743 pins/bushings

[kyosho]

I just bought a 743. The machine overall is in good shape, except for the bushings and pins. The lift arms bushings/pins on the top are shot. (Above where it says 743 on the side of the machine). When the lift arm/boom is raised it is not level, and if you grab the bucket you can twist the lift arms back and forth - so you can see the upper pivot points are loose. What is the best way to replace them? The bushings are welded onto the frame, and the inner bushing is welded onto the lift arm/boom. Is the bushing what normally wears out? Or the pin? Or both? Looks like it had not been greased in there in a long time. In fact the zerk fittings were busted off one of the bushings. Is this something that I need to have a dealer do? Or are there sleeves that can go in there with perhaps a smaller diameter pin? What is the normal course of action in this situation? I find it hard to believe that the bushings (a wear item) are welded on - seems dumb to me but it is what it is.

 

[OldMachinist]

If the previous owner/owners failed to maintain the pivot points the wear could be on both the pins and bushings. With proper maintainance the pins seem to wear more than the bushings and are easy to replace. If the bushings are wore bad they can be line bored and sleeved or welded up and line bored. There are machine repair people that specialized in doing those types of repairs. I would pull the pins and see how bad things are and depending on what your plans are for using the machine you may be able to get away with just replacing the pins.

 

[kyosho]

If the previous owner/owners failed to maintain the pivot points the wear could be on both the pins and bushings. With proper maintainance the pins seem to wear more than the bushings and are easy to replace. If the bushings are wore bad they can be line bored and sleeved or welded up and line bored. There are machine repair people that specialized in doing those types of repairs. I would pull the pins and see how bad things are and depending on what your plans are for using the machine you may be able to get away with just replacing the pins.

Ok, thanks. I was thinking of just replacing the pins to see what would happen. Like I said there is ALLOT of play in the boom when it is raised - the bucket raises up quite crooked - tilted to one side. If you grab one end fo the bucket, you can flex the whole boom and it looks like all the play is at those top mounts. If I need them line bored and sleeved - any ideas on how to find a shop to do that? What would I search for in my area? As far as pulling the pins - I am assuming I need to support the boom at the pivot point from above - say a chain and come along up to the rafters in garage? Any other ideas on how to support the boom when removing the pins? THANK YOU

 

[OldMachinist]

Ok, thanks. I was thinking of just replacing the pins to see what would happen. Like I said there is ALLOT of play in the boom when it is raised - the bucket raises up quite crooked - tilted to one side. If you grab one end fo the bucket, you can flex the whole boom and it looks like all the play is at those top mounts. If I need them line bored and sleeved - any ideas on how to find a shop to do that? What would I search for in my area? As far as pulling the pins - I am assuming I need to support the boom at the pivot point from above - say a chain and come along up to the rafters in garage? Any other ideas on how to support the boom when removing the pins? THANK YOU

If the bucket is really out of level when its raised the arms may also be bent. With the bucket off and the arms all the way down are the Bobtach pivot points the same height from the floor.
You could ask the dealer who does line boring in your area they should know.
Yes working on one side at a time you should be able to support it come along the rear and a floor jack in the front.

 

[Tazza]

If the bucket is really out of level when its raised the arms may also be bent. With the bucket off and the arms all the way down are the Bobtach pivot points the same height from the floor.
You could ask the dealer who does line boring in your area they should know.
Yes working on one side at a time you should be able to support it come along the rear and a floor jack in the front.

The way i install new pins is use the new one to push the old one out. No real need to support the arm as the new pin takes all the load.
Sadly they never made mushings for inside the lift arms or lift rams. If they are REALLY worn you can get them line bored as OM stated, or you can drind the old ones out and install new ones (i have done this before). No matter what, if the pins are badly worn, the bushings in the arms will be worn too, just hopefully not too badly.

 

[kyosho]

The way i install new pins is use the new one to push the old one out. No real need to support the arm as the new pin takes all the load.
Sadly they never made mushings for inside the lift arms or lift rams. If they are REALLY worn you can get them line bored as OM stated, or you can drind the old ones out and install new ones (i have done this before). No matter what, if the pins are badly worn, the bushings in the arms will be worn too, just hopefully not too badly.

Ok, thanks. Sounds like my next course of action is to try some new pins in it. If that works, then great. If not, then most likely I will need to grind the welds off the bushings in the lift arm/boom and have some new ones welded in there...