Draft control problem.

[woodlandfarms]

So now this got me thinking..... My pt has the worst leak down. I mean it reall goes down quick with a load. I wonder if this circuit has anything to do with it.

 

[ponytug]

Carl-
The likely candidate is the the check valve on the hydraulic control. I have had to clean debris out of mine.

Looking at the above figure, if the check valve to the tank is not seating properly, it would cause leak down in the arms. It should be pretty easy to clean out. Just be careful of the aluminum block. Terry once warned me about being gentle with it so as not to strip threads.

All the best,

Peter

 

[SpringHollow]

My lift leaks down too. I believe this is typical to the valve used. I had catastrophic leak down a couple of years ago - would randomly drop. It ended up being the steering cylinders needing to be rebuilt. They are in the same circuit but have priority.

Ken

 

[J_J]

Unless you have reliefs in the work ports, it is not the valve relief that is leaking.

The valve relief does not come into play until you move the lever.

So if your lift arms are leaking down, with the lever in neutral, it is most probably the cyl seals, and maybe 10 % chance it is the valve spools.

With the lift cyl retracted, remove the base end hose from both cyl and retract some more.

If the seals are leaking, fluid will flow out the cyl base end ports. You might have to isolate which cyl by capping a hose

 

[Bob999]

A while back, on my 1430, the draft control stopped working. After some time I isolated the problem to the adjustable hydraulic valve in the draft control unit. Terry doubted that was the trouble and Keith said he couldn't remember ever sending out a replacement for one. I ordered a new one anyway, for close to $200..
The replacement is not exactly the same as the original but the draft control is working, but only when I crank the valve all the way down. I'm going to call Keith back this week to see if I can get the correct valve. Just wanted to share and wondering if anyone else has had draft control problems.

I had a similar problem. I was mowing and the draft control suddenly stopped working. (As others have posted what is called a draft control on the PT differs from draft control on a conventional tractor--on the PT the draft control transfers some (or all, depending on the setting) of the weight of the attachment to the tractor.)

I called Terry and he suggested that it was likely a small bit of foreign matter disrupting the operation of the draft control valve. It took me a couple of tries removing the control valve from the aluminum block and cleaning before it began normal operation again. I never saw any foreign matter but apparently there was some that was dislodged/removed by removing and cleaning the valve.

 

[RegL]

Bob, how did you clean the valve. I didn't throw away the old one yet.

 

[Bob999]

Bob, how did you clean the valve. I didn't throw away the old one yet.

I removed the valve cartridge and cleaned it using a clean cloth and compressed air. I also carefully examined the o ring and spacer to ensure they were in good shape.
I used suction to pull oil out of the cavity in the aluminum block on the theory that foreign matter might remain in the cavity.

As an aside, my valve cartridge is Sun brand and there are identifying numbers on the side(s) of the cartridge that allowed me to find the cartridge on the Sunhydraulics web site. That gave me a better understanding how it works.