Friday, April 8, 2016

PTO Measuring

Almost go time .
 I had a little time left to figure out a problem and repair it now so next winter season it's ready to go . 
Recently I rebuilt one end of the PTO shaft on our tractor mounted snow blower . The tractor end was almost impossible to remove and needed a closer look to see why . 

I spent a few hours before managing  to get the other end off.
 Most of the time PTO shafts will fit with no issues but you never know if it was the right one delivered and should be checked to be 100% sure the first time out .  What has happen is the shaft was to long and drove/bent bolts over the splines . The groove you see mid shaft is were the bolts lock it in place . 
Took a lot of heat /air hammering etc . to get it off the shaft . I'll be replacing the gear box seal you see in the picture in case it was damaged in the removal process. 

Newly rebuilt end . Ruined the catch/locking end on tractor side from being just a little to long . . 

The above pictures show that I'm at the exact minimal measurement . This is why the Male side of PTO shaft had a grove in it from hitting the roll pin on the the other end . 

Before measure to cut PTO shaft , you have to measure from the ends of splined shafts . Take one measurement with implement on the ground and one in transport position .  Some tractor implements have a lot of travel range . For example The Kubota 5040 and Lastic mower on a hilly course has a much larger travel range . Some other things that affect this measurement are : Is it being pulled or backed up when being used ? Top link setting on tractor ,the lower it is on tractor the higher it will lift off the ground = longer travel on PTO shaft . If the work involves backing up while in use then worn bushings etc. may come into play and the PTO shaft may bottom out causing damage to PTO shaft or worse yet drive it into the tractor case or gear box on implement . 

I used the longest setting (transport ) and moved half shafts in 4.5 " to cut off where they line up with the union . 

Their are charts to help you figure out if you need to cut the PTO drive line .Most golf equipment has the cat.1 - 3 point hitch. When you start getting  over 50 hp tractor it may have the cat. 2.  

Longest end of spline shaft measurement was 29"
now slide one of the 2 shafts back 4.5" .Then mark of the union where it needs to be cut.  You can see top left the size of the steel collar to keep the shaft from splitting . Lots of torque moving snow . 

Same at the other end . You can see the notch on this shaft where it was bottoming out  . This one was about 1.75" to long .

Set in vise enough to hold it and cut it of square on the lines . 

Safety shields will need a trim too . 
When reassembling the shafts use a fair amount of grease so the will slide easily . I have seen them wear through in a few seasons . Should be greased often along with unions . 

If you want to check PTO with implement off machine you can use a straight edge and measure from 3 point hitch (lower  pins ) to end of splines on tractor and attachment and add both together . Check it in travel to make sure its good after its hooked up .

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