I was replacing a unit bearing on my 99 SD for the second time, but the first time doing it myself.

I bought a seal for the axle shaft that is loacted on the back side of the knuckle by the u-joint, but haven't the foggiest on how to replace the seal??? It seems like it can't go over the u-joint side or the more outer side. Though this is not that big of deal since I mangled the thin steel flange that is part of the outer axle stub - when I was pulling the axle out of the knuckle.

Any ideas? The dealer quoted me $600 for the whole RF axle shaft assembly. I think I may want to do the knucke as well since the inside of it is a bit rusty even after a lot of sanding.


The brakes had been dragging slightly on the RF for a long time and contributed the knuckle getting hot enough to dry up all the grease complicating the matter.

 

The seal I think your talking about is at the endoff the axle tube???
to put that on the axle gets pulled out of the tube.
You just pry on the u-joint with 2 screw drivers and work it out.

If you are leaking axle fluid ,that means that your inner seals are shot or your axle is rusted and pitted where the seal rides.

The big knuckle seal needs a special tool to put on or the tool that can be made from parts at your local hardware store.

Do a search for a post on How to change your ball joints

Depending on how deep the rust pits are on the inside of the knuckle are ,you cantake a cylinder hone and clean it up.
Rich

 

Actually the seal I am having trouble with is F81Z3254CB, the knuckle seal as some call it.

If I did make a special tool to install that seal, would it pass over the u-joint area of the axle shaft to get to its final placement?

I will have to purchase a new outer stub shaft as I bent the flange that the knuckle seal butts up to. I am debating if I want to just put a new knuckle on too.

 

How does the ABS sensor come out of the knuckle on SD's with 4 wheel ABS?

I am considering buying a whole new axle assembly, since I could upgrade to the Dana 60 for a little more than a new knuckle and RF axle shaft, but I have RWABS.

Did the Excursion have the Dana 60 from 2002 and newer?

 

I don't know specifically what you bent, but the stub shafts are pretty doggone hard to bend up. Might be easy to nick some machined surfaces, but bend up? Sounds to me like you bent part of the seal, not the shaft. Here is a link to a post on how to change ball joints that includes pictures of the tool used to install the seals. First put the seals on the shaft, out of the axle tube, then put the seal/shaft assembly into the axle with the same installer. I made mine from a piece of 2" threaded pipe 10" long with a cap on one end and half of a screwtype union on the other end.

Can you post pictures of what you have so we can see exactly what is broken and what is not? It would help us help you.

As far as the ABS sensor, I don't know, I have never replaced one because the unit bearing always went out before the sensor did, and new ones come with a new sensor.

 

I did not bend the stub shaft itself, I bent the steel rim/plate that butts up against the knuckle bearing. It is only bent at the edges due to all the yanking it took to get the axle shaft loose from the knuckle.

 

If I recall correctly, that part of the shaft that the seal goes onto and butts up against is machined steel, so you are not going to bend it. I think what you are reffering to is actually a portion of the seal. The knuckle seal is quite complex in design and has the ability to move in and out within itself. It also is not surprising that it got bent either, as it often happens on removal. Have you aquired the new seal yet?

 

The metal piece your refering to is pary of the seal. Remove it and replace. You can make an installer out of PVC pipe or the like.
F81Z3254CB Hub Seal
F81Z1S175HCA Axle Seal
F81Z4A322AA Yellow O-Ring
Make sure neddle bearings are greased well.

 

So the metal flange that the plastic hex washer(the one with grooves facing the inside) is placed up next to is removable from the stub shaft??

I kinda tried to see if that was a separate piece, but it seemed to be part of the shaft.

I have these
F81Z3254CB Hub Seal
F81Z4A322AA Yellow O-Ring

I do not have
F81Z1S175HCA Axle Seal

 

Yes, that is part of the hub seal and will be all nice and new again with a new seal. Just remember to use the installer tool, or you can booger up the new one real easy! In addition to the parts you have, I would suggest you get the black o-ring that goes on the lockout, and new stud kit for the unit bearing. It saves a lot of fooling around after the fact. When you put everything back together, just remember to apply a light coating of grease to the surfaces that the seals and o-rings seat against. The hubs are vacuum actuated and will not operate properly if the assebled hub/unit bearing assembly has a leak.

 

Thank you!

I got everything you list except for the part I bent up, so I'm going to make a trip to the dealer to try and get it. Also, I'll have to create the driver for the seal.

 

I'm almost done with mine. The RH side is back on. I made my own driver as well. I got an 8" section of 1 1/4" pipe from Home Depot, also a 1 1/4" floor flange, which was about 4" in diameter. Grind that flange down to a 3.75" diameter, use a marker tip which is about 1/4" and mark all of the way around, then grind off the marker. It worked out well. Put a 1 1/4" cap in the end of the tool to hit on. I held the axle stub in a vise by the yoke. Don't hold it through the U-joint, grab the end of the stub you're working on and support the free end as well. Make sure the seal is lined up on the shoulder of the axle and set the tool down and apply some down pressure against the seal. Take one swing and check to see if it started. You'll want to swing and hit a good double to help make it start, don't try to tap it on. I had a 3lb small sledge for persuasion. One swing and check it. Also, I put a couple wraps of tape on the end of the axle stub which helped align the shaft inside the pipe and keep it straight. I was surprised how well it worked.

 

If you can, take the bent stuff with you so you can match it up.

 

I have it all in working order again - the tin piece that I was worried about was actually just part of the knuckle seal.

I drove the seal on using the old unit bearing assembly. I just set the old assembly wheel studs toward the floor, set the new seal on the old assembly, placed the axle on the top and tapped the end of the axle that goes into the diff.

 

I have a 2000 250 4x4. What is the best way to align the front axle shaft splines when installing.