The 'E' Type Forum

What's the best way to seal the diff drain plug? Mine weaps though there is no significant level drop.

I was thinking thread lock, but it's near impossible to create a clean thread in the diff casing after draining it. I've a vague recollection of someone recommending ptfe tape.

What works for you?

Ptfe tape will work.

I use Loctite non hardening thread sealant.

The back plate will still leak anyway.

PTFE tape!

Phil,

The main issue with getting a good seal is preparation and a good sealing face. The problem on the diff drain plug is that it is usually a black iron casting where the thread profile is not cleanly cut - which when tightening the taper thread into the diff cast thread makes for a poor contact area.

Apart from choosing what taper plug you use see http://www.myetype.co.uk/forum/viewtopi ... 611#p60611 you can ensure the thread is a clean as possible and burr free before fitting. I use blue Hylomar around the thread to get a good seal on the drain plug.

On the diff cover, there is no reason that this should leak if the diff sealing face is well prepared and free of any old gasket material, plus the cover is completely flat around the mounting holes. The main reason for any leaks is the Parts Manual only shows spring washers under the heads on the bolts and the holes in the pressed metal diff cover are made slightly oversize which can see the edge of the spring washer distorting the sealing area if overtightened. I therefore use a plain washer against the cover followed by a spring washer. Not concours I know, but if anyone choose to crawl under my car to point that out, I would point out that I have no leaks.

I use a very fine smear of black Loctite non-hardening joint sealer on both sides of the new gasket and ensure the diff breather is completely clear as with a vented diff and bolts not overtightened there will be no leaks.

regards,

Dave

2000 miles later and PTFE tape is still sealing nicely.

Bear in mind it is possible that the leak may be originating further up - pinion seal or whatever; it will always drip off the drain plug & it's easy to be fooled!