Rebuilding Bendix 4-piston calipers

[hemi68charger]

Hey gang.. I'm reading the service manual for my '69 C500 and it mentions applying #55 Dow-Corning Pneumatic Silicone Grease (or equivalent) to the inner bores and coating the seals prior to installing on piston.. Anyone know if I can use regular wheel bearing grease or is that a big no-no?

Thanks.

[roger440]

Do NOT use regular grease. It will degrade the rubber. I used a silicone grease whuch wont have any affect on the seals.

[Chryco Psycho]

I agree wheel brg grease is a no no . just using brake fluid is often enough

[resq302]

Troy, where did you go to get the bores sleeved?  Or did you just hone out the original ones?

[hemi68charger]

Troy, where did you go to get the bores sleeved?  Or did you just hone out the original ones?

I've honed out the bores... They aren't "prefect", but I believe they will do with the honing. There are a couple of places I can ever-so faintly feel something to the fingers...

[resq302]

Ok, I have used JB weld as they said it will not be effected at all by brake fluid.  I wire wheeled out the rust pitting as best as I could and then applied the JB weld and then sanded it down through the different stages of grit and then honed it out.  So far it seems to be working fine.  But what I will likely do with the spare set I have is when I have the money send them out to be stainless steel sleeved so as to never worry about the pitting issue ever again.

[HeavyFuel]

So how smooth do the bore walls need to be?

I understand that in a perfect world, they should be like a mirror.  But there are probably a lot of cars on the road today, where the calipers are working fine with some slight pitting/corrosion on the bore walls.

But does anyone have any idea what we can get away with?  I cleaned up the bore pits yesterday with a tiny Dremel stone, then honed, scotchbrited them smooth. 

You can still see and feel some very small imperfections, but hey these brakes worked when I took the calipers off the car, so anything should be an improvement, right?

What's the worst case scenario with these tiny pits?  A little seepage, or are the calipers going to leak like a sieve?

[John_Kunkel]

What's the worst case scenario with these tiny pits?  A little seepage, or are the calipers going to leak like a sieve?

Either is a distinct possibility. Any irregularities would warrant sleeving.

[HeavyFuel]

Re-sleeving  

$260......each.  

I guess I'll put on the re-maned ones I have that are super shiney/galvanized looking.......they'll look totally stupid next to all of my OEM finishes on the front suspension. 

I could wire wheel those and shoot them with a cast metal color paint.

[resq302]

What I did with mine was put a little JB Weld into the pitted areas.  Prior to doing this I called up JB Weld company and asked them if it would have any reaction with brake fluid and they said it shouldnt.  So far, its working great on my charger!

[Brightyellow69rtse]

theres nothing jb cant handle lol. honestly its never failed on anything i ever tried to use it on.   well i gotta take that back. i tried it on a pretty badly cracked gas tank on a chain saw. that didnt work, but i coulda prepped it better. 

[HeavyFuel]

What I did with mine was put a little JB Weld into the pitted areas.  Prior to doing this I called up JB Weld company and asked them if it would have any reaction with brake fluid and they said it shouldnt.  So far, its working great on my charger!

I thought about using a product like that, but at this point the bore walls have very small irregularities...no more "pits" so to speak.  So I don't think I would have much success in getting the stuff to stick to a very small smooth surface.

Did you smeer a paper thin layer of putty over the pitted areas, then hone?  How did you prep the bores to recieve the putty?

[resq302]

I wire wheeled the pitted area with a dremel tool and then used a hard rubber rectangular glazing putty spreader to lightly spread it into the bore.  After I let it dry for 24 hrs, I sanded down the area by hand until it was pretty much smooth and flush with the rest of the bore.  I then took a hone and did a final hone on the bore making it as smooth as what it would have been after a professional rebuild.