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Leaky brakes - Male 3/8 stainless threads into brass 3-way union.
TimC - 28/1/18 at 06:39 PM

Hi All,

I’m wondering if I’ve missed a trick (or golden rule) here. I’ve gone to fill my front brakes for the first time and have leaks - two I think on the same brass 3-way union where flexible hoses with male fittings are screwed in. Should I not have used this method? Should I have used a stainless 3-way connector? Any other idea what’s gone wrong? The hex-heads on the flexi hoses are tight against the union body.

On the plus side, I’ve used silicon fluid so I don’t have a whole lot of nasty stuff leaking all over the car but it looks like all the lines will have to come off which is bad news!!

cliftyhanger - 28/1/18 at 07:05 PM

. My thoughts are that "normally" a flexi will seal by it pressing against the copper flare. Otherwise it will need a copper washer to seal the shoulder of the flexi against the body of the union. ( like they are used on a caliper)

ste - 28/1/18 at 07:07 PM

If the hex head is touching the union it means the flexi hoses don't have long enough threads to get the end to meet the bottom of the union. That is where it seals.

take them apart and measure the depth of the union, you may be able to trim a small amount off to get them to bottom out and seal. otherwise it's new ends on the flexis, or a shallower union or an adapter.

voucht - 28/1/18 at 07:21 PM

also check that seats on the flexi hose fittings match the seats in the bottom of the tee piece : convex seat should seal against a concave seat. If you have convex seats on both the flexi (male) and the tee-piece (female), then here is your problem. Same if you have concave seats on both of them.

TimC - 28/1/18 at 07:26 PM

Thanks all,

It all makes sense - I think Ste probably has root cause. I never thought about it which is dull in hindsight. This will be painful - lots of rivets holding p-clips to drill out.

Bugger.

CosKev3 - 28/1/18 at 07:32 PM

I would use copper washers as suggested above

mark chandler - 28/1/18 at 07:54 PM

Copper washers here as well, lasted 12 years so far without issue

TimC - 28/1/18 at 08:21 PM

Really Chaps? Good (safe) enough?

I’ll get some ordered.

CosKev3 - 28/1/18 at 08:23 PM

Yeah,as suggested above they use them on some caliper's

CosKev3 - 28/1/18 at 08:40 PM

They will only work if the ends are fixed though,not swivels?

TimC - 28/1/18 at 08:44 PM

quote:
Originally posted by CosKev3
They will only work if the ends are fixed though,not swivels?


They are all fixed.