What are the signs that show it's time to replace the break calipers?

I have ATE now, but I looked at Fastlane and Bendix are almost half the price, any reason to stay with the ATE?

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

As far as I am aware, the only reason to replace a brake caliper is if it has partially frozen. This would be evident with the vehicle pulling to the side away from the partially frozen caliper. I need to replace at least the left front on the SDL because it pulls heavily to the right on moderate braking.

If the caliper is acting incorrectly then replace it.
Replace it for the following

Leaking brake fluid.
Binding
One pad has worn but the other half has not, one piton binding.
ripped rubber seal, or replace, but the dirt may have already damaged the piston/cylinder area.

So asess the caliper. Clean it completely with brake cleaning fluid. Check the rubber seals, look for brake fluid leaks, and look at the wear on the pads.

I see know reason to keep ATE or Gerling, as long as you replace both calipers on the axel with the same manufacture.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

The wear on the pads was not even, slightly more wear to the sides.

And there is a sizing/squeaking sound if a apply the brakes softly that stays for a second or two after letting the breaks go.

What do you mean with Binding?

Thanks

__________________
1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

A sizing/squeaking sound if you apply the brakes softly that stays for a second or two after letting the brakes go, is likely due to the piston slightly sticking in its bore or the lack of anti-sieze on the edges of the pad backing plate.

Binding probably refers to the piston sticking in the bore. Several things can cause this: Thin rotors that allow the pad backing plates to come in comtact with the "cross spring", or loss of the rubber boot and then dirt getting into the bore, or moisture --corrosion of the piston / bore. Probably other causes as well.

ATE calipers seem to be a bit better constructed, plus you often get what you pay for in areas of safety.

__________________
1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

Lately I just don't trust the brakes that much, just a feeling I have....they brake fine but don't feel smooth.

I guess I will replace the calipers, lines and rotors next month. Depending on jobs coming in it will be ATE or the Bendix.

I saw ATE rebuilds at "Rusty's" for a good price; good choice?

Any tips or suggestions?

__________________
1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

Not putting down Fastlane or Rustys. But O'reillys does carry the Calipers with a lifetime warrentee. And at a good price. Have them on my 300Td and my sons 65 Mustang (rears) and no problems in the last 8 years.

Dave.

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Hi Jorn,
I'm not everyone, but these folks do have very good advise for ya. I'm just one of those that starts noticing the brakes are starting to not do as well, I usually replace everything, and have the rotors turned. and all those brake parts have been exposed to the heat and miles, I just replace every thing. I don't want muphy law to come back to bite on the back-side for the one part I didn't have replaced. It just depends on if you can afford to do it all at once, or do 1 set, then the next month do the other. For me I spend the bucks where brakes and tires are involved. but if its just marking it's spot from say a leaky oil pan, it don't get fixed till I have to add oil inbetween oil changes... hehehe

You can try rebuilding your calipers instead of replacing them. It would be a lot cheaper and it's not that hard to do. Fastlane sells the rubber for the job.

Scott

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

Rebuilding is the way to go. Kits go for little more than $20-$25 for both calipers.

My front left brakes on the 300SD were binding. So much that the ABS kept engaging and those rims were HOT!

I found that the pins holding the pads in place were not in all tha way and the collet was missing on one of the pins. I used a collet from a w123 donor car, bought new pads and fixed the pistons/bores.

I found that one piston was basically frozen and not receeding back into the bore when brake pressure was released. I removed both pistons in the caliper. One wanted to come out easily (inner) and the other wanted to stay in place. I removed the outer by holding the inner in place with a thin plate and a couple of vise-grips. I then pumped on the brake pedal until the piston finally popped out. (make sure you have something to catch all the brake fluid that will come out)

Remove the line from the caliper and take off the rubber boot and inner seal from both bores. I used a screwdrive to remove the corrosion at the outer edge of the caliper bore and then used a fine sanding pad (looks like a thin rectangular green scouring pad) on the piston surface and bore surface. Once everythin is shiny and smooth again, put in a new seal (I used the old as I didn't get the rebuild kit yet) and coat both piston and bore with new brake fluid. Insert the piston and push back into the bore. Do this with both pistons and then put on the new boots. Then put the heat shields back in the outer recess on the pistons.

Press in the rest of the way, attach the brake line. Attach the caliper, put in the pads, spring, pins. You will have to bleed the air out of the line again. Half of the resevoir may be empty though. There will be a LOT of air.

All my brake problems have gone away. The ABS doesn't activate anymore and the rims are all at the same temperature again. I will get the rebuild kit and do the same with the right caliper. It's probably a good thing to do with a 20 year old car.

Don't worry about the small pitting you will see on the surface of the piston. Most of the corrosion will go away without any sign to be left, but some will leave a small pit. It's nothing to throw away your caliper over. The rubber seal is fairly wide and any pitting will have to be a couple of millimeters in length and have some depth to it to have any possibilty of producing a leak. If it didn't leak with all that corrosion build-up, it won't leak with a smooth even surface and microscopic pits.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Briuan,

It may be that the right caliper is working correctly and the left caliper is not working. This will also make the car pull to the right.

P E H

It could be also that a break hose is in need of replacing. When they go bad, they collapse internally. When you apply the brakes, there's enough pressure to get by this collapse, but not enough by the piston to push it back when released.