I just changed the rear brake pads on my 1979 450SL. I used after market pads, cost $28. Also installed new anti-rattle springs. Brakes work fine but squeal when braking in forward and reverse. Removed pads and coated metal backs with Disc Brake Quiet gunk I purchased at NAPA. Brakes were quiet for a short time then started to squeal again. Removed the pads again, scraped off the old gunk and put on a heavier coat of the same stuff. Brakes again were quiet for awhile then started squealing again. Is there any way to stop this squealing short of replacing pads with Merc. Benz Original equipment pads?

Whats the condition of your rotors?

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Vehicle odometer reads 82k but I cant be sure that is the original mileage. Rotors look ok but I have not measured the thickness of the rotors. The pads I replaced were original equipment and would have lasted at least another 10k miles estimated.

You can try the MB brake pad paste. Sometimes that stops it. While you have the pads off to apply it, measure your rotors to make sure they are within spec.

Len

OEM pads (non metalic) are generally quieter than metalics and other compounds. The Mercedes brake systems are somewhat sensitive to non spec materials... probably best to go with OEM or Balo rotors and Textar pads. Sometimes the squeal will fade away and some squeal problems just can't be worked out any way but new spec parts. Till then just live with it... takes a little luster off an SL but at least the bumper won't get crumppeled.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Question: Did you coat the edges of the pads? That is where most of the friction occurs during braking as it rides against the calipers. True they say to put some on the back where the piston rides but there are anti-squeal plates available for that purpose and will probably last much longer.
I always do the edge treatment like this:
First, while the pads are out I run a small round wire brush in there to remove all the brake dust that accumulates (avoid hitting the piston seals). A wire brush designed for use in preparing 1/2 in copper pipes before soldering fits nicely.
Then dab some anti-sieze on the top and bottom edges of the backing plates (wear eye protection and do NOT run your eyes until you are free of the stuff!).
Also slightly bevelling the very edge of the brake pads using a grinding wheel or a flat file seems to reduce the squealing some pads make. Rears always seem to squeal - especially with Pagid and some Metal Masters (the latter should be banned!)

__________________
'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

I use the very same method.
Works every time.
FWIW. brakesqueal is always caused by the pads vibrating in the caliper.
I also subscribe to the "chamfer "method.

__________________
2007 C 230 Sport.

I don't mind chamfering the pads but only when I install them onto old rotors. If you do it with new discs it can upset the wear of the disc and cause it to lip prematurely. The reason for chamfering new pads is to prevent the lip on the old discs rubbing before the rest of the pad hits the disc which can cause squealing.
I'd probably measure the discs and machine them if possible.
And I'd only use genuine pads.
I put ATE discs and pads in the 300e once and they turned blue from normal use!! Worse than that they caused the grease in the bearings to melt and seep out thought the end caps. Luckily I caught it in time, regreased the bearings and threw out the ATE's in favour of genuine parts.

__________________
Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi

Thanks everybody for all the tips. I will follow deiseldiehard suggestions and hopefully will be able to brake the old SL without being embarrassed.

I replaced every item, Balo rotors, PAGID deluxe pads, anti-squeal...and yet it continued to squeal, My problem was the spring clips holding the pads. I put new ones in and cured the problem.

94 E320

I went thru this on mine a few yrs. ago. Replaced several sets of rotors for runout issues and several sets of pads for squealing issues. Did the paste thing as I've always done with other cars.

In the end, the solution was to buy a set of MB dealer pads. I realize they may be made by Jurid, Pagid, etc. on any given day, but that's what did it for me.

I will never use anything else.

My 2 cents

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Use only MB brake pad gunk. Cheap and works. I like to chamfer th edges as well

__________________
Ron
2015 Porsche Cayman - Elizabeth
2011 Porsche Cayman - Bond,James Bond
Sadly MERCEDESLESS - ALways LOOKING !
99 E320 THE Queen Mary - SOLD
62 220b - Dolly - Finally my Finny! Sadly SOLD
72 450SL, Pearl-SOLD
16 F350 6.7 Diesel -THOR
19 BMW X5 - Heaven on Wheels
14 38HP John Deere 3038E Tractor -Mean Green
84 300SD, Benjamin -SOLD
71 220 - W115-Libby ( my first love) -SOLD
73 280 - W114 "Organspende" Rest in Peace
81 380 SL - Rest in Peace