Restoring Pin-Bushing Fit.

[George7941]

This is on a hydraulic liftgate on a truck. The pin is exactly 1 in dia. As you can see there is wear on both the pin and the bushing. I will be replacing the pin but I estimate I will still end up with a gap of about a 1/16 in. This pin and bushing is exactly like the one below it shown in the photo.

I plan on applying a metal filled epoxy like Quick Metal to the bushing and then grinding the inside to accept the pin. The bushing has a thru hole, 1/4 in dia, so that a roll pin can be driven through the bushing and the pin to lock the two together. I will be using a 1/4 in grade 8 bolt to accomplish the same thing.

The load could be up to a thousand pounds on the pin. Will the Quick Metal hold up? Since the pin will not be turning in the bushing, I am hoping it will.

 

[old1]

I don't quite understand-- if the pin doesn't turn in the bushing, how did it wear out?

 

[George7941]

Just from the bouncing around of the truck and the slight relative movement it induces in the joint, combined with heavy loading of the joint, no lubrication and grit getting into the joint. The pin is not drilled and so it was never locked into the bushing and that is the way it was originally assembled when the truck was built. Funny thing the same joint on the other side of the gate has the roll pin locking the pin to the bushing and has no wear.

 

[doitmyself]

Any chance this might work: http://komatsueq.com/expander-system/ ................also: http://www.expandersystem.com/ca/

It also seems that you might be able to tack weld/braze a new pin in place in such a manner that you can break the welds for future pin replacement.

I would not have too much faith in epoxy, but who knows.

 

[George7941]

The expander pin will not work in this case because immediately next to the bushing is the bushing on the end of the arm seen in the photo. That bushing has a grease fitting and has been kept lubricated over its 17 year life and does not have any appreciable wear, so the pin is passing through two bushings, one worn and one unworn.

I did not think about welding the pin to the bushing but, now that you brought it up, I might just do that. The truck is nearing the end of its life and I don't expect ever having to remove the pin again.

 

[Linctex]

I would get the bore and pin both as round as absolutely possible...
then measure...

Then buy a 1 foot long piece of 4130 Chrome-moly aircraft tubing from Wick's Aircraft Supply in the required OD and ID and make a bushing out of that. It should double the life of the lift-gate.

 

[Linctex]

Originally Posted By: George7941

I did not think about welding the pin to the bushing but, now that you brought it up, I might just do that. The truck is nearing the end of its life and I don't expect ever having to remove the pin again.


OK, if that's the case,
then just get a piece of electrical conduit close to that size and make a bushing out of that.
Just cut a vertical slit on the bushing with a hacksaw if you need to reduce the OD.
\
Pound it in, and just tack weld it.
It'll last another 5-10 years.