JCB loadall 550-170 hydraulics dead

[Newguy]

Hi everyone,
A friend of mine has a 2007 JCB 550-170 telehandler which was working fine when they finished their job and plugged it for the night, the next morning the temperature was like -30 however the machine starts right away but all the hydraulics are dead and nothing is working, no steering, no transmission forward or reverse, no boom or outriggers, even the fan which is run by a hydraulic motor does not work, the owner told me that they checked the hydraulic oil (the boom is still raised a little but all sections are retracted) and they added quite a bit of oil, so when i checked the hydraulic oil the next day there was excessive oil in system but iam not sure that it's the issue, there's two warning lights on the dash the first is a battery light, so iam thinking the alternator needs to be replaced or rebuilt, the owner said it's been on for over a month! the second light is a gear with a drop of oil inside of it, we checked all fuses they were all OK, there's no broken hoses and no visible leaks on the machine and it looks in fairly good condition, so the first thing that comes to mind is the pump, however i haven't done any pressure tests so far as the weather is brutaly cold outside and the machine cannot be transported with the boom raised, any idea if this is electrical or a faulty solenoid somewhere or maybe the hydraulic system is air locked! there's another issue with this machine which is the engine lacking power, even with no transmission and the hydraulics dead the engine is barely picking up RPM with the pedal literally to the metal! also when i riv the engine i can't hear the turbo spool, the machine has a JCB 4.4L Tier 3 SE Engine.
Any ideas or tips would be much appreciated
Thanks.

 

[jcb jeff]

This will either be the vibration damper between the engine and the bevel box or a major fail of the bevel box drive gears .
Go under neath and remove the two oblong rubber bungs from bevel box and transmission bell housing.
Keeping your fingers out of the way start the engine both the vibration damper and the torque converter should be turning with the engine running.
The damper normally starts to make a noise before it brakes up usaly on start up and stopping like a rattle metal on metal sound.
To change the damper this can be done on sit need to remove lower engine cowling and then remove engine only from the bevel box and replace coupling which is bolted to the flywheel.

 

[Newguy]

This will either be the vibration damper between the engine and the bevel box or a major fail of the bevel box drive gears .
Go under neath and remove the two oblong rubber bungs from bevel box and transmission bell housing.
Keeping your fingers out of the way start the engine both the vibration damper and the torque converter should be turning with the engine running.
The damper normally starts to make a noise before it brakes up usaly on start up and stopping like a rattle metal on metal sound.
To change the damper this can be done on sit need to remove lower engine cowling and then remove engine only from the bevel box and replace coupling which is bolted to the flywheel.

hank you very much Jeff, this makes lots of sense, i got the repair manual yesterday and been reading every section, but couldn't find anything that could cripple both the hydraulic system and the transmission in the same time, i will try to go to the job site if the weather improves and look at the machine and will update on my findings, i contacted JCB on how to lower the boom and the service guy said that i had to support the boom and then undo the two lift cylinder hoses slowly and warned me of a considerable amount of hydraulic oil shooting out the cylinder/ lines, this doesn't make any sense to me because the moving boom is the purpose of this machine, so someone should have thought that the hydraulic system might fail with the boom raised?? anyway i don't see myself doing that, i think i'll just pull the cylinder pin from the boom side and lower both so we can get the machine to the shop rather than working out in the cold.
Your help is greatly appreciated :salute

 

[jcb jeff]

To lower the boom you will have check valves fitted as long as its the same as here in the uk .
If you just pull the pipes off you still wont get the arm to lower as these valves prevent this until you supply oil to the check valve from the valve block as it needs pressure to lift the relief valve off its seat to allow the oil to flow thats why they are hose burst check valve as the name says if the hose burst or like thay said take the hose off the boom will stay where it is or the whole lot will go south very quick.
The only safe wat to carry this out with dead hydraulics would be to have some means of lifting the boom with another machine or crane so as to take the pressure off the check valves and then unscrew them slowly as to vent oil .
Once you have removed them from the ram cylinder with the other machine you will be able to lower the boom to the ground or onto timber off of the chassis to support for transport,you will get a lot off oil flow out of these valves as you are emptying out the cylinder lift ram x 2 so will need to catch the oil.
Remeber the check valves will have pressure on them which will injure you unless you lift the pressure off them by lifting the boom with a crane about and 1" or so .
f

 

[Newguy]

