Bucket truck hydraulic tool circuit issue

[Diy mechanic mike]

My hydraulic tool circuit in the bucket isnt working. when I flip knob to engage tool (basket controls)there is a whining noise coming from outrigger/dump valve.?.?.? Everything else operates as it should, with the exception of basket controls seem a bit slower then the pedestal controls. According to my manual the hydraulic system pressure goes from pump, straight to outrigger/dump bed hydraulic valve bank, then to pedestal valve bank, then to basket valve bank (after the override valve on pedestal bank is engaged). But I'm really thrown off that there is no noise when operating the lift from pedestal controls, then when I operate from basket controls its operating at half-ish speed compared to pedestal controls. Also there is a very faint noise coming from outrigger/dump valve bank when using basket controls, but when the tool valve at basket bank is engaged the noise is really whining from outrigger valve bank and it doesnt operate my saw. I had this working about 6 months ago when I acquired the saw. Didn't use it for a while and tried to today and nothing. Only thing that has been done since then is a hydraulic line in lower boom was replaced and topped off hydraulic fluid since i lost a decent amount before it started draining out the end. Darn squirrels chewed a line up. Could those chewings have gotten in system causing something like this?

Thanks
Mike

 

[Matt Coolen]

Sounds like the relief valve is whining. I would check your couplers, make sure all is good there. Sounds as though all your valve banks are connected in series, through power beyond sleeves, and main system relief is in dump/outrigger valve. If your basket controls are only working half speed, you have a hydraulic loss somewhere, either a spool sticking, making something go against relief or something of that nature.

My .02

 

[Diy mechanic mike]

Thanks for replying I actually haven't got much help on this site with hydraulic issues and it's hard to find good info online about hydraulics. But I'm trying the best I can with my manuals' somewhat guidance and my lack of hydraulic knowledge. But I do know that all my valve banks have been taken apart and new seals put between sections and new o rings on the spools. done this myself after the hydraulic shop I got seals from showed me how to do one section. I'll post a picture of my valve bank that is making the noise. I have a question about the relief valve location on my controls. And the purpose of this shut-off valve inline with dump control. It basically controls the flow going to dump valve(open= dump valve works closed =dump valve doesnt work). My manual doesnt go into this much detail on the hydraulic system.

 

[Diy mechanic mike]

Sounds like the relief valve is whining. I would check your couplers, make sure all is good there. Sounds as though all your valve banks are connected in series, through power beyond sleeves, and main system relief is in dump/outrigger valve. If your basket controls are only working half speed, you have a hydraulic loss somewhere, either a spool sticking, making something go against relief or something of that nature.

My .02

When you say check the couplers, are you referring to the quick attach couplers for tool or where the lines connect to control valves? And what exactly should I do just unscrew them and look inside for debris clogs/retighten??

And basket control issue, could these two issues be caused by the same problem?

Seems like the same outcome is occurring with both issues (relief valve whine @outrigger/dump valve), but obviously the outcome is more serious when giving power to the tool circuit. And the relief valve is "saying no"(loud whine) to operating tool, but when basket controls get power its half-ish speed and the relief valve is just "monitoring" (faint whining noise) that operation. And when lower controls get powered the relief valve "has its feet on his desk kicked back" not making any noise and good operation of controls. I'm just trying to be as clear as I can as to what is exactly happening when I operate different things. However if you need more info please let me know.

Thanks,
Mike

 

[Matt Coolen]

Yes, the quick couplers for your saw. I have seen them fail, it doesn’t take much. Could you take a pic of the couplers? You say they screw together? Are they going together completely? I have been working 15+years in the trucking industry, we build bucket trucks where I work.

 

[Matt Coolen]

I’m just looking at your pics and re-reading your blurbs. I am thinking the issues are both related. If there is no whining noise from anything until you switch to basket controls, that tells me your problem lies in your basket, someplace. Does the whining noise go away when you use a basket function, at the basket controls? I would highly doubt that the squirrel chewing your line could cause this, but stranger things have been know to happen.
When you switch from pedestal to basket controls, you eliminate the pedestal valve altogether, flow gets redirected to your basket valve, so if the issue only shows itself once you make the switch, you can eliminate the pedestal valve. Make sense?
That needle valve in your dump hose is likely a throttle valve, to slow the bed when coming back down. It’s hard to know, without seeing how the system is plumbed.

