Is this hole supposed to be there?

[Guest]

Grasping at straws now. Trying to figure out why my brakes have had an air leak since I assembled and installed a stainless line back in March.

Have torn the calipers down and am about to install new seals---again--but I am trying to test all components while I have the system torn down.

Put a vacuum on the line to confirm that the line itself isn't leaking. Seems to hold the vacuum appropriately. Noticed this hole in the assembly and can't find any pictures of other bolts with this hole.

Can anyone confirm that this hole in the bolt (upper left of the picture just before the threads) is normal?

[Agemax]

the hole looks to be just in the nut area and not into the bore itself. have you tried poking a thin bit of wire in it to see if it goes right through anywhere?
it could have been used to attatch a bit of lock wire to it.
if fluid was leaking from it you would easily see it squirting out.
the hole does not look normal but i dont think it is your problem

[Crankthat]

I am not seeing a clear hole (upper left of the picture just before the threads) even when blown up.

Now the bolt that goes through piece that you have posted the picture of will have a hole between the threads and the head of bolt.

The hole allows passage of fluid through hollow bolt to your line.

Hope you posted wrong picture!

Might check all surfaces that match up to one another for scratches that might allow weep.

Clean everything really good so if leak appears when reassembled you can search for it better.

[oldrookie]

It looks like a large spec on the bolt. It is where the wrench would tighten down so you can twist the bolt to tighten it up.

[Dogma]

That's for safety wiring, no? I think the fittings I bought had that. Anyhow, it's not in a sealing area. Keep looking.

[Crankthat]

Am not familiar with how the stainless break lines are put together.
Braided cover over rubber hose?

If you cant find a fluid leak, possibly a high spot only sucking air?
Would imagine a air intake leak without fluid leaking out is possible and would be close to impossible to find.

Have read a couple of threads with people tying/strapping down lever to allow air bubbles to settle and make way up lines to res.

Try that next time.

And like I said earlier clean everything real good to help spot leak if your problem continues.

Will add as I just thought of.
Pump them suckers real tight and spray some talcum or similar on all parts, blow with compressed air to clean dry areas off and look for whats sticking.

I wish you the best of luck as I know how difficult some leaks can be to find, have had my best method to be clean, run, and inspect.

[Agemax]

is the level in the fluid reservoir going down at all? if not then there is no leak, just air in the system

[hjfisk]

That is there for safety wiring if you are using them on a track bike

[oldrookie]

Spent all summer chasing this issue. Tied the handle back multiple times. Brakes firm up, but within minutes I'm back to soft brakes.

Vintage bike rider group here in Indy suggested that it could sucking air back into the system around the caliper piston seal. Tight enough to prevent fluid leak, but sucking air back in when the piston releases the disc.

Had changed the seals and cleaned everything in early summer, so decided to try another set of seals. They arrived this week, so I am double checking everything as I reassemble the system.

Thanks for the suggestions and for the information about the safety wiring hole.

[sedelen]

That is there for safety wiring if you are using them on a track bike

That would be my bet also.

[tatu]

Spent all summer chasing this issue. Tied the handle back multiple times. Brakes firm up, but within minutes I'm back to soft brakes.

Vintage bike rider group here in Indy suggested that it could sucking air back into the system around the caliper piston seal. Tight enough to prevent fluid leak, but sucking air back in when the piston releases the disc.

Had changed the seals and cleaned everything in early summer, so decided to try another set of seals. They arrived this week, so I am double checking everything as I reassemble the system.

Thanks for the suggestions and for the information about the safety wiring hole.

If the level is not going down then there is no leak, are you sure the m/c seal is fitted the correct way round?
It's the only reason I can think for soft brakes. Other than old expanding original pipes.
Did you fit new, or at least aneal the copper washers, all of them?
Tying back the lever only closes the resovoir port and allows the air to work its way up to the top allowing it to burp when the lever is released. Not a fix for me but seems to work for some.