Hydraulic pump problem

[barrell]

In 1993 I discovered and bought a pt1425 from a dealer who has since folded. Through the years I have tried to break and have fixed almost everything on this tractor. Recently though the main hydraulic pump in the front of the Kholer 25 blew its main seal and was fried. I pulled it and took it down to jersey to a shop with 30 years experience. After he figured out what type of pump it was (with no help from pt- they refused to tell me) He blew me away with the cost for a rebuild kit $800
He told me another $150 for labor would be tacked on so I told him to do it. When I got the pump reinstalled and reatached all but the top two lines. I left those a little loose. I turned it over with plug wires removed to bleed out all air. I then started it and have no preasure on the high end side. I bought a guage to find that out. Terry at pt says I should have bled it from the plug back on the low preasure side,so I tried that still nothing. The mechanic who rebuilt it says that every part inside is new. He only used my old housing and that it should work. He says he has never had a rebuild fail before. He was a littler fearfull that a piece of brass from the first pump failing may have gotten into the rebuild. I wish he mentioned that before. I would have pulled the bottom line from the filter and cleaned it out. Any ideas guys. I have it on the trailer but wasnt looking forward to the 4 hour drive down to jersey 4 times to drop it off and then go back for it.
p.s. I have alot of other experiences with pt and their tractors I can share.this problem is a priority right now.
Barrell

 

[MossRoad]

Welcome to TBN. Sorry it is under these circumstances. I don't know of anyone here that has dealt with a blown pump yet, but I'm sure someone will jump in with some thoughts.

 

[pajoube]

Unable to help you with your problem as I have a new machine. But, I am very interested in your experiences over the years with your PT. What attachments do you have and what do you use it for? I assume it is a three point system.
PJ

 

[duane]

Barrell,

Did you find out the type/manuf. pump?. You need to get the charge pump primed, so that it can feed the piston pump. I was wondering whether you could take the suction line, disconnect from the filter, and hold that end up above the pump. Fill the hose with oil, and try to get the charging pump primed that way. After it's primed, reconnect to the filter and purge again the same way after a filter change. After a filter change, I think the charge pump body has enough oil to prime, but after a complete rebuild, it would be essentially dry.

Keep us informed.

Duane

 

[barrell]

I have a mower,tiller,heavy bucket,and brushog. I bought everything in 93 new for $14,000 I was shocked to see they cost less than that now.
Pt told me to remove the long brass cap from the low end side of the pump and turn over until I get oil and no air. I get a good solid stream of oil from that nipple. But I am not getting the 4,000 pounds from the high preasure side that terry told me I should get. I have nothing but maybe the same low preasure stream. My mechanic said he finds it hard to beleive that pump produces 4k. but he said its possible.
It took weeks to find out what kind of pump it was . We had to photgraph it and send the pics to a couple of parts suppliers. A supplier in Tennesse who was familiar with pt recognized it as a custom pump made just for pt. That is why the rebuild kit was so expensive. Pt refused to tell me who made the pump they wanted me to buy a pump from them and would not cooperate. I have run into this attitude with them many times if they felt they werent getting the sale.
I was running a mix ot mercon and oil in the tractor because this is what pt told my dealer I should do. This was after I complained the first winter I owned it when it wouldn't turn over enough to start in zero degree weather.
Are the manuals better nowadays? Back then all I got was a couple of blurry photocopys. There was no explaination of what parts were or what they do. Im curious if I can wire the cooling fan to run constantly as it seems to have a mind of its own as to when it comes on. It looks like the two wires that atach to the vertical copper tube on the side of the radiator are connected to some type of thermostat. Or is that simply a temp sensor?
Barrell

 

[duane]

Hi Barrell,

I'm in uchartered territory here. I rebuilt a hydrostatic tranny in a yard tractor that had a variable piston pump (no charge pump). After rebuilding, I went throught the air purge process. Ten minutes into the process, no axle movement (meaning no piston pump discharge pressure). I thought I had done something wrong. After trying for another ten minutes, the axle finally started to move. Another ten minutes and I had the air purged. The short of it, it took a long time to purge the air successfully.

Maybe you could try the following: If you think you have the charge pump primed. jack and block the tractor (all 4 wheels off the ground). Work the tredle forward (5 seconds), reverse (5 seconds). Continue to do so to try and purge.

Does the business that rebuilt the pump have any suggestions?

Good Luck

 

[Schultz]

Welcom aboard!

How many hours do you have on your PT?

Tim

 

[barrell]

duane, Maybe I didnt bleed long enough. I only left the hoses loose till oil apeared leaking past the threads. Maybe 15 seconds. Pt told me the pump will burn up in 45 seconds if air is in it so I am afraid to run it anymore than I have. Your idea sounds intresting. Its the first thing anyone has come up with but if the pump is still good I dont want to fry it by playing around.
Barrell

 

[J_J]

The device you mention that is on the side if the hyd radiator, is a temp switch which allows the fan motor on top to help cool the hyd fluid. you could bypass it with a switch to run when ever the engine is running.

J.J.

 

[Bob999]

<font color="red"> Im curious if I can wire the cooling fan to run constantly as it seems to have a mind of its own as to when it comes on. It looks like the two wires that atach to the vertical copper tube on the side of the radiator are connected to some type of thermostat. Or is that simply a temp sensor?
</font>

You can certainly bypass the thermostat so that the cooling fan runs continuosly--but, in my opinion, it is not a good idea. When the hydraulic fluid is cold it is quite viscous. I installed a vacuum meter on the inlet to the charge pump on the variable volume pump. On a cold start the vacuum will register 20 inches at high rpm. Vacuum drops to about 6 inches when the fluid warms and the fan engages. When there is a high vacuum there is increased possibility of cavitation which can cause severe damage to the pump.

Therefore, I believe that warming the hydraulic fluid as rapidly as possible is desirable and the temperature controlled fan aids rapid warm up.