The Stovebolt Site Forums The Shop Area Engine Shop Rear Main Seal

I have a 59, 235 striaght 6 that is need of a rear main seal. How difficult is this to do ?

Since no one else answered you, I'll take a crack at it. These instructions are for a 216, but I believe the 235 is the same.

• Remove rear bearing cap
• Remove old seal from groove and make sure groove is clean
• Insert new seal in groove with fingers
• Using a rounded tool, roll the seal into the groove
• Cut the small portion of the seal that protrudes from the groove flush with the surface of the bearing cap NOTE: To prevent the possibility of pulling seal out of groove a round block of wood the same diameter as the crankshaft flange may be used to hold packing firmly in place while the ends are being cut off
• If it should be necessary to replace the upper half of the seal, it will be necessary to remove the engine from the chassis and remove the crankshaft
• Replace cap and adjust bearing

Some guys have had a real hard time getting that seal to stop leaking, so make sure you buy a quality seal.

Clem:
If you do a search on this, you will find that there have ben significant discussions on this. There have been plenty of experiences and points of view exchanged on this topic. I know that when I followed those threads I learned a lot about what I originally thought was a fairly simple repair. My experience with the "rubber" replacement seals, which install fairly easily since they come as two halves, has been poor. That's why when I rebuilt my 261 I made sure it was the original-type "rope" seal. So far (knock on wood) it seems fine.

Donsz

Is there any type of neoprene oil seal available for the 261? Never heard of it here in Brazil!!

Alexandre:
Yes there is, it is some type of compound, somewhat like neoprene I guess. If I remember correctly, each half has a spring internally embedded to provide tension (I guessing). I was able to get them at NAPA auto parts here. I tried two of them and while they helped, they didn't stop the leak entirely. Others have had the same experience, while some have had them work for them. I actually got a set in my 261 gasket- engine rebuild kit. If I still have it, I would be glad to send it to you if you can't acquire one locally.

Supposedly the 53-54 1st series 235s used a 2 piece rope seal. The 55-62 2nd series engines used a 2 piece neoprene molded rubber seal.

The replacement rope seals are no longer made with asbestos. The asbestos in the old ropes made for a better seal against the crank surface. Stovebolt engine company has some NOS asbestos seals left.

I don't know if the ropes will work in a 2nd series engine, or if you have to use the neoprene seal in them.

The upper half of the neoprene seal will rotate out easily. It is possible to replace the upper half of the rope seal too. It requires a rope seal installer available at good auto parts houses. But if the crank surface is pitted or worn, it won't seal up anyway unless you get the crank polished.

These engines leaked oil from the factory anyway. The dealers would put cardboard or wax paper under them to keep the oil off the showroom carpet. A 235 is like an old harley. If its not leaking, its low on oil!

chip

I have my 235 down to one small oil leak. The fuel pump. Should be easy to fix. The new asbestos rear seal is bone dry.

Clem, If you would email me I can send you some instructions for changing the rear oil seal that are "blonde" proof. I have sent them to many other Bolters on here, with nary a complaint. This covers both wick and neoprene type seals. This WORKS and takes about an hour.
[email protected]

Thanks everyone !

Donsz,

Thanks, trhe deal is very simple: the 261 is somewhat common in the classic car scene here because of the chevy trucks produced here during the 60's using them. From times to times, someone asks me to assemble one. Like all other bigger american made engines available here, they use the rope rear seal. I assembled a lot of 318 Mopars, and for these ones I can get a seal for the Magnun 318 for Cherokees(part is available here, no problem, and works perfectely, no to mention that it is inexpensive) so I naturally assumed that the same process on a 261 would be desired. If You have one laying around of course I want it. The only issue is how to pay You for this, since the bank charges me a US$50,00 fee for any amount of money send overseas. Thanks anyway!!

Alexandre:
Email me your address, if I still have it, I'll send it to you. No payment needed, it's not doing me any good. If it helps you, then great.
Don

Donsz

Thanks a lot, fellow!

Alexandre de Souza Lima Garcia

Donsz

Thanks a lot, fellow!

Alexandre de Souza Lima Garcia

Quadra 05, Conjunto C, Casa 46
Sobradinho, DF
Brazil
CEP 73030-053

Donsz I have some rope seals here, that I have no use for, they are best we have, with asbestos, want me to send them to You? If so, send adress!

hahaha

Oh that's just great....

NOW you guys tell me!!! After I bought one.

Man I read half those posts before I looked at the date. Dejavu