I’m currently wrestling with a poorly surfaced area for my banjo bolt crush washer to seal on my remanufactured Mopar disc brake caliper. I wish I knew where to get a 7/16” piloted spot facing cutter that could maybe even make the concentric ribbed sealing circles like a stock one! Does anyone know where to get such a cutter with a pilot for 7/16 banjo bolt? Or would it be a worthwhile venture to have a machinist make a handful like a group buy type deal? Or does anybody know if the russel stat-o-seal style washer with the captured o-ring is compatible with dot 3? I know a lot of bikes run those but they also run dot5 silicone brake fluid.

I guess for most if they can’t get a good seal the cheapest option is a new reman caliper at $30-$50. I am going to remove the caliper, inspect and possibly file it a little flatter if there’s a burr or something. I have freshly annealed new copper sealing washers to try but after that I’m going to either rebuild my old caliper or buy another unless I figure out how to resurface this one.

Radar

The mopar washers worked for me when I have a issue with sealing at the caliper. I had to tighten and loosen a few times and no more issues. The aftermarket washers seem to be too hard.

I would get a pair of the used OE ones with the circular ribs & clean em well & try them or as you said, rebuilt calipers (it'd be the easiest).

You might just need thicker washers. I've run into instances where the banjo bottoms out before crushing the washers.

If it's a reman caliper why don't you take it back and get another one? When I did the disc brake conversion on my D250 I had to go back about 3 times to get good calipers.

Anneal the washers by heating them up with a propane torch til red then allow them to air cool. Might need to lightly hit them with a wire brush to clean them up afterwards. When this is done reinstall them and it should seal up. Just had to do this with an aftermarket rear disc kit on my D60. Fought like hell making sure the bolts weren't bottoming, used different washers, etc, etc.

Yup. Like I said in the first post- I have some freshly annealed copper washers. I don’t trust the manufacturer to soften them up and they are probably somewhat work hardened from being punched out of a sheet of copper. I was hoping someone would know something about dot3 dowty or stat-o-seal washers.

I am also surprised nobody makes a tool to touch up the sealing surface. I wish I had a lathe and a heat treating kiln I’d just whip some up out of tool steel. I could probably make a cutter with my caveman tools but it’d be too much work when I can just get another reman caliper.

Here’s a pic of my annealed washers and the style of captured o-ring I’m talking about. I got a little clamshell kit of them- apparently they’re oil resistant but an overnight soak in dot3 softened up the rubber so I won’t be using these on brakes.

Stat-O-Seals are all I use on brake banjo bolts, gave up on the copper washers.

IIRC, I had a issue with aftermarket banjo bolts. They were a little longer then OE. Check and make sure they are not bottoming out like suggested.

Well I found the problem! I guess I shouldn’t have trusted the reman caliper to have a decent surface- it was like the dark side of the moon! I know the copper prefers a nice concentric ridge to bite into it but dead flat has to be better than this!

I filed it flat until the craters were all gone and then sanded in opposite directions up to 800 grit. I figure almost polished is better than lengthwise sanding scratches. Still gotta bleed it more but it has a better chance of sealing now and if it leaks I have a set of stat-o-seals on order for the next problem banjo.

Thanks for all the helpful suggestions and if anybody works at (edit:) cardone tell your boss to clean up the banjo surfaces as part of the remanufacturing process! I’d sure pay $5 extra!

What a before & after, that was terrible. No wonder it wouldn't seal !

Yeah it was really bad. I looked it up- it’s a cardone rebuild.

i would have taken that back to where it came from before i went to the trouble of painting it.
when i pick up calipers from the parts store that are re-mans, i always take them out of the box[es] and inspect thoroughly. there have been some incredibly stupid things found, such as no dust boot installed.

You do nice work.

Thanks man.

I sealed it up with the flat surface and annealed copper just fine but I woke up with this idea- a grade 8 bolt should be plenty hard to cut soft cast iron. A nice fitting pilot shaft chucked in a drill welded to a chunk of grade 8 bolt cut lengthwise and a few threads left on the bottom to cut the grooves would probably work great. Oh well glad I didn’t have to make it.