Oil pan gasket and rear main seal

[Scott Santora]

So after some searching, I only found one discussion about replacing the rear main seal. That post was for a 64 DeVille, I have a 63.  The post wasn't clear if the job could be done with the engine still installed in the car.

 Before I go digging into this, can someone confirm if the oil pan and rear main seal can be replaced with the engine still in the car?

Thanks

[Kurt]

Yes it can. The procedure is outlined in the Shop Manual. You should also do the bearing cap modification which has been discussed often here & is in the Help tab above.  

https://6364cadillac.ning.com/forum/topics/rear-main-seal-oil-leak-fix

[Scott Santora]

Thanks, That link gave some great information. Unfortunately, before I joined this group, I went out and purchased an engine  gasket set from Speedway Gaskets. The set I bought was manufactured by Best. I have seen here that the Best brand rear main seal leaks and is not any good. Do you know if the rest of the Best brand of engine gaskets are any good? I have not used anything from the kit I purchased. If they are not any good, since the gasket set is unopened, maybe I can return them.

[Russ Austin]

The other gaskets are good to use. 

[Scott Santora]

That's good to hear, otherwise I might have wasted $200. I bought the gasket set back March. I doubt I would have been able to return them.

[Russ Austin]

DO NOT GET the Best Gasket brand rear main seal. It is a known failing seal. It leaks immediately upon engine start.  I have talked to the company and they don't care. The rubber is too soft and the seal has no pressure on the crank to seal.  

Get with Caddy Daddy and get the rear main seal that they stock. 

[Scott Santora]

How about the other gaskets made by Best Gasket? I purchased a complete engine gasket set before I joined this group. I have not used any of them yet. I was about to replace the front seal. Do you know if those seals are any good?

[Russ Austin]

Yes, the engine stays in the car.  The pan is removed by rotating the crank so the balance weight up front is up top. That gives the oil pan the clearance to be pulled back. 

Loosen the main caps so the crank drops JUST A LITTLE BIT.  Do not use the Best Gasket brand rear main seal, it leaks right away 

[Jason Edge]

Here is my take on the Rear Main Seals:
It has been stated that doing the bearing cap mod ( what I will call Step A) and using the Rebuilders Choice Rear Seal (Step B) together will prevent the rear seal from leaking. 
So we have at least a couple of examples where if you do A + B = No Leaks.

This has always made me question what happens if you do the bearing Cap Mod (Step A) and use the Best Gasket (I will call Step C).   That is, does A + C = a leak? 

I just can't remember anyone doing the bearing mod AND installing the Best gasket and what the outcome was. I am not questioning that the Rebuilders Choice seal is not a "better seal" but I am wondering of the bearing cap mod take enough pressure off the seal to also stop leaks off the maybe inferior Best seal?

If we had a few, or at least a couple of people that have made the bearing cap mod and used the Best gasket and it still leaked, I think that would absolutely confirm that you do have the use the Rebuilders Choice seal even with the bearing cap mod.

As far as using other Best brand gaskets, I have used them off and on for 30 or 40 years and never remember any issues.