Little bit off topic but might get more response here?

I'm fitting some hydraulic/oil hoses to a remote oil filter on an old VW, the fittings are tapered threads and are going into an alloy filter mount and, I think, cast iron oil pump … question is how much do you do these up? I'm concerned about doing them up too much and splitting the mount or oil pump. Is it a case of try it and if it leaks keep nipping them up,or something like hand tight plus 1 full turn?? 😕

Tighten it until it strips then back it off one. 😉

id be impressed if you got a full turn on a tapered thread.

as you said, do it up comfortably and see if it leaks.

I'd use some PTFE tape on the threads and just nip them up !

Mick

wrap in ptfe tape. Then just nip them up.

It's a very shallow taper so it could be easy to do them up just a bit too much, did them hand tight plus about one turn and they leaked … but I'll try the PTFE tape and see how that goes.

make sure the ptfe does not get into the pump!!!

better getting a heat resistant liquid sealer(loctite stylee)

Why are you using a tapered fitting? Is the female end tapered?
Can you not get a hose with a straight connector and use a copper/compression ring? That is more the norm I think.

It's quite common the mix taper and parrallel threads as it removes the need for additional mechcanical seal (o ring or fibre washer etc, think about the parallel threads on your bike disk brakes, they don't seal metal on metal). If you use two parallel threads then it keeps turning until you bottom out the thread. PTFE or similar only fills the gap between the male and female thread. The taper thread turns until the effective diameter is too big and plugs the hole, subsquently sealing the hole like a mechcanical seal.

Oh, make sure its the same thread type though. You can mix and match different pitches.

Oh, make sure its the same thread type though. You can mix and match different pitches.

I have found it very easy to mix ISO/BSP and NPT fittings. You can thread BSP into an NPT fittings and vice versa so be careful.

Further to what Conespanner said, on some Ford hydraulic joints the tapered thread on the pipe is designed to be a one-shot-deal – the act of the threads being tightened plastically deformed the thread to form the seal. If you break the seal and refit it, it may seal, but probably won't. This may or may not be the case for the OP, but I swore for ages at a power steering pump…. and then swore again when I found out what was wrong and how much the new pipe was…. 🙁

The female fittings are not tapered, but the original kit came with tapered male fittings, but the oil pipes were just rubber held on with jubilee clips so I had some steel braided pipes made up and they put the same type male fittings on the ends, they are the same pitch and thread type, but not sure how tight to do these up. Like Conespanner says 'taper thread turns until the effective diameter is too big and plugs the hole, subsquently sealing the hole like a mechcanical seal', but I've seen in the past an engine case crack when someone didn't realise it was a tapered thread so being a bit over cautious … araldite repaired that one though.

make sure you wrap the PTFE tape clockwise so that the tape tightens as you tighten the bolt.