 

[Diy mechanic mike]

Yes, the quick couplers for your saw. I have seen them fail, it doesn’t take much. Could you take a pic of the couplers? You say they screw together? Are they going together completely? I have been working 15+years in the trucking industry, we build bucket trucks where I work.

Sorry for my confusion on the couplers.... I actually replaced those ports when I got the saw cuz yes the old ones were seized up. But here are more pictures of control valve and my saw/couplers.

I dont think the tool circuit is the direct problem since I have new parts for that. Im thinking the supply to upper controls from lower controls is the issue, since lower controls operate fine, then when power is sent to upper controls and a valve is opened the "slight whine" from outrigger/dump valve occurs, but still operates just slower, then when power is sent further to the tool circuit from upper controls the whine gets loud from outrigger/dump valve and no power is present at tool circuit. But of coarse when that whine starts I shut the tool circuit off cuz it sounds like something is being overworked.

Obviously my brain is being over worked right now thinking about this but I'm wondering if my supply line to upper isnt kinked causing this... what do you think?

And by the way thanks for your input here. I appreciate it alot.

Thanks,
Mike

 

[cookies]

you need to use a pressure tester to see what pressures you have in each circuit

 

[Del_]

On my 65ft. high ranger it had a bypass gate valve so that when the tool was being use that flow rate could be controlled. If the tool circuit was not being used we would open up the bypass valve and no 'squealing' from the hydraulic system. I'm sure it reduced heat in the system because we hardly ever used the hydraulic tool outlet in the bucket.

 

[Matt Coolen]

Did the problem start since rebuilding the valves? I see all the coloured ty raps on the hoses, I always check the last thing to be worked on when troubleshooting

 

[Diy mechanic mike]

Did the problem start since rebuilding the valves? I see all the coloured ty raps on the hoses, I always check the last thing to be worked on when troubleshooting

No I re-done those valves when I first got truck. It had hydro leaks all over but they have all been fixed since then and everything worked including tool cuz when I got the saw I immediately tried it out and it worked. Only thing that happened since the saw did work is the truck sat for a bit while fixing a carb issue and that's when the squirrels got me. So got lines fixed and then bled air out of system from lower controls by cycling upper boom up 45° and back down like 5 times before I flipped it over the back and cycled it all the way a few times and figured it was bled. I did not cycle the system from upper controls since the hoses were replaced. My book didn't say anything about basket controls needing bled. Could there be air in the upper section of hydraulic system? Maybe it needs the upper controls cycled. But I'm still thinking maybe the line going from lower controls override valve to basket controls input could be kinked at the knuckle. I replaced a hose there earlier on in the project because of a kinked line right in that knuckle section. That's what is making me think that but I dont have a pressure tester so I have to trace it down the old fashion way. But bucket truck plumbing is much more time consuming then regular plumbing haha.

 

[Diy mechanic mike]

But I'm still thinking maybe the line going from lower controls override valve to basket controls input could be kinked at the knuckle. I replaced a hose there earlier on in the project because of a kinked line right in that knuckle section.

Unfortunately when I replaced that kinked line my truck wasnt running due to carb issues so I wasnt able to assess an issue from that kinked line so idk what a kinked line can act like. I just got lucky and noticed that kinked line when fixing carb.

 

[Matt Coolen]

Sounds like you might be on to something. Your saw requires good flow to operate, the boom requires pressure to move, not too much flow.
If you have a restriction in your line (kink) you will lose flow quickly, when a function is used.
Think of it the same as your garden hose, if you kink the hose so that there is only a trickle of water coming out (no pressure, low flow)and then cover the end over with your thumb, the pressure will build, but as soon as you let your thumb off, the pressure drops again. Imagine having a sprinkler on the hose that requires water pressure and flow to spin the sprinkler, if you have very low flow, your sprinkler only dribbles and will not turn.
Your upper valve block is open center, meaning, if no function is used, oil comes into the valve and travels directly back to tank. Meaning, there should be no restrictions, no demand on the pump. If you are hearing a hissing noise, you have a restriction somewhere between lower and upper valve bodies, on the pressure side. Your saw won’t turn and your boom is slow because of the restriction. Your saw is like the sprinkler mentioned above.
Hope this is helpful and not confusing...

 

[Diy mechanic mike]

Your explanation made total sense, however I'm about to embarrass myself here.... my tool circuit wasnt working because I was pushing lever the wrong way!!!!!! I went out there after starring at my book all day and being on here and was tracking which lines are the supply and then I went to look at basket controls and started messing with the tool knob and it pushed the opposite way I had been trying. It has three fixed positions and center is the off and away from bucket it makes the hissing noise "like you said" by outrigger/dump valve, and bring knob toward bucket and saw works!!!!

