Hello i have changed the pilot hose on my bobcat because it burst and was leaking heavily. All went smooth except my boom control which i changed the hose for goes up normally but doesnt go down or when it does very slowly. Also sometimes it keeps going up without any input. All other inputs on that joystick or the other one function normally. Does the pilot hose need bleeding or is this a sign of something else. The cause is the repair that is clear cause before the hose burst it was doing just fine. I had a hydraulic shop make the hose, the hose is the same size but more sturdy then the original pilot hose. Can that be a problem?
Double-check the hose isn’t internally twisted, kinked, or rubbing when the boom moves. Pilot flow is low, so even minor restriction matters.
I am going to order a original bobcat hose once they add it to the european store, because i think from what i read the hose is indeed the problem since they are very important on pilot flow. I have tried to bleed it but that makes zero difference.
I took it off and checked no kinks or internally twisted, the only thing i do notice is a difference in resistance between the original and new one when i blow on it. Could this explain it that the resistance is different between the two even if it is minor?
At the risk of sounding crass? You’re blowing a hose? Do you mean blowing air through it? If so and there is a difference, then that is a problem. Are you sure the fittings are correct to the original?
Haha yes i was blowing air through it and there is a difference. The new hose needs more force.
That could very well be a problem.
Since the issue started immediately after the pilot hose replacement, it’s very likely related to the hose or air in the pilot circuit. Pilot lines usually don’t need traditional bleeding, but air can get trapped and cause slow response, no return, or even self-actuation like you’re seeing
I tried bleeding by pulling off the pilot hose at the highest point which is at the joystick and then i ran the excavator and pulled the joystick up and down so it squirted hydraulic oil out. I do not know if this is the way but i do not really see other ways to try and bleed it? It didnt make it better, i actually had the feeling it made it worse.
Update, i finally got the pilot hose from bobcat and installed it. Same scenario i have to push the joystick down litterally for 5 minutes for the boom to come down. I cracked the other pilot line on the valve block to maybe get air out that way because i can not reach the other one to do that. No change.. Then i disconnected the new pilot hose completely from the joystick and on command up it comes out like a jet from the joystick so that works but then on command down nothing comes out of my new pilot hose? I am at a bit of a loss now because the original damage was the burst hose which i replaced now with an original one to be 100% sure and no fix. All other commands work perfectly on the excavator. Any ideas?
I cant edit my post, but sometimes i can get it like somewhat working as in i get the boom down slowly and if i do the boom up slowly i can get it down again but then the boom up function suddenly gets the overhand again and we are back to trying to get it down.
I got it working, took both pilot hoses off and checked their function and that was 100% so it couldnt be the joystick or the main pilot circuit. I had another look at the manifold where the hose goes to and i saw a extension on it which turned out to be a non return valve i think. I blew it out with the compressor, fitted everything and presto everything works. Thank you to everyone who responded in this thread!
Happy we could help!
check for blockage restriction,from the hose that you remove, may have old hose line at nipple on the control valve.end, or swap over hoses for that function, as reversing can be done at the joystick .problem should change from down to up posistion