bleeder valve threads leak

[R N.]

Hi Everyone,

I've replaced my calipers with rebuilt units on my '67 and had no problems bleeding the system, but I do have a problem after the fact with the actual bleeders leaking at the threads where they screw into the caliper. The bleeders will not seal.

I did a search here and didn't find anything that could help me, so I'm wondering if anyone else has had the same problem?

I have tried different sets of bleeders (supplied by the rebuilder) and the problem still persists. I have spoken to the person who rebuilds the calipers and he states he does machine the seating face where the bleeder valve seats.

The company I purchased the calipers from will replace the calipers with another set of calipers, but at this stage I'm wanting to learn more about what may be the cause of my problem.

As always, thank you for the help.

[Gene M.]

Re: bleeder valve threads leak

Kurt,
It's not the threads that causes the issue. The problem is the taper seats. Either the casting is bad or the bleeders are wrong.

I would see no reason to remachine the casting seats. If they had rusty seats or mared up throw them away.

[Lynn H.]

Re: bleeder valve threads leak

I have run across similar problems with rebuilt calipers where the rebuilder repaired damaged bleeder threads by drilling out and bushing or sleeving the threads for the bleeder screws. As Gene stated the taper seat is what seals the brake fluid in, but in the above mentioned situation it kept leaking around the threads, as the repair was not done correctly. My suggestion would be to replace the calipers in question, as this problem could very well come back to haunt you at a later time even if you get them to stop leaking now. Some of the rebuilders will go to great lengths to keep from throwing out a damaged core. I would inspect "replacements" carefully before installing to make sure they do not show evidence of repairs in the bleeder screw areas. Nothing like spending the time, effort, and money only to have to do it over at a later date because of defective parts.
Lynn

[Joe L.]

Re: bleeder valve threads leak

Hi Everyone,

I've replaced my calipers with rebuilt units on my '67 and had no problems bleeding the system, but I do have a problem after the fact with the actual bleeders leaking at the threads where they screw into the caliper. The bleeders will not seal.

I did a search here and didn't find anything that could help me, so I'm wondering if anyone else has had the same problem?

I have tried different sets of bleeders (supplied by the rebuilder) and the problem still persists. I have spoken to the person who rebuilds the calipers and he states he does machine the seating face where the bleeder valve seats.

The company I purchased the calipers from will replace the calipers with another set of calipers, but at this stage I'm wanting to learn more about what may be the cause of my problem.

As always, thank you for the help.

Kurt-----


As the others have stated, if the bleeder leaks when the bleeder valve is tight, the problem is almost always with a damaged bleeder valve seat. Very rarely it can involve a damaged bleeder valve, itself, but that's more uncommon since the bleeder valve is WAY harder than the soft cast iron seat. It's worth checking, though. Just install a new bleeder valve and if it still leaks, you know it's the seat. It is possible to repair the seats, but it's not a job you can do.