Problem with hydraulics on L555 deluxe

[deaop06]

Slow bucket and boom plus noise on left side drive. Sounds like a plugged screen but screen is clean. Oil is full. I was working about 2 hrs when this started. It made noise when I backed up left side while forward on right stick. Then slow up and down on boom and bucket. I got it loaded and home. Put gauge on bucket ram and cold it was 1850 hot was 1600 at full throttle. Book states 2000 to 2300. So the psi is way low. Could this be the problem? I hate to spend $400 for relief valve and not be the problem. Any thing else I can do to be sure? Machine has 2450hrs on clock. This is an 1989 build or after serial# 700000. Thanks

 

[deaop06]

I pulled the gear pump and rebuilt it. The center section had some scaring so I replaced it and put a rebuild kit in. Put it back together and now have nothing. Two questions. Is the gear pump self priming? Should there be hdy. fluid between the rear of pump and transmission? The pump has new seal so fluid is coming from transmission. I am going to take pump apart again and make sure everything is in the right place. Any ideas or comments would be welcome. Ron

 

[Tazza]

I pulled the gear pump and rebuilt it. The center section had some scaring so I replaced it and put a rebuild kit in. Put it back together and now have nothing. Two questions. Is the gear pump self priming? Should there be hdy. fluid between the rear of pump and transmission? The pump has new seal so fluid is coming from transmission. I am going to take pump apart again and make sure everything is in the right place. Any ideas or comments would be welcome. Ron

Priming can be a little harder if the oil tank is lower than the pump, if it's higher, it will self prime.
In the past, i have primed a dry system by manually cyling the cylinders to pull fluid from the oil tank through the pump and control block.
When you re-assemble the pump, you should ideally use light grease to allow it to run “dry” till it primes.
Is there a chance the pump was not assembled correctly?

 

[deaop06]

Priming can be a little harder if the oil tank is lower than the pump, if it's higher, it will self prime.
In the past, i have primed a dry system by manually cyling the cylinders to pull fluid from the oil tank through the pump and control block.
When you re-assemble the pump, you should ideally use light grease to allow it to run “dry” till it primes.
Is there a chance the pump was not assembled correctly?

The old pump would not work. Didn't figure it out. Just bought a new one put it in and problem solved. I now have 2150psi on the bucket with oil hot and I can live with that. The old pump has been going bad for a while I just didn't notice it.

 

[Tazza]

The old pump would not work. Didn't figure it out. Just bought a new one put it in and problem solved. I now have 2150psi on the bucket with oil hot and I can live with that. The old pump has been going bad for a while I just didn't notice it.

Glad it was an easy fix