Cat 311B tracking issue

[Mike L]

Pumps just got returned from cat where they disassembled them, inspected, resealed, ran them on an dyno, and charged me $4000 to do it. We actually sent them to New Hampshire where they had a dyno because I originally thought I had a flow problem.

 

[Nige]

Out of interest did they supply the dyno reports when the pumps were returned.?

@John C. Attached the Hydraulic SysOp just in case it's any use. Use anything that says 8GR it will also apply to the 8HR machine.

 

[B&B]

Serial number 8HR00272. Gray market machine. right side track runs slow. Been chasing this around half the summer. Thought we had a pump flow issue. Cat went through the pumps and it didn’t fix anything. I’ve got 500+ pilot pressure. Both pumps build 5000 psi and I’m getting 5k out of the main control valve on the track pressure lines. Negative pump pressure is at 500 when I start the engine and drops to 100 when I activate a function. Points to a track motor right? If I swap the pressure lines coming out of the mcv, the issue immediately switches sides. If I swap pilot lines on the mcv, the pedals run backwards but issue stays on the right side. If I track the machine and hit a joystick function the machine will straighten out. Cat installed a mulching head and had to add a diverter valve to make it work. We have also bypassed that but the problem persists. I’m at a loss and the cat tech support is also at a loss. They are usually excellent help and he finally suggested that we get a cat tech on site who has access to a hydraulic guru. That idea disgusts me. Any ideas? Did I miss something?

I had a similar issue with slow swing and one slow track, ended up being the governer in the pump was sticking. If I moved multiple functions I could get it to speed up as well. It was a 315BL

 

[John C.]

Thanks Nige for the attachment. I'm still reading through it and trying to resolve in my mind how it says the system is supposed to work and ways in which it is actually working presently.
Mike L, have you done any cycle times on the boom up and stick out functions. It would also help if you have cycle times for track rotations.

 

[pittsburgh cat man]

Here is a dumb thought are the plungers on travel pilot valve worn ???