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Posted by: 914 RZ-1 Mar 11 2022, 07:10 PM

I am rebuilding my rear brakes. I've taken everything apart, cleaned them with Simple Green and am currently soaking the parts in Evaporust. However, I might need to sandblast them.

1. Anything I should know before I proceed?
2. What to plug/tape up? I'm assuming all holes and machined surfaces?
3. What about the area in the caliper where the piston goes?
4. What blasting media should I use? I have some dull aluminum oxide I've used several times.

I've looked on the 'Net and found a few tidbits, but nothing specific to 914 brake calipers, so I thought I'd post here and see if anyone had any experience, tips and advice.

Thanks!

Posted by: Shivers Mar 11 2022, 10:30 PM

Some info here

https://www.pmbperformance.com/brakehowto.html

Posted by: 914Sixer Mar 12 2022, 07:17 AM

Use glass beads not sand.

Posted by: 914 RZ-1 Mar 12 2022, 12:02 PM

Thanks! Will do!



Thanks! This was helpful, but there was only a brief mention of sandblasting. I have the PMB video bookmarked as well, so between this and that I should have what I need to rebuild these, but I'd still like to know what I need to do to properly sandblast these.

Posted by: 914 RZ-1 Mar 12 2022, 12:12 PM

Here's a photo of the cleaned parts. I've labelled the areas I think I need to cover with tape:





A are mating surfaces, so it seems those need to be kept smooth and flat.
B may not be critical, but they are mating surfaces so...Any thoughts and comments?
I'm mostly concerned about the piston bore area (area C). According to the PMB document linked above, this area will be plated, so it needs to be cleaned.

Posted by: 914Sixer Mar 12 2022, 01:12 PM

I always cleaned the complete. I used duct tape to cover what I did not want to blast.

Posted by: mepstein Mar 12 2022, 01:33 PM

Are you getting them replated? Getting the piston bores replated is really the important part to longevity.

Posted by: Shivers Mar 12 2022, 02:21 PM

Don't forget to plug the bleeder ports.

Posted by: Sycolyst Mar 12 2022, 07:42 PM

I glass beaded mine covering all the internal openings. I then wiped them with lacquer thinner and blew them out with compressed air. I took 1500 grit sandpaper to de-glaze the piston bores. I painted mine with caliper paint and installed all new rubber and rebuilt them. They came out great. Take your time, it's not a hard project.

Posted by: PatMc Mar 13 2022, 12:41 PM

Depends...are you going to have the castings replated or leave them bare or paint them?

If replating, don't mask anything, blast everything. Assuming this is a relatively small home based blasting setup and not some 300 PSI deal where you can blow holes through things, nothing will be damaged or hurt at all. Aluminum oxide or glass bead or whatever media you choose will work fine. All calipers at the commercial level rebuilders are blasted with steel shot, and nothing is masked....and if they don't leave them in the blaster for 3 times as long as they should, there is zero damage to the casting or any machined surfaces.

If you're not going to be replating the castings, then I'd mask off anywhere that plating still exists...like on the mating surfaces between the halves. I'd also follow up with a wire brush on a drill or grinder to polish the bore and seal groove as best you can after blasting, then coat the bore/seal groove with a good caliper assembly lube (containing rust inhibitor) ASAP. The caliper will still likely be short lived without any plating or surface conversion treatment of the bore (when my customers request painted calipers, the castings get a zinc phosphate treatment for at least SOME protection and better paint adhesion).

Posted by: 914 RZ-1 Mar 13 2022, 07:40 PM

Yes, I will be re-plating them. Can anyone recommend a good local (SoCal, near near the Santa Clarita or San Fernando Valley) plating company?

Posted by: Shivers Mar 13 2022, 07:50 PM

Three I found on google


Van Nuys Plating Inc
3.5
(8) · Plating service
Van Nuys, CA · (818) 785-5885
Closed ⋅ Opens 7AM Mon


Pacific Plating
No reviews · Plating service
Sun Valley, CA · (818) 896-1102
Closed ⋅ Opens 7AM Mon


M & R Plating Corporation
5.0
(1) · Plating service
Pacoima, CA · (818) 896-2700

Posted by: PatMc Mar 13 2022, 08:54 PM

Sent you a message

Posted by: 914 RZ-1 Mar 14 2022, 08:23 PM

Thanks. I was hoping to see if anyone had firsthand experience with a plating place that was local to me.