Hey all, hope I can get some help with an issue I'm having on the 299D skid steer. So originally, I got called out to the skid steer because it wouldn't start. We troubleshot it and found that the implement pump wasn't allowing the engine to turn over fast enough to start, also, the customer mentioned that the lift and tilt functions weren't working before the no start issues started. I installed a new pump, the machine fires up, runs and drives perfectly, but we cannot get any implement function. I've tested all electrical solenoids and wiring; everything there seems to be working properly. All the Cat literature walks through the pressure testing procedures, but I have little to no pressure and we cannot use hydraulic functions to check pressures. I have 3-400 psi at the implement valve block at all rpm's; I have no pressure at the pilot pressure line on the bottom of the reman pump. I also checked all the hydrostatic pressures, and they all are within spec. Please let me know if there are any other advice or suggestions. Thank you.
Have you looked at the electronic system.? On this model the implements are all electro-hydraulic. Are there any Diagnostic Codes present.? There are over 20 different flavours of 299D. Can you post a serial Number to identify which one of those you have. It helps when looking for information. Back to the work tool pump for a minute. Was the old one disassembled to figure out why it failed.? Also you don't mention whether or not the implement system filter was replaced and if so what was found in the pleats of the old one. This could be a disaster looking for somewhere to happen.
Thanks for the reply. There are no codes, I have been through the electronics extensively, I've checked all the safety lockouts and monitored the status of everything through ET. The serial number is JST00827, its XHP version. The old pump was not disassembled, and the filter was clean, we also replaced it. No debris above normal was found in the system.
The last time I had the problem on a 299D it was the dam magnetic sensor on the pull-down arm.
Are you getting the expected duty cycle changes on the joystick position sensors.? With ET it should be easy to monitor.
new pump fires the engine but no implement function points to a pilot pressure issue preventing the main spool from stroking. Check : Pilot relief valve: If stuck closed or set too high, you won't build pilot pressure to command the pump Charge pump section: Pilot pressure typically comes from the charge circuit; if that section is faulty or air-locked, no pilot = no flow Shuttle valve/priority valve: Routes pilot oil; can stick or have debris blocking passages Since you have 3-400 psi at the valve block (likely just charge pressure), the pump isn't being commanded to displace. Verify the pilot circuit is getting oil from the charge pump and the relief isn't dumping it immediately.
Yes, the joystick is working properly, no other issues with the electronics that I can find anywhere.
What duty cycle measurements do you see with the implement joystick in the centre then at the extreme movement in both directions.?