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MG MGB Technical - Overdrive Solenoid Cover Leak - Solutions?

The solenoid cover plate gasket on my LH overdrive isn't keeping the fluid in. It appears to be a coated paper (came from Moss).

Is there a reason not to use some Permatex instead of a gasket for this application? And a little on the screw threads?
Steve Simmons

I have yet to find a way for keeping this cover leak free. Both my 70B and 69CGT leak from the cover plate on the OD. I have pretty much just accepted a minor leak here. RTV, permatex, etc all did not work for me.

Ron
Ron Smith

The first time I removed the cover, it had never leaked before. It had some sort of soft orange gasket that tore apart. It may have been something like Permatex but I'm not sure. Ever since I put the 'paper' gasket in, it's leaked.
Steve Simmons

Try using Hondabond, available at motorcycle shops. It goes on as a liquid and never fully hardens allowing for an excellent seal. I've used it for years and have never come accross an application where it doesn't work. Ray
RAY

Thanks Ray, I'll give that a try! I had to get the car back together today so I will try other options on the next service.

For today, I smeared a very thin layer of grey silicon Permatex on each side of the old gasket. We'll see if it does anything at all.
Steve Simmons

If you cna not find the Hondabond, try three bond 1104. It is basically the same thing. It did work for a while, as some of the other did but eventually it to leaked. It helpd to put some thread sealer on the screws/bolts as well.

Ron
RJS Smith

The oil leaking from the O/D solenoid cover is not beacuse of a bad gasket. The solenoid assy has 3 O rings on it & these are what stops the leaks - hopefully. Too thick a gasket will only prevent the main O ring from being crushed sufficiently. The Seal kit is NKC99S
Garth
Garth Bagnall

So my solenoid assembly should not be flooded in oil? Guess the o-rings aren't doing their job at all!
Steve Simmons

I can say that Hylomar did nothing to stem the slow oil seeping
out between the OD plate (in my case).

Whatever sealant you decide to use, be sure to use the most
minimum amount in order to prevent it's squeezing out between
the gaskets when the plate is torqued down - and getting inside of the gearbox and possibly clogging up the OD solenoid valve
and pump, etc.
Daniel Wong

Daniel,This is why Hondabond (3MBond) is recommended for motorcycles. Unlike silicone, it does not brake off and clog small internal passages. I've rebuilt hundreds of bike engines and have yet to have a failure. It is also a very good sealent on the tappet covers and will last almost indefinetly. On my supercharged '67, which I've owned for 34 years, it has been a godsend. Ray
RAY

You might want to try an anerobic sealer. It cures in the absence of air. GM uses it to seal the large rear aluminum castings on their transfer cases which use no gasket. It can be found at auto parts stores.
John H

DONT FORGET....to place the cover in a vice and make sure it's flat....took me months of resealing and resealing and O Ring replacement til 1 day it dawned on me that the cover might not be true...it wasn't...took 3 seconds to flatten...never leaked a drop since!!!! Boy did I feel stupid!!!!
P J KELLY

This thread was discussed between 23/10/2006 and 26/10/2006

MG MGB Technical index

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