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Old June 23rd, 2019, 05:16 AM   #1
nocturncal
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Brake Bleeder Valve Keeps Leaking After Rebuild

Hey all,

So I ended up rebuilding my calipers. Everything worked out good the first time, but then I decided that I wanted to put some Galfer SS Lines on.

So took the calipers apart, cleaned everything again, and put the SS Lines on, and put everything back together.

This time around, the bleeder valve keeps leaking, causing the brake lever to become spongy under hard braking (pumping the brakes restores the lever firmness). I think I may have tightened the bleeder valve waaaay to tight (looking back it felt much tighter than the 48.7 inch lbs stated in the torque specs)

Could I have permanently messed up the bleeder valve/caliper by tightening em too tight? I think it has something to do with the bleeder leaking bc when I place a tube with fluid on the tightened valve (49 inch lbs) and squeeze the lever, I see the fluid slowly start to move forward. .
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Old June 23rd, 2019, 06:16 AM   #2
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I suppose an easy thing to try would be to put a new bleeder in and see if that one seals. It's possible the one you're using is cracked at the threads.
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Old June 23rd, 2019, 02:05 PM   #3
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Are you sure it's leaking from bleeder screw?

Clean caliper off completely with brake cleaner so it's dry.
Then squeeze lever while looking closely at caliper to see where new fluid appears.

You may have gotten some grit in between end of bleeder screw and csliper, preventing it from sealing. Remove bleeder screw completely and inspect tapered seating surfaces on both surfaces.

Did you use new banjo-bolt copper crush washers when installing new lines?
I've seen some of these kits come with steel washers which will not seal.
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Old June 27th, 2019, 03:40 PM   #4
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Quote:
Originally Posted by DannoXYZ View Post
Are you sure it's leaking from bleeder screw?

Clean caliper off completely with brake cleaner so it's dry.
Then squeeze lever while looking closely at caliper to see where new fluid appears.

You may have gotten some grit in between end of bleeder screw and csliper, preventing it from sealing. Remove bleeder screw completely and inspect tapered seating surfaces on both surfaces.

Did you use new banjo-bolt copper crush washers when installing new lines?
I've seen some of these kits come with steel washers which will not seal.
I was thinking it was leaking from the bleeder screw because after tightening the screw, I'd hook up a tube to the screw that had a little fluid inside it, squeeze the brake, and I could see fluid slowly moving out of the caliper into the tube.

The all balls kit came with copper washers. I put 2 new washers on, one on each side of the brake line bolt hole and tightened to 49 in lbs

In any case I'll reclean and rebuild the calipers again and check back in.
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Old July 26th, 2019, 09:07 AM   #5
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So I finally figured it what happened. The put the o ring attached to the bleeder screw cap on wrong. now that it's sealing the bottom of the bleeder screw cap on, my brakes are rock solid.
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Old July 26th, 2019, 09:10 AM   #6
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I'm not following. What connection is there between the bleeder cap and the bleeder screw sealing?
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Old July 26th, 2019, 09:19 AM   #7
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Quote:
Originally Posted by Triple Jim View Post
I'm not following. What connection is there between the bleeder cap and the bleeder screw sealing?
Sorry maybe I typed that wrong (haven't had my coffee yet). I placed the o ring that's attached to the cap between space where the bleeder valve screws into the caliper
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Old July 26th, 2019, 09:26 AM   #8
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I've never seen a bleeder that uses an 0-ring to create the seal. There's a lot of pressure in there when the brake is applied hard, and the seal should be metal to metal. Unless I'm missing something.
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Old July 26th, 2019, 09:49 AM   #9
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Shoot...that today makes sense about the an o ring not being able to resist high pressure. I've been having leakage from the crevice between the bleeder valve screw and where the screw screws into. And placing an o ring in between seems to be the only thing that keeps my brake lever feel rock hard. The o ring so far has held up so far under normal city driving conditions.

I'll try putting the brakes under more harder braking and report back. I'm guessing the ring is going to tear tho

Maybe instead of an o ring, maybe a crush washer? I'm really trying to avoid buying another rebuild kit and more so just curious.
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Old July 26th, 2019, 03:26 PM   #10
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Most likely conical surface between caliper and bleeder screw is not mating properly. This could be due to corrosion or distortion of screw. O-ring is just gimmick to fill mismatched surfaces. Need to remove bleeder and examine both surfaces closely to determine why they aren't sealing.

There should be nothing between bleeder screw and caliper.

