John Deere 350C Crawler axel

[Jamie Dunn]

JD 350C crawler axel bolt holes for the track drive sprocket are shoot. I have re-tapped but not enough steel left. Can I drill out and tap larger size? I know I will need to re-drill sprocket hole also. I there an easier fix? Or just get another axel and replace...

 

[Janicholson]

Insert type
Thread inserts (see link) are a solid solution not requiring bigger bolts. Bigger bolts are also a good solution. Helicoils in larger sizes can be painfully difficult. Jim

 

[Fritz Maurer]

If that axle is heat treated you can forget tapping. You might drill it, but you're gonna need a 3/4-10 tap if you go the insert route. That's a he!l of a lot of metal to remove in one pass (especially if it's forged or heat treated) you have no control over the feed rate like you do a drill bit.

An easier solution , if you have the clearance, is get some B7 threaded rod and thread it through what's left of your threads, far enough in that you can put a nut on the back side of the axle. You'll be pretty close to the step, you might have to grind some 7-sided nuts to make it fit, but I think that would work. Use copious amounts of Loc-Tite to keep the unwanted movement to a minimum, maybe even tack weld the sprocket to the axle to key it on there. The sprocket moving on the axle is what caused this mess in the first place so every effort must be made to keep it stationary if your repair is to last.

 

[Russ from MN]

Insert type
Thread inserts (see link) are a solid solution not requiring bigger bolts. Bigger bolts are also a good solution. Helicoils in larger sizes can be painfully difficult. Jim

I see Grainger is still in St Cloud, but it looks like they moved? The Sartell paper mill did a lot of business with them, and exelent supply house. We employees could buy personal items from them too , at good prices. Last week I stopped at Midway iron to get some steel to fix my tractor, I sometimes miss St Cloud! Our local steel supply in Bemidji is pretty limited.

 

[JD Dave]

X2 what Fritz said. This is not a pretty situation trying to keep the sprockets super tight on the axles. Poor tightening, service and torque on those bolts has been the problem in the first place over all the years. The best you can do is this or go get some new axles with solid threads.