Hello This is my first post and i really need help

[choppper51455]

I have a 843 with no lift I have tilt if I move the lift pedal back and forth it will lift a little and stop . like something is stuck

 

[mllud]

I am not a bobcat owner. It sounds like your safety lockout isnt energizing the solenoid to open . Check the wire going your hydraulic control block. Troubleshoot your safety interlock system. Someone else will advise further. Mike

 

[Tazza]

I am not a bobcat owner. It sounds like your safety lockout isnt energizing the solenoid to open . Check the wire going your hydraulic control block. Troubleshoot your safety interlock system. Someone else will advise further. Mike

These machines have no safety coils, all mechanical..... It does sound like a safety device though as mike said. Check your pedal lock outs just to ensure they un-lock the pedal. If thats ok, check the linkages back to the control block. The relief would cause you to have no tilt either so that should be ok.
I'm pretty sure it has no coils.....

 

[skidsteer.ca]

These machines have no safety coils, all mechanical..... It does sound like a safety device though as mike said. Check your pedal lock outs just to ensure they un-lock the pedal. If thats ok, check the linkages back to the control block. The relief would cause you to have no tilt either so that should be ok.
I'm pretty sure it has no coils.....

No electric safety lock on this model, lucky you.
Either the pedals are not moving the valve spools enough, ( would have to be a serious linkage problem, or the mechanical lock beside your legs the seat bar pushes on is not releasing, both vary obvious extrenal checks)
Or you relief valve is shot and you have no hydralic pressure
or you pump is malfunctioning and you have no hydraulic pressure
Or you have a major bypass problem in one of you lift cylinders, or a mechaincal binding in a lift cylinder
Hook a 3000 psi pressure guage into you fron quick couplers, activate the aux flow and see what your pressure reads, you should have 2250 to 2750 psi depending on the spec fro that loader.
If it when like the flick of a switch, I'm betting on the relief valve broke or stuck open and therefore no hyd pressure.
Ken

 

[choppper51455]

No electric safety lock on this model, lucky you.
Either the pedals are not moving the valve spools enough, ( would have to be a serious linkage problem, or the mechanical lock beside your legs the seat bar pushes on is not releasing, both vary obvious extrenal checks)
Or you relief valve is shot and you have no hydralic pressure
or you pump is malfunctioning and you have no hydraulic pressure
Or you have a major bypass problem in one of you lift cylinders, or a mechaincal binding in a lift cylinder
Hook a 3000 psi pressure guage into you fron quick couplers, activate the aux flow and see what your pressure reads, you should have 2250 to 2750 psi depending on the spec fro that loader.
If it when like the flick of a switch, I'm betting on the relief valve broke or stuck open and therefore no hyd pressure.
Ken

The mechanical lock is ok it has a new pump on it I am a forklift mechanic and work on hyds so i know some to check the pressure dont you have to have that peace of gold (gauge) bobcat uses to load the hyd system? it also checks flow this machine also has high horsepower hyds on it i did notice on the back of the lift spool there is a coil dose anyone know what it is for? I will try to check the pressure with my gauge to make sure the relief is ok but i would think the tilt would not be working its pry something im overlooking the pedals are a little sloppy thanks for the info if you have anyother ideas let me know this thing is bitting me in the butt

 

[skidsteer.ca]

The mechanical lock is ok it has a new pump on it I am a forklift mechanic and work on hyds so i know some to check the pressure dont you have to have that peace of gold (gauge) bobcat uses to load the hyd system? it also checks flow this machine also has high horsepower hyds on it i did notice on the back of the lift spool there is a coil dose anyone know what it is for? I will try to check the pressure with my gauge to make sure the relief is ok but i would think the tilt would not be working its pry something im overlooking the pedals are a little sloppy thanks for the info if you have anyother ideas let me know this thing is bitting me in the butt

Oh, also you aux hydraulics is not locked on is it?
The 743 (not sure on the 843) you push the rh steering lever sideways to run your aux coupers. It has a detent and can stick to the right and stay locked in. Makes the hyd valve do goofy things like you mention. (I tend to forget this one because its electric over hyd on the newer machines and disenguages itself when the key is off, these types of hyd valves have 2 coils and not a linkage to the 3rd spool) You coil may be to combine the hi flow option into the hyd valve??
Your pressure would have to be pretty low to not lift the empty boom.
Ken

 

[choppper51455]

Oh, also you aux hydraulics is not locked on is it?
The 743 (not sure on the 843) you push the rh steering lever sideways to run your aux coupers. It has a detent and can stick to the right and stay locked in. Makes the hyd valve do goofy things like you mention. (I tend to forget this one because its electric over hyd on the newer machines and disenguages itself when the key is off, these types of hyd valves have 2 coils and not a linkage to the 3rd spool) You coil may be to combine the hi flow option into the hyd valve??
Your pressure would have to be pretty low to not lift the empty boom.
Ken

I just checked the aux detent again and the linkage tried to pry to get more travel and it didnt make any differance I did take the bucket off and it will lift slow at full rpms but it you step on the bobtach it stops I cant find my gauge so i will have to get a new one tommorw but i tried to turn the relife a little with no effect on lift the main relife i adjusted was on the back of the lift spool is that the main ?

