F935, w/60 Side Discharge: Installing new belt questions

[Big Wave D]

Need the power of the collective brain force on this site.

I am doing some badly needed maintenance on an F935 mower that is owned by a local non-for-profit organization. It gets used and abused.

As part of the upkeep, it needed some new idler pulleys and a new belt. After getting the new/updated parts, I am putting everything back together again. What I need to know and that the Manual that was on the mower doesn't answer is:


1) What tension should the belt have and where do you measure to find this?

2) Is this simply a matter of the tension that the spring connected to the idler arm imparts?

3) There is a rubber bumper that tightens down to a track that is welded onto the mower's deck. Is this bumper to ride against the idler arm or have some gap to keep the idler arm from moving to far in the direction of the back of the mower?



If necessary, I can take and post some pictures.

Thanks to all and any that can help shed some light on this for me.

 

[zzvyb6]

I have the 72" side discharge on my F-935, but mechanically the mower decks function the same. If the idler tension spring is rusted or corroded, the tension may be wrong anyways. If its OK, then the nominal tension is low, as measured by a finger pull. The bumper is there to keep down the noise level when the bracket wacks the deck track. There's actually quite a bit of cyclic motion in the tensioner because of blade balance, belt flat spots, grass thickness variation and engine torque pulses. The covers keep you from staring at this phenomenon ( ! ).

While you are at it, check the driveshaft isolator (in the driveshaft between the motor and the transmission. Also check the lube in the pto bearing zerk under the inspection door in the floor. Its often forgotten about. Clean out the radiator screen and the crap behind it by pulling the screen out and run an air nozzle or leaf blower thru this area.

Lastly, check the play in the rear axle. This can be tightened up by simply tightening up the pivot pin bolt or run some shims into it. If you have the snow blower (now recently referred to as a 'snowcaster'), you may need to check out the glow plugs for ease in cold weather starting.

I love the F-935 platform. Mine's been bullet proof except for a lot of loose bolts that the previous owner (a county park system) left for me to fix.

 

[Big Wave D]

zzvyb6

check the drive-shaft isolator (in the drive-shaft between the motor and the transmission.

Bingo! I found a bolt laying on the ground, looked and looked for where it could have come from. Seems like it has sheared one of the 'prongs'. I will have to take that part off and see what's what. Doesn't look cheap to replace.

I also saw that one of the ends of the left side motor mount has cracked off completely. I guess I will be taking the whole unit off to effect some kind of repair. Welding it on the machine makes me nervous and doubt that any on-machine repair would last very long.

The machine gets no TLC and basically beat on for use, as the above failures prove. However, considering how completely clogged the radiator and air cleaner were with grass, it is a testament to these being some tough little machines.


Thanks for your tips and areas to look at.

 

[zzvyb6]

There are used motor mounts, drive shaft sections for sale on eBay. Often, someone is parting out a machine. You can email them and ask them to post a specific set of parts for you and ship them all in one box. Get some extra gauge wheels for the deck, too. (the ones in the rear). Mine seem to wear funny from hard turns on concrete and they break apart every so often. Save the outer bearing race and roller bearings because new wheels don't come with them. They just punch out.

By all means learn how to bleed the fuel system because someone will always run it out of diesel. Crack the filter, the injector lines and then the injectors for the best, fasted bleed to get it restarted.

 

[Yellowfever440]

Don't loosen the actual injectors, just the lines going to them, and you don't have to loosen the lines on the injection pump, just the ones on the injector. Another high wear Item is the pro shaft from the deck gear case to the top of the front axle, if you can move it side to side replace it. Also check the bearings on the pot shaft from the back of the tractor to the top of the front axle. I had to replace that for someone on a mower and it was 490 bucks thought Deere, but they redesigned the shaft a few years back so it should last longer.

 

[Big Wave D]

zzvyb6, Yellowfever440

Thank you both for the items to pay attention to and places to source parts from.

I will make sure and inspect these items.

Any idea how much the part that bolts to the crankshaft, and mates with the rubber iso puck, might be?

 

[Yellowfever440]

I have no I idea on that I was wondering how may hours are on that mower and also make sure the other motor mount isn't cracked or nothing. But any ways that rubber is prolly 20 or 30 bucks.

 

[Big Wave D]

Yellowfever440,

I checked the other motor mount. It is solid. The break has been there for a while, it has rust on the raw edges.

It isn't the rubber disc that is bad. It is the metal disc with the 3 fingers that bolts directly onto the engine's crankshaft. It appears to have had 1 of the fingers break off.

The mower has 2002 hours showing on hour meter. I don't actually know if the meter works. I haven't ever run it long enough for it to move any.