Thread: 8" Ford diff leaking around pinion nut

Tweet

I just assembled the rearend for my A pickup. I had purchased a rebuilt
third member with new gears with no warranty. The problem appears to be
oil leaking around the pinion nut through the spline in the center of the yoke. The pumpkin does look to be assembled with new parts. It's my understanding if I remove the nut and yoke to check the seal, I'll have to have the gear lash reset because of the crush washer. I really don't want to tear it all apart.
Would a few miles on it seat the seal? (Wishfull thinking)
Any ideas or suggestions or cures would be helpfull and much appreciated!
Thanks! Joe

i allways use RTV on the pinion spline to yoke when i set a gear up if oil coming out under the nut you could try washing it with carb cleaner and try sealing it

We bought two 9 inch rears from a builder in Pennsylvania, one for my 27 and one for my Son Dan's rpu. Both of them leaked like mad from day one. We sent Dan's back and he sent us a new one that didn't leak, but he accused us of "overfilling" the rears, which caused the leaks. How you overfill an 8 inch or 9 inch rear I would love to know, because as soon as the fluid hits the correct level it starts coming back out and you stop.

I was so mad at this guy, TJ Rebert, that I didn't even send my leaker back and will deal with it down the road sometime. It still leaks all over the garage floor, and I have put a lot of miles on it, so no, they don't seal up after driving them for a bit......if they leak they leak.

Since having my run in with this shyster I did some googling and found others who have had the same bad experience with him. BTW, he sells a lot of units on Ebay, so if you see a Pennsylvania 8 or 9 inch advertised, run, don't walk!

Don

Joe, pick up or borrow an older Ford shop manual (it really doesn't matter what year, some time from the mid 60's to the thru the 70's and it should explain about checking the pre-load prior to and after replacing the pinion seal without replacing the crush sleeve.

Another method is to mark the nut and pinion shaft prior to disassembly and count the number of turn to take the nut off. When you reassemble tighten just a touch past the mark.

I’ve replaced a lot of pinion seals over the years on rear ends with crush sleeves and only screwed up one of them......you can tell before you even try to drive it if you got it too tight.

If you’re not comfortable doing it yourself, find a good shop (a local garage or rear end shop who still have some old timers working there) and have them do it.

OK - leaking 8 and 9 inch Ford 3rd members were, even new, not unusual. While I've never had a problem with one that I've put together, others will and do. Fact of life.

Now, as far as having the pinion lash reset after replacing a seal - not necessary. You already have the crush washer or stack of shims set and it has already become a solid one piece unit which will not change if you disassemble it to just replace a pinion seal. Also, if this guy does these on a regular basis, he probably uses a solid spacer and shims to set the preload.

Install a new seal, torque the nut to spec with a small amount of sealer on the threads. Obviously, check the yoke for burrs as well. If there is any failure it isn't from just replacing the seal - you don't really think dealerships or garages replaced anything but the seal if it leaked plus they did it on a lift with the differential in place (and probably seldom even used a torque wrench if a couple garages I worked PT at in the '60s and '70s was any indicator)

if leaking out of the pinion spline and they can... rtv on the nut thread is not going to help much the stock tin slinger may slow this down oil roping then seeping many times it never get put back in or you just can not find them so by using rvt on the inside spline of yoke stops this. i use solid shims on all 9s i build so its not a big deal to go back and change out a yoke