troybilt tiller belt

[swanny]

I have a 1981 troybilt tiller w/8hp Briggs&Stratton that has gone through 2 belts & noticed trans pulley was wobbling so I removed engine & keyway on pulley has worn champher on one edge & so does trans shaft & was wondering if this would cause belt wear & disengagement of tiller & foward gear & how expensive to replace trans shaft. Any help would be greatly appreciated as I am getting the wifes boney finger pointing at me for trying to kepp this old one going.

 

[BCSSHOP]

Welcome Swanny,

TroyBilt Horse of that vintage were notorious for having the transmission drive pulley get very worn and wobbly wearing both the cast iron pulley and the soft steel driveshaft. The pulley is held between two snap rings and a shim with a 3/16" key locking the pulley to the shaft. It worked pretty well when they ran two belts between the engine and the transmission and had only two speeds for the tiller. When they went to a single belt and stepped pulleys folks ran them nearly always in the faster tiller speed with the belt hanging on the front pulley of the transmission causing it to concentrate the load on that end of the driveshaft. By running only one heavy belt more force on the belt was needed to keep it from slipping so they put a stronger spring on the belt engagement roller assembly.

The bottom line is the wobbling transmission pulley causes excessive belt wear and belt slippage. Later models had the pulley bolted onto the shaft which corrected the problem. You can replace the driveshaft fairly easily but they are rather costly. The replacement shafts sell today on ebay from $122 to over $200. Shimming the driveshaft to less than .010" of end play is important for the life of the tapered roller bearing.

If you don't want to spend the time or money just run it until it breaks. It won't cost much more to fix then. Belts are not that expensive

 

[swanny]

Thanks for the response. I would like to keep running it to at least get it tilled for this season but I cant keep belt tight & it just keeps disengaging tines & even forward speed. I didnt know if there was a way I could rig it just to get garden done. Can trans shaft be replaced without removing wheels as they are welded over with rust & no matter how much wd-40 I could not get wheels off to replace tires last fall. Any suggestions would help me alot. thanks again

 

[stihlman]

I can't help you with your transmission pulley but I am assuming you have adjusted the roller block to tighten the belt. I had a 1981 Horse with the 7 HP Kohler and the previous owner had never taken the wheels off, they seemed to be welded on like yours. I ended up heating the wheel stub between the tiller and the tire and put a pipe wrench on the wheel. After several heat applications and wiggling with the pipe wrench it finally started to spin on the shaft. After I got the wheels off I sanded and greased the axle shafts before I put the wheels back on. I do that every year now to keep the wheels from "growing" to the axle

Steve

 

[swanny]

Yeah, Ive already gone through a new troybilt made in China belt after only a few hrs running & block has no more adjustment & the drive pins for the wh eels on the axels are fused to the wheels&axel so I didnt know if I could replace input shaft in the trans without complete removal of trans is what Im trying to figure out. Let me know if I can. thanks

 

[BCSSHOP]

The drive shaft replacement does not require removal for the wheels or axle. It can be slid in from the rear once the old shaft and front bearing are removed. Slide the driveshaft in without the front bearing attached. Be sure to get new bearings and a new front oil seal when replacing the shaft. The rear bearing is pressed on before installation but the front one just slides on after the shaft is in place. Shim the driveshaft to less than .010" end play but not zero with shims at the rear.

Sounds like you'll need another new belt. Run it in the slow speed to get better grip. Good luck!

 

[swanny]

Thanks everyone for the responses. Is there a local supplier for the input shaft other than ebay & Im also going to need the pulley.?

 

[Horse II]

I search around for a solution to this same problem, and instead of going back with a new shaft with snap rings and the 3/16" keyway, which the problem from the start, I may have found a more permanent fix. I purchased a "keyless bushing" from MacMaster Carr ($50), and had the original transmission pulley bored out and a new sleeve pressed in at the machine shop ($50) to fit the keyless bushing, then simply installed the bushing and pulley onto the transmission shaft.

It was a little difficult to line up the belts since there is no longer any play in the pulley between the snap rings, but after a couple tries I'm close enough. The keyless bushing is rated to handle much more torque than the engine can produce, so I simply left the keyway open. So far, so good.