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The mkiv Supra Owners Club

Oil drain fitting - how to avoid leaks?


Homer

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My oil drain is leaking like a sieve where it joins to the block. It’s a BL oil kit with an aluminium flange and 45 deg fitting, but when warm the oil appears to be leaking out where the flange meets the block.

 

How do you guys avoid a leak here? I used one of the plastic gaskets which cam with the XS kit, but obviously this didn't work. Is the Toyota one the best to use and should I use any sealant - if so which type?

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Also if you get time double check the earl's/aeroquip fitting to see if it has been assembled all good and not been pinched too much.

 

The fitting for the drain is has 'Sumit' stamped on it, but looks exactly like aeroquip. The flange is a rather flimsy looking aluminium one but also has a 45 deg alu male/male adaptor to clear the steering rack bolt. Though its done up tight, I was very concerned about stripping the thread on the alu flange when fitting the 45 deg adaptor. Obviously there's only one position the 45 deg fitting can be in, so its always plus or minus a full rotation when tightening. I'm not sure it could take another turn without snapping the flange or stripping thread. It is leaking too, but only a tiny amount compared to the block fitting.

 

Here's a pic of the fitting:

oil fitting.jpg

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Agreed it can be a worry on the flange and 45 deg fitting but they are not as weak as we think they are , just don't go mad on it. TBH although it's a tapered thread on the 45 to flange they are prone to weeping, I would put a bit of PTFE or sealing compound on there before you wind it in as it does help to prevent this weeping. You wont need any sealing aiders on the actual flared Earl's types unions as they seal on their respective faces.

 

The join I was referring to in my post above ( sorry for the confusion) is the actual braided hose to fitting union. These sometimes can be put together in a rush and either not fully pushed home before assembly or over pinched, rare but not to be ruled out.

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Looks like you didn't use PTFE tape on the NPT thread there. You need PTFE tape on NPT fittings as they seal by the thread deforming when you tighten it and without you can get oil working its way round the thread and out.

 

nooooooooooo PTFE is for plumbers you need a proper hydraulic thread sealer, PTFE tape when exposed to oil turns to mush, trust me i worked with hydraulics for 18 years

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I had already used a good amount of ptfe when fitting the 45 deg adaptor but didn't use any compound (Presuambly Univeral blue is okay?). I thought ptfe was okay on npt fittings?

 

I refitted both ends of the clamps onto the braided hose as it was too long (xs power manifold strikes again), they're both done up very tight and are not leaking.

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I had already used a good amount of ptfe when fitting the 45 deg adaptor but didn't use any compound (Presuambly Univeral blue is okay?). I thought ptfe was okay on npt fittings?

 

I refitted both ends of the clamps onto the braided hose as it was too long (xs power manifold strikes again), they're both done up very tight and are not leaking.

 

no forget PTFE tape it has no place on oil systems period it is for sealing water go to a hydraulics specialist and get a proper thread sealer

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Or the tape you used might have been oil resistant anyway?

 

I have used "normal" before and if fitted clean and dry seems to work OK but as soon as it comes into contact with oil is disappears like the Fizzy UFO sweets we used to get as a kid. Test a bit in some oil and see.

 

All depends on make and its resistance.

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Oh ok, cool. Think Auto who make all the fittings say PTFE tape can be used, so that's good enough for me! I've disassembled a few that I sealed with PTFE and it was fine after a year of use, maybe it's something specific to hydraulic oil?

 

Simon an oil system is an oil system whatever-the only difference is on a hydraulic system the pressures are higher, as an apprentice i was nearly beaten to a pulp for using PTFE, as well as not being capable to stand up to oil it can "wind" off the thread on installation and end up anywhere in the system causing blockages believe me leave it for the plumbing thats what its good at

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Thanks for the reponses guys, much appreciated :)

 

Before I go ahead an mess this up a 2nd time, could anyone answer the following?

 

Where would I get a suitable sealer? I'm been to all the local motor factors and they only have Hylomar universal blue, is that alone suffcient or should I use some sort of thread lock too?
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Thanks for the reponses guys, much appreciated :)

 

Before I go ahead an mess this up a 2nd time, could anyone answer the following?

 

Hylomar for the flange, Loctite 577 thread sealant for the thread, a local hydraulic factor should be able to sell you this or an equivalent, check the yellow pages

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as well as not being capable to stand up to oil it can "wind" off the thread on installation and end up anywhere in the system causing blockages

 

Good point, this, although I still commit the sin of using PTFE, I make sure I'm about two thread turns away from the end of the fitting when I start, and wrap in the direction of fitment so that fitting it actually tightens the tape and there is no chance of getting a strag end into the system when installing it.

 

-Ian

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