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Leaking Overdrive and Gearbox Drain Plugs

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bighealeysource

bighealeysource

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Hey Y'all,

Any suggestions on how to get rid of very slow but always there oil drips from transmission drain plug and the overdrive drain plug on a BN2?

I have tried a couple of different loctite-type products on the threads, but still gets by it. Tried yellow teflon type tape which is used on natural or propane gas connections. Replaced the trans plug, but doubt that quality was any better than the one I took out. I do install the fiber drain plug washer on the overdrive, but have always questioned the fit on those make it ineffective.

Any suggestions to rid my Healey of these annoying minor leaks?

Thanks,
Mike
 
Most Loctite sealing products work great on machined surfaces. I use light application of Permatex Ultra Grey or the green one for "Gear-Oil" on threads and the OD drain plug sealing surface. Then again, my transmission likes to drip elsewhere.
 
This has been a bugaboo of mine as long as I've owned a Big Healey (going on 40 years). The 'stock' fiber washer is too hard IMO--I do soak them in oil to try to soften them up before installing--but I don't know if an O-ring or softer material would work either. Like you, I've tried various sealants, and I have a special socket for use on the notched big brass cap. I use synthetic oil, which likely makes things worse but I've managed to otherwise seal up my gearbox and O/D pretty well. My recently rebuilt unit just dumped a half-quart on the garage floor, but I managed to tighten the cap a few degrees so we'll see what happens (the fiber washers do seem to take a set and need re-tightening).

This stuff worked for me to seal up a water pump plug when nothing else short of brazing would, I may give it a try on the O/D cap:

www.permatex.com

Permatex® Seal & Lock Thread Compound, 35 ML - Permatex®

www.permatex.com www.permatex.com

For the gearbox and differential plugs normal thread sealant has worked well.
 
bighealeysource said:
Hey Y'all,

Any suggestions on how to get rid of very slow but always there oil drips from transmission drain plug and the overdrive drain plug on a BN2?

I have tried a couple of different loctite-type products on the threads, but still gets by it. Tried yellow teflon type tape which is used on natural or propane gas connections. Replaced the trans plug, but doubt that quality was any better than the one I took out. I do install the fiber drain plug washer on the overdrive, but have always questioned the fit on those make it ineffective.

Any suggestions to rid my Healey of these annoying minor leaks?

Thanks,
Mike
Click to expand...
Not having OD on my car I don't know if that drain plug will accept a copper crush washer but I use them throughout my cars and anneal them when draining and changing lubes. I have the usual small weeps in the usual places but not at or through the plugs.
 
This drain plug is, maybe, 2-2&1/2" in diameter; I don't know where you'd get a copper washer that big but, yeah, that would probably work.
 
Thanks guys ! I have some of the High Performance Permatex thread sealer. How do you handle the problem of
threading it into the female fitting since that will have oil still dripping out ? I know that's kind of a stupid
question but getting that last few drops out seems impossible and contaminates the newly applied thread
sealer. Should be letting the thread sealer "set up" before screwing it in ?
 
Seems as those are too small, the ID of a new fiber washer being 2.08"
When I recently rebuilt my overdrive I took a good look at the sealing surface of the aluminum housing because I had a leak there for over 40 years regardless of the oil changes and new sealing washers. There were some defects such as pits and scratches, but the big problem showed up when placing a machined short aluminum round, face to face with that surface. Clearly it was not flat.
So I contact cemented some 320 grit wet to the round bar and lapped the OD surface and then transitioned to 400 grit and then 600 grit. The sealing surface was now flat and using a new fiber washer, the OD is now leak free. I did add some white teflon tape to the threads, being careful not to let any go lower than the 2nd to last thread.
 
I thought the ID of the copper crush washer shown in my post was 2.25" but in any case I'd check out that source.

Also, leaks due to metal porosity, esp. in AL castings are quite common. The materials used in our cars often came as scraps from WWII leftover aircraft, etc and as such was less than the best. The AL sump of the FWB Coventry Climax engine in my Elva MK IV SR is obviously an old casting and oil sweats right through, though a good coating of Glyptol helped out.
 
