KingPost Bushes

[007]

Hi Guys, i have an almost new excavator and if i measure the lower kingpost pin and bush clearance from side to side using a dial gauge i have .035'' or .889mm without putting a huge amount of weight on it which probably will produce more.
Has any one fitted new pins and bushes to a machine and got big clearances?
Is this normal for new or repaired machine.
Kubota agent says its fine but i think is very ordinary.
Any comments please.

 

[John C.]

The only free play I consider is on the vertical pin. Most machines have two retainer bolts holding that pin down and if they are there the joint is OK.

 

[007]

The vertical movement needs shimming but is the side ways movement I am concerned about.
Measured with dial gauge as per pic.
Cheers

 

[squidrig]

What's the model of machine? And is it new or are they new parts? If not they can get pretty sloppy b4 the bushing wears thru. I've got a kh 41 with a spoon sized bucket and just about every joint is loose ,eventually I'll have to fix it but not with kubota parts, too pricey.I'll change the bores to something reasonably priced.

 

[John C.]

The photos tell me what you are looking at now. That is the free play I was talking about. Basically if the retainer bolts are still in the flag at the top of the pin the machine is OK. It will slap a bit and the operator complain but it is not considered much of a problem.

 

[007]

Hi Squidrig, the machine is kubota u25-3 and is about 5 months old. 150hrs.
I was questioning this from kubota from the moment i received it.
The top bush has hardly any play compared with the bottom.
When you are digging you can see and hear it clunking around and even more annoying it smashes the grease out of the joint quick smart.
Up and down is bit over 1mm and kubota is sending me a shim to loose some of that but I carn't get a side ways clearance from them.
I personally think that clearance is a disgrace but i carn't get anyone to tell me what they are like when new.
I would have thought some one here would have re-bushed there machine at some point and comment how tight they are when new.
I realize they are not required to be formula 1 precision and bit of clearance for grease in this application is a good thing but being nearly 1mm is a laugh.
If it turns out this is the norm i won't be buying genuine parts if this is there clearances.

 

[squidrig]

Well it is possible that the bushing or pin was defective from the beginning. The only real way to see what's going on with it is to pull the boom off it which is abit of a chore but not to bad a job considering u are going to be installing the shim when it arrives. I've always liked kubota Equipment and engines , simple and long life. My only gripe with them is their parts are outrageously overpriced and all the pin / bushing setups ive seen were in between sizes so u had to source them from them. Is there another new similar sized machine at the dealership that u could look at?

 

[007]

I was hoping i only had to slip the bottom pin out, i hope all the shims don't have to go ether side of the top pin.
Not sure if there would be any thing to look at any way unless the bearing surface white metal was damaged.
Good idea to check another machine, i might be able to do that next time i go to dealership.
Yes i have to agree with you about kubota they are a bit basic and lacking a few features that the others have i like.
We don't have a big market here like the US and kubota has big portion of the mini market so better chance of being able to buy parts with them here.
There are so many guys on this forum with electronics giving them grief i think im glad mine is basic.