Rear differential drain plug leak

[Lin]

I tried some thread sealant but a small leak persists from the drain plug. To those who have solved this annoyance, what did you use on the threads? Silicone sealant?
Thanks!
Lin

 

[steveg]

My original square-hole drain plug had a crack in it, causing a leak. I replaced it with the Moss hex design.

 

[Jack T]

I tried some thread sealant but a small leak persists from the drain plug. To those who have solved this annoyance, what did you use on the threads? Silicone sealant?
Thanks!
Lin

Might be the type of sealant you used. Make sure it's suitable for use with oils.

 

[Keoke]

I tried some thread sealant but a small leak persists from the drain plug. To those who have solved this annoyance, what did you use on the threads? Silicone sealant?
Thanks!
Lin

Try plumbers Blue tape Lin.

 

[Bob_Spidell]

I tried some thread sealant but a small leak persists from the drain plug. To those who have solved this annoyance, what did you use on the threads? Silicone sealant?
Thanks!
Lin

I've always liked to experiment with sealants and adhesives (much to my father's annoyment), but don't like using teflon tape where a piece could break off and 'gum up the works' (yes, I know it wouldn't do much in a diff). Permatex Thread Sealant (with teflon), has always worked for me; if it doesn't for you I'd look closely for a crack or defect in the plug or the threads of the diff case.

As an aside, the following shows some, er, 'interesting' things going on in a diff:

https://www.youtube.com/watch?v=9-yG3D3JBRs

 

[Drone Dog]

i use the pink teflon tape. worked fine and is for oil.

 

[Randy Forbes]

Loctite 518. It's what I use on bolts that are in open-end threaded holes into BMW differentials (below oil level).

It works as a bit of a thread-locker too, so additional effort will be required the next time you go to drain the fluid.

Good stuff to keep around, as it will substitute for a gasket altogether. https://www.walmart.com/ip/Gasket-S...MIqvzMotG-3gIVCJyzCh1pVgNbEAQYAyABEgJPsPD_BwE

 

[Lin]

Thanks, gents.
I appreciate the guidance!
Lin

 

[pkmh]

I just replaced my differential gear oil last weekend. I used the black sealant from Permatex, also referred to as, "Make a Gasket" Sealant. Claims to be good when using with oil. Used it in conjunction with my cork type gasket to my valve cover, too. No leaks.

 

[Michael Oritt]

Lin--

Consider drilling and safety wiring all your drain plugs--diff, engine, transmission. It is mandatory on race cars for a good reason and there will be one less thing to obsess about!

 

[Bob_Spidell]

OK, I can't for the life of me see how you can safety wire the diff and gearbox plugs; they're recessed and if you drill you'd likely go through threads. I've never heard of one backing out, as I believe they're pipe threads and you can torque them down pretty tight.

 

[Michael Oritt]

Bob--

There is enough thickness on the face of a plug to through-drill a small hole in at an angle into which you can insert the wire. Some plugs stand a bit proud of the surface of the housing and they are easiest. For those that go flush when tightened it may be necessary to drill two angled holes so they meet and allow the wire to be passed through. Finding a place to anchor the wire is easy and on diffs I use an oval or oversized washer near the plug and drill a hole through that.

Needless to say, drilling out the plugs should be done with them off the car....

 

[Bob_Spidell]

Probably not necessary on a street car; at least, I don't lose any sleep over them falling out. Presume you use stainless wire? What thickness of wire do the tracks specify?

 

[Michael Oritt]

Bob--

It's probably not necessary on a track car either but it is what it is. I have never seen a spec for either size or type of wire--just that all drain plugs must be "wired"--nor have I ever seen a tech inspector get under a car to check, though engine sup drains are usually easy to see from above. Personally I enjoy the exercise.

 

[John Turney]

Lockwire is 0.041" stainless.

 

[Randy Forbes]

I built this engine for a guy that races, and asked him to send me the engine specs out of the rule book__I didn't want to inadvertently get him in trouble...

You know, just to present a visual aid to Michael's suggestion!

 

[Bob_Spidell]

Lockwire is 0.041" stainless.

Safety wire is available in a number of diameters:

https://www.aircraftspruce.com/catalog/appages/safetywire.php?clickkey=4386

0.041" isn't the thickest, but it's perfect for the one place I know of that's pre-drilled in a Healey: