941B drive problems

[Jgarrett392]

Hey guys I have a 941B serial:80H5655

The problem I’m having is the machine will only move about 10ft in forward and reverse. I jacked the tracks off the ground put it in gear and the tracks will almost make a full revolution. If I depress the left pedal the left track stops and the right track started to move but if I press the right pedal the left track disengages after moving about 10 ft. I’m thinking there’s something going on with left final drive but I’m a newbie to these machines. Any help would be greatly appreciated.

 

[Nige]

Have you removed the drain plug on each final drive to inspect the oil for metal particles.?

 

[Jgarrett392]

Planning to do that this weekend. I have an endoscope I can send in there as well. Will report back as soon as I’ve inspected it. Thank you for the reply

 

[Jgarrett392]

Well I figured out what was causing the issue, the rail for the tracks rubbed a hole through the final drive casing. What would cause this?

 

[Dave Neubert]

I don't see how the tracks can rub on that but also don't know else that could happen

 

[Nige]

I don't see how the tracks can rub on that…..

It might be interesting to see what the track links and bushes look like on that side.

 

[sawmilleng]

I'm wondering if you might have a bent track pad that went un-noticed because it was thought to be broken off? Conveniently taking a scrape off the final housing each round of the track?

It looks like the pad might have had to be bent almost at 90 degrees to do that.

How far is that scrape mark from where the centerline of the track chain would ride on the sprocket? It looks like it is a good 6" or so.

I thought track pads were hardened up the yinyang so that they didn't bend-they broke. But maybe not this time!!

Jon.

 

[Jgarrett392]

I’ll double check this weekend when I’m out at my property but I inspected the rails, bushings and track pads and nothing is bent, the bushings are in great shape. The only thing I can think is that the sprocket is wore out causing the track rail to ride lower but I’m not sure what the sprocket is supposed to look like. Mine looks okay from the naked eye. Is there a measurement I can take to reference to a new sprocket?

 

[Nige]

Mine looks okay from the naked eye.

Post a photo.? Maybe post photos of the sprockets on both sides.

 

[Jgarrett392]

Post a photo.? Maybe post photos of the sprockets on both sides.

I will this weekend when I get back out to the property

 

[Nige]

Make sure to take at least one photo on each side from directly side-on to the machine.
Also see if you can get a photo from the opposite side to the damaged one showing how close the track links run to the final drive case.

 

[Jgarrett392]

Left side (problem side)

 

[Jgarrett392]

Right side

 

[Nige]

In your earlier photo showing the LH case worn through, was that taken from above.?

Both sprockets have had a replacement rims installed but for some reason I can't see at the moment the RH sprocket teeth appear to be sitting higher than the other side. The two sprockets don't appear to be the same.
Time to break out the measuring tape I think.

EDIT: Maybe it’s the fact that one track is off and the other one is still installed but a tape measure and/or counting the number of teeth should tell you the answer.

 

[sawmilleng]

Nige,
I think you are on the right "track".
Another way to check this out is to count the # of sprocket teeth on each side.

There was some comment earlier that some machines had "hunting tooth" sprockets and others did not have "hunting tooth". The difference of one tooth could be the difference between dragging the chain on the final housing or riding clear of it.

Jon.

 

[Jgarrett392]

In your earlier photo showing the LH case worn through, was that taken from above.?

Both sprockets have had a replacement rims installed but for some reason I can't see at the moment the RH sprocket teeth appear to be sitting higher than the other side. The two sprockets don't appear to be the same.
Time to break out the measuring tape I think.

Yes it was taken from above, that’s the route I’m leaning towards. The sprockets are definitely not the same. Time to drop the tracks and count the teeth and get some precise measurements.

 

[Jgarrett392]

Nige,
I think you are on the right "track".
Another way to check this out is to count the # of sprocket teeth on each side.

There was some comment earlier that some machines had "hunting tooth" sprockets and others did not have "hunting tooth". The difference of one tooth could be the difference between dragging the chain on the final housing or riding clear of it.

Jon.

That sounds like a winner, the clearance between the final housing and chain on the RH side has about 1”-1.5”. Looks like I’ll be having some fun this weekend.

 

[tctractors]

On the 951B the Track chain was 6.75" pitch from new, but there was a conversion to adopt the later 951C Track Group that was 6.91" this made the sprocket a Non Hunting Tooth rim, if you look at the sprockets on this 941 they look in a queer shape and should be hunting tooth.

 

[Jgarrett392]

On the 951B the Track chain was 6.75" pitch from new, but there was a conversion to adopt the later 951C Track Group that was 6.91" this made the sprocket a Non Hunting Tooth rim, if you look at the sprockets on this 941 they look in a queer shape and should be hunting tooth.

Based on the part numbers in my book they should have 29 teeth so I’m gonna count them tomorrow

 

[Jgarrett392]

Based on the part numbers in my book they should have 29 teeth so I’m gonna count them tomorrow

What does it mean to be a hunting tooth sprocket?