This is the tool I machined to insert the seals into the front knuckles on our GMC with the axles in place. It can also be used when the knuckles are off the coach as well.

I choose nylon as the material because it holds it shape well & is easy to machine. You can easily make it out of PVC if you can get a pipe size close .

Just a simple tool, that has worked well, twice for us.
John Szalay

Drawing dimensions are in inches. This clearance allows plenty of room for the shaft, when you place the seals without removing the knuckles from the coach.

The tool puts the seal into the proper position and seats it with a slight tap with a mallet without any chance of bending it or twisting.

The material is a piece of Nylon rod.

looking through the tool

Bill Brown's aluminum version of John's tool

$25 shipping included
Bill Brown of Coshocton, Ohio