ARK System 9000 Loader pump

[SmilinSam]

I recently rebuilt and installed the above loader on my Pow'Max. I am having "Herky Jerky" problems with the lift cylinders and I'm sure it is caused by air in the system. Works OK when it is cold but deteriorates rapidly with several lifts. This loader has a very large replacement pump installed on it, with a displacement of 1.25 cubic inches per rev. This works out to about 7 gpm @ 1500 rpm. I think the pump is too large for the unit and although it doesn't leak oil I wonder if it is sucking air past the seals. Anyone know what size pump was used by the OEM? Any other suggestions to eliminate the air?

[JoeJ]

Hi, I have heard of Hyd oil over heating, do to lack of reserve. Also return oil churning and creating bubbles. Don't know if it's any help to ya, but just some input! JoeJ[A href='http://www.oldwelder.com']http://www.oldwelder.com[/a]

[powermax_paul]

My Danco loader has the same size cylinders as yours and I'm using a 3-4 GPM pump at about 4000 RPM. My loader didn't come with a pump so I had to calculate volume of the cylinders and divide by timing to come up with a pump size. I got my pump from Northern and jury-rigged a bracket to mount it on. My pulley is only about 4" in diameter so the pump runs pretty fast. Paul

[Byam]

Thanks to all of you that replied. I have ordered a smaller pump but while the existing pump was related to the problem it wasn't the exact cause. I wanted to load a diffrential in my pickup to deliver to the crusher along with some other scrap. The loader jerked away and wouldn't lift it high enough. I finally got out of the seat and watched the pump while I opened the lift valve. The load was stopping the pump! I had used a 4L belt and it just wasn't strong enough with the large pump. I'll try a b section belt for temp. but I'm sure things will go better with a smaller pump. Doug Byam