Bushing Removal Questions

[Bill VA]

I've got my knotter drive sprocket off my NH68 baler and also the pitman arm for the plunger. I'm replacing the bushings in both. Both of these have brass or bronze bushings at either end of the part where the shaft they ride-on goes through - so to bushings at opposite end.

I'm trying to figure out how to get these bushings out! I suppose with the knotter drive sprocket, I could drive both bushings out in the same direction and replace from either end. However, the plunger pitman arm, the tube those bushings are in is about 5 or 6 inches long. The bushings are at least 2 inches in length themselves. I think it would be difficult to drive them out in the same direction - but I suppose I could do so if necessary.

What I'm thinking is using a brass punch and going to the inside shoulder of each bushing and trying to tap them out. Not sure if this will work.

Any suggestions? Worse case, I can take them to a machine shop.

BTW - the New Holland replacement bushings are steel. I guess this is OK, but I'm concerned about the potential for galling or which is harder, the shaft the part rides-on or the bushing itself - seems to me something needs to be sacrificial, especially with a bushing. I like the brass/bronze bushings - not sure why the change to steel. Sounds like a bigger can of worms to repair down the road than a softer material like brass/bronze. Who knows - maybe by then, the industry will have come out with a superior baler to the New Holland 68 and I'll just make a change..... ;-)

Any tips or tricks are much appreciated.

Thanks!
Bill

 

[Steve@Advance]

Try punching them out like you described. If that doesn't work, you can split the bushing with a Sawsall. Just be careful not to go too deep. Once it's split as deep as you dare, drive a chisel between the bushing and the housing, collapsing it inward. Should come right out.

As far as going back with steel, you're right about it being hard on the shaft. It's your call, if you don't want to go with steel, you can probably get the aluminum bronze bushings from a bearing supply or McMaster Carr.

 

[M-MAN]

You could use a piece of pipe, threaded rod, nuts and washers that are a tad smaller than the od of the bushing and pull them out. Or you could drive them out with something a tad smaller than the od of the bushing. Water pipe works well. I have a lathe now to make specialty drivers but rarely have to.

 

[jon f mn]

Unless you want to save the old bushings for some reason just use a steel punch from the back side and dtive them out. They usually come out fairly easy and unless you want to save them for some reason why do you care if they get nicked. If you want bronze or brass this company will have them and will ship them to you.
bushings

 

[JRSutton]

That's how I do them.

I find those bushings can be VERY hard to drive out.

I don't fight them, I just split them with a hacksaw blade. Slice it right down the side, and be careful not to go into the cast iron. If you DO nick the side a little, don't worry about it - it really doesn't matter.

One cut is all you need to loosen it - you can then usually tap it out with a punch. If not - you can sort of "peel" it off with a punch.

If all else fails - make another cut opposite the first and the two halves will pretty much fall out.

 

[jeffcat]

You also could have checked with a good machine shop. They can order almost any size you can think or turn one to what you need. If a sawsall would fit, dremel tools, etc.. Can you press them out with a jack and some correct size socket?? Jeffcat.

 

[willie in mn]

Quick & dirty, not usually recommended. If by more dumb luck than good sense the bore of the sprocket etc is smooth, not shouldered, & there is room, just push the worn bushings in far enough to put the new bushings in place, leave them in.
Otherwise, if a press is available,place a socket against the bushing & push just a fraction of an inch. That will break it loose, then come in from the other side with a punch & drive out.
I like to use an impact socket to push against. Theory is, whether true or not, that in case of failure, an impact socket won't send shrapnel around the shop.
Willie
p.s. I have been called a "hatchet carpenter" & "sledge hammer mechanic", but usually get the job done.

 

[Bill VA]

Me and the boys worked these bushings a bit this evening.

Knotter drive sprocket bushings out (cut a groove into them) and new steel bushings in (tapped in with a piece of wood between the bushing and ball peen hammer).

Might get to the plunger pitman bushings tomorrow night, but more likely late in the week.

Thanks everyone for your help.

Bill

 

[showcrop]

Bill, under the right conditions a soft metal or even plastic bushing will wear wear steel more rapidly than a steel bushing. What happens is that the brass, bronze or plastic will pick up particles of abrasive material such as silica sand which can become firmly enough imbedded in the soft metal that it will wear the steel. I had this happen on a piece of equipment that I used to service many of for customers. The manufacturer replaced a bronze bushing with a plastic one hoping to increase the life of thrust washer. What happened was that under most conditions the plastic would load with hard particles and wear into the Thrust washer way faster than the bronze had. There is usually no shortage of dust in your hayfields when baling.