MG MGB and MGB GT Tech Talk
On my '79, I'm replacing the solenoid gasket, as well as the gasket/screen that is next to it. I'm getting a lot of leakage from this area, should I use some RTV along with the gaskets? My fear is that the screws, going into aluminum, have been overtorqued in the past and don't snug up like they used to. If the general consensus is NOT to use RTV, do I use a thin coat of oil on the gaskets before installing? Thanks in advance.
Greg
IMHO an OD unit with all of it's small oil passages, and any engine for that matter, is no place for the Blue Goo stuff. I know that some folks like it but my feelings are that the potential for damage outweigh any benefits. In reality just a standard gasket is enough to seal properly mated surfaces, but sometimes you do need a little extra and the Permatex Aviation Form-A-Gasket in a tube and their gasket sealer in a bottle are about as good as you are going to find in your local parts house.
If you want the max seal without the max torque on the screws do this.
Clean EVERYTHING with a high fraction distillate, like naphtha, until it is REALLY clean. No runny oil, no drippy oil allowed.
Then make sure that the plate surface is FLAT. Then clean it again.
Then coat the plate with Permatex gasket sealer, the shellac sort of stuff in a bottle with a dauber brush on the cap. Place the gasket on the plate and coat the top face of the gasket with the same stuff. Use enough to cover the surfaces but not so much that it will ooz out when the thing is clamped down.
Use your own judgment about torquing the screws but they don't require much in the first place. Just snug them up and then add a tad more pressure. The Permatex will do the rest.
Let the whole thing sit over night before adding more lube to the gearbox.
Jack
You might want to try cooper coat spray, but I personally wouldn't use anything, dry.
if you suspect the threads in the housing then look at getting helicoils fitted.
Russ
Regarding this screen/gasket replacement, I heard that the reproduction parts we get are not actually made to design specification, hence possibly the source of leaking in this area after you replace the screen. If I understood correclty, the screen is sandwiched between two paper surfaces. If the screen extends out to the edges of the gasket, this might be a way for the oil to find it's way out--between the paper. Has anybody heard of this? If this really is an issue, might some sealant applied around the perimeter of the screen/gasket be in order?
Jack and all,
I went out and found a can of the Permatex and used it as suggested. However, Permatex recommended brake cleaner to clean the parts, so I used that. Those were some squeeky clean parts when I was finished! And I DO think the threads bit better after cleaning. I used a screwdriver handle on the socket to tighten things up; got a better feel with that over the ratchet. The only place I used RTV was to seal the grommet for the solenoid, taking care not to let it ooze in toward the solenoid itself. I will fill it up with oil tomorrow. Thanks for all the help, I do appreciate it!
Greg
Rick, I have tried sealant around the perimeter of the sump gasket and I still get leaks in a few months. I have lapped the gasket surface of the sump with wet/dry on a glass plate and tighten the screws gently with handle type driver. When I remove the gaskets the seal between the gasket inner and outer parts fail and the gasket seperates. I feel it's a lousy design, I have seen some with the screen extending to the edge of the gasket. I just replaced mine in June and it's already leaking, it was dry two months. I have tried them dry, grease and a light coat of sealer and they still leak in a few months. The photos show what happens to the gaskets I have removed. Is there another type gasket available? I even thought of making a gasket from some gasket paper but cannot figure how to install a screen in it.
Clifton
The gasket that I took off did not separate, but it sure had failed. I was losing LARGE amounts of oil from that gasket. I will put oil in the trannie tonight, since ol' Twigworker Jack advised me to wait a day before filling again. I'm sure the gaskets will have a better chance of setting up with the Permatex that way. After that I'll take her for a good hard run, and then throw my wife's favorite white sheets under the car to prove to her that it doesn't leak any more.
Greg