Also use torque-wrench to tighten. Might be too late now as bleeder may be bent out of shape permanently from over-tighening.
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Old July 26th, 2019, 03:50 PM   #11
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Post picture of screw you have, especially close-up of conical tip. Let's see if it's been swapped for incorrect one. As you can see, bleeder screws vary greatly in shape, it's possible someone installed incorrect one on your brakes and that's why it's leaking. Note none of them uses O-ring to seal.



What you saw as "O-ring" is probably remnants of loop holding sealing rubber cap on outside. If you look closely at "O-ring", it has square cross-section, not round?


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Old July 31st, 2019, 10:05 PM   #12
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The bleeder screw was definitely the problem, either through over tightening it or having a fit mismatch. I ended up buying a speedbleeder #SB8152. Tested it out under hard braking for 2 hours and the bleeding problems are gone!

I initially bought an All Balls caliper rebuild kit off of eBay from All Balls seller, and I can't remember if the it included new bleeder screws or not.

Now onto the next problem... My brakes initially have good bite, then the lever goes soft after maybe 15 min of hard braking. Brakes also intermittently pulse.

I checked my stock rotors thickness and it's at 3.9mm, under the service limit for OEM rotors. So now I'm waiting for a new EBC Contour Front Brake Rotor, hoping that will solve the problem.

When the brakes are functioning correctly, they feel AMAZING. Galfer SS Lines, EBC sintered pads, stock calipers, and stock rotors (soon to be EBC rotors). The only thing is it feels like the EBC pads eat through my stock rotors. Since changing out my brake lines and pads from stock to aftermarket (appx 2600 mi and 2 months of riding) my rotors went from 4.6mm to 3.9mm in thickness. This is 99% city riding in the hilly city of San Francisco.

Not complaining though cuz I like having the extra braking power in the city.

Last futzed with by nocturncal; August 1st, 2019 at 09:26 AM.
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Old August 1st, 2019, 06:25 AM   #13
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Is the lever really going soft (lever goes to handlebar), or is the brake fading, when overheating causes the pad's coefficient of friction to be reduced, so you squeeze hard and don't get much stopping?

If it's really going soft, I'd flush the system and put in new fluid. There may be enough moisture in there to let the mixture boil when it gets hot.
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Old August 1st, 2019, 09:07 PM   #14
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Quote:
Originally Posted by Triple Jim View Post
Is the lever really going soft (lever goes to handlebar), or is the brake fading, when overheating causes the pad's coefficient of friction to be reduced, so you squeeze hard and don't get much stopping?

If it's really going soft, I'd flush the system and put in new fluid. There may be enough moisture in there to let the mixture boil when it gets hot.
I flushed the system today, and I think you are right. I didn't use brake fluid from an unopened container (I admit I was trying to find some use for the big container I bought and wanted to see if I could get away with an opened container). So I went out to but some new, unopened brake synthetic brake fluid and presto, my problems are solved.

There brakes are solid as a rock and stay solid. Feels like I can stop on a dime and have change to spare.

I went to bleed the rear brakes since I was already bleeding the front, and found some air bubbles. Now the rear almost feels TOO sensitive. I kind of want to bleed some air back INTO the system haha.
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Old August 1st, 2019, 09:12 PM   #15
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Quote:
Originally Posted by DannoXYZ View Post
Post picture of screw you have, especially close-up of conical tip. Let's see if it's been swapped for incorrect one. As you can see, bleeder screws vary greatly in shape, it's possible someone installed incorrect one on your brakes and that's why it's leaking. Note none of them uses O-ring to seal.



What you saw as "O-ring" is probably remnants of loop holding sealing rubber cap on outside. If you look closely at "O-ring", it has square cross-section, not round?


I took a picture of the bleeder screw but somehow it didn't get uploaded to the image site and lost the photo, I'll try and post a pic for anyone that runs across the same issue as me in the future.

When I'm back in my garage tomorrow I'll link a picture.

Sidenote: how do I put an image up so that it shows up directly on the forum thread reply, vs a separate link that opens the picture? I've tried using the image icon button on the advanced reply page but when I used that button I can't see the image on my post
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Old August 6th, 2019, 12:38 AM   #16
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Here's a picture of the brake bleeder screw that came with my all balls caliper rebuild kit

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Old August 6th, 2019, 12:52 AM   #17
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Left one looks too short and taper looks deformed!
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Old August 6th, 2019, 06:07 AM   #18
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I've had very good experience with All Balls' customer service, in case there is a problem with one of both.
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