Squealing Brakes

[hnichols]

Last year I had my brake pads replaced, and the new pads squeal horribly (only with light pedal pressure, though). I have since removed them and applied the red anti-squeal gel (please see pic), which worked for a day or so, then the squealing returned. I did this operation twice, thinking that maybe the first time I hadn't allowed enough time for the gel to dry. No difference.

I also considered replacing the current pads with a set I won at last years Midwest 02 fest (also pictured). These have the same dimensions of the pads in the car, except they have the shims, which should eliminate the squealing. Only problem is that they don't fit into the calipers.

I can live with the squealing, but I'm curious to see if anyone here has any insight.

Thanks in advance!

Hugh

[JsnPpp]

Hi,

When you say "don't fit" do you mean width or thickness?

I have found sometimes with brand new pads that I need to make sure the caliper pistons are as recessed as possible to let them squirm in.

If it's width, then they are the wrong pads!

Keep at it, I had the same problem and finally switched brands to get rid of the squeal.

~Jason

[Mike Self]

my'69 was silent. I tried the gel on the pads, aluminum shims, chamfering the edges of the pad etc etc. Nothing helped.

Several folks told me to try (then) REPCO (now PBR) Metalmaster pads. I was skeptical but I tried 'em, and the car hasn't squealed since--I switched in 1980...

I'm sure there are other pads out there now that are just as quiet, but I've always had good luck with both PBR Metalmaster and de luxe pads.

cheers

mike

[c.d.iesel]

MANY THINGS CONTRIBUTE to squeaaa!l!ing brak!es

no lubricant between the edge of the pad

backing plate and sliding edge inside the caliper

escessive clearance at the same sliding surfaces

from poor quality pad backing plate, or rusted

corroded surfaces

your retaining spring clip lacks tension - it also needs

brake paste where the retaining pins make contact

wrong positioning of the caliper pistons (see attached illustration)

thanks to the last PO caliper rebuilder

brake pad friction material

brake rotor surface/wear pattern/rust/pitting

lack of original pad shim which dampens the vibrations that cause the noise

try a set of BMW TEXTAR or JURID, new shims, BMW Brake paste,

clean all dirt, rust out of the caliper sliding surfaces, brake paste to the edges of the pad backing plate.....

double check the position of the notch on the caliper pistons (see illustration)

[Mike87]

If you chamfer the edges of the brake pad where they contact the rotor it might help your squealing.

[hnichols]

Wow, thanks everybody. More things to try. ...

Jason, its the thickness, not the width. The pads have the same dimensions as the ones that fit, except they have the shim. Since the pads already in there are new, the calipers are recessed as much as they can be, I think. I tried tapping the shimmed pads in gently with a hammer, but they wouldn't budge -- and I didn't want to force anything, since I'm not certain they were the right pads.

[Colin]

If you chamfer the edges of the brake pad where they contact the rotor it might help your squealing.

Yeah my old boss (who was a master mechanic) used to do this and it worked great, even on limos.

[JsnPpp]

Ok!

I use a large screwdriver carefully as a pry bar to pull on each piston separately. Usually I am surprised but they tend to move back just a bit and allow it to fit (with a few light taps with a hammer).

It's hard to say without looking at it - yours indeed may be too thick to fit.

~Jason

[hnichols]

I guess I was asking if the pads have the same dimensions but with the shims, then they must fit. Or does the pad itself have to be thinner to compensate for the shim for it to be the right size?

[JohnS]

If you chamfer the edges of the brake pad where they contact the rotor it might help your squealing.

I guess you would use a dremel tool or a sanding block to chamfer the edges?

I'm going to try that on my '73 tii. I rebuilt the brakes on both of my tiis recently using the same setup. New BMW rotors, rebuilt calipers, Hawk HPS pads, Ate grease, new shims and the '73 has always squealed, but the '74 never has. I was careful and followed the recommended way of breaking in the pads that was mentioned here and on the Hawk pad box on both cars. '73 squeals and it pisses me off,

John

[tim385]

Ive got a 4x4 and recently changed the pads , my Mrs Complained that it squeeled .....and it did so I said drive it down a dirt road and jump on the brakes a couple of times ......problem solved......was it the dust lube ..?? who knows.

[tim385]

Ive got a 4x4 and recently changed the pads , my Mrs Complained that it squeeled .....and it did so I said drive it down a dirt road and jump on the brakes a couple of times ......problem solved......was it the dust lube ..?? who knows.

[Mike87]

Just use a large file. About 1/8" chamfer is more than enough.

[JohnS]

Just use a large file. About 1/8" chamfer is more than enough.

10-4 Mike, Thanks