One of my SVA fail points was a leak from the brake light switch. The switch is screwed into a 4-way connector. My guess is it's leaking because
it does not bottom out in the connector, so it is just the threads sealing it. I have tried two different types of washer (fibre and copper), instant
gasket (the blue goo) and even ptfe tape, but still it weeps a little.
Any suggestions? I am fed up with getting oil everywhere, and having to bleed the brakes every 10 minutes to try my non-fixes....!
its a tapered thread on switch and if you overtighten it will split.
It happened on mine causing a hairline crack in the switch.
Change the switch and just "nip" it up, enough to seal it.
I reckon a new switch is the only way. My mate had the same on his T25 bus. He tried alsorts then bought a new switch. I think it was about 7 quid from GSF.
If you've tried all that and it still isn't sealing, are you sure they're matched thread and pitch wise?
Thread tape is a bodge and will fail an MOT test if spotted let alone an SVA test. It sounds like you are using a mismatched switch and connector ? It may be that you have damaged the body of the connector if you have overtightened the switch in which case it may be best to replace both with matching items ? Metric switches tend to use a tapered thread , Imperial may use a copper washer but never a fibre washer.
Both parts are new (well at start of build), and are M10 fine. The 4-way connectors rely upon the seal being made at the bottom - which none of the
brake switches I can find seem to do.
I have this one. As you can see, the threaded part is short (too short to bottom out in
the 4-way). I will try to search for one with a longer thread...
Make a little extension using brake pipe and use a short union on the switch end?
the brake switches are tapered thread hence dont bottom out,you need a 4 way with a tapered thread on one union
quote:
Originally posted by rusty nuts
Thread tape is a bodge and will fail an MOT test if spotted let alone an SVA test.