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Ptfe or not?


Mathew

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A hopefully quick questions.

I have a stainless waterpipe hopefully on its way to me as my steel one was leaking. 

1. Should i pre clamp the olive using a spare waterpump housing prior to fitting?

2. Should i  use ptfe tape to aid sealing like you would on household plumbing?

3. If possible should i flair the two ends where the rubber hose goes or will they be alright?

Thanks Mathew 

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My answers as  follows:

1.  Yes. It's  easier to tighten the nut and compress the olive off the car, plus you can disassemble  to check the olive  is gripping  the pipe properly.

2. Yes, but make sure strands of PTFE tape can't get out of the joint into the cooling system. 

3. I've  never tried flaring the pipe so can't comment from experience. But it sounds like a good idea. 

Nigel

 

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Whilst I have used PTFE in a variety of situations. I would never recomend it`s use on a "new" connection. The olive should seal the connection without any assistance.? I would also caution about flaring the pipe, the flare could remove slivers of the hose  inner whilst being pressed on?.

Pete

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56 minutes ago, PeteH said:

Whilst I have used PTFE in a variety of situations. I would never recomend it`s use on a "new" connection. The olive should seal the connection without any assistance.? I would also caution about flaring the pipe, the flare could remove slivers of the hose  inner whilst being pressed on?.

Pete

Was thinking more like a brake flare to aid the pipe staying on under pressure. 

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12 minutes ago, Mathew said:

Was thinking more like a brake flare to aid the pipe staying on under pressure. 

Shouldn't need it; the hoses are a suitable length and not really under great pressure so it's unliklely they could be blown right back and completely off the pipe.

Frost actually sell a flaring machine for cooling pipes that puts a flange round the pipe to help hoses stay on, but it's big money for home use.

 

 

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35 minutes ago, Mathew said:

Was thinking more like a brake flare to aid the pipe staying on under pressure. 

A brake pipe type 'flare' would not work. Consider something on the lines of a plumbers 'Yorkshire' fitting. Swagged ring

This is standard practice in industry and our car parts should have them without asking. 

If you are desperate for the swagged ring but do not want to buy the machine to do it, consider soldering a ring of copper wire in the appropriate place.

However. the down pipe from my pump to the bottom of the radiator on my 4A has no flare and always has stayed put.

Use the PTFE only if there is doubt over the joint.

 

Roger

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never had a problem with any stainless bypass tubes letting hoses slide off

but on truck production many years back someone in their wisdom deleted the barrelled ends and with a nice black paint that became slippery when hot the hoses all popped off under pressure       ,  i was always of the idea the belled end sealed the hose clip keeps it on type of design

agree no ptfe  maybe a smear of grease to easy the nut  torque compressing the olive

stainless tube is a bu**ger to flare  its too hard for most diy flare tooling  

i would rough up the tube surface a bit to give the hoses some grip 

fit and forget

Pete

 

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I think i will pre nip up the olive, saves it slipping off. I have new hoses and clamps so will leave alone, suspected it would be ok, just wanted to make sure. I will leave the ptfe off unless it leaks. Pete i will put a bit of lube on the threads as its an awkward nut to do up and assistance would help.

Thanks  everyone 😃

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You would get the same "effect" by putting a Pipe Fitting "olive" on the end of the pipe, getting the fitting off after might be problematic, and sacrificial, and require the use of a small hacksaw to remove?.

Pete

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I am also thinking of replacing this pipe but am worried about shearing of the old connector which I suspect is rusted in. What is the best way of treating the joint before gently swinging on it? No gorilla tactics, I can almost feel the joint fracturing as I try to unfasten it.

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Plenty of heat, or a long soak in proper penetrating oil; alternate as often as possible without going bang... and light tapping on the side of the housing with a small metal hammer can also break the seal. The longer you treat it, and the longer you give it to soak or cool down, the better it is.

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45 minutes ago, Colin Lindsay said:

Plenty of heat, or a long soak in proper penetrating oil; alternate as often as possible without going bang... and light tapping on the side of the housing with a small metal hammer can also break the seal. The longer you treat it, and the longer you give it to soak or cool down, the better it is.

What is the best penetrating oil these days. I remember plusgas but that was in the dark ages. I may even have some in the shed somewhere

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