Sitrex 48 belts

[BillH-HT]

Nice hot Summer but I'm getting a jump on it.

I have a Sitrex SM120 finishing mower that I need to change belts on (but haven't got around to getting a manual for). Should be straightforward, but there is not enough clearance between the "gearbox platform" (Part #32) and the double pulley (Part #25) of the center blade hub to pass the belt over. I can see that I probably need to unbolt the center blade hub and drop it down for clearance. Of course, the bolts are nasty and rusty and ain't budging by hand tools, so I need to borrow an impact wrench to zap the bolts.

Alternatively, that "gearbox platform" (Part #32) will need to come off eventually for work on the center hub or the gearbox itself, so I might want to loosen it's rusty bolts (and one bolt head is rounding off) so I can raise the "gearbox platform" (Part #32) for the new belts to clear. And not mess with the center hub (the bearing "feels good") for right now.

Parts diagram for the Sitrex is here:
http://tractorpartscentral.com/store/category/SM48.htm

Or a third alternative I'm leaning towards: With an oxyacetylene cutting torch I could carefully cut a window in the top of the "gearbox platform" (Part #32) that would allow the belts to pass over the center double pulley (Part #25). This would also give access to the spanner nut (Part #21) and allow the pulley to be removed and the hub to be removed for later maintenance without needed to unbolt that "gearbox platform" (Part #32). I don't think that this will create a structural weakness in the platform nor create a safety hazard from exposed whirring parts.

What think you? A, B or C? <E>:lol:</E>

Happy Fourth! <E></E>

--Bill

 

[winston-HT]

Try this and happy 4th to you also. Pretty big downloads so be patient. Note there is a part 1 and part 2 manual for your model. Not sure it is going to answer your questions but I doubt your going to find any more manual than that. http://www.agequipmentusa.com/manuals/

 

[BillH-HT]

Thanks, Winston. Those sections of the manual weren't too bad at 3 Mb apiece.

But-- amazingly-- they covered everything <U><s></s>but<e></e></U> replacing the belts. Back to square one. Nice little mower, and thankfully the belts won't need to be replaced that often.

--Bill

 

[BillH-HT]

The belts weren't all that difficult to replace-- being confronted with rusted seized bolts in tight locations, I was borderline overthinking this project.

I ended up removing the six bolts that hold the "gearbox platform" platform to get clearance to slip the belts on and off. A nice new 6-point socket, a wobble-drive extension and a can of Kroil and MAPP gas heat worked a miracle. And I cleaned the threads with tap and die and greased the bolts on reassembly, so next time that platform need to come off (years down the road when I rebuild that center hub/spindle) it'll be easier.

I briefly considered cutting an access hole in the top of the "gearbox platform". It is substantial and could prolly have handled the static loads well enough, but bouncing around in the rough the dynamic loads could have easily trebled the total loading.

While I had things apart I sharpened the blades-- the test cut went well. Old, dull merely beat the grass into submission and sharp blades cut so much better.

--Bill

 

[winston-HT]

Glad it went well for you.

 

[BillH-HT]

One quickie question--

I'm going to have to add these "serrated washers" to the blade-end of my spindles.

<IMG src="http://tractorpartscentral.com/storeimages/BAB-34026018.jpg"><s>

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<LINK_TEXT text="http://tractorpart...tore/product/SM48/SM-34026018.htm</LINK_TEXT>

Mine came with flat washers of assorted parentage. These washers look like "serrated lockwashers", which means to me to put them between the big nut and the blade. BUT the parts description says "This special washer is what keeps your blade from slipping on the shaft" which suggests that it is placed between the blade and the flange on the shaft.

Which should it be? I don't speak Eye-tallian. <E>:lol:</E>

--Bill

 

[winston-HT]

According to all the sitrex sm120 parts lists that I looked at there aren't suppose to be any washers, only this locking nut. http://tractorpartscentral.com/store/product/M18LN.htm

 

[BillH-HT]

Odd. The Sitrex 48" mower, SM120 parts page at Hoye (aka Tractor Central) shows the "serrated washers" , Part #65. on the right side with the spindle/hub breakdown:

http://tractorpartscentral.com/store/category/SM48.htm

Anyways, I've got three ordered.

Old parts. Ain't they fun. <E></E>

--Bill

 

[winston-HT]

Very interesting why some parts list show the washer and some don't. In any event my "opinion" would be to put the washer between the nut and blade.

 

[BillH-HT]

What I've figured out is that the serrated lockwashers are a European equivalent to our usual split lockwasher and are to be used <U><s></s>with<e></e></U> a conventional shaft nut, instead of using only the big nyloc nut on the shaft. What threw me was the Hoye comment "is what keeps your blade from slipping on the shaft". May need to drop an email to Hoye for clarification.

Anyways, I have three on the way (along with a Tiller manual), and the existing nylocs lost their "ny-" long ago, so I can use them.

--Bill