On this 950H the boom drifts down when the bucket is full at a fast pace, and seems worse when the hydraulic oil is up to full temperature. To check the lift cylinders I put a block off plate on the lift hose of each cylinder one at a time (cylinders at room temp) and with the engine off and key on put the control lever in the float position. After 20 minutes on each of the cylinders seperately the boom didn't move down more than 1/4 - 1/2 inch so it seems they should be good. I replaced the anti drift solenoid on the lift valve and the ride control solenoid and it didn't seem to help and I'm getting flustered Has anyone else had any experience with these 950H's drifting?
Whats the main relief set at ? Can it be adjusted up ? Is it leaking/weak/not seating ?
PROBLEM The 194-1723 Ride Control Check Valve can fail under certain circumstances on 950H, 962H, 966H, and 972H Wheel Loaders as well as the IT62H Integrated Tool Carrier Machines that are equipped with the ride control option. Failure of the 194-1723 Ride Control Check Valve will typically result in excessive boom drift or drop when the ride control function is placed in the On/Manual or Auto mode. Failure can also cause hydraulic system contamination. Certain 9S-8001 Plugs on the 253-4026 Ride Control Function Block that can come loose under certain circumstances on 950H, 962H, 966H, and 972H Wheel Loaders and the IT62H Integrated Tool Carrier machines. Loosening of the 9S-8001 Plugs can cause internal and external leakage as well as result in boom drift and potential loss of implement function. There are a pile of service letters on ride control problems but we need a serial number to narrow it down. Also does it change the drift if you shutoff the ride control?
Thanks for the help, I have ordered the ride control check valve and can try that soon. When shutting off the ride control it didn't seem to change noticeably when cold but will try again when its up to operating temp and see if it makes much difference. The serial # prefix starts with K5K and will try getting more information tomorrow.
Do the cylinders keep drifting or do they drift a certain distance then (kinda) stop..? Had that on a 962H - it was the cylinder piston seals. For an explanataion of why this happens - see this thread. HeavyEquipmentForums
Found the problem today. When we brought it up to operating temp it stopped drifting with ride control ON , so we tried replacing the larger ride control check valve 367-3012 (old #270-1768) in the 253-4026 ride control block and it stopped all the drifting. Thank you for all your input, this is a great forum.
That's good to hear. Thanks for the update , its always good to know what the fix is for future reference. Its funny that in the service letter for that one they say it will be noisy as the failure.
Yes that"s the one and it didn't seem to make any noise and the operator said the symptoms seemed to come on quite quick. The part # updated a couple times so not sure if it would be an updated and improved part now.