Im trying to figure out which calliper repair kit to order. Theres two types listed on the catalogue im ordering from. One is for ATE and the other is for Bendix.

As there are no visible marks on the front callipers with "ATE" on them like on the rear ones does this default them to Bendix?

They are likely the original callipers that came with the car.

Thanks for the support.

Maybe you could compare the pictures of the calipers on the Fastlane website. There are some very obvious differences between the ATE and Bendix models.

bendix calipers have wire springs, ate uses flat plate springs.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

With no pads installed, it's reasonable to assume one piston will move and the other one won't since there's nothing holding either one back then the easier one will move. The sealing ring in the caliper may be "fighting" going backwards so it may be difficult to get it going in that direction. Once it starts it should be easier.

As stated above, pressing the pedal with no pads is probably asking for a piston to pop out too far, and then you've got trouble.

To push the piston back in, try a simple spring glue clamp like one of these: http://www.ronshomeandhardware.com/Spring-Clamps-s/2751.htm

Or one of those pistol grip clamps. http://www.ptreeusa.com/ratchetClamps.htm

Put one old pad back in (if you can) before you try to depress the piston on the other side or all you'll do is see-saw the pistons in and out. If you can't get the pad in since you've moved the pistons out with the pedal, then try to clamp the piston in place with the ratchet or C-clamp while you squeeze the other one back in.

You might want to remove the caliper and use the old pad(s) as backing plates on the piston so you get the clamping force "square" to the piston and don't make the piston go askew in the bore and jam up. You may need to do this in any case to make the C-clamp work.

The fact the pad was difficult to remove is inconclusive by itself. It may not have had any lube on the slide rails, it may have been crudded in there with caked on dust. But that may help explain the squeaking if the pad didn't easily move away from the rotor when pressure went off the piston.

That may contribute to your pedal feel as well (speculation) if the pad didn't track with the piston and you had to push a little extra to get the piston/pad/rotor into good contact.

I wouldn't jump into planning a caliper rebuild yet. Get the pistons fully retracted. Clean the old calipers, make sure your heat shields are in place and properly oriented (you do have heat shields, right?), properly lube the back and slide portions of the new pads and see what happens. Apply "brake grease" at the arrows (specific high-temp product, not regular grease) http://www.peachparts.com/shopforum/attachments/diesel-discussion/60623d1225870900-how-guide-replace-front-brake-pads-rotors-w123-pad-grease-point..jpg

Pics would be helpful.

You do know that you are breathing brake dust as you drive? It's coming from the cars in front of you when they step on the brakes.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

That is a LITTLE different from what I ( and others ) used to do regularly... use the compressed air nozzle to clean the brakes while simply holding our breath... inside a garage...
and we are all breathing diesel particulate even when we are not driving our diesels in the same fashion... even when we are not near any roads or driving at all......

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Az,

I just went through an episode of squealing brakes on my 85 300DT. What I found is the front pads were worn out. I also found the disc was worn to the point the disc could hold water ( looked like a bowl). The squealing noise was the backing plate coming in contact with the lip of the bowl on the disc. I didn't take any measurements, but I think my disc was below the minimum thickness for the disc. I could not remove either puck as the rim on the disc had the pucks caged in.

Pedal felt soft with the old pucks in. I sent the car to my mechanic to do the disc and pad replacement. Lifts and air tools are wonderful when dealing with 20 year old rusty bolts.

BTW, my car has Bendix on the front, and ATE on the rear.

Hammerwerfer

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1985 300DT 241,000 miles
1979 300SD 202,000 miles

Thanks for that. The just heat sheilds are what again? I just ordered a new caliper repair kit, would they be included iun there?

Ill try some way of getting the pistons to push back in as suggested. I think Ill just take the callipers off to gte a good cleaning and might as well do a bleed while im there.

Ill try posting some pics today once I take everything apart again (I had to pack up for two weeks so had to put the wheels back on to move the car)

The link in post #1 in this thread: Bent something inside the front right caliper...

Notice how the shield (metal thing in the middle) has a crescent? That crescent fits into a cutout on the piston so the pad can sit nice and flat. If the shield is mis-installed, then the pad won't sit right.

If you end up doing a rebuild, you'll need to get the piston oriented correctly in the bore for the shields to fit and the pads to fit. It's all straightforward, but not necessarily simple or obvious.

