New venhill SS hose is leaking at the banjo

[M42]

Hi all. Got a weird problem here. This weekend I swapped out my crappy rubber front hose with a venhill SS brake hose (they have great customer service btw). Worked fine, rode it a few miles to test it, everything functioned. Then I left the brake lever tied down, per the wiki, for like a day. When I went to check up on it, I saw that it was slowly leaking from the lower banjo/swiveling nut joint. By slowly I mean, it didn't even form a drop in 24 hours, there was just a wet sheen on the caliper. I know it was the lower banjo because I pressed my finger to it, and it left a streak of brake fluid only where the banjo threads into the swivel.

I had been checking for leaks all day before I tied down the lever, and also didn't see any leaks when I got back from my short ride. This morning I took a 11 mm wrench and tried to turn the locking swivel in either direction. It opened up when I loosened it, let a little fluid out like you'd expect, blah blah. Then I closed it fully, but it wouldn't close any more than it had previously, when it was leaking (unless it did, but the increment was so damn small you couldn't tell). I know I tightened the banjo/swivel connection fully before attaching it to the bike originally, so it's not like the case where some people don't tighten it at all and it dumps all the fluid immediately. Also, it's not crossthreaded. I went to check the banjo again like 4 hours after messing with the swivel joint this morning, and it doesn't seem to have leaked more, but I don't know... it was a very slow leak in the first place.

My front brake also seems to be stuck in the on position right now, I just noticed. Wasn't like that while riding, there was definitely a space between pads and rotors once I had finished the job. Nothing moves when I squeeze the lever. Whaaaat the hell. Did I just tie down the lever too hard or something? Are my pistons seized in addition to the leak problem? Or is this because some pressure tomfoolery from the leaking fluid? There's plenty of lube under the boots.

It's currently swaddled in some paper towel while I wait for extra crush washers to come in the mail tomorrow, because I suspect I'll have to disassemble things to see what's up. So, what do you guys think?


Have a pic also. The line where my finger is touching between the swivel and banjo is where the fluid came out.

[alex.s]

what is the theory behind tying the brake lever down

[M42]

Pressure squashes the air bubbles into smaller ones (you can see this if you're flushing the lines with a clear tube), apparently it helps get some of the more stubborn ones out of the hose when you tap the banjos with a rubber mallet. I did it the last time I flushed my brake fluid, seemed to help.

[alex.s]

i simply fill up the caliper with the banjo off. shake it to get the air to the top. fill it up the rest of the way, put the line on, fill up the line from the top letting the air come up the line. then attach the line to the master. then bleed it.

if you can't move the front wheel because the brakes wont let go then it sounds like a stuck piston to me

[Venhill USA]

Hi there,

Chris from Venhill USA here. Sorry to hear you've had some issues with the swivel. In most cases, a leak from a swivel is due to over tightening or debris. Really cranking on the swivel will cause it to distort which faults the seal between the banjo and spigot. If you've loosened and re-tightened and have no more leak, you should be good.

As far as needing to remove the banjo to investigate the leak, I wouldn't think that necessary. As long as you used the recommended torque settings for the bolt, it should be ok.

Just remember, no sealant or treatment of any kind on the swivel or sealing surfaces between the banjo and spigot. The swivels work on the same physical principle as virtually every threaded connection in an automotive brake system, that is, a mechanical seal. Snug the swivel, not power tight, snug.

If you like, let me know how things look after a few days. I have a Google Alert set up to tell me about new threads with the word "Venhill" in them...

Chris
Venhill USA

[M42]

@ alex - yeah, your way makes a lot more sense. I'll do that when I'm replacing the rear pads and hose.

@ Chris - thanks for your post! Would you by any chance have a recommended torque value for that swivel bolt? That would probably take a lot of guesswork out of this (my definition of 'snug' has... changed... since I did some suspension work). Hasn't leaked since the loosening/retightening, but it'll be good to know when I'm doing the rear.

[csmith12]

Originally Posted by Venhill USA

Hi there,

If you like, let me know how things look after a few days. I have a Google Alert set up to tell me about new threads with the word "Venhill" in them...

Chris
Venhill USA

Welcome Chris!

Those google alerts are awesome!

[Venhill USA]

Originally Posted by M42

@ Chris - thanks for your post! Would you by any chance have a recommended torque value for that swivel bolt?

It's difficult to offer a torque value for a nut requiring a wrench rather than a socket because you need a special tool and modification formula for use with a wrenched fitting. Rather than requiring our customers to have to go buy a special tool, we just offer the term "snug." When I tighten mine, I just wrench until the nut stops then give it a little bump just to be sure.

Chris

[M42]

Whew, that's what I did. Thanks man, I'm really glad your company takes the time to help out schmucks like me on the internet. You guys are great. Cheers!

[baxtc1]

I haven't used swivel type brake hoses before, but I would be concerened about tightening the swivel joint before fitting the hose to the bike.

[Venhill USA]

Originally Posted by baxtc1

...I would be concerened about tightening the swivel joint before fitting the hose to the bike.

The last step in installation is tightening the swivels (you have to bleed the system of course). We actually recommend you loosely install everything, torque the banjo bolts to fix the banjos into place, then snug the swivels.

Chris

[baxtc1]

I suspect this may be the issue here.