Rear brake caliper confusion

[Roadstir]

Last month, I had a leaky rear passenger-side ATE brake caliper and wanted to rebuild it. I ordered a Raybestos kit from Amazon but found that the rubber piston seal was too small for the caliper. I made sure I ordered the rear caliper rebuild kit. After returning it, I found another on RockAuto, and it also didn't fit—it was too small.

Am I missing something?

Thanks~

[johnk]

I did not have any problems with the seal size when I rebuilt my calipers. Unfortunately I don’t remember what kit  bought. I can see if I still have one of the boxes from the rebuilt.

[Roadstir]

Much appreciated, John.  It worries me that two different kits from different vendors, didn't fit.  The OD on the two seals I pulled out were approx. 48mm for the old one and 44mm for the3 two new ones.

[Leester]

The piston seal in your first photo looks like it should fit a caliper with 42mm pistons, which I believe is the correct size for W113s.  There are several rear calipers with different piston sizes that I believe will bolt up but the others have smaller diameter pistons.

If you measure the diameter of the piston and post its size, that would be useful information.

[WRe]

Hi,
Our cars had ATE brake calipers with 57mm pistons at the front and 42mm at the rear.
The corresponding repair kits were 13.0441-5706.2 and 13.0441-4206.2. Other models and brands had 48mm pistons, afaik the W100 (600) at the front.
Are you sure your brake calipers are original? Perhaps different ones have been installed over the years.
...WRe

[Roadstir]

LeesterI, just measured the piston and it was 42mm in diameter.  The first photo is the larger seal I just pulled out of the caliper, so we know that fit.  The other seal photo is of the replacement seal that Raybestos and Amazon sent that is way too small and would not stay in the seal cutout. 

How strange that both replacement seals are too small.  As far as I know, the calipers are original and they are both ATE as shown stamped on them in the photos.  I sent an email to ATE this morning with photos asking if they were the original calipers, but no answer back yet.

Also, does anyone know where I can find the pistons.  All the replacement ones I see online do not show them having the “guide pin receiver” in them to slide onto the post.

Wre- thanks for the part numbers.  Hopefully, they are still available.  Do the stampings on the calipers tell us what model they are?

[twistedtree]

You probably got the kit that I returned to RockAuto because it didn't fit......

[Leester]

I think you're in luck.  Try:  https://pmbperformance.com/collections/vintage-brake-calipers?page=5   

I believe the Porsche 914-4 (70-72) front calipers were ATE 42mm and PMB has the kits on sale for $24.95. But call them and make sure I am correct that these will fit.  PMB also has the little seals that go between the caliper halves and correct bleeder screws if you need them. Obviously you've done this before but they also have a great write up on caliper rebuilding:  https://pmbperformance.com/pages/the-ultimate-brake-caliper-restoration-guide

Let us know how this works out.

Lee
 

[WRe]

Do the stampings on the calipers tell us what model they are?

Sorry no idea, maybe production marks.

[mdsalemi]

Apparently the danger in having multiple different sized brake calipers bolt right on in place, is that...people will bolt on anything that fits especially if they are either unaware, using only what's available (maybe a junkyard scavenge) or trying to do the job in a, um, er, "thrifty" manner.

Our member AlexD had some issues with the wrong calipers, mismatched, etc. that took a while to figure out what happened. I think he got it all sorted by now.

[Benz Dr.]

Those calipers with the pins are not regular 113 versions and look more like 300SE or 600 units.

[Lugnut]

Not sure if this will help, but also going through brake caliper confusion. Found a kit from Centric that is for 42mm pistons, part number 143.35003. I was also unable to find pistons with guide in holes, looks like I will settle for 38mm calipers for rear.