M135 Questions, need answers please.......

1. I have a couple leaking wheel cylinders. Before I tear it down I'd like to have the correct cups or kits. What size are the cups?

2. Seems the rear main seal is leaking. I just started running this older new rebuilt engine after maybe 10 yeras. Almost no time on it but it's been sitting all that time. Do you think it might quit leaking? Probably not, so how whats invilved with replacing the seal?

Many many thanks in advance for your help.
Regards,
Brad Foust

Wheel cylinder cups are NAPA United #14451 I don't know diameter.
To replace the rear seal you have to remove the oil pans and loosen all of the main bearing caps enough to allow the crank to drop down far enough to work out the seal top half. The bottom half is in the rear main cap; you have to remove this bearing cap from the engine. If you get any deeper into the main bearings, remember one important thing about these engines: the main bearing journal diameters are of decreasing diameter from the back to the front. Don't get bearings misplaced! Voice of experience here! Main cap torque 90 to 100 Ft. Lbs.
If it is not leaking very much, it is far easier to live with it.
Other part numbers I have: Points NAPA Echlin CS777A Condenser NAPA Echlin RR175
Regards Marti

Hey Brad,
I have been putting off repairing my leaking rear main seal on the M215 for too long. Replaced it once already, M543A2's outline is spot on. When I replaced my rear main seal I discovered that the crank surface that the seal rides on was pitted, The new seal lasted about a year before leaking again. I'll need to pull the engine and crank to have the surfaces re-faced, hopefully before next spring.

Does anyone know if a seal option other than rope that is available for the GMC 302 ?

Good luck on your leaking seal.
Karl

just did rear main seal on my truck,buy a new FEL-PRO seal,dont use an old seal from an engine kit,buy a tool called SNEAKY PETE made by CARLISLE from NAPA ,you dont have to drop the crank ,only remove rear main cap,once you see the tool you will understand why,very neat tool for removing and installing the old style rope seals,and no there is not a modern replacement for the rear main seal,,or oil pan seals and on the cork oil pan seals,soak them in warm water before install,they will swell up and be less likely to break,good luck on your project

some very good info here guys.. Thank you for sharing.

Thanks so much for all the help on the seal.
Any idea of the wheel cylinder cup sizze??
Thanks

in the TM 9-8024 manual it says that the bore diameter of the wheel cyls is 1 1/4 inch,however i bought new wheel cyls from NIAGARA MILITARY PARTS ,and they have 1 3/8 dia cyls and cups,these have a Canadian part # but are a direct replacement for the original GMC wheel cyls