 

[Tazza]

I just checked the aux detent again and the linkage tried to pry to get more travel and it didnt make any differance I did take the bucket off and it will lift slow at full rpms but it you step on the bobtach it stops I cant find my gauge so i will have to get a new one tommorw but i tried to turn the relife a little with no effect on lift the main relife i adjusted was on the back of the lift spool is that the main ?

That should be the main relief.
I guess there could be something stuck under the poppet in the relief, this would give you no pressure to the arms or bobtach.
So the right lever moves from left to right easily and when you let it go, it springs back to centre?

 

[choppper51455]

That should be the main relief.
I guess there could be something stuck under the poppet in the relief, this would give you no pressure to the arms or bobtach.
So the right lever moves from left to right easily and when you let it go, it springs back to centre?

the bobtach (tilt) works fine the lever stays in aux till i manually move it back to center

 

[Tazza]

the bobtach (tilt) works fine the lever stays in aux till i manually move it back to center

Sounds like your spring may be broken....
If you hold the aux in the centre, do your arms work correctly?
On some machines, there is a separate relief in the lift section that is there to protect the hoses from high pressure spikes.
Can you put your toe forward on the lift pedal, do the arms pull down and can you hear a squeal from the relief?
I am assuming your tilt still has full power? when the ram bottoms out you hear the relief squeal too?
If so, i really think its a problem with either the load checks (doubtful) or the relief for the lift section if fitted.
Does that make sense? if not, i can try and clear it up a bit for you.

 

[skidsteer.ca]

Sounds like your spring may be broken....
If you hold the aux in the centre, do your arms work correctly?
On some machines, there is a separate relief in the lift section that is there to protect the hoses from high pressure spikes.
Can you put your toe forward on the lift pedal, do the arms pull down and can you hear a squeal from the relief?
I am assuming your tilt still has full power? when the ram bottoms out you hear the relief squeal too?
If so, i really think its a problem with either the load checks (doubtful) or the relief for the lift section if fitted.
Does that make sense? if not, i can try and clear it up a bit for you.

When you just push your aux control a little right or left it returns to center by itself does'nt it?
It should only stick to the right when you push it hard to the right. It should center spring loaded otherwise.
Run you tilt cylinders to the end to see if they slow the motor down when they bottom out. If the engine slows and the relief squeals when they bottom then the tilt sound like its running at correct pressure.
Most loader I have worked on only had the "main relief" , there was not a separate one for lift and another for tilt. Lift, tilt and Aux all 3 spools ran the same pressure from the main relief valve.
Lets say when its barely lifting the boom that takes 300 psi. That 300 may be plenty to make the tilt appear to function normally.
If you idle the engine it should almost stall it if you bottom the lift, tilt or AUX functions They should all drag the motor down equally and noticably.
You need to get a guage in the systemm somewhere to see what the pressure is on each function. Then go from there.
Ken

 

[choppper51455]

When you just push your aux control a little right or left it returns to center by itself does'nt it?
It should only stick to the right when you push it hard to the right. It should center spring loaded otherwise.
Run you tilt cylinders to the end to see if they slow the motor down when they bottom out. If the engine slows and the relief squeals when they bottom then the tilt sound like its running at correct pressure.
Most loader I have worked on only had the "main relief" , there was not a separate one for lift and another for tilt. Lift, tilt and Aux all 3 spools ran the same pressure from the main relief valve.
Lets say when its barely lifting the boom that takes 300 psi. That 300 may be plenty to make the tilt appear to function normally.
If you idle the engine it should almost stall it if you bottom the lift, tilt or AUX functions They should all drag the motor down equally and noticably.
You need to get a guage in the systemm somewhere to see what the pressure is on each function. Then go from there.
Ken

Yes it does it returns and you have to push it harder to get it into detent working fine I have my gauge but pry wont be able to hook it up tonight I belive its pry a relief problem its not doggin down the engine I was looking at the flow charts and manual I just got and it shows the relief has two adjustment the high horsepower first then the main relief man the high horsepower adjustment look like a b@#$% to get to

 

[Tazza]

Yes it does it returns and you have to push it harder to get it into detent working fine I have my gauge but pry wont be able to hook it up tonight I belive its pry a relief problem its not doggin down the engine I was looking at the flow charts and manual I just got and it shows the relief has two adjustment the high horsepower first then the main relief man the high horsepower adjustment look like a b@#$% to get to

Ken - all the sections run at the same prssure, its just there to protect the system if a load gets dropped onto the bucket. When the line is full of oil it has nowhere to go and can exceed the hoses rated pressure asn maybe burst. Just a safety device, my 731 had one.