Inliners International Forums General Discussion Engines 235 Rear main seal

Just purchased a 1957 Chev with a 235 and 3 speed on the column. There is an excessive oil leak at the rear of the pan so presuming it is the rear main seal. Want to order a new seal and gasket before I take it apart. Was on the Fel-Pro site and they offer a 2 pce rubber seal, part # BS13363 and is available locally. Has anybody ever tried this seal compared to the original rope style? Looks much easier to install and hopefully seals it up. Any comments?

I have used that FEL-PRO set a couple of times with no problems
on the install or after running the engine. Others here a suggested BEST seals as seal to use if you want to check their site. http://bestgasket.com/

BEST gaskets hands down. They actually send a kit with instructions on how to install and trim the rear main seal using the inclosed template and knife. The rocker cover gasket is also the best I've ever used. Patrick's has them.

Use the two piece neoprene seal. You will be much happier. The early 55 blocks had to use the rope, but all of the 57 235s I have built I used the neoprene. Btw, if you have to use a rope seal, try to beat the bushes and find an nos seal that is 20 or better years old. These should have the asbestos in the seal that allowed them to work. I agree with everyone else, the best gasket version is the best of the current stuff but you should really get an older seal for the best chance of success. Btw, I apparently do not possess the required skill to install a rope seal so the the motor does not leak, lol.

Agreed with mdonohue05 - I have used new rope seals, new BEST seals and NOS asbestos seals and the NOS seals work the "best" followed by the "BEST" brand seals if you are using sticking with the original rope design.

The new split rubber lip seals are easy to install and if you clean the mating surfaces well and put a small micro-dab of silicone sealant on the ends where they meet . . .

If you are sold on going with a rope seal - the only way to do this well is to remove the crankshaft. You cannot effectively pack enough of the seal into the block cavity with the crank in the way.

I have just over 2000 miles on my last NOS rope seal in a GMC 270 and nary a drop (and yes, the crankcase is full of oil)

I got a N.O.S. McCord neoprene 2 pce seal today from a supplier. Took awhile to get the pan off in the car, had to take out the 2 gravel shields at the bottom of the rad support so I could get at the front pan bolts and also dropped the idler arm just giving me enough clearance to pull the pan. Was told to crack all the main bearing cap bolts loose before I do the seal. I presume a "Sneaky Pete" is the easiest way to get the old seal out?

I got a N.O.S. McCord neoprene 2 pce seal today from a supplier. Took awhile to get the pan off in the car, had to take out the 2 gravel shields at the bottom of the rad support so I could get at the front pan bolts and also dropped the idler arm just giving me enough clearance to pull the pan. Was told to crack all the main bearing cap bolts loose before I do the seal. I presume a "Sneaky Pete" is the easiest way to get the old seal out?

There is also a one piece rear seal conversion that many have done successfully that seems to be a good alternative.

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My buddy used that one on his 261 rebuild but machining is required. Suppose to be a real good fix but I am not taking the engine out of the car at this time so hopefully the 2 pce works. Find out in a day or two when I can get back at it.

Probably not a cost effective mod if you had to pay someone else to do it, but if your a die hard DIY'er then its likely to be a benefit.

The two piece seal works well if the crankshaft surface isn't scored or pitted.
I've done Best and NOS rope seals in a GMC and several Chevys. Works well if done with the crank removed as mention by Ken.

If not removing the crank you may want to follow the GM service bulletin for rope seal repairs on 80's Buicks and Chevy 2.8's.
Remove rear cap and replace lower rope seal by rolling it in.On the upper seal,use a wood dowel and light hammer to press up the seal ends. Then cut short lengths of the remaining new half and pack them up into the space ( NOS asbestos seal is preferred). Trim the excess carefully.

The neoprene seal worked excellent. Took longer to clean up the oil pan and clutch covers than it did to remove the rope seal and install the 2 pce rubber one. Lots of oil and a little patience. Re-torque the main caps and now wait for the paint to dry on the pan. Then onto the next job............

Outstanding!

And ? .

Here we are one year later , does it leak or is all well ? .

TIA