Over the last several months, the brakes were giving off that familiar (at least to me for the last couple of decades with this car) ringing sound indicating pad wear. It turned out to be the rear pads that were down to their last 25% or so.

Upon installing new pads (including using the anti-squeal paste as usual), one of the anti rattle springs fell apart. I replaced both. After all was said and done, however, I still get the ringing sound for the first mile or so in the morning on the way to work and in the afternoon on the way home. After the first mile or so, no more ringing.

Questions (rear calipers are ATE):
1. Is the ring (like a pencil eraser's ferrel) that is located around the head of each pad retaining pin responsible for the ringing sound?
2. Is it possible that the pad retaining pins (maybe the culprit is the ferrells?) wear down ever so slightly, become loose in their holes over the years, and thus the pins generally and the ferrells specifically, rattles just a bit and this is the source of the problem?

Perhaps the issue is: Once the brakes heat up enough, the metal pad retaining pins (and ferrells) expand ever so slightly and their looseness is overcome and thus there is no room for the ferrells to begin their ringing?

I'd appreciate any insights on this one. Thank you.

I would suggest, and I am by no means an expert, that it might be worth purchasing the shims that go between the pads and the piston. That may help reduce your squeaking. They can be found at the "Buy Parts" link on the forum. Good luck!

__________________
1982 240D - 292,000 miles and counting
Same family for 33 years
Newly rebuilt Monark injectors
Newly replaced clutch
New Bilstein shocks

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Dog: I had this problem on my '81 CD. I screwed around with various pad backings and other supposed "fixes" for a couple of months, but in the end what fixed it was new rotors. (in my case it was the fronts)

I read on various websites that the ringing is caused by the pads having to ride over tiny "bumps" on the rotor surfaces.

__________________
'81 300CD - 180K, cannot be killed by any conventional means
'99 Ford Escort - good MPG

Also the pads have to be MB brand to lessen the chance of noise. The ringing is usually a pad vibrating on the rotor surface. Rear rotors cost a little more than fronts but if the elimination of the noise is important to you, replace them.

__________________
81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.

Thanks for all of the useful information!

Incidentally, the pads I just installed were Mintex - OE I think

In more than 20 yrs. of owning this car, I've never replaced the rotors (a pro. mechanic did the work). Now that I've replaced the cylinder head and ignition assembly on this vehicle (plus *lots* of other work), rotors can't be as bad as either one of those two doozies!

I'll have to look in my records and see when the rear rotors were last replaced - bet it was years and years ago.

Oh yeah, last Thursday, Dec. 18th, marked the 25th anniversary date of the manufacture of the car!

Thank you for the help-