Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

[Jacob A.]

Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

I have just installed the fresh L-71 into my car and it appears the rear main leaks just a little.

I am told this is common and not to worry about it, but what are other's opinions on this, as I don't want it to leak a drop!

Thanks,
Jacob

[Mike M.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

I have just installed the fresh L-71 into my car and it appears the rear main leaks just a little.

I am told this is common and not to worry about it, but what are other's opinions on this, as I don't want it to leak a drop!

Thanks,
Jacob

rope seals went out in the 50's. your l-71 has a two piece neoprene seal. it shouldn't leak a drop. and if it does leak and you intend to PV the vette, it'll fail on this issue. good luck,mike

[Wayne W.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

I have just installed the fresh L-71 into my car and it appears the rear main leaks just a little.

I am told this is common and not to worry about it, but what are other's opinions on this, as I don't want it to leak a drop!

Thanks,
Jacob

Two piece lip seal, but if you want a Chevrolet not to leak a drop, good luck.

[Clem Z.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

here is why most rear seals leak not the seal but because they don't put sealer where shown with cross hatch.

[Joe L.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

I have just installed the fresh L-71 into my car and it appears the rear main leaks just a little.

I am told this is common and not to worry about it, but what are other's opinions on this, as I don't want it to leak a drop!

Thanks,
Jacob

Jacob-----

The only big block that ever used a rope type seal was early 1958 348 cid and they never used one of those in a Corvette.

Getting a Chevrolet engine with a 2 piece rear main seal to be 100% leakproof can be a real challenge. Applying sealer to the area that clem describes can go a long way. But, getting it to 100% leakproof can be almost impossible. That's why GM gave up on the 2 piece design for small blocks in 1986 and big blocks in 1992. It was an expensive design change for them but I suspect they felt it was the only way to get crankshaft rear main seal leaks "behind them".

[Clem Z.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

rear main seals leak when you shut off the engine because the oil pressure that pushes the seal lips against the crank journal to form the seal goes away. on boat engines where oil leaks in the sump causes a big problem i grooved the bearing insert to allow the oil to run back towards the oil pan and it worked to where it cut the leaks and i had fewer complaints

[Jim T.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

I have just installed the fresh L-71 into my car and it appears the rear main leaks just a little.

I am told this is common and not to worry about it, but what are other's opinions on this, as I don't want it to leak a drop!

Thanks,
Jacob

This is what I am going to use in my 68, 70, or 85 Corvettes when I replace the real seal.
"Part # 10121044
Rear oil seal for V-8 and V-6 engines with pre-1985-style two-piece oil seal design. Used by many NASCAR teams for superior leak protection.

This is a GM part number, it is also available as an FEL-PRO seal. This seal is listed in the Chevrolet Performance Parts book.

[Joe L.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

This is what I am going to use in my 68, 70, or 85 Corvettes when I replace the real seal.
"Part # 10121044
Rear oil seal for V-8 and V-6 engines with pre-1985-style two-piece oil seal design. Used by many NASCAR teams for superior leak protection.

This is a GM part number, it is also available as an FEL-PRO seal. This seal is listed in the Chevrolet Performance Parts book.

Jim-----


The 10121044 is the best seal available. It's the exact same piece as Fel-Pro (in fact, I've even gotten Fel-Pro seals that have the GM part number on them which I would guess was a Fel-Pro mistake in packaging). However, this seal is only applicable to 59-85 small blocks. It won't work for a big block. For big blocks the equivalent seal is GM #10117767.

[Jim T.]

Re: Is a 67 L-71 rear main seal a one piece rope or 2 piece lip design?

Jim-----


The 10121044 is the best seal available. It's the exact same piece as Fel-Pro (in fact, I've even gotten Fel-Pro seals that have the GM part number on them which I would guess was a Fel-Pro mistake in packaging). However, this seal is only applicable to 59-85 small blocks. It won't work for a big block. For big blocks the equivalent seal is GM #10117767.

Joe

Good information on the seal for the big block. Only big block I have owned and installed a rear seal in was the 348 in 1964.