LT-1 front and rear main seals

[Rick Dorminy]

When replacing the front main seal in an LT-1 from a '92, is it necessary to pull the engine? There is very little room from the balancer to the radiator. What is the best way to be able to remove the balancer. I am assuming you can just drop the front of the transmission to replace the rear main. Is that right?
thanks

[Joe L.]

Re: LT-1 front and rear main seals

Rick-----

You can replace the front seal on a 92-97 LT1 without removing the engine. However, you'll have to remove a lot of components to do it. You'll need to remove the water pump, balancer and hub, steering rack and distributor. You shouldn't need to remove the radiator, though. After you've removed all of the above, you can remove the cast aluminum engine front cover. The seal is easily removed and replaced with the cover off. A note of caution: when removing the front balancer and hub, be sure to index the hub to the balancer. The engine was balanced with these in place and they must be returned to the same relative position when they're re-installed or engine balance will be disturbed. Also, make sure that you don't lose any of the "roller bearing-like" weights from the balancer.

The rear main seal can be replaced with the transmission and flywheel removed from the car. To ensure that the new seal is properly installed, you should use a special tool (Kent-Moore J-35621). Unfortunately, this tool won't be found very often for rental and it's expensive.

One other thing: although I provided a synopsis of the procedure in the paragraphs above, I would not recommend that you even attempt this repair without obtaining and following the specific procedure covered in the 1992 Corvette Factory Service Manual available from Helm, Inc. This manual is expensive. However, if one wants to do any serious work on their car, you ABSOLUTELY MUST have it and USE IT.

[Terry M.]

more on Gen II LT-1 front and rear main seals

In addition to Joe's excellent advice --

The front balancer hub is not keyed to the crankshaft, so you will have to mark the hub and shaft in order to reinstall the hub properly.

Also, the three ears on the hub are NOT spaced 120 degrees apart, and while not absolutely necessary, the hub puller from Kent Moore, J-39046, will make the job much easier and less likely to damage something. There is a step inside the hub and many general purpose gear pullers have a threaded insert large enough to contact that step. One needs a puller that is small enough to contact the crankshaft through the opening in the hub, and something to insert into the threaded hole and bottom on the crank itself. And yes there is a bolt in the center of the hub which threads into the crankshaft, but don't think about loosening it a few threads and pushing on it -- you will destroy the threads in the nose of the crank.

[Joe L.]

Re: more on Gen II LT-1 front and rear main seals

Terry-----

Yes, I was not clear when I described the hub and balancer. It is the hub which must be marked to index it properly to the crank. Not keying the hub to the crank is one of the stupidest things that they did with the GEN II engine. I expect that making the PRODUCTION balancing of the engine easier was the reason for it, but they sure screwed up field servicing with this. They could have keyed it and still balanced it, albeit with a little more complexity in PRODUCTION. Much better that the complex procedures be done in PRODUCTION than expecting them to be taken care of in field SERVICE.

[Terry M.]

Re: more on Gen II LT-1 front and rear main seals

Much of the field servicing of this engine is needlessly complex, but its reliability and longevity is superior to Gen I engines. It is a shame its production life was so short.
BTW: I knew what you meant, but without having been there I thought some clarification would be helpful for others.