Jacobsen AR-5 Rear Decks won't cut Cancel The title field is required!

1. Steve Abe

   

   6 posts
   
   5/24/2018 12:05 PM

   Our Jacobsen AR-5 rotary mower is having a hard time mowing with the rear decks. It doesn't seem to matter what conditions we are in (wet grass, long grass, dry grass), the back two decks wont cut, leaving two nice stripes that we must mow over again. The front decks will mow perfectly in all conditions and at even greater speeds.
   
   We have recently replaced the hydraulic motor. The hydraulic motor was bad 7 years ago when we had this problem, so naturally i thought replacing this motor again would solve the problem but it has not. The only way we can seem to get a really good cut from the rear decks it to slow down to a crawl. The specs say you can mow over 6 acres per hour, but i would say we don't even mow an acre per hour the way it is now. Has anyone else had this problem? Any solutions or suggestions? Thanks in advance for any help!!!

   
   
   
   
2. Todd Bishop

   

   1 posts
   
   5/24/2018 1:05 PM

   Steve,
   when you say you replaced the hydraulic motor, are you talking about the the deck motors? It sounds like one of your deck motors are bypassing. We had that problem a couple times and it was difficult to pin point which motor was bad.

   
   
   
   
3. Steve Abe

   

   6 posts
   
   5/24/2018 1:05 PM

   No. I guess I should have said the hydraulic pump. Several years ago the machine was doing the same thing and our mechanic took apart the pump and said it was bad. Replacing it solved the problem. All the deck motors are working.....moving the blade. Are you saying if a deck mower is bad it would still spin the blade but maybe not as well (or fast) to give a good cut??

   
   
   
   
4. Roland McPhearson

   

   9 posts
   
   5/25/2018 7:05 AM

   Very likely one of the deck motors is weak and bypassing as Todd says. Probably the first motor in the circuit (the one the fluid goes through first). If they have 3 hyd hoses on each motor you should be able to do a case drain check on the motor(s) and compare the results to the front motor(s).
   
   A poor mans case drain check takes 10 minutes and requires only wrenches and a bucket.

   
   
   
   
5. Steve Abe

   

   6 posts
   
   6/11/2018 10:06 AM

   Performed a case drain check on the rear decks and the back right unit failed. Replaced the deck motor and the unit is now running perfectly!!
   
   Big thanks to Mr. Mcpherson and Mr. Bishop. I appreciate your input and help.