Rattling Front Brakes

[david.g.chapman]

Now that the weather's warmer and the windows are down, I can hear my front brake pads rattling on my +2 when going over bumps. Apply the brakes lightly and there is no sound.

I recently replaced the pads with EBC greenstuff pads, with a fair amount of clearance on the retaining pins. The makers recommended that anti-squeal shims were not required, so I ditched them. Sure enough, no squealing.

Has anyone else had this trouble? Can you get a spring assembly to stop the rattle (as on other brake designs)?

On a separate subject, my rear brakes tend to squeal, even though I use plenty of copper grease between the pad and piston. The pads on the back are held below the retaining pins, with no anti-squeal shims. Any ideas on this one? Am I missing something?

Dave Chapman.

[pereirac]

Don't ditch the anti-squeal shim, I hear they are difficult to get hold of if you ever want to use them again

Carl

[john.p.clegg]

Yes,there is a fair amount of clearance on the pins,a "blob" of silicone sealant on each end of the pins will stop them rattling and is easy to remove
John

[GrUmPyBoDgEr]

Elan +2 front calipers differ depending upon their age. I think the earlier ones had a larger pin diameter than the later ones. New anti squeal shims are available. Classiccar Automotive in Cheshire are the experts on this subject, suggest you give them a call. (No business contact, just a satisfied customer)
Cheers
John

[type26owner]

Those shims are there to asymetrically exert the force from the pistons onto the pads. They are marked with an arrow because there is an particular orientation to install them in. That's to compensate for the rotation direction so the pads don't wear themselves into a tapered wedge shape. They don't really serve any anti-squealing function. The special brake pad lubricant that one is suppose to apply does that.

Once the pad is worn out of being parallel there is another problem that develops. The piston is loaded in such a way that it's cocked sideways in the caliper bore with great force. That force is a rotational degree of freedom that is normal to the axis of motion. This wears on the piston and the bore of the caliper at a higher rate than normal. Good way to polish off the calipers and have to buy new ones.

As far as the rattling goes this is greatly influenced by the preloading of the wheels hub bearings. Enthusiastic driving also flexes the axles and knocks the piston back so a dab of the brakes to pump them up before getting to the braking point is sometimes needed. Also most calipers have the seal groove profiled in a trapizoidal shape so the compliance of the seal is used to keep the piston in contact with the pads up against the rotors and not allow too much knockback. Replacing the old hard piston seals will do wonders reducing the rattling. The EPDM elastomer gets harder with age and this is accelerated by the amount of heat cycles it endures.

[david.g.chapman]

Thanks, everyone.

I think I have lost the old shims, so I will have to get some more. I was tempted to fabricate them, but the material was a thin springy steel, which I do not have.

Dave Chapman.

[GrUmPyBoDgEr]

Classic Automotive can only supply new shims for the later +2 calipers. These differ in having a slightly smaller hole size for the pad smaller pad retaining pins.
I managed to open these holes out to fit my earlier caliper pins when upgrading the front brakes on my Elan to +2.

Good luck.
John

[elansprint71]

Rimmer Brothers usually have shims in stock for all three types of +2 shims, if you order the wrong sort (like I did) they are a pleasure to deal with. Classicar (just down the road from me) were happy to sell me new +2 calipers but could not care less when I asked about shims.
John's suggestion to use silicon sealer is a good one, also try creasing/curving the shims slightly to mainatin contact- not too much or you'll push the pads back.

Pete, Sprint with big brakes, no servo.