Any Tricks to getting the Oil Tank Sending Unit to not Leak?

IAN · 07-31-2004, 11:49 AM

I have finished rebuilding my oil tank for my 72 T.

I actually put it all back together a few weeks ago and drove the car for a while. I noticed that my sending unit gasket was leaking. When I replaced it I used the cork gasket and tightened the nuts very lightly. Perhaps too lightly.

This time I figured I would try the rubber fuel tank gasket as suggested by folks here. I also ordered new washers. Any other tricks? Gasket sealer? Jedi mind tricks??

Thanks,
Ian

cowtown · 07-31-2004, 11:54 AM

I used the old gasket with a small bead of Permatex RTV. No leaks.

fintstone · fintstone's Garage

I used the cork gasket/no sealant without problem. Tightened them down pretty tight. I tightened them all once then went back and torqed them down. I used a criss-cross pattern to them as not to warp the sender and to tighten all fasteners equally. What type nuts did you use? The nylock type or flat ones? I replaced mine with the nylock type like used on valve covers (only smaller), and reused the flat washers. I have no leaks.

Thomas Owen · 07-31-2004, 12:09 PM

One surface or the other may be warped. Also, around the nuts may be pulled in (from over tightening in the past) so that the nut feels tight, yet the surrounding mating surface is not pulled against the gasket.
Good luck,

RoninLB · 07-31-2004, 01:30 PM

Quote:

Originally posted by IAN

This time I figured I would try the rubber fuel tank gasket as suggested by folks here. I also ordered new washers. Any other tricks? Gasket sealer? Jedi mind tricks??

I didn't realise it's the same gasket. I just greased up both sides of the rubber and gently tightened to a low torque. I used never-seize on the studs then some silicone gasket stuff on the vulnerable to road crap bare threads.

Early_S_Man · 07-31-2004, 02:11 PM

Ian,

If the nuts were overtightened in the past ... the sender plate may have 'dents' in it at each stud location rather than a flat surface ... just like the sump plates tend to do! If so, the cork gasket will never seal properly!

My suggestion is to pull off all of the nuts and washers and clean the area around each stud thoroughly with Brakleen. Examine around each stud with strong light ... looking for signs that the plate has been distorted.

If the plate has been distorted ... sender must come out again ...

The plate can be flattened by peening each stud hole with a small ball pein hammer while backing up the other side with an M6 nut. In this case ... don't try to actually hamer the hole/dent directly, but, rather, place the circular head of the ball pein hammer directly on each hole, and use a larger hammer/mallet to hit the ball pein hammer head firmly. It is better to use a series of lower-force impacts to do the sraightening ... rather than a single, huge blow! Test the sender plate each time with a machinest's rule to see when the dent is gone.

76911S · 07-31-2004, 03:55 PM

Wow, now that’s a lot of work for an oil tank. Cork gaskets are for sh$#t. Clean the surfaces well, use a new gasket preferably rubber and a little permatex and you should be good to go. Over tightening is a big problem with these type of sealing situations, nuts or bolts just need to be snugged up good, lock washers and or nylocks are always a good idea.