2001 F-150
@ 75k mi. I had Ford Racing pre-lapped 4:10's with "Cobra" LS. I also used the FRPP master install kit. Immediately the FRPP pinion seal leaked something fierce. I had them pop an OEM seal in with RTV and it held till the current 98k mi. Only difference is this time, there are signs of seepage between axle housing and pumpkin, just not nearly as bad. Is it crap seals? Improperly installed? ...or just telltale signs of using Royal Purple that probably creeps everywhere? I talked to the shop and they remembered the truck. We agreed that the crush washer needs to be replaced this time to ensure this isn't going to be a new regular maintenance interval. I just want to make sure the washer, pinion seal and 4qt. (there abouts IIRC) of unicorn tears will get the job done.

Is there anything better than OEM for the seal and crush washer?
Has anyone run one of those SOLID Ind. diff. covers? Cast Iron and power coated. CHEAP.

Aside from the diff cover, it's gonna run $100+ in parts and $180 in labor, and about the worse part is bucking up for the Motorcraft quick set RTV. Seems like $15+ and you have to have 2, IIRC.

Click the thumb for full screen.

 

Last time I had the fluid changed in my 8.8, they used a $5 Fel-Pro cover gasket.

 

Any brand name gasket or regular RTV will seal the cover. A brand new pinion seal should not leak.

 

Is the surface where the pinion seal makes contact with the yoke grooved from the old seal or is it rust pitted? If so they make a sleeve that slids over the yoke so the surface looks new again.

 

Not sure man, but thanks for the info. Would this be an OEM sleeve or?

 

What is with the seepage on each side of the pumpkin?

Should I just have the seal / nut replaced again and be done with it, or should I also buck up to have them replace the 25k mi. old pinion bearing and crush sleeve as well?

Last time they replaced the seal, they didn't replace the nut, but I assume they at least used a thread locker on it. If loose, this could be the issue itself, but not sure what that would do to the bearing also.

Can I tell anything by where the leak is? It seems to be from between the housing and seal rather than between seal and yoke, but I will have to check this again to be sure.

 

The seepage on either side of the center casting at the axle tubes is not unusual. Those tubes are pressed in at the axle factory and retained by large puddled spot welds only. It is a tight fit, but with time, heat, cooling, stresses ..... seepage such as you see is not at all uncommon. You can use some 2+2 Instant Gum Cutter from NAPA, clean the joint area really well, wire brush it really well, then use some paintable silicone sealer and seal the outside and paint it like you would your houses window moldings if you like?

The crush washer has NOTHING to do with leakage.

The nut has NOTHING to do with leakage.

There is a good reason to NOT use a new nut or crush washer or other new part when simply replacing the seal itself ...
... please read below for pinion seal replacement and you'll see why. You should inspect the surface of the yoke where the seal rides and if not smooth, if pitted, get a sleave for it at NAPA .... but only if needed. It's possible that the seal was damaged by the installer.

If you change the crush washer (actually, a "crush sleeve") or change the nut or other part in the stack up, you esentially start from scratch setting bearing preload all over. You've driven from 75K to 98K and the rear end isn't making unusual noises so why reset everything?

Pinion Seal Replacement.

My method is to first get the truck / car parked or raised and secure where I can get under it. F-250, I'ld just back it up on my 8" ramps. Set parking brake and block front wheels .... don't need tire tracks on my shirt. Put trans in neutral, paint or punch mark driveshaft at rear yoke so it can go back same as removed, then remove driveshaft from rear axle at U-joint.

Now, I clean the exposed threads of the pinion shaft, the nut, the rear flange / yoke with wire brush if needed. Once clean, I take a sharp center punch and hammer and I punch mark ... the end of the pinion shaft ... the pinion nut ... and the yoke or flange.

I also measure the length of the threaded pinion shaft sticking out past the nut and count threads, and I write it down.

This way when time comes, I can put that yoke back on that shaft and tighten that nut back to exactly the same relationship ... and NO FURTHER. I do NOT want to compress any crush sleaves any further, I want to retain the exact same bearing clearences .... I just need a new seal wrapped around it all.

Now, I use a BFW and remove the nut and yoke and then pull the old seal and install a new seal (and if it's a lose fit inside the housing, you can use a locktite product on the outer side of the seal to fill voids but not on the lips) driving it straight in (not ****ed at an angle) ... lube it's lip ... slide yoke back on so it's punch mark is same relationship to that punch mark on the end or the shaft ... and then I slip the same nut back on with same side against yoke as it was when removed ... and apply some locktite on the threads.

I tighten it until close to original setting, then I sneak up to final setting so when I stop, the three punch marks are in the same relationship with each other and same length of shaft sticking out as when I started .... and NO FURTHER.

DO NOT GO TOO FAR.

I then .... if the nut was a loose fit, may take a punch and punch the threads of the pinion shaft in two spots just to make sure the nut doesn't loosen, though the locktite should prevent that.

But that's just my way. I've done it on my vehicles a few times over the years, even a couple police cars ... always sucessfully.

 

That sounds a LOT cheaper / easier than the route I was going...but I guess I was just concerned it wasn't done right to begin with since the first seal leaked immediately and the second one only lasted this long. Seems like excessive wear to me.

If I were to do this myself, what kind of torque is involved? About 150 ft/lb?

Thanks for taking the time!

 

Likely near that ..... but re-read it.

You don't tighten to a torque figure, you tighten the nut back to where it was origfinally, using the exact same washer and yoke. I use locktite on the threads to make sure the nut doesn't back off as well as lightly staking the threaded end of the pinion shaft.

I have to stress .... you do not want any changes in the relationship of the parts, you want the exact same stack up.

You just want to wrap a new seal around the yoke inside the housing .... so you have to remove and reinstall items. If you have used a couple seals and suspect leajking at the shaft, take the yoke and get a sleeve pressed on that's polished and provides a new surface for the seal and lube it well.