Brake bleed bolt question
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Road Warrior
Joined: Oct 2009
Posts: 1,317
Likes: 16
From: Texas
Brake bleed bolt question
I have an 04 dyna and was doing some maintenance and the rear master cylinder brake fluid was filthy. So i figured I'd bleed it out with some new dot 5 and be finished with everything.
Well the bleeder bolt wouldn't budge. Like it was cross threaded in there. Finally get it out and it's rusted to hell. I go to local auto store and get a pack of 3/8 - 24 bleeder bolts 1 1/4" long. They match up in size with original one so i screw in to shoot same depth and try bleeding the brakes and i can't get fluid to stop coming out when depressing brake when tightening down.
could the auto store bleeder be different from harley? Id hate to have to get a new caliper. Man, both bleeder screws won't stop fluid when pressing brake. Any help or advice appreciated.
Well the bleeder bolt wouldn't budge. Like it was cross threaded in there. Finally get it out and it's rusted to hell. I go to local auto store and get a pack of 3/8 - 24 bleeder bolts 1 1/4" long. They match up in size with original one so i screw in to shoot same depth and try bleeding the brakes and i can't get fluid to stop coming out when depressing brake when tightening down.
could the auto store bleeder be different from harley? Id hate to have to get a new caliper. Man, both bleeder screws won't stop fluid when pressing brake. Any help or advice appreciated.
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Road Warrior
Joined: Oct 2009
Posts: 1,317
Likes: 16
From: Texas
they look good from what i can see. It's not leaking from threads though. It's coming through center of bleeder bolt.
Advanced
Joined: Jan 2019
Posts: 57
Likes: 16
From: Missouri
My guess is the bleeder is not fully seated in the caliper. Either due to debris or damaged threads.
If it was rusted, threads could have been damaged.
the old one didn't break off down in there? Unlikely but might look.
If it was rusted, threads could have been damaged.
the old one didn't break off down in there? Unlikely but might look.
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Road Warrior
Joined: Oct 2009
Posts: 1,317
Likes: 16
From: Texas
Didn't break off as far as i can see. Any suggestions on cleaning threads? Guess I'm gonna have to pull the caliper off now. Maybe for it with some compressed air to make sure no debris in there?
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Road Warrior
Joined: Oct 2009
Posts: 1,317
Likes: 16
From: Texas
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Beveled end looks close enough. Run a blind tap into the hole to clean up any munged threads.
The threads on those don't seal. They're just regular machine threads. All the sealing is done by the tip of the bleeder screw in the bottom of the hole. As long as it's getting down to the bottom, and as long as there aren't any defects in the bottom of the hole, it will seal.
The threads on those don't seal. They're just regular machine threads. All the sealing is done by the tip of the bleeder screw in the bottom of the hole. As long as it's getting down to the bottom, and as long as there aren't any defects in the bottom of the hole, it will seal.
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Road Captain
Joined: Sep 2010
Posts: 514
Likes: 17
From: SW Mississippi
Dude, those threads on the new one are seriously messed up. They don't seal, but they do have to not be stripped out so that they can tighten up enough to seal the beveled part. You may have a big problem. Like said previously, chase those threads in the caliper, and be very careful with a new bleeder and don't overtighten it...
Seasoned HDF Member
Joined: Aug 2009
Posts: 9,243
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From: west Michigan
Disassembling an old caliper and cleaning out the rust is no big deal but sometimes there's too much rust and they can't be saved. That's what can happen when motorcycle owners don't change the brake fluid every couple of years.
Last edited by RK4ME; Feb 17, 2019 at 12:24 AM.