C2 Original Brake Caliper Bleeder Screws???

[James W.]

I had my original, rear brake calipers rebuilt by Lonestar Caliper. I am having issues with the caliper bleeder screws seeping at the threads, not through the bleed hole. The screws that were in them when they were sent out did not have this problem. I am assuming new bleeder screws were installed and sent back to me. Could this be an issue with improperly machined bleeder screws?

Anyone else have this issue?

Thanks,

James

[Michael M.]

Re: C2 Original Brake Caliper Bleeder Screws???

I would call Ken and see what he has to say about it. From your post it sounds like the issue occurred after the rebuild.

[Joe L.]

Re: C2 Original Brake Caliper Bleeder Screws???

I had my original, rear brake calipers rebuilt by Lonestar Caliper. I am having issues with the caliper bleeder screws seeping at the threads, not through the bleed hole. The screws that were in them when they were sent out did not have this problem. I am assuming new bleeder screws were installed and sent back to me. Could this be an issue with improperly machined bleeder screws?

Anyone else have this issue?

Thanks,

James

James------


I do not understand how the bleeders could leak at the threads but not the through the hole. These bleeders do not seal at the threads. They seal at the tapered bottom-to-seat interface. The threads only serve to draw the bleeder valve to the seat and hold it there. So, if they are not sealing at the seat, they should be leaking at both the threads and hole. In any event, any leakage is due to a problem either at the tapered end of the bleeder or at the seat in the caliper half.

[James W.]

Re: C2 Original Brake Caliper Bleeder Screws???

I found another pair of old original calipers in the basement, the bleeder screws are in excellent shape. I plan to remove the bleeder screws and will change the ones in my rebuilt calipers to see if that make a difference.

James

[Edward J.]

Re: C2 Original Brake Caliper Bleeder Screws???

I found another pair of old original calipers in the basement, the bleeder screws are in excellent shape. I plan to remove the bleeder screws and will change the ones in my rebuilt calipers to see if that make a difference.

James

Wow Jim, I just rebuilt my rear calipers and had the same probem, I looked inside the bleeder hole and could see the seat was pitted and rusty. Could not stop weeping no matter how I tight I tighten bleeder. I tried some thread seal paste and it seemed to stop but have not taken any trips yet. I did have another caliper and tried those bleeders to no aval. Still leaked.

[James W.]

Re: C2 Original Brake Caliper Bleeder Screws???

Ed,

I haven't done anything yet. From your description, it sounds like I am dealing with the same issue. May look into making a sanding device out of one of the bleeder screws to lightly smooth the seating surface inside the caliper.

James

Wow Jim, I just rebuilt my rear calipers and had the same probem, I looked inside the bleeder hole and could see the seat was pitted and rusty. Could not stop weeping no matter how I tight I tighten bleeder. I tried some thread seal paste and it seemed to stop but have not taken any trips yet. I did have another caliper and tried those bleeders to no aval. Still leaked.

[Edward J.]

[Ed D.]

Re: C2 Original Brake Caliper Bleeder Screws???

Had the same problem with right front rebuilt caliper that Bair rebuild. I reluctantly use a non hardening sealer on it and it stopped. I was concerned the sealer would flake into the braking system and cause a clog. Did not have any problem with clogging. Dot 5 is another issue with leaks.
Ed

[James W.]

Re: C2 Original Brake Caliper Bleeder Screws???

I have found the issue with the brake caliper bleeders screw(s) seeping/leaking. Upon removal and inspection yesterday, I found that the bleeders screws provided by the rebuilder were not machined correctly or completely. I've included some pictures of the vendor supplied bleeder screw(s) and a picture comparing the vendor supplied bleeder screw and an original/earlier version that I removed from another set of original brake calipers I have. In the last picture, the vendor supplied bleeder is on the bottom and the old/original screw is on the top. As you can see, the machining was not fully completed as seen in the first and third picture which shows a slight shoulder at the bottom or the base of the chamfer. The sealing surface machined finish of the vendor supplied bleeder screw also appears to be a rougher or more course finish when compared to the old/original bleeder screw sealing surface.

I cleaned the brake caliper bleeder seating surfaces and the threads, applied some Permatex thread sealant on the threads, and installed the old bleeder screws and the so far the leak or seeping has stopped. I use DOT 3 fluid.

Be sure if you are having brake calipers rebuilt that you keep your original bleeder screws. When I reassembled the car and installed the calipers, I did not remove the bleeder screws and do a thorough inspection of them or the caliper bleeder screw seating surfaces, be sure you do.

James

[Mark F.]

Re: C2 Original Brake Caliper Bleeder Screws???

WOW - what a crappy machining job for a safety-related part like that !
Excellent work, James !
Hopefully the sprue (burr) on the repros didn't damage the seats.
Not that I ever have - but never throw away original parts no matter how bad they may look

[Edward J.]

Re: C2 Original Brake Caliper Bleeder Screws???

I think my take is the seat has some rust, and then once you loosen bleeder the seal is lost, as I had no leaks with blenders on my r/rear before I rebuilt the calipers. At least that’s what happened in my case.