Troubleshooting
80Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| Control valve sticking or working hard | Damaged o-rings on valve spool | Repair control valve |
| Control valve sticking or working hard | Cylinder seals damaged | Repair cylinder seal |
| Control valve sticking or working hard | Damaged o-rings on valve drop check | Repair control valve |
| Control valve sticking or working hard | Broken oil lines | Replace hose |
| Control valve sticking or working hard | Loose hydraulic fittings | Tighten fittings |
| Control valve sticking or working hard | Oil leaks past seal | Replace seal |
| Control valve sticking or working hard | Faulty relief valve | Clean or replace valve |
| Control valve sticking or working hard | Dirty valve | Clean valve |
| Control valve sticking or working hard | Scored bore or bent spool | Replace valve section |
| Control valve sticking or working hard | Control linkage misaligned | Correct misalignment |
| Control valve sticking or working hard | Return spring broken or binding | Replace spring |
| Control valve sticking or working hard | Foreign matter in spool bore | Clean bore |
| Surging of loader and bucket actions | Worn or malfunctioning pump | Repair or replace pump |
| Surging of loader and bucket actions | Stuck relief valve cartridge | Repair or replace pump |
| Surging of loader and bucket actions | 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 pump linkage |
| Surging of loader and bucket actions | Bending of linkage or cylinder rod | Repair or replace pump |
| Surging of loader and bucket actions | Loose cylinder piston | Repair or replace pump