Questions and Answers

Rear Main Seal Replacement Q. Hi my name is Gary, and I have a 1986 Ford F-250, fuel injected, 302 5.0 liter, it has about 142,000 miles on it, it is an automatic, no ABS, and there is a leak in the main seal. Someone told me that it could be repaired without removing the engine. My question is: is that true? If not is there a place where I could get information on how to do it?

It's a big job I know, but I like a challenge. Any info you could give me would be great.

Thank you.

P.S. it is a 1985 body with a 1986 engine

A. You don't have to remove the engine, but you do have to remove the transmission. Here is the procedure:

Removal:
NOTE: If crankshaft rear oil seal replacement is the only operation being performed, it can be done in the vehicle. If the oil seal is being replaced in conjunction with a rear main bearing replacement, the engine must be removed from the vehicle. To replace the seal only, proceed as follows:

1. Disconnect battery ground cable from battery, then remove the starter motor.
2. Disconnect the transmission from the engine and slide it back.
3. On a manual shift transmission, remove the pressure plate and cover assembly and the clutch disc.
4. Remove flywheel attaching bolts and remove the flywheel and engine rear cover plate.

   CAUTION: Avoid scratching or damaging the oil seal surface.

5. Use an awl to punch one hole into the seal metal surface between the seal lip and block. Screw the threaded end of a Jet Plug Remover or equivalent into the hole, and remove the seal.
6. Clean the oil seal recess in the cylinder block and main bearing cap

Installation:

1. Clean, inspect, and polish the rear oil seal rubbing surface on the crankshaft.
2. Coat new oil seal and crankshaft with a light film of engine oil.

   CAUTION: Do not apply grease on seal for lubrication.

3. Start the seal into the recess with the seal lip facing FORWARD and install it with a rear oil seal replacer tool. Keep the tool straight with the centerline of the crankshaft and install the seal until the tool contacts the cylinder block surface. Remove the tool and inspect the seal to ensure it was not damaged during installation.
4. Install the engine rear cover plate. Position the flywheel on the crankshaft flange. Coat the threads of the flywheel attaching bolts with Pipe Sealant with TEFLON(R) or equivalent, and install the bolts. Tighten the bolts in sequence across from each other to 102-115 Nm (75-85 ft-lbs).
5. On a manual shift transmission, install the clutch disc and the pressure plate assembly.
6. Install the transmission. On an automatic transmission, do not adjust the transmission linkage.

I can tell you from personal experience, be sure the new seal is installed absolutely square with the block and crankshaft. if it isn't, it will leak.

Additional Information provided courtesy of ALLDATA