Jacobsen GK4+ rear unit slow Cancel The title field is required!

1. Bill Brooks

   

   18 posts
   
   9/23/2013 12:09 PM

   We have a 2008 GK 4+ with 1800 hrs and recently have been having a problem with the rear cutting unit scalping into the collar. I was watching the rear unit and it is coming up very slowly. Wondering if anyone has run into this before and what the cause was for the unit coming up slowly. Note: front units come up quick and all other hydraulics seem to be fine.

   
   
   
   
2. Matt Falvo

   

   0 posts
   
   9/23/2013 12:09 PM

   Bill Brooks said: We have a 2008 GK 4+ with 1800 hrs and recently have been having a problem with the rear cutting unit scalping into the collar. I was watching the rear unit and it is coming up very slowly. Wondering if anyone has run into this before and what the cause was for the unit coming up slowly. Note: front units come up quick and all other hydraulics seem to be fine.

   
   
   
   Most likely either an internal leak in the front or rear lift cylinder, an issue with the sequencing valve, or the orifice at the rear lift cylinder has something partially blocking it. See attachment for info on the orifice and sequencing valve.
   
   
   Bret Hart
   Equipment Manager
   Turning Stone Resort

   
   
   
   
3. Bill Brooks

   

   18 posts
   
   9/23/2013 2:09 PM

   Thanks for the reply I have a known good rear lift cylinder that I will try first. I will also do some testing and look into service bulletin.

   
   
   
   
4. Bill Brooks

   

   18 posts
   
   9/24/2013 11:09 AM

   No luck with cyl. We don't have tooling for testing pressures as per bulletin, probably going to have to take to dealer shop for testing?

   
   
   
   
5. Matt Falvo

   

   0 posts
   
   9/24/2013 11:09 AM

   I know it may sound odd but the front cylinder can cause your slow lift issue as well.
   
   Was there anything blocking the hole in the orifice?
   
   
   Bret Hart
   Equipment Manager
   Turning Stone Resort

   
   
   
   
6. Norma O'Leary

   

   1 posts
   
   9/24/2013 7:09 PM

   Bill:
   
   I had the same problem earlier this year. It was nearly impossible not to scalp with the center reel. After replacing the center lift cylinder and the sequence valve, I finally discovered a very small leak from the valve spool underneath the front cowling. Contrary to what the Jacobsen service tech told me, I went ahead and replaced a .10 cent o-ring at the bottom of the valve spool, and my mower has never worked better! Take off the front cowling and see if any of the valve spools are wet.
   
   Norma

   
   
   
   
7. Henry Heinz

   

   0 posts
   
   9/25/2013 5:09 AM

   I have to agree with Bret, we had one and it was the front cylinder. We had gone through the rear cylinder and valve, and replaced it with a new style, also one from another machine and still had the same problem. Funny thing was while having the same issue, and replacing a few of the items, the front reels were coming up very hard and fast, but hardly nothing at the rear. We went through it all, so I decided to have the guys pull the front cylinder and sure enough it had a bad seal. We repaired the cylinder and everything was fine. We did have are share of leaking valves in the front bank, so re-sealing them would be a good idea as well. As Norma, if you're seeing oil then start there, it could very well be your problem, and even if it's not, it's still a problem that needs a fix:)
   
   Regards,

   
   
   
   
8. Bill Brooks

   

   18 posts
   
   9/26/2013 11:09 AM

   Anybody find that they may be having issues due to running greens care bio hydro oil verses an atf dextron oil? This 08 GK is only machine in our fleet that uses the greens car bio.