Hydraulic pump problem

J_J · Nov 6, 2003

My reply was for after warn up. On my system, the fan hardly ever comes on, even though the holding tank is hot to the touch. I therefore bypassed the temp sensor with a switch to run the fan whenever I wanted. Cold fluid is not good for the system and very hot is definitly not good. I think most hydraulic manuals say to keep the temp below 150 degrees. Do any of the newer machines have hyd temp sensors?

J.J.

duane · Nov 7, 2003

Barrell,

I agree, caution is the word, don't burn that baby up. The newer units have a hose which connects to the charge pump discharge and the reservoir. It purges air from the suction line. Then the charge pump is capable of providing oil to the piston pump. Not sure of your set-up.

I would call Power Trac and have them give you step by step purge advice.

Charlie_Iliff · Nov 7, 2003

Barrell:
On my 1845, the bleed port is essentially in the middle of the head of the pump. When I change filters, I hook a line to it and immerse it in a cup of oil so I can watch for bubbles. I am amazed at how long I have to crank before it runs clear
I've never started from completely dry. There may be a way to prime the charge pump initially, which PT should be able to tell you.
There is a thread on the board recently about a similar problem with a Kubota, which wouldn't move after a fluid change, but ultimately purged the air. I don't know if the pumps are similar, but certainly air lock in hydraulic pumps can be persistent until the right procedure to clear them is found.
Good luck and keep us posted.

barrell · Nov 7, 2003

Duane, Pt told me yo crack the brass cap on the right rear
( low preasure side) side of the pump. Then to turn it over without plugs connected until oil comes out. This I did without positive results. That is why I posted . its sitting In the driveway on the trailer ready to go down to Jersey On Sunday to the shop. I may or may not fiddle with it tommorrow. I have to take a building inspectors exam tommorrow morning. Anyone familiar with the new International building code?
Barrell

jfh230 · Nov 7, 2003

<font color="blue"> Anyone familiar with the new International building code? </font>

Yes, I unfortunately have to deal with codes everyday. The IBC is very similar to BOCA and where the items are different I have found the IBC to be more forgiving. I would strongly advise you to get the commentary book that goes along with the IBC. Its like an instruction manual for the code.

Good luck on your exam.
Jack

duane · Nov 8, 2003

Pt told me yo crack the brass cap on the right rear
( low preasure side) side of the pump. Then to turn it over without plugs connected until oil comes out. This I did without positive results.

<font color="black"> </font> This is the charge pump discharge. After the rebuild, the charge pump casing is dry. It needs to be wetted with oil to provide sealing to create a vacuum to pull oil. Try disconnecting the suction line from filter, hold above the charge pump and fill with oil with the brass cap removed. This should wet the charge pump cavity, and then try what PT said again.

good luck

barrell · Nov 11, 2003

Duane, I took the machine down to the guys shop who did the rebuild and he is flustered . He spent most of Monday looking at it. We do get a stream of oil out of the low preasure cap but he says he is only getting 70lbs and it should be a 100lbs. He jacked it up and gets the wheels to turn slowly but thats it. He even called the pump manufacturer and they could not explain what might be wrong. He now is considering that the oil is flowing past one of the wheel motors and not providing enough back preasur for the pump to develop full preasure. The wheel motors could have received chuks of brass from when the seal blew out on the pump as the pistons in the pump were chewed up pretty good. He was suposed to investigate that theory today but I havent heard from him yet.
I would think that until you push down on the pedals no oil should flow to the wheel motors. Is that a correct assumption?
Barrell

duane · Nov 12, 2003

"I would think that until you push down on the pedals no oil should flow to the wheel motors. Is that a correct assumption?"

I also believe that to be true.

Duane

pajoube · Nov 12, 2003

That should be correct. Watch out when you get on and off the machine if you leave the engine running. Easy to bump the treddle which will give you a real jolt. I have also had a rock get under the treddle without knowing it and that caused real panic untill I found it.
PJ

Charlie_Iliff · Nov 14, 2003

Barrell:
Any progress?
Your mechanic's observation would also be consistent with the valve not directing the flow completely to the wheel motors, but returning some to the tank, although I haven't a clue what type of failure would lead to such an effect.