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Oil Leak - Gear Box

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Oil Leak - Gear Box
#1
  This topic is about my 1967 MG Midget MkIII
Kensmg.project Avatar
Kensmg.project Silver Member Kenneth Bundesen
Sunshine Acres, Qld, Australia   AUS
1967 MG Midget MkIII "Snow White"
Hi Guys,

I am having a problem with the oil in my gearbox. I have a persistent leak from the drain bung. It is a very slow leak and takes days drain the gearbox. I am currently using the recommended oil (Penrite Small Engine SAE30). I am thinking that I may be able to solve the problem by using a thicker oil. What are your thoughts? Is it possible to use some silicon tape to wrap around the thread on the bung to help it seal better?

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ice Avatar
ice Gold Member Larry Ice
Lawrenceville, GA, USA   USA
Try the tape over the threads first. when you pull the plug carefully examine to be sure no one before you has buggered the threads. The threads on that are pip threads which are supposed to get tighter as the plug is tightened.



Iceman

Atlanta GA

60 AH MK1
62 AH MKII
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Abington, PA, USA   USA
1976 MG Midget MkIV "Rodney"
Hi Ken,

I've worked a few Midgets and Sprites since the '60's, but I bought a brand new one in '76, and have the original owner's manual and shop manual. They didn't change much in all those years. The factory spec for trans/rear gear oil is quote: Syncromesh = top up with H.D. 90 (MIL-L-2105b) above -10C -10 F; gearbox and rear axle = top up with H.D. 80 (MIL-2105B) below - 5 C/ 20 F; or H.D. 75W below - - -30C/- 20F. Complete fill with E.P. 80 (MIL-L-2105B) all temperatures. I just run 90 weight in both.

Now, I've never seen an MG that didn't leak something unless it was totally dry. The Brits used tapered thread drain plugs that expand the holes as you tightened them and sometimes over-tighten them to the point they seal nothing. I've replaced most of those with modern screws with sealing washers.

See attached '76 owner's manual lube specs. Hope this helps you.

Regards,

Richard

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Attachments:
MIdget Lubes Spec Page.jpeg    44.7 KB
MIdget Lubes Spec Page.jpeg

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refisk Avatar
refisk Rick Fisk
Frankenmuth, MI, USA   USA
Richard,

Every Spridget from '58 to '74 used motor oil in the A-series gearbox. The early cars used 30W non-detergent and then later this was changed to 20W50. Starting in '75 the Triumph gearbox used in the rubber bumper Midgets used 90W gear oil. smileys with beer

Ken,

I wouldn't use tape on the threads. There are oil resistant thread sealers available from Permatex and others.



In reply to # 3908903 by Richard P. Senatore Hi Ken,

I've worked a few Midgets and Sprites since the '60's, but I bought a brand new one in '76, and have the original owner's manual and shop manual. They didn't change much in all those years. The factory spec for trans/rear gear oil is quote: Syncromesh = top up with H.D. 90 (MIL-L-2105b) above -10C -10 F; gearbox and rear axle = top up with H.D. 80 (MIL-2105B) below - 5 C/ 20 F; or H.D. 75W below - - -30C/- 20F. Complete fill with E.P. 80 (MIL-L-2105B) all temperatures. I just run 90 weight in both.

Now, I've never seen an MG that didn't leak something unless it was totally dry. The Brits used tapered thread drain plugs that expand the holes as you tightened them and sometimes over-tighten them to the point they seal nothing. I've replaced most of those with modern screws with sealing washers.

See attached '76 owner's manual lube specs. Hope this helps you.

Regards,

Richard

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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
Rick, whats wrong with Teflon tape? I've used miles of it on pipe threads over the years. Plumbing situation and permanently tightened pipe should get a more suitable pipe compound but for an oil fittings??

Kurt

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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
BTW, be careful not to over tighten a tapered pipe plug into a gearbox because you can crack the box plug flange.

Kurt

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refisk Avatar
refisk Rick Fisk
Frankenmuth, MI, USA   USA
Yeah, I've used a lot of it on water pipe threads too. But neither teflon tape or silicon tape were designed for use on threaded oil fittings.

In reply to # 3908962 by S1 Elan Rick, whats wrong with Teflon tape? I've used miles of it on pipe threads over the years. Plumbing situation and permanently tightened pipe should get a more suitable pipe compound but for an oil fittings??

Kurt

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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
I'll concede to you Rick. I am sure not as up on what else is available so will ask the next time I'm getting parts.

Kurt

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Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
x2 to seal the threads (with any kind of appropriate sealer, be it liquid or tape)

Don't go trying to solve a leak issue (which sealer is designed for) by changing oil viscosity (which will risk messing up the gearbox).


N

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Abington, PA, USA   USA
1976 MG Midget MkIV "Rodney"
HI Rick,

That's interesting. I don't even remember what we used with old Midgets and Sprites in the '60s and early '70s when I worked at a used sport car dealer in Phila.'s lower Northeast where i was in HS and college. Probably used whatever the shop boss said. I wonder: Is there any place one can get a list of specified lubricants used in various British cars from 1945 - 1980? A tabular compendium of such would be very useful and important.

Regards,

Richard

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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
Till I ran out of it I used 50 wt non detergent for early gearboxes. They were never driven in winter so I figured a little heavier oil wouldn't hurt. Seemed to quiet the gear box a bit. My supplier went out of business and I haven't made the effort to special order it now so back to 30 wt.

Kurt

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PeterC Avatar
PeterC Platinum Member Peter Caldwell
Madison Wisconsin, USA   USA
I highly recommend this stuff. The first blue can. Lasts a lifetime.

http://www.gasoila.com/products/pipe-thread-sealants.html


Peter C


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Kensmg.project Avatar
Kensmg.project Silver Member Kenneth Bundesen
Sunshine Acres, Qld, Australia   AUS
1967 MG Midget MkIII "Snow White"
Update on my Gear Box leak. I first thought it was leaking from the Speedo Cable but have since found that is not the case. Definately leaking from the bung. I have firstly tried the silicone tape. Seems to be working so far; however I haven't taken it for a drive yet as the weather in inclement. Will keep updated.

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