PT1850 Tilt Seat Issues

   / PT1850 Tilt Seat Issues #1  


Bronze Member
May 6, 2018
I just finished up a suspension install on my PT1850 using a Trac Seat suspension kit. The suspension is wider than the standard seat setup, so the rotating mounting plate had to be modified (widened).

Got everything back together and the setup seemed fine. The seat had been at stable level rest prior to the swap out. I marked the mercury switch connections, so I am sure the wiring is back as it was. I called it a night without cranking the machine.

When I came back the next morning, the seat had fallen over to its limit on the left side (the hydraulic cylinder had leaked down, suggesting the valve was open). I cranked up the machine expecting the seat to return to level, but nothing. I unbolted the cylinder leaving its hoses attached and moved the seat back and forth, but the cylinder did not respond.

The tractor is sitting at a remote location and I didn't have any time to track the problem down. And, didn't have a multimeter with me at the time.

I did check the wiring diagram and follow the physical wiring as best I could and found no fuse in the circuit.

Any hints on how to go forward with my trouble shooting? I haven't been back to the machine since, but would like to have a clearer idea of how to approach this.

One thought that I did have is that I have interrupted the ground. If memory serves, both mercury switches ground to a post in the box on the back of the seat meaning the seat itself is the ground. After we modified the rotating seat base, it got a new coat of paint, the seat was off, so its rusty bottom got a new coat of rust converter paint, and the suspension unit had intact factory paint. Perhaps the switches aren't getting a good ground from the ground post through the suspension through the rotating seat base to the frame. ( The suspension unit is mounted between the rotating seat mount and the seat.)

Any suggestions or hints greatly appreciated. I will report back after I get the chance to go back to the machine.
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   / PT1850 Tilt Seat Issues #2  
I like your idea of a poor ground. It seems consistent with the sequence of events and would simply explain the issue. I would run a new ground wire off the seat ground to somewhere on the frame.

All the best,

   / PT1850 Tilt Seat Issues
  • Thread Starter
Thanks. I will start with that.
   / PT1850 Tilt Seat Issues #4  
I had a solenoid go bad on the seat tilt system a few years ago, if I can find the post, I'll link it here
   / PT1850 Tilt Seat Issues #5  
PT woes..... 1850 wiring

I had a couple good pics in there that had disappeared, but there is a ton of info on the seat tilt system from other members, as well as my solution.
   / PT1850 Tilt Seat Issues #6  
In a similar scenario one of the wire ends in the black box did not survive being disturbed after 20 years in place.
   / PT1850 Tilt Seat Issues #7  
My wires broke to me seat in the tunnel. I am currently having an issue with my west not going back to center quickly. Mercury switch issue. Also the seat switch did you leave it in?
   / PT1850 Tilt Seat Issues
  • Thread Starter
I didn't remove the mercury switches when I removed the seat. I disconnected the black and white wires running through the seat frame tube and labeled which was which.

I had the machine back at PT for a main pump rebuild about a year ago and they re-did the seat system with new wiring and mercury switches. The previous owners had rewired the seat with a manual left/right toggle switch on the dash.

Everything seat related was functioning fine prior to the seat suspension installation.
   / PT1850 Tilt Seat Issues #9  
Something got pinched, crossed connected, or disconnected.

(I learned that in science class).

Sorry I can't be of help.
   / PT1850 Tilt Seat Issues
  • Thread Starter
I ran a new ground from the ground post on the back of the seat through the seat mount tube to the frame. Everything works fine now.