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Thanks everyone for their suggestions ! Going to try the pink teflon tape on trans plug and see about the crush washer for the OD plug.
 
In general the color of the tape is only for identification purposes. PTFE is PTFE, white or pink still seals the same, oil or water.
Some colors are thicker and denser though, mainly for natural gas sealing, since the natural gas molecules are smaller than water or oil molecules.
 
An old mechanic said to put the fibre washers in boiling water to soften them then tighten it up and you get a better seal.
 
Looks like the vendor Michael Oritt referenced might have one. I get 1.98 ID if you measure on the flat side of the top of the large brass plug - just beyond the threads - and 2.35 OD on the diameter of the actual plug. If you can squeeze the crush washer over the threads (???) would be a good fit. Guess that's the crux of the problem is getting it over the threads as that measurement is 2.10. I have asked the vendor if they have something available.

Has anyone tried the same type of gasket sealant used on valve covers - RED RTV Silicone gasket maker ? That would be pliable when cured and would seem to make a decent seal. Or a rubber O ring that fits well ?

Also, good suggestion about trying boiling the fiber washer, sure don't seal as is.
 
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Hey y'all,
I have gone ahead and tried an O ring in lieu of the hard fiber gasket for the OD drain plug. It is a metric sized one and fits very tight and seems to be doing the job. No leaks from that plug so far. Buddy of mine said that after time oil might degrade it so will keep a watch. Still going to try
and get a crush washer but thinking one of those that would fit tightly will not be able to be forced over the threads.
 
bighealeysource said:
Hey y'all,
I have gone ahead and tried an O ring in lieu of the hard fiber gasket for the OD drain plug. It is a metric sized one and fits very tight and seems to be doing the job. No leaks from that plug so far. Buddy of mine said that after time oil might degrade it so will keep a watch. Still going to try
and get a crush washer but thinking one of those that would fit tightly will not be able to be forced over the threads.
Click to expand...
Mike, rather than force it over the threads, try to thread it on; a slight V-notch on the i.d. may ne necessary to get it started...

Coincidentally, immediately before sitting down at this website, I was examining the offending port on a BCF member's* overdrive! At a minimum, I will make it flat__it is not at present__but dezand makes a good point about checking that it's perpendicular to the port face too!

* while still very much a work in progress (waiting on a relatively small parts order, as that's all that was required) here's a photo-documentary on the absolute best existing original condition BN6 overdrive I have ever seen: > DR_HLY-OVD | spcarsplus.com photo gallery <
Note that there will be a 2-week hiatus beginning next Saturday when head to the beach to work on our tans (ironic sarcasm, we're more naturally pale than anyone living in Florida has a right to be) my point is, if you're one of the 1 or 2 people checking for updated pictures, don't give up ;)
 
Randy Forbes said:
Mike, rather than force it over the threads, try to thread it on; a slight V-notch on the i.d. may ne necessary to get it started...

Coincidentally, immediately before sitting down at this website, I was examining the offending port on a BCF member's* overdrive! At a minimum, I will make it flat__it is not at present__but dezand makes a good point about checking that it's perpendicular to the port face too!

* while still very much a work in progress (waiting on a relatively small parts order, as that's all that was required) here's a photo-documentary on the absolute best existing original condition BN6 overdrive I have ever seen: > DR_HLY-OVD | spcarsplus.com photo gallery <
Note that there will be a 2-week hiatus beginning next Saturday when head to the beach to work on our tans (ironic sarcasm, we're more naturally pale than anyone living in Florida has a right to be) my point is, if you're one of the 1 or 2 people checking for updated pictures, don't give up ;)
Click to expand...
Hey Randy,
How's my BN6 buddy doing ? Sounds good and have seen on FB you've had some medical issues but being 75 myself, new ones come
up all the time ! Still hanging in there with the 100M but a black over red BN6 at the British Car Club of Charleston show this weekend
sure brought back good memories on BN6 964. Thanks for the advice on the crush washer, I will try it that way. Plus getting ready to
watch the photo doc you sent over. The rubber O ring is holding good but cautious with the long run.
Regards,
Mike
 
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