850 Rear Brake Repair - AGAIN - Tips

[PeteB]

DIY:




Low cost DIY Zinc plate:
Zinc Plating Steel on the Cheap and Applying Yellow Chromate (Part 1of 2) - YouTube

[PeteB]

I'm looking at rear calipers again at FCP and noticed that there's mention of 10 vs. 11mm mounting.
I don't remember checking this the last time I replaced the calipers, anyone know how to determine
what is the right fit?
Just noticed that FCP web site says the 10mm fits our car and not the 11mm.

[abscate]

I can’t remember if this is an issue with brake hose thread or the caliper mounting bolt diameter. I think it’s the brake hose thread

[PeteB]

Low cost DIY Zinc plating:
and:

[PeteB]

It is 12-6-2022 and a bit over a year since I last inspected the rear brakes. Our car has
143767 + 63,462 = 207,229 miles and 4767 miles since the last time I worked on them in 10-2021.
I put new ATE pads in on the 19th of October 2021 and today it looks like less than 1/4 of the pad is used.
They have even wear and seem to be okay. The rotors also look very good.

I noted that one of the pistons was stuck and I freed it in 2021, today it seems stuck again but we wouldn't
have even wear if it was. I'm unable to move it but it is not possible to use a C clamp in there. Perhaps it
moves with the brake line pressure.

The calipers are uncoated Cardone rebuilds from 2017 and while they are rusted it is nothing like the super
thick rust shown in pictures at the start of this thread. In fact just light wire brushing brings back the silver metal.

However, I tried to remove the pads and while they were not frozen it took a lot of effort to get them out,
mostly prying with a screw driver. This was due to rust. Once they were out I used a small wire brush to
clean the area of the caliper where the pads ride, and the edge of the pads themselves. Then I apply caliper
grease to the slide area and the edge of the pads that rides in them.

I ordered a small roll of the sheet zinc and plan to plate a new pair of calipers from FCP then return these,
but since they seem to be working I might wait until Spring. On the other hand I hope that FCP doesn't
discontinue the caliper rebuilds for such an old car.

[abscate]

There still seem to be a lot of these calipers in the supply chain, parts Geek reports 20-50 count rebuilds in stock for rear caliper under $50 with core.

I’ve sent back two unrebuildable cores so I was getting worried about this , too, but it looks like we have time still.

[PeteB]

That's good news about the supply!

Forgot to mention that there is a scraping sound on the passenger side and it did it even with the
pads out so it seems to be the parking brake. Seems that I have to take the caliper off in order to
remove the rotor and see what's going on in there.

I should probably do the new calipers and parking brake at the same time but the zinc sheet won't
be here until next week.

[abscate]

My caliper rust problem has been solved as my 6th car in my fleet becomes the latest to ride the FreeCP train of free replacement parts. The Centric calipers seem to be lasting 5 years plus on my P80s, but once they seize they get a trip to Milford for new ones. I keep a new set on my shelves so I can flip a car in a day, and return them the following week.

Tell them you're not paying for the ones you keep in inventory until you pull them off the shelf and install them.

Ha! I missed that one , old school. Enjoyed it.

Been a good year at FCP so far in 2023, only $3000 spent. Most of that was two cats for the Bavarian money waster