Troubleshooting
80Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| Allmand TLB fails to move under power | Parking brake set | |
| Allmand TLB fails to move under power | Dump Valve engaged | |
| Allmand TLB fails to move under power | Inadequate oil level in hydraulic reservoir | |
| Allmand TLB fails to move under power | Control pedal, or linkage, broken or loose | |
| Allmand TLB fails to move under power | Inadequate oil flow through suction strainer | |
| Allmand TLB fails to move under power | Hydrostatic pump failure | |
| Allmand TLB fails to move under power | Drive motor failure | |
| Allmand TLB moves in neutral | Control pedal neutral centering device broken or out of adjustment | |
| Engine running, voltmeter reading 13.5 to 14 volts | Normal condition | |
| Engine running, voltmeter reading less than 13.5 volts or more than 14 volts | Alternator or regulator malfunction | Contact dealer |
| Won't start, voltmeter reading 12 to 12.5 volts | Weak battery | Charge battery |
| Won't start, voltmeter reading less than 12 volts | Weak battery or defective battery cell | Charge or replace battery |
| Stopped, excessive current draw | Short circuit | Inspect system |
| Slow steering, hard steering, or loss of power assist | Worn or malfunctioning pump | Replace pump |
| Slow steering, hard steering, or loss of power assist | Stuck flow divider in gear pump | Replace flow divider cartridge in gear pump |
| Slow steering, hard steering, or loss of power assist | Malfunctioning relief valve allowing system pressure to be too low | Replace the relief valve |
| Slow steering, hard steering, or loss of power assist | Overloaded steering axle | Reduce the load |
| Slow steering, hard steering, or loss of power assist | Leaking or kinked load sensing signal line | Correct |
| Slow steering, hard steering, or loss of power assist | Malfunctioning priority valve | Check spring and sticking spool; Check damping orifices in both ends of main bore for debris; Check system pressure at SCU inlet for proper system pressure; If not, correct replace priority valve relief cartridge |
| Slow steering, hard steering, or loss of power assist | Air in the system due to low level of oil, cavitation of pump, leaky fitting, pinched hose, etc. | Correct as needed |
| Wander — vehicle will not stay in a straight line | Worn mechanical linkage | Repair or replace |
| Wander — vehicle will not stay in a straight line | Bending of linkage or cylinder rod | Repair or replace |
| Wander — vehicle will not stay in a straight line | Loose cylinder piston | Repair or replace |
| Wander — vehicle will not stay in a straight line | Severe wear in steering orbitrol | Repair or replace |
| Drifts — veers slowly in one direction | Worn or damaged steering linkage | Replace linkage and align front end |
| No loader lift or bucket rollback | Inadequate pressure | Inspect, clean or replace relief valve |
| No loader lift or bucket rollback | Fluid flow to loader cylinders too high or too low | Inspect or replace priority valve |
| No loader lift or bucket rollback | Cold hydraulic fluid | Warm hydraulic fluid by running engine |
| Inappropriate lift speed | Low engine R.P.M. | Move throttle control to fast position to increase R.P.M. |
| Slip — slow movement of steering wheel fails to cause any movement of steered wheels | Leakage of cylinder piston seals or accessory valve between cylinder line or ports | Replace seals or accessory valve |
| Slip — slow movement of steering wheel fails to cause any movement of steered wheels | Worn steering control unit meter | Replace steering control unit |
| Temporary hard steering or hang-up | Thermal shock | Check unit for proper operation and cause of thermal shock |
| Erratic steering | Air in system due to low level of oil, cavitation of pump, leaky fitting, pinched hose, etc. | Correct condition and add fluid |
| Erratic steering | Loose cylinder piston | Replace cylinder |
| Erratic steering | Thermal shock damage | Replace steering control unit |
| Erratic steering | Sticking flow control cartridge in gear pump | Replace flow control cartridge or gear pump |
| "Spongy" or soft steering | Air in hydraulic system. Most likely air trapped in cylinders or lines | Bleed air out of system |
| "Spongy" or soft steering | Low fluid level | Add fluid and check for leaks |
| Free wheeling — steering wheel turns freely with no feeling of pressure and no action of steered wheels | Steering column upper shaft is loose or damaged | Tighten steering wheel nut |
| Free wheeling — steering wheel turns freely with no feeling of pressure and no action of steered wheels | Lower splines of column may be disengaged or broken | Repair or replace column |
