1990 JGL 40H boom lift Help please!

[wisco]

Hello forums! i am new to these lifts just bought a used one for what i think is a good deal. obviously it has some problems that i hope you guys can take the time to answer.


1. my hydo fluid is white/milky i figure its water.. How did it get in? i have no visible leaks anywere, and how do i got along changing it? ive searched for a drain plug but no dice.

2. i know its old but when engaging into forward or reverse it is very very jerky and harsh and when you stop, it stops on a dime and bounces the entire lift. also on raising it up after about 20 feet it begins to stutter going up causing the machine to bounce pretty hard back and fourth.


3. . when ever i go to use my sterring 50% of the time my left turning dosent work. you can phisiclly see its trying to move but dosent have enough juice to do it. even while moving it wont work. im not sure if its a hydo problem or electrical. like i said the fluid is whiteish yellow and low about an inch on the sight glass.


4. last question. in my controll box when i open it on the back wall of the box is a bolt with 3 black wires that split of and go places but one has what looks like a fuse,capacitor or small battery looking thing that is must of been pulled out from somewere. its the only piece that looks like this in the box.


i know its alot of questions and im thanking everyone in advanced for the help.

 

[willie59]

Welcome to the forum wisco. :usa

It's going to take a while for us to sort through this, so stick around and be patient. First of all, a little more info about your machine. What engine does it have? I assume you have electric proportional controls at platform controls, are they PQ controllers or OEM controllers? And what proportional valves does your machine have, Bertea, Racine, or Vickers?

As for the hydro tank, it should have a drain plug in the bottom, albeit a small plug, will take a while to drain tank, I use a small electric pump to drain these things myself. Access to drain plug may be a small hole in thick plate that makes turret base of machine.

 

[wisco]

wow this will take me time to. so when you say you pump it out, i take it that wont get the oil out of the lines? if so what is my best bet on changing the hydro oil out from the lines? also im not very familiar with lifts. so bare with me. ive seen id tags on the engine so i know i can find that one. But what about the proportional valves? and the controller? looks old and in bad shape.. worse then the entire machine.

 

[wisco]

That is the In bad shape control box and the lower picture is inside that control box that was unplugged from somewhere and cant seem to locate it. wiring diagram inst helping, at least not the one i have. again thanks for the time

 

[willie59]

Those are PQ controllers. Now, what engine do you have and what type of proportional valves? Be patient, it's gonna take a while for us to sort through your problems.

 

[wisco]

well thats the problem how to i Id my proportional valves? ive seen tags on the motor so that shouldnt be hard were are my P valves or how can i id them?

 

[wisco]

the engine says KHD DEUTZ

 

[wisco]

Bump>>.

 

[willie59]

Those are Vickers proportional control valves.

 

[willie59]

The proportional valves control drive, boom lift, and boom swing.

 

[wisco]

ok so i know what the engine is and the valves. whats my next step. what would be the best way to flush out my hydro fluid from the system? i looked for the bolt under the tank but its solid steel?

 

[willie59]

The reason you need to know what controls are at platform, what engine, and what proportional valves, is the diagrams are different and for when you need to order parts.

If you don't have a drain plug, then your alternative is siphon (which would take a long time), or some form of pump. I use one of these,

http://www.grainger.com/Grainger/SHURFLO-Flexible-Impeller-Pump-4UN25?Pid=search

As was mentioned previously, you can't get all the oil from the system, still a lot of oil trapped in components. At best, change what's in tank, run it for some hours using all functions, change oil again until it is fairly clear.

 

[wisco]

if i decide to crack a low hydraulic line to get as much out as possible will i need to bleed the system?

 

[willie59]

You can crack or remove as many hoses on the machine as you wish, still won't get all the oil that's in components, lot of stuff to those machines, especially what's in the cylinders. But you won't have to bleed anything, things should resume normal when you fill tank and start operating functions.

 

[wisco]

what is the capacity of the hydraulic system? ive pulled close to 25 gallons out already, i need to know how many gallons of new oil i should use... and what is the best oil to run in my machine? and hydro oil? i can i get it at a hardware store? or is it specific

 

[willie59]

Hydraulic tank is 35 gallons. Total hydraulic system including tank is 70 gallons. Like I said, lot of oil in trapped in system that you can't get to by draining tank. As for the oil, I use AW hydraulic oil. Since you're in Wisconsin, AW 32 or AW 46 will work fine, no real specific oil required, just a good quality oil will work.

 

[wisco]

one more Q where would be the best place to crack a hose to get oil out from the lift and swing portion?

 

[wisco]

thanks for all the help by the way. im gonna replace as much fluid as i can. see if that helps my problems with steering and lifting. but still need to figure out why the driving is so harsh on the machine, i have cleaned up and lightly greased the controls but it starts and stops so violently. not very safe.

 

[willie59]

It may take some time to sort out your various issues wisco, but you still need to get some clean oil in the system, that's a given. Be sure and replace the filter inside the tank as the filter media can retain water. You can use an aftermarket filter, such as Wix 51434.

As for your drive problem, likely a problem with the PQ controller for drive. Two questions, 1) does the wiring harness for each controller have a white plug connection? And 2) does swing work smoothly through the range of movement of control lever?

 

[wisco]

were can i find a decal kit for this controller. i want to replace them because of the wear and tear. i got a quote on a replacement box just the shell and they told me $700 only for the box no switches or controlls does this seem right?