To lower the boom you will have check valves fitted as long as its the same as here in the uk .
If you just pull the pipes off you still wont get the arm to lower as these valves prevent this until you supply oil to the check valve from the valve block as it needs pressure to lift the reliefView attachment 163630 valve off its seat to allow the oil to flow thats why they are hose burst check valve as the name says if the hose burst or like thay said take the hose off the boom will stay where it is or the whole lot will go south very quick.
The only safe wat to carry this out with dead hydraulics would be to have some means of lifting the boom with another machine or crane so as to take the pressure off the check valves and then unscrew them slowly as to vent oil .
Once you have removed them from the ram cylinder with the other machine you will be able to lower the boom to the ground or onto timber off of the chassis to support for transport,you will get a lot off oil flow out of these valves as you are emptying out the cylinder lift ram x 2 so will need to catch the oil.
Remeber the check valves will have pressure on them which will injure you unless you lift the pressure off them by lifting the boom with a crane about and 1" or so .
fView attachment 163630

Hi Jeff,
Thank you very much for your help, your diagnostics were dead on in regard to the hydraulics, first off i replaced the alternator with a brand new one from JCB which took care of the battery light but the hydraulics problem was not solved, so i had the owner sit in the cab and i went below and removed the dust covers off the power train assembly and asked the owner to start the engine, sure enough the torque convertor was not turning, so i asked the owner to shut it off and looked around, there was a shaft which connects to a receiver piece on the engine side (if i remember correctly ) and the spline on it was completely hooped, so this was the cause of the whole problem.
As for the engine lacking power problem i checked the combustion exhaust temperature with a laser thermometer and found that one injector had noticeably less heat that the other 3, and also the turbo still didn't spool so i was going to do further investigation on that once the main problem is fixed.
I did quote the owner to replace the damaged parts using the method you recommended by removing the engine only but i was going to remove the lift cylinders pins to lower the boom ( instead of venting oil through the hoses and check valves) and then transport the machine to my shop to perform the repairs there, well the next morning he calls me and asks if we can weld the pieces together!! of course i recommended strongly against it and asked why would he want to do something like that instead of the proper repair, he replied that he's a little short on cash and he wanted to lower the boom so he could transport the machine back to his yard, and i never heard from him again in regards to this machine !
Sorry it took that long to respond but my computer was down and i had to look for a mechanic

 

[jcb jeff]

Looks as if you saved a time and hassle there then.
No worries im glad the info was of help.
Jeff

 

[Newguy]

I

Looks as if you saved a time and hassle there then.
No worries im glad the info was of help.
Jeff

I believe i did thanks to you, not fund of patching up stuff especially if it's new like this one and he paid a good chunk of money for it

 

[Kobus Oosthuizen]

Hi

I'm helping someone with a 541-70 Loadall, I've got almost the same problem, but the hydraulics are fine, but it won't go forward or reverse. He has replaced the selector next to the steering wheel, still the same.

if you play with the selector it starts going after a while but still not as it should. have you got any ideas?

 

[jcb jeff]

Hi

I'm helping someone with a 541-70 Loadall, I've got almost the same problem, but the hydraulics are fine, but it won't go forward or reverse. He has replaced the selector next to the steering wheel, still the same.

if you play with the selector it starts going after a while but still not as it should. have you got any ideas?

 

[jcb jeff]

With regards to drive issue i would check things like you have enough oil and of the correct grade,electrical fuses and relays.
Do you have any drive in any gears in any direction?
May be start with serial number which helps to pin point model of machine.

 

[Kobus Oosthuizen]

Hi Jeff

oil level is fine, it's got the jcb spec oil in, we have found some wiring that is damaged so running around to see what goes where. There are no forward gears and no reverse gears.
this is the serial number we found inside the cab 61450, and here is the chassis number if it will help JCB5ADKGV1532454.

 

[jcb jeff]

Check wiring on the dump circuit there are buttons on the loader joystick which allow you to disconnect drive so as to put into neutral tese often rub the wires through at the base of the lever through the tube.You could try disconnecting the switch wiring plug at base of lever.
To give no drive either you have major gearbox failure or i would think electrical is your fault.
There are two types 1 uses relays that control f / n/ r and then you have a ecu control this is either bolted to the top of the solenoids on gear box or is bolted under the seat base .

 

[jcb jeff]

How many gears have you got this is a ps750 gearbox i guess with either 4 or 6 speed powershift?
Also make sure that your handbrake switch is working correctly as this will also cause it not to drive,

 

[Kobus Oosthuizen]

Hi Jeff

Sorry i am only getting back to you now, I've been running around.
it is a 4 speed, the owner drained out all the oils and then filled it again, then the machine ran for about 20 meters and stopped again, could it maybe be that the charge pump inside the gearbox is cavatating? or like you said maybe serious damage inside the gearbox. i don't think that draining the oil could reset something on the electrical side, but i will have another look. this machine has got 6000 hours on now and it started with this gearbox problem after 1000 hours

 

[jcb jeff]

In that case i would say you need to start with the basics correct amount of oil correct grade and has any debris been found in the strainer in the gearbox under the oval plate with two bolts.
Next will be to put a gauge on the transmission you should have about 9-11 bar on main test port ontop of gearbox.
See what you get then report back.