Calipers - PeachParts Mercedes-Benz Forum

adamkat22 · #1 08-05-2017, 01:24 PM

I'm replacing brake pads on my 84 300TD and the pistons on one side won't retract. My first question is...does this mean I need a new caliper. If so, can I have different calipers on each side of the rear? Looks like these are ATE calipers...which seem to cost $300. Can I just got a $60 caliper of another brand and put it on? Would I need to do both sides? Can I unfreeze my pistons somehow? Thanks

kendogg · #2 08-05-2017, 03:10 PM

You can probably rebuild them if you're up to the task. But yes, it's going to be a different caliper each side. They're mirrors of eachother. Mostly due to bleeder location.

dkr · #3 08-05-2017, 06:32 PM

I highly recommend NOT to have a different caliper on each side. If you do, you will have uneven pad wear and end up prematurely replacing pads. Also, you will loose braking power.

Dkr.

Junkman · #4 08-05-2017, 07:23 PM

Brands need to match on one end of the car. There are 2 brands available. It doesn't matter which one you get. Buy locally because you may need to exchange them and shipping kills any savings.

You should get new hoses because they haven't been changed. It would also be good to change bearings if you intend to keep the car. No sense doing the job twice.

Pads used to be specific to caliper brand. All jobbers now spec to be used in any brand.

How are the rotors?

Note that bleed valve is installed on the high side. I've had calipers mis boxed and rears in boxes for fronts.

Be sure to keep your cores until everything has been working for up to a month. Stores won't replace your cores if you want money back and need them to buy elsewhere.

Carpenterman · #5 08-05-2017, 08:16 PM

My advice is to install a rebuilt caliper with a brand that matches the other side.

A stuck piston, in my experience (even if you can free it up) means that it will always be prone to re-sticking. Once it corrodes to that point, it's toast.

my123ca · #6 08-05-2017, 09:12 PM

According to the FSM, you can have different brands of caliper on the rear. You can try to unstick the caliper by using a clamp. I tried unsticking one of the girling caliper but it did not move, so i replaced it with an ATE.

dieseldan44 · #7 08-05-2017, 09:58 PM

did the car sit for a while?

i really like using large pump pliers to set these free -

https://www.amazon.com/gp/product/B000189GSI/ref=abs_brd_tag_dp?smid=ATVPDKIKX0DER

if that doesnt work, go to chain a autoparts store and buy two matching rebuilt calipers for $120 total and dont look back. i have installed many and every one has been fine. (cue everyone with bad chain store caliper experiences)

cfh · #8 08-05-2017, 11:25 PM

I would go to the junkyard and get a used set of calipers and rebuild them. I prefer ATE calipers because you can get rebuild kits for them from this website. It's kind of "steppy" but satisfying because you avoid the well-documented problems with rebuilt calipers not fitting right and you don't run the risk of disabling your ride waiting for the right parts to come in.

I use Dow Corning High-vacuum silicone grease to lubricate the pistons for re-assembly.

I've read about upgrading to W126 rotors and calipers that might also be something to think about.

I kind of remember reading that wagons have thicker calipers in the back - the w126 calipers are also thicker so that shouldn't be a problem. Gen2 w126 (86 to 91) uses a larger wheel - that might be a cool mod, too.

Father Of Giants · #9 08-05-2017, 11:59 PM

You CAN unfreeze it. But if the piston is stuck, then more than likely you have a bad caliper, and unfreezing it will have it get stuck again almost immediately. It's what happened to me personally.
I recommend just going to NAPA and ordering the calipers. And then give them your old ones for a core exchange refund.

Also, how do your rotors look? My calipers were so bad that I had a huge lip on the rotors, so I have purchased replacement brake disks as well to go along with my pads, brake lines, and calipers.

tdhawk · #10 08-06-2017, 01:23 AM

300TD's (wagons) have different sized rear calipers. I rebuilt mine when I had a sticking/stuck caliper about a year, 30K miles ago, and it is sticking again - like posters above have said. I used my injector pop tester to force the stuck piston out. If your situation is like mine, kind of uncertain, it might not be so simple to rebuild.

The rebuild kit I got from this site, for a 300TD, did not fit, but I was able to reuse the old seals and o-rings with careful and painstaking trimming. No leaks and they worked fine - for a while. I am not sure if in the past someone put different sized rear calipers on my car, or if this site does not have kits for rear calipers. Looking at different sites for rear calipers for a 300TD and local parts stores, it does not appear most recognize there are different sized calipers for the wagons than all the other 300's.

My right rear sticking again, I'm not sure whether I'll try to rebuild again, buy rebuilt, or new ATE. Part of my indecision is not knowing whether I've got the correct calipers on the rear, if anyone has a rebuild kit for rear calipers only used on the wagons, or if whoever I buy a rebuilt one from knows there is a difference.

Does anyone know if a sedan rear caliper will line up with the bolt holes and fit on a wagon?

If not, then this site sold me a rebuild kit it said fit a 300TD caliper that did not fit. Way off. If a sedan or coupe caliper can bolt up to a wagon, then maybe some PO or shop put the wrong calipers on my car, and not knowing that, I ordered the wrong kit.

Anyway, just something to keep in mind with rear calipers on a wagon. If the others fit also, then its probably not a big deal to just replace with whatever you want.

I'm hoping I find out if they are interchangeable too.

Thanks to all you knowledgeable folks out there in advance.

1985 300TD, egr, arv, trap oxidizer delete curtesy of rollguy, 367,000 daily driver

t walgamuth · #11 08-06-2017, 05:45 AM

The rear calipers on a wagon have a slightly larger bore but use the same pads. This gives the heavier rear end of the wagon a little more braking power. I would not mix with a sedan caliper. I would not hesitate to use different brands caliper on either side though. The bores of the different brands are the same as are the pads.

The fsm is written for a dealer so makes recommendations in order for a business to make money and avoid any potential problem. A hobbiest 40 years later has different needs.

tdhawk · #12 08-06-2017, 11:50 AM

Thanks t walgamuth. I think you answered my question, but just to be sure - will sedan calipers bolt onto a wagon. I think that's probably what was done to mine, and why the kit was too big.

Carpenterman · #13 08-07-2017, 06:47 PM

I recently had a stuck rear wagon caliper that wore down to the metal. The damn rebuild was less than a year old! I don't like ordering calipers online because of the shipping on the cores so I went to my local NAPA. They couldn't get a wagon caliper. Since I needed the car (and I'm a redneck mechanic), I ordered the sedan caliper and installed it, knowing it was not correct.

The car brakes fine and there is no pulling or unusual behaviour. As was said, the pads are the same as the wagon. I took a chance and so far it is working out.

Your results may vary.

t walgamuth · #14 08-07-2017, 07:10 PM

It should be perfectly safe but with slightly longer stopping distance than the stock wagon calipers because of the extra weight of the wagon.

torsionbar · #15 08-07-2017, 07:36 PM

Quote:

Originally Posted by Carpenterman

A stuck piston, in my experience (even if you can free it up) means that it will always be prone to re-sticking. Once it corrodes to that point, it's toast.

I think this depends on which part has corroded. If it's the piston, and the seal-swept area has pitting or roughness, the piston is garbage. If its the caliper body, usually it can be smoothed back into spec with some fine grit sandpaper.