BUT, my upper controls are still half the speed as the lower controls. And as I operate from lower controls I get a hissing noise out of lower control bank. And when I operate from basket controls the outrigger/dump valve hisses.
Sorry for the little goose chase there on the tool circuit. But I think were getting somewhere with the hissing noises and possible restrictions. Good to know the tool circuit is working cuz that was just an extra brain scrambler. And I also used the saw to cut a 2in branch that was close so it does have torque and wasnt just spinning. And the tool circuit operating made zero noises besides the chain spinning.

 

[Matt Coolen]

Write something on that knob!!! Lol. That's a good one, I have been guilty of that myself.
Still sounds like you may have a flow restriction someplace.

 

[Diy mechanic mike]

Yeah I'll forsure mark that valve. Haha. And now that I've been thinking more about it, one of the hoses I replaced that hooks to the outlet port on lower control bank to the rotation coupler down in turret, I believe when I took old hose to napa to get one made. I think I remember them telling me they didn't have a fitting that match my threads so they put a fitting on and gave me a adapter to fit the control port. But I think the crimp on fittings' orfice was smaller diameter then the old hose. They told me it shouldn't make much of a differance which I was questionable about but went with it. I think the i.d. of original orfice was 3/8" and the fitting they put on had a 1/4" orfice. Could this orfice issue be causing all this?

 

[Matt Coolen]

Definitely. Any orifice will create some restriction. Your hydraulic pump is probably not very high flow or pressure, if I had to guess, likely 2200 to 2500 psi and probably 6-8 gpm. Now try and push that through a 1/4" hole. Pressure will remain the same, but flow rate will drop off.
Think of the garden hose again, typical i.d. is 5/8". Fill a bucket up and time it, just with the hose. Dump the bucket up and do it again, but this time, to reduce the outlet of the hose, put a washer with a 1/2" hole over it and fill the bucket again. Did you get wet?
Which time took longer to fill the bucket?
So, all this means is that, yes, the smaller inner dimension of that fitting will cause your issue, because now you are restricting flow, and it need to travel the length of the boom before it meets resistance again and makes your cylinders move, just like the hose with the washer over it filling the bucket.
Your hydraulics will have the same power, but less speed.
Make sense?

 

[Diy mechanic mike]

Yes totally makes sense. And your garden hose comparison is great. I do alot of gardening so I play with garden hose stuff alot. So if I were to use it with this restricted line would it cause any issues with the system becides just being slow. Like any back pressure on pump or anything? I have a small trim job at my house I'd like to do before I go and replace that line. But if you think I should change it out first I'll do that because I dont want to cause any issues with the system.
And again thanks alot for your professional input. It's very much appreciated.

Thanks,
Mike

 

[Matt Coolen]

I wouldn't worry about it too much, just make sure the oil is not getting hot as you're using the truck, restrictions will cause heat. But I dont suspect you would be using it enough to worry about. Would be more of a concern on an excavator or something like that, where the hydraulic load is significant.
No worries about back pressure on pump, that's what it's made for.

All the best to you and yours
Matt

 

[Diy mechanic mike]

Ok I wont worry about the line then. I'll just make sure I make note in my manual of that hose fitting orfice being the cause of my slow bucket controls. And next time I have to fix something like a hose I'll add that to the list. And honestly the bucket controls being slower almost seems like a safety restriction so I'm not jerking the lift around with my weight in bucket cuz when operating from lower controls without me in it, the controls are almost too good and I have to really concentrate on not moving lever to fast but when I'm in bucket using those controls I dont have to ease into the lever as much since they are slower. So end of the day my wrist isn't as worn from straining to ease into the levers, so I'm not jerking myself and bucket around. And btw I used the truck yesterday for about 3hrs doing some trimming with the saw, and the hydraulic oil got warm (90°-100°f if I were to guess)to the touch at the saw couplers but not hot or anything. But the temp outside was 40°-50°f so next summer when we hit 80°-90°f I'll have to recheck that if I haven't changed the line out.
If it were getting too "hot" as you mentioned, do you mean so hot it's untouchable or touchable but not comfortable?? Just need a referance for when it warms up outside and I can check to be sure there isnt too much heat build up.
And once again thanks for your input/knowledge sharing here, very much appreciated. These service manuals just dont give enough in-depth info on certain things. Haha.

Thanks,
Mike