The stick on my '86 CAT 416 5PC01199 backhoe won't respond. Even with the hoses off on both ends of the cylinder, moving the stick control up and down will not send any new oil to either hose. From the outside, the stick valve seems to be going up and down normally without resistance. With the hoses disconnected still, and curling the bucket, oil did shoot out the stick cylinder hoses. I marked up the pictures below to try to convey this easier. Blue is the stick valve body. Red is the adjacent bucket curly valve body. Yellow are the seals and BB I replaced in the stick valve. From searching through older threads, I've found enough to suggest when one function on the hoe isn't working, or is slower than expected, first thing to check are these seat and resolver valve seals. Seals on both that seating BB bolt and the underneath resolver were old and cracked. All swapped for new. Still no oil getting to Stick Cylinder. I've read enough to suggest it could still be the seals on an adjacent valve (the bucket curl did send oil to stick cylinder), but possibly any one of them? I still don't really grasp fundamentally what's going on with this seating valve and resolver valve and how it functions, or is supposed to. Asking for a beginners explanation on how the internals of this valve body work, and any recommendations on where to go next. Wondering if I should start by replacing all other seat and resolver seals, or pull the control lever valve out of the stick housing and look for blockages or something like that. Appreciate any education and recommendations on what to try next! Thank you. -Sean
You need to check resolvers in bucket valve
this will probably help I would start with just seals careful not to loose the ball on the one that is not caged
Thank you for this! I will get more seals and do both bucket resolvers this week. Will reply in this thread if that does it.
If you are planning on resealing resolvers I would suggest you get parts for all the sections in the control valve, however many that is. If seals are starting to fail in one section then they are close to failing in all the others. Give the caged resolver, #29 in your illustration, a good shake. You should be able to hear the ball inside it rattle. If you can't then you have no other option than to replace it.
I had replaced every resolver, primary and secondary in the whole rear valve assembly. Still the Stick won't get oil. I took the hoses off the stick cylinder, with the bucket curl, a little oil will shoot out of the hoses, but nothing when the stick is the only spool moved. Thinking maybe it was a relief valve issue, or more directly tied to this part I circled in green - What is this part? - and what does it do? I removed the caps - part 17 in diagram on a few valves, first of all, none of them had the spring #19 or small cylinder pieces crossed out in red, secondly, the swiss cheese cylinder (circled in green) was stuck down the hole below the threads only on the stick cylinder which is having the issues. I relate this to my problem, is it stuck in an open porting position, essentially acting as a permanent open relief valve, routing oil to the tank? Would it be stuck in the down position from hydraulic pressure, or surface rusting/ or broken springs? I have yet to pull it out, tried picks, a heated rod for some localized heat. Purchased an expansion collet bearing puller to try next, but if it's pulled down from hydraulic pressure, I assume it's not budging and there's another reason/ thing to try. Any thoughts?
Just one thing to point out the reliefs in the valve sections have to be set with external hydraulic pressure they are line reliefs. You could pull the whole relief and check the seals. Do it one at a time as they are set different for individual valves and each side of valve