the expertise and equipment to accommodate this work.

FWIW, these and other noise reduction techniques are incorporated into some modern day pads. I find them to be quite effective.

[Ulf]

Thanks for you advices, but they only started squealing after the winter storage, before being stored for the winter, they were completely silent. But I'll take them to my mechanic and have him look at them.

best regards

Ulf

[Naj ✝︎]

MB sell the brake paste in a sachet enough tp do one axle set. A 001 989 9451.
You don't want too much on them!

naj

[Ulf]

Naj, a single axle set will do fine as it is only the front brakes that are acting up, do you just remove the wheels and smear a thin layer on or what?

[RickM]

Typically the directions for this type of product are: Apply a thin layer of the "paste" onto the back of the brake pads and reinstall. The package should elaborate.

FWIW, make sure the paste is for damping brake pad vibration and not one of the many "pastes" used for lubricating the caliper mechanicals. I'm not questioning Naj's part # info, rather, letting you know that there are other "paste" products used in the maintenance of the braking system.

[Naj ✝︎]

Hi, Ulf,

Rick is right. It goes in a thin layer on the back of the pads, however, to be able to do that, the pads have to come out.

Be sure none of it goes on the friction surface!!

naj

[Ulf]

Will do - but first I'll try and give it a blow of compressed air as I'm beginning to suspect that it might be dirt

Regards

Ulf

[RickM]

The number one no-no when servicing brakes is hitting the assembly with compressed air. The dust (even with asbestos free products ) is not anything you want in your environment. I also doubt this will solve your noise problem.

BTW, are you using OE pads? If not, what brand and compound?

[jacovdw]

I fully agree with Rick.

Rather use brake cleaner than compressed air.
You don't want that dust in your nasal passages or lungs...

[Ulf]

Thanks for the warning - I believe the pads are OE, btw