| Free wheeling — steering wheel turns freely with no feeling of pressure and no action of steered wheels | Steering control unit meter has a lack of oil. This can happen on start-up, after repair, or long periods of non-use | Usually starting engine and allowing hydraulic oil to circulate will cure the problem |
| Free wheeling — steering wheel turns freely with no feeling of pressure and no action of steered wheels | No flow to steering control unit — low fluid level | Add fluid and check for leaks |
| Free wheeling — steering wheel turns freely with no feeling of pressure and no action of steered wheels | No flow to steering control unit — ruptured hose | Replace hose |
| Free wheeling — steering wheel turns freely with no feeling of pressure and no action of steered wheels | Internal steering control unit damage due to "Thermal Shock" | Replace the steering control unit |
| Free wheeling — steering wheel turns with slight resistance but results in little or no steered wheel action | Cylinder piston seal blown out | Determine the cause; Correct the cause and replace the blown seal |
| Excessive free play at steering wheel | Loose steering wheel nut. Steering column shaft worn or damaged. There should be very little play in the unit itself | Repair or replace steering wheel connection or column |
| Excessive free play at steered wheels | Broken or worn linkage between cylinder and steered wheels | Check anchor points in steering linkage between cylinder and steered wheels |
| Excessive free play at steered wheels | Leaking cylinder seals | Replace cylinder seals |
| Steering unit locks up | Large particles in meter section | Clean the unit |
| Steering unit locks up | Insufficient hydraulic power | Check hydraulic power supply |
| Steering unit locks up | Severe wear and/or broken pin | Replace the unit |
| Steering unit locks up | Thermal shock | Replace the unit |
| Steering wheel oscillates or turns by itself | Parts assembled wrong. Steering unit improperly timed | Correct timing |
| Steered wheels turn in wrong direction when operator activates steering wheel | Lines connected to wrong ports | Reconnect lines correctly |
| Steered wheels turn in wrong direction when operator activates steering wheel | Lines connected to wrong steering cylinder ports | Reconnect lines correctly |
| Slow lift or roll back, loss of power | Worn or malfunctioning pump | Repair or replace pump |
| Slow lift or roll back, loss of power | Stuck relief valve cartridge | Repair or replace |
| Slow lift or roll back, loss of power | Worn pump allowing system pressure to be less than specified | Repair or replace pump |
| Surging of loader and bucket actions | Air in the system due to low level of oil, cavitation of pump, leaky fitting, pinched hose, etc. | Determine the cause and correct the problem |
| Surging of loader and bucket actions | Worn, or binding of, mechanical linkage | Repair or replace linkage |
| Surging of loader and bucket actions | Bending of linkage or cylinder rod | Repair or replace |
| Surging of loader and bucket actions | Loose cylinder piston | Repair or replace |
| Loader and bucket actions too slow | Cold hydraulic fluid | Warm fluid with engine at idle speed |
| Loader and bucket actions too slow | Engine speed too slow | Open throttle |
| Loader and bucket actions too slow | Oil leaking past control valve | Repair or replace worn section |
| Loader and bucket actions too slow | Oil too heavy | Use recommended oil |
| Loader and bucket actions too slow | Pump damaged or worn | Repair or replace pump |
| Loader and bucket actions too slow | Oil leaking past cylinder seals | Replace seals |
| Loader and bucket actions too slow | Dirty return oil filter | Replace return oil filter |
| Loader fails to hold up a load | Faulty relief valve | Clean or replace relief valve |
| Loader fails to hold up a load | Broken or leaking lines | Replace defective hose and check for leaks |
| Loader fails to hold up a load | Dirty hydraulic oil | Drain and refill oil, replace filter |
| Loader fails to hold up a load | Oil leaking past cylinder seals | Replace seals |
| Loader fails to hold up a load | Oil leaking past control valve | Repair or replace worn section |
| Oil overheating | Faulty relief valve | Clean or replace relief valve |
| Oil overheating | Dirty oil | Drain, refill oil, replace filter |
| Oil overheating | Partially plugged suction strainer | Drain oil, clean suction strainer, and refill with new oil |
| Oil overheating | Control valve held open too long | Return control to neutral position when not in use |
| Oil overheating | Worn pump | Replace pump |
| Oil overheating | Relief valve set too low | Reset relief valve correctly |
Fault codes and symptom→remedy steps extracted from this unit’s service/owner documentation; verify against the official manual before servicing. Showing the first 80 of 84 entries.
Available documents
Service manual
About
Allmand TLB 425 ESL — light tower. Specifications and parts compiled from manufacturer documents.