1965 differential leak

[Bruce W.]

Hey Guys,
Need a little help. I am preparing my car for PV. I have a slight leak coming from the rear cover on the differential. do I have to pull the differential to cure this or does someone have a simpler fix? Always appreciate the wealth of knowledge and experience.
thank you Bruce

[Gary B.]

Re: 1965 differential leak

Bruce,

A leak from exactly where? The fill plug? Or from the main cover gasket?

Gary

[Bruce W.]

Re: 1965 differential leak

Gary, main cover gasket
Bruce

[Gary B.]

[Frank D.]

Re: 1965 differential leak

Tighten the bolts around the gasket and add some Blue Devil Oil Stop Leak.&lt;br /&gt;<br />
&lt;br /&gt;<br />
https://gobdp.com/blog/fix-differential-leak/<br />
<br />
And then follow up with a thin layer of this aroumd the ccover after cleaning with lacquer thinner<br />
<br />
https://www.permatex.com/products/adhesives-sealants/sealants/permatex-black-rubber-sealant/

[Jimmy G.]

Re: 1965 differential leak

Product called "Seals All" Worked on a front seal on my 60

[Bruce W.]

Re: 1965 differential leak

Jimmy, does this go in the differential or on the outside of the case?
Bruce

[Edward J.]

Re: 1965 differential leak

Bruce, be sure to check the fill plug sometimes it looks like the lower case gets wet with gear oil, you can use some pipe sealant on the threads if it’s leaking. Be sure to use a cleaning solvent like brake cleaner on a rag. And wipe clean. I do not believe in any quick fit stop leaks for a gasket or seal leaks. Be sure to check the cover bolts for being loose.

[Jimmy G.]

Re: 1965 differential leak

Seals All is kinda like guue the goes on the outside. Seals leaks and can be applied over oil as well Not a permanent fix but works

Best fix is to remove the unit and re seal it with new gaskets

[Frank D.]

Re: 1965 differential leak

Seals-All is an adhesive whereas the Blue Devil producit is a chemical formulation that reconditions seals and will generally stop most leaks related to old seals.
No, its not the same as replacing seals, but I used the products below on my 63 differential anad it was leak free for the 3 years prior to me selling the car.

Tighten the bolts around the gasket and add some Blue Devil Oil Stop Leak.

https://gobdp.com/blog/fix-differential-leak

And then follow up with a thin layer of this aroumd the ccover after cleaning with lacquer thinner

https://www.permatex.com/products/ad...ubber-sealant/

Last edited by Frank Dreano (48332); Yesterday at 04:26 PM.

[Bruce W.]

Re: 1965 differential leak

Frank, thanks I will pick up this product and give it a try.
Bruce

[Bruce W.]

Re: 1965 differential leak

Frank, i got blue devil and put it in. If this works i will be one happy camper. Will let you know. thanks for the advice.
Bruce

[Bruce W.]

Re: 1965 differential leak

Frank, do you know if Blue Devil can be used for engine leaks. I have a small leak I think maybe coming from the rear main seal. this was replaced with Fel pro 2912 seal but still a problem. oil pan gaskets have been replaced. no oil coming from there? No oil coming from valve covers. Is there an easy way to determine if it is the rear main seal? thanks for your help.
Bruce

[David H.]

Re: 1965 differential leak

.... I have a small leak I think maybe coming from the rear main seal. ... ... Is there an easy way to determine if it is the rear main seal? thanks for your help. Bruce

Bruce

Have you tried UV light?

Dave

[Frank D.]

Re: 1965 differential leak

Frank, do you know if Blue Devil can be used for engine leaks. I have a small leak I think maybe coming from the rear main seal. this was replaced with Fel pro 2912 seal but still a problem. oil pan gaskets have been replaced. no oil coming from there? No oil coming from valve covers. Is there an easy way to determine if it is the rear main seal? thanks for your help.
Bruce

That is actually what I first used it for; I had a rear main seal and a front crankshaft snout seal weeping on my base motor 63 and put the Blue Devil Oil Stop Leak in with a fresh oil change and drove about 250 miles and both leaks stopped. The intent was that this would be a stopgap until I replaced the seals. As it turned out, the leaks never returned and so I just kept driving the car.

The problem with both of these seals is that a groove can be worn in the metal and just replacing the seal will not completely fix things, in the case of the front crankshaft seal there is actually a sleeve that can be used to permanently fix the defect. If this is the case an oil additive may or may not help.

As far as finding a leak the first step is a thorough cleaming of the engine areas around the gaskets/seals....particularly around the rear of the engine heads and upper bellhousing. The dye does work but sometimes even talcum powder sprinkled on the rear of the block and bellhousing will reveral a leak. Careful inspection with a strong light on a lift, if possible, at the rear of the block will usually reveral the source of a leak in those areas. valve covers will often leak down the very rear due to the tilt of the engine and don't forget the oil sending fitting on the rear of the block as well as the gasket where the distributor is seated. Often these leaks are mistaken for rear main seal leaks incorrectly. If you can't spot a leak there and there is still a drip on the oil pan/ or bottom of the bell housing its prob a main rear seal,

Valve covers invariably leak over the top of the gasket. When replacing, I clean the head area and cover gasket area with lacquer thinner and put a layer of Ultra-gray RTV on the cover, place the gasket in it, invert the cover and set it on a flat surface with weight on the cover over night, then I use PAM outdoor grill cooking spray (most any hi-temp grease will also work) along the ridge on the head where the valve cover sits so it can be removed easily multiple times and install the covers and avoid over-torquing the mounting bolts/screws. On non-judged solid lifter cars I always use the thicker Fel-Pro gastets as repeatd removal for lash adjustment and reinstallation can be done many times. Fel-Pro 1603 7/32" cork/rubber.