Hi all, I’m having a problem with a bobcat s300. When I’m using pallet forks and have a load on them I can lift the loader arms up and down no problem. When I use the tilt, I can tilt towards the cab and take my foot off the pedal and it will hold the load fine. However if I need to tilt it even more when I depress the pedal the tilt goes down for about 3 seconds and then quickly comes back up. If there is no load on the forks it tilts up and down normally. Also what I noticed is when the lift arms are all the way down and I hold the pedal down for the lift arms the tilt starts to slowly drop. What I’ve done so far: I haven’t seen any external leaks. I did disconnect the return hose from the tilt cylinder and capped it off. I then depressed the tilt pedal and held it, initial trickle of residual fluid came out the tilt cylinder but then nothing. Same thing happened with the other tilt cylinder. I then went to the control valve. I thought maybe something is up with the load check valve. I removed the one for the tilt and for the aux. Both are identical. Visually they looked ok to me. One had a bit more of a shiney ring where it would contact the seat but not enough for a finger nail to catch. I swapped the check valves around but same thing is still happening. To me it seems that somewhere in the hydraulic circuit the tilt valve is loosing pressure when stationary. Then when I need to use the tilt it drops down until the pressure catches up. That’s what makes me think it’s a check valve. I’m no expert and this is all pretty new to me. I did see this machine also had a bucket positioning valve and the diagram shows that also has a check valve. I am not activating the BPV but am wondering if that check valve is always in use. I hope someone can chime in and steer me in the right direction and where to look next. All help is appreciated
Just want to provide an update. I started looking into the port relief/anti cavitation valves and a parts diagram. I didn’t find anything stuck in the port relief valves. However, when I looked back at my check valves (C2 and C3 on the diagram) it looks like they were replaced with port relief valves. At first I thought it was an updated design but when I looked at the most up to date parts diagram from bobcat it shows the check valve design stayed the same. So I ordered 2 new check valves (you can’t buy the check valve complete, you have to order the parts individually plug-spring-seat-oring). Bobcat doesn’t have all the parts in stock and will order them. About a 5 day wait. I’m hoping this fixes my problem. Will update once I get the parts in.
So I replaced all 3 of the check valves in the control valve and it’s still doing the same thing. If you press the tilt pedal back the forks tilt down before they start to tilt back. I’m a bit stumped. Looking for suggestions or feedback. I’m thinking I need to look at the spool valve next