rear main question

[long69]

i have a leak at the rear of the motor that i'm thinking is the rear main. how hard is it to replace in the truck? its the rope kind and i think i may want to have it done. any idea of the cost of having it done?

[truckster]

I'm assuming it's a SBC. Do you have a 2wd or 4wd? I was able to replace mine in my Blazer 4wd without pulling the motor. I had to loosen the mounts and raise the front of the engine a little to pull the pan off. After that it was pretty easy.

Before you go to all that effort, though, I'd make sure it's not coming from the heads or intake manifold. Use a light and an inspection mirror to get a gool look back there.

[long69]

yes a sbc and 2wd. thanks for the response at least i know it should be do-able.

[69GWC]

Yes very doable, not the most fun though..lol
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[rsavage]

If the intake has been off or changed out at some point look very carefully at the back of the manifold. These small blocks are noted for leaking out of the rear of the intake when not sealed correctly. Oil runs down the engine block and make it appear that it is leaking from the rear. Valve covers leaking will also do the same thing. You should have a two piece neoprene seal in the rear (as long as your motor is 85 or older). Make sure the joints are staggered and not straight across even with the block surface when you install the new one.

[asolde]

I just did my oil pan gasket in my truck 1972 c10. I had to use a engine hoist to get the front of the engine high enough to get the pan out. I also removed the transmission mount to get a little more angle on it. Loosen your fan shroud, disconnect your exhaust,disconnect your engine mounts, drain oil, remove oil filter, remove starter. I pulled my carb and attach my hoist to my intake manifold and carefully lifted my engine.

[truckster]

Originally Posted by asolde

I just did my oil pan gasket in my truck 1972 c10. I had to use a engine hoist to get the front of the engine high enough to get the pan out. I also removed the transmission mount to get a little more angle on it. Loosen your fan shroud, disconnect your exhaust,disconnect your engine mounts, drain oil, remove oil filter, remove starter. I pulled my carb and attach my hoist to my intake manifold and carefully lifted my engine.

You can still do the job without a hoist if you don't have one. Just use a jack with a wooden block under the balancer. Make sure it's out of the way of the front lip of the oil pan.

[long69]

i have only rebuilt two motors before. one a 396 and the other a pontiac 389 both had a rope seal so i assumed that this was a rope type. a rubber kind sounds easier than rope?

[Tx Firefighter]

Yes, you'll be changing a rubber lip seal. It's really pretty easy. Once you remove the rear main bearing cap, just push the top half of the seal out with a little screwdriver or something. It just rolls around the crankshaft with a little pressure.

[GRX]

A piece of stout brass wire works well for pushing the rubber seals