Power-trol idler

[Paul Hearsey]

The idler gear that drives the drive gear of the Power-trol pump on my JD model 70 Gas has tremendous wobble. Some is wear on the shaft but most is bushing wear. What are my options? The manual says bushings were never sold separately anyways, so replacement of the gear was once required. Can I find replacement bushings somewhere, or could a local machine shop do something like modify similar off-the-shelf bushings? I really don't want to just ignore an obvious problem. Thanks! Paul

 

[F-I-T]

Paul:

If it were me.....

If the old bushings are still there, but worn, that will give a machine shop a clue as to what material was used, and the gear bore and shaft diamter will give them the id/od dimensions, less an appropriate amount for clearance. In that oily environment, brass was often used, and even copper. I doubt that they used steel bushings on a steel shaft, as that leaves the shaft prone to wear, and they really wanted the bushings to give first. Why they are not sold separately is surprising to me, but a decent shop, or a buddy with a lathe and some naval brass should be able to fix you right up. McMaster Carr sells a lot of standard bushings, so that you might be able to buy what you need and just shorten them. Remember, you can also search jdparts.com for parts by dimension and material, so you might find a jd part that will substitute, again, you will have to probably shorten them after pressing them in. At over $500, I can see why you would like to avoid replacing that idler gear...

 

[Paul Hearsey]

Thanks, F-I-T, I'll first search JDparts. I didn't realize I could search by dimension. There's lots of bushing left (two bushings, actually) and I believe I see copper, so there's a clue for a machine shop if it comes to that. My tractor has a loader and so the Power-trol pump gets used plenty. It'd be stupid NOT to fix this now. Thanks again! Paul

 

[F-I-T]

Good deal. You can make a nice bushing out of rigid copper water pipe, too. Search away, though. Sometimes you get lucky.

 

[Mike M]

Last time I did some of those was likely back in the early 1990's and that gear wasn't too bad of price back then.
The funny thing is when JD first started using those gov. mounted pumps on the model AR they had a gear with needle bearings or rollers in there. I don't know why they went to bushings ?
Under heavy use these don't get enough oil. You can plumb in pressure oil teed in off the gauge line and drill and tap the gov. case on the RH side where the pin bottoms out. The pin is drilled through allready as to let oil flow through. I put sealer around the little pin that locks the big pin in so oil can't get out there.

 

[Paul Hearsey]

Hmmmm...... clever idea, Mike. The governor is sitting on my workbench already, so maybe I will add that little upgrade. Thanks! Paul