With brakes, it's also important to know when you're in over your head. If it isn't working, ask for help; or go for a set of warranteed rebuilts and new hoses.

Heres some pics of the calliper on the drivers side. Looks like the heat sheilds are in place but not the best condition. I do have a rebuild kit. The boots look intact surprisingly.

As you can see the inner piston has not been able to retrac. I was ale to press th outer one all the way in usig my fingers wih a steady force. The other one wouldnt budge.

The other pic obviously is the pad, and its comparison to a new one. I measured and its rougly 7mm of pad-not including the metal of course.
I cant find what the recomended spec is for them. In the manual as well as in my repair manual they say "check for reccomended wear thickness"

Im going to go for taking it apart to see if I can get it moving again. I may try presing it in gently with a clamp first.

Do you think one seized up piston could cause poor braking - i.e. soft brakes or brakes that you need to push hard on to get to function?
My guess is that theyve been like this for some time, - the seized up piston, but I only started noticing strange behavior in the last month or two.

Attached Thumbnails

   

Pad wear is down to 2 mm, so the notch that's almost worn all the way through should be about the limit. Backing plate is supposed to 4.5, so 2 + 4.5 puts you really close to your measured 7 mm.

Compare the inboard pad to the outboard pad. Are they worn about the same, or was one side much thicker or thinner? If they were close, then the caliper was probably working okay and is less likely to be seized but only difficult to push back in.

Clamp the outboard piston in place. Expect it to retract/compress almost flush with the caliper. Once that is clamped, then squeeze the other side hard. Put an old pad in there and use a clamp. Try to compress from the center, not from the edges.

There's no evidence of grease on the slides and your pad is worn nearly to the limit. That may explain the squeaking. You've also got a LOT of crud in there and it'll be difficult to fit the new pads into the caliper until it's scraped out of the corners.

Pedal feel is subjective. If the piston is really seized, then yeah, it could explain a soft pedal and harder braking since you'd only be pushing on one side of the rotor, but for that to be the case I'd expect significant difference in pad wear between inboard and outboard so you'll need to compare them to help determine that.

Since the caliper is off, you might as well inspect the rotor for thickness, warping, etc. Consider replacing the hoses since they're undone as well.

OK so I got one of the pistons out using a bicycle pump like someone had suggested. I cleaned up the calipers and now Im wondering if I have heat sheilds in place or not. There are thin metal plates seemingly permanently riveted or bolted to the piston, but their shape is a little different from the new sheilds that came with the repair kit.

It looks to me like the new ones are actually supposed to sit in the ones that are built into the piston, am I right? The ones that are there, (the backing plate?) are a little bent here and there. Ill try and reshape them.

Ill try pushing in the piston with a c-clamp and a metal plate to see if I can get it to moe. Is it better to push it in rather than try and pull it out somehow?

Update: I managed to sueez the other piston down using a vice. It fit just right into the caliper but was pretty hard to push down. Now the chore is getting it out. How to do that now. I will have to plug the other side first obviously, but I wonder if its a sign of damage that it was significantly harder to push down than the inner calliper?
Off to bed

Ive been trying this morning to get the inboard piston to move out of the caliper without success. This is using a bicycle pump, with the other piston in place and
clamped down so as not to come out. Ive put all the force I can into the bicycle pump, (which ejected the other piston well) and it doesn't budge. Ive fully pushed it in with a vice but now cant get it out.

My only Idea is to reconnect the caliper to the brake line and bleed it and try using the brakes to push out the piston. I dont know how else I can get enough force to eject it.

Any Thoughts?

Update: I managed to get it to move out now that I hooked it back up and bled the line. Now I was thinking of pushing on the brakes till it popped out. my concern now is how to gte it back in if it was so difficult to come out.

Also I noticed the repair jit that I bougt for bndiz=x callipers have a heat sheild type ring which matches roughly th size and shape of the metal plate already on the piston, however there is no way for it to sit on there snuggly or at all it seems as there are some little parts bent a certain way that the original one doesnt have. Are you supposed to be able to remove the plate thats attached to the piston?

I saw the other thread. Do you have one or both pistons out now?

Its not looking good. Ill be looking for a new set of calipers..