Ford 9" pinion seal

[yoshi]

Has anyone fitted a new pinion seal on a ford 9" & can give me some guidance? Thanks

[Speedbumpauto]

It might be easier to do that on a bench with the possible exception of loosening and tightening of the pinion nut. If you have a way to hold the pinion like a big vise with soft jaws, etc. do it all on the bench by removing the 6 (I think) bolts from the piniion housing and removing the pinion and bearing assembly. Be prepared to catch the oil. The housing assembly is pretty snug and is sealed with a large O ring on the outside. You usually have to wedge a putty knife or a small screwdriver inbetween the housings to start working it out. Once out clamp the housing in a vise and, using an inch pound torque wrench, determine the rotational torque needed to turn the assembly. Should be around 15 to 25 inch pounds. If the pinion was assembled with shims instead of a crush washer, the bearing pre-load will not change with the loosening and tightening of the pinion nut, but if a crush washer was used, you must come very close to the same rotational torque when torquing the pinion nut. In either case, make a small punch mark on the edge of the pinion shaft and a corresponding mark on the pinion nut then count the number of rotations it takes to remove the nut. This will give you a reasonable spot for the re-torqued nut to start checking the inch pound rotational torque. IIRC, th pinion nut torque is around 150 ft. lbs. Since you will probably not know whether the pinion was assembled with shims or crush washer, this is the preferred method to get the pinion bearing pre-load back to where it was, which is VERY important. Some will say you have to use a new pinion nut. It's good insurance but I have re-used old ones many times with red loctite. Choice is yours.
Having said ALL this, I have changed quite a few under the car, where the bearing pre-load can't be checked by marking my dots, using a good impact wrench to remove and install, going a tiny bit past the old mark for good measure and putting it on the road with good success. The down side of that quick and dirty method is if a bearing or such caused the seal to fail, you won't know it and it will fail again, possibly worse. Good luck.

PS There will be a shim(s) between the two housings when you get it apart. MAKE SURE ALL the same shims go back in during the re-installation.

[yoshi]

Ok thanks, if using the under truck method, how would you go about removing the old seal?

[Speedbumpauto]

Most of those ford seals have a lip that fits against the outer housing. A small chisel will start it out of the housing. If you have the older model without a lip, use a body dent puller, slide hammer with a screw in the end. drill the seal, screw in the screw and pop it out.

[yoshi]

All done back on the road, many thanks

[Speedbumpauto]

Ain't it great when stuff finally works.