Three Point Hitch Pulsing

   / Three Point Hitch Pulsing
  • Thread Starter
#11  
The tractor has just over 900 hours on it. Only change recently is I put a 1/2 ton disc harrow on it. That's the heaviest I've ever carried on the TPH, but even with the extra length, well within the 2400 @ 24" rating for this tractor. I'll try to track/adjust that valve this weekend.
 
   / Three Point Hitch Pulsing #12  
The tractor has just over 900 hours on it. Only change recently is I put a 1/2 ton disc harrow on it. That's the heaviest I've ever carried on the TPH, but even with the extra length, well within the 2400 @ 24" rating for this tractor. I'll try to track/adjust that valve this weekend.

With those hours and implement weight this would seem to be within the operating parameters of your tractor. Just be careful how you trouble shoot this so you don't get hurt. Note your starting points before changing settings and make small adjustments.
 
   / Three Point Hitch Pulsing
  • Thread Starter
#13  
Thanks for the tips. I'll try to get into this afternoon.
 
   / Three Point Hitch Pulsing #14  
www.jdparts.com
kinda middle and to the right, type in your model number and go from there.

it will give you "part diagrams" and part numbers. the diagrams may not be the best, but might help ya some.

a shop/service manual. should give you a much better exploded diagram of things. along with all the various specs / torque / tearing stuff apart / putting it back together steps.
 
   / Three Point Hitch Pulsing
  • Thread Starter
#15  
MP35389________UN28OCT04.gif

Using numbers off the attached image. The feedback rod (28) has no noticeable bending or other issues. I adjusted the location of the feedback rod by adjusting the nuts (24 x2) across the range of about an inch. This had no noticeable affect on the frequency of pulse. All this adjusted really did was change the height of the TPH lift arms compared to the setting of the control valve handle. The plate (26) is attached to the left TPH lift arm and provides the lift arm location to the feedback rod (28), which transfer that to the level (17). Allowing 26 to move forward lowers the attachment, but does not change the pulsating. Moving 26 backward raises the attachment, but does not change the pulsating. Moving the lever (17) toward the front of the tractor causes the TPH to rise, which is the exact same effect as allowing 26 to move toward the rear of the tractor.

What else can I try to adjust to see if an adjustment is the only issue before I have to tear into the rockshaft valve (something I'm really not looking forward to doing)? To provide scale, just about every part on this diagram is on top of the rockshaft valve, left side of the tractor, below the seat except for the control handle (7), which is on the right side of the seat and connected to everything on the left via part 13. Any additional expertise is greatly appreciated.

Thanks,
Ed
 
   / Three Point Hitch Pulsing #16  
Pulsing of 3 pt is caused from either a leaking 3 pt control valve or a leaking 3 pt rockshaft piston seal.
 
   / Three Point Hitch Pulsing #17  
To check the leak on the 3pt cyl, raise the 3pt to max and turn the descent knob to close.

If the 3pt drops, it has to be the seals.

If the valve leaks, it seems like it would leak steady.

I would think something is trying to regulate the flow.
 
   / Three Point Hitch Pulsing
  • Thread Starter
#18  
With the TPH fully raised and the ROD valve closed, the TPH maintains its height. With the TPH fully raise and the ROD open, the TPH drops from full height to ground in 4-6 seconds where it would normally maintain it's height when the tractor is turned off.

So, combining comments from J_J and TX Jim, I'd need to look at the seals in the control valve or rockshaft piston/control valve area. Sound about right? Looks like this might be delayed until I get the factory service manual in. There is no external hydraulic leak, so any busted seals must be internal to the system. I'll start looking for parts on the diagrams that could be the culprit.

Thanks for the inputs so far.

Ed
 
   / Three Point Hitch Pulsing #19  
If 3 pt stays up with R-O-D closed then RS piston seals should be fine. I'd suggest checking RS control valve for internal leakage.
 
   / Three Point Hitch Pulsing
  • Thread Starter
#20  
New info. I creating a storage solution for the backhoe so I had to load it up today. Because of the problems with the pulsing, I closed the ROD completely when I lifted the BH. Upon lifting the backhoe to the highest position, with the ROD closed, it still pulsed, extremely slowly (maybe 1/4 Hz or once every four or five seconds). It didn't do this with lighter attachments. Makes me now suspect the ROD valve. Any thoughts on this additional info?

Thanks,
Ed
 

Tractor & Equipment Auctions

2016 John Deere 35G Mini Excavator (A49461)
2016 John Deere...
2006 International 4400 LP Crew Cab S/A Heavy Haul Truck Tractor (A49461)
2006 International...
2009 Yamaha YDRE Electric Cart (A50324)
2009 Yamaha YDRE...
2020 Barreto 20RTK 36in Stand-On Trencher (A49461)
2020 Barreto 20RTK...
2019 Chevrolet Tahoe SUV (A49461)
2019 Chevrolet...
1982 TANDEM AXLE CEMENT MIXING TRAILER (A50854)
1982 TANDEM AXLE...
 
Top