# Friction Drive System



## Curtis328 (Jan 9, 2016)

I've got an older Craftsman 8/25. It's a Canadian model, C950-52677-9.

My question is, with tire chains on should the wheels be able to stall the engine at all?

Basically I'm chasing an issue where the wheels stop spinning when encountering heavy opposition, but the engine speed doesn't slow down at all. I feel like this should put at least some of a load on the engine...

Over the past couple of weeks, I've:

- Installed a new friction disc (the one that I replaced looked absolutely fine, didn't seem to be worn in any way, even though it had been in use for years)

- Cleaned friction wheel spotless with isopropyl alcohol

- Replaced traction drive belt (drive belt tension appears to be good, as the drive belt continues to rotate when the wheels have stopped turning)

- Replaced Idler Arm Pulley Spring

- Tightened the traction drive engagement cable as much as possible

There appears to be no worn bushings/bearings/etc. in any of the shafts connecting the friction wheel and friction disc

I feel like the friction wheel isn't being pulled hard enough against the friction disc, but there doesn't seem to be anything further I can do about this.

I should add that this "slippage" occurs when all of the components are dry, and water hasn't had a chance to lubricate anything.

I guess it seems like most snowblowers would be able to pull a car, and I'm pretty sure my wheels would just stop turning if I tried.

Thanks for any help that can be provided!


----------



## guyl (Jun 12, 2016)

You might try observing the transmission (with the bottom access cover removed) while someone else is trying to move the machine forward against something to make it slip. See what still turns and what doesn't.


----------



## YSHSfan (Jun 25, 2014)

guyl said:


> You might try observing the transmission (with the bottom access cover removed) while someone else is trying to move the machine forward against something to make it slip. See what still turns and what doesn't.


Agree with this suggestion and if you can do the same with the drive belt and see if there is slippage.

With a helper it should be straight forward to determine what is slipping.


----------



## motorhead64 (Dec 15, 2013)

You might want to check that the roll pin on your drive gear (in the belly) is intact. When they snap, or fall out, there is often enough friction between the gear and shaft to allow forward motion except under resistance as you described, and then they will spin on their shaft. MH


----------



## Curtis328 (Jan 9, 2016)

Thanks for all the great suggestions. I'll give them all a try, and report back.

I should add that it's not as if the wheels have no power; I'm able to clean my driveway no problem (which is quite a feat in Winnipeg). But if I were to drive the blower into a large snow-bank, the wheels would stop turning, without the engine slowing down whatsoever.


----------



## Curtis328 (Jan 9, 2016)

I think I just figured it out!

The friction wheel shaft bushing has quite a bit of play on one end of the shaft; the other end of the shaft has nearly no play whatsoever. This makes sense since the friction disc is closer to this end of the shaft, therefore this bushing would experience a great deal more cyclical radial loads.

Thanks for all of the guidance!! I'll try to grab a new bushing tomorrow, and will report back with my results.

-Curtis


----------



## DriverRider (Nov 20, 2016)

Don't be cheap. As long as you are in there that far replace both bushings. Pre-seasonally oil them to minimize future wear.


----------



## HCBPH (Mar 8, 2011)

DriverRider said:


> Don't be cheap. As long as you are in there that far replace both bushings. Pre-seasonally oil them to minimize future wear.



Also check the shaft, I've seen them 'cut' over time with a bad bushing. Also check your belt for glazing and the insides of the pulley for a buildup of crap from a slipping belt.


----------



## Taurus04 (Dec 10, 2014)

Check the trunion bearing under the friction plate as well. When it wears, the drive plate can wobble when pressure is placed on the friction wheel. My OPE repairman tells me that is what sends most of the Murray built Craftsman blower to the scrapyard. A sure symptom is when you hit a tough snow pile the blower will stop going forward and reverse itself.


----------



## Curtis328 (Jan 9, 2016)

Taurus04 said:


> Check the trunion bearing under the friction plate as well. When it wears, the drive plate can wobble when pressure is placed on the friction wheel. My OPE repairman tells me that is what sends most of the Murray built Craftsman blower to the scrapyard. A sure symptom is when you hit a tough snow pile the blower will stop going forward and reverse itself.


Thanks for the advice.

If interested, I've joined into someone else's thread who was having a similar issue:

http://www.snowblowerforum.com/forum/craftsman-snowblowers/88842-drive-slipping.html


----------

