PT1850 Tramming Issue

[BWSwamper]

Recently I had my PT1850 back to the factory to track down a leak, - which ended up being a leaking seal on the system pump. The shop rebuilt the pump and did a few other odds and ends (replaced worn center link bushings, sorted out electrical issues). The main hydraulic filter was replaced in the process.

When I went to pick up the machine I ran it forward just long enough to pull it out of the building. Then Terry backed it up on the trailer, I chained her down and off I went. In retrospect I remember having a vague impression that forward tramming was a bit sluggish, but I attributed it to low rpm (which I increased during the 20 yard run to the parking lot). In retrospect I should have run the machine more extensively before I left, but having just come out of the PT factory shop, and being keen to get underway to prevent a late night towing run...

In any case, when I went to unload, the machine's forward tramming was clearly sluggish to start moving and results in a noticeably lower speed than the reverse. Reverse function seems totally normal in both response and top speed.

Also, at first cranking the steering seemed very heavy, but that seems to have resolved after a few minutes run time. I attributed this to the steering circuit clearing itself of a bit of air.

I'm planning to check in with Terry next week, but have been studying past posts here, the PT manual-lite, and what the PT website suggests under FAQs.

The machine's behavior makes me think there is some sort of blockage (air or debris) in the forward circuit. Or, that some tramming related adjustments on the pump are off as described in other post on this site.

Any thoughts or suggestions would be greatly appreciated.

 

[m5040]

First off, there are old versions with a cable controlled and new versions with pilot control.
Either way I would run it around for 1/2 hour to heat it up and get rid of any air. Then see if it is better.

 

[BWSwamper]

First off, there are old versions with a cable controlled and new versions with pilot control.
Either way I would run it around for 1/2 hour to heat it up and get rid of any air. Then see if it is better.

Thanks. This one is a 2007 and has the hydraulic treadle block. I'll run it a bit this afternoon and see if it clears by itself.

Also, from the diagrams, I don't understand how the lift and tilt system fits into the other systems. The diagrams show the tram pump also powers the tilt seat cylinder, and the PTO and steering use the same pump. I may be short a diagram since what I have is loose leaf photocopies.

 

[m5040]

It is not good that they don't proof read the manuals. My 1460 says to remove the floor to get to the hyd filter. Although I haven't removed the floor to look, I do see the hyd filter all the 14XX tractors normally have by the fuel tank. I think they meant the 2460 needs the floor removed.

 

[m5040]

The one area that may be confusing is the draft control. It is the only place I believe that the hyd controls interface with the tram. (maybe the park brake too). The variable pressure that drives the wheel motors also (when daft control is switched on) applies drive pressure to the loader lift cylinders. So if you are rolling along, little lift is sent to the loader arms/attachment/mower deck. When climbing a hill the tram pressure is high, this is sent to the lift cylinders to apply lift to the attachment and give the front wheels more weigh/traction.
When reading a hyd circuit diagram make note of this. Otherwise no pressurized oil comes from anywhere else then the hyd pump (steering/loader lift/3rd valve)(maybe seat as none of mine have a tilt seat).

 

[MossRoad]

Thanks. This one is a 2007 and has the hydraulic treadle block. I'll run it a bit this afternoon and see if it clears by itself.

Also, from the diagrams, I don't understand how the lift and tilt system fits into the other systems. The diagrams show the tram pump also powers the tilt seat cylinder, and the PTO and steering use the same pump. I may be short a diagram since what I have is loose leaf photocopies.

Don't know about your particular model, but my PT425 has 3 pumps. No tilt seat, so can't comment on that. Maybe your model is completely different plumbing than their little brothers, but this might or might not help. If not, ignore it.

2001 PT425 has:
1. The variable volume tram pump (forward/reverse motion and speed).
2. The main PTO pump (large powered implements like mowers, tillers, etc...).
3. The AUX PTO pump (the quick attach OR power angle blades, mini-hoe curl, etc...).

On my machine, it's the AUX PTO pump that first sends fluid to the steering box, then out of the steering box through a power-beyond port to the FEL valve bank, then back to the tank. That FEL valve bank powers UP/DOWN, DUMP/CURL, and the AUX PTO. The AUX PTO is the small connectors on the FEL arms that supply the quick attach.

 

[MossRoad]

The one area that may be confusing is the draft control. It is the only place I believe that the hyd controls interface with the tram. (maybe the park brake too). The variable pressure that drives the wheel motors also (when daft control is switched on) applies drive pressure to the loader lift cylinders. So if you are rolling along, little lift is sent to the loader arms/attachment/mower deck. When climbing a hill the tram pressure is high, this is sent to the lift cylinders to apply lift to the attachment and give the front wheels more weigh/traction.
When reading a hyd circuit diagram make note of this. Otherwise no pressurized oil comes from anywhere else then the hyd pump (steering/loader lift/3rd valve)(maybe seat as none of mine have a tilt seat).

I was wondering how their draft control system worked.

 

[BWSwamper]

Followed M5040's suggestion and ran the machine until good and warm, then mowed for about half an hour. Situation improved gradually to near normal, so apparently the system is purging itself.

Still curious why just the forward circuit would be the one affected. Woodlandfarms reported precisely the same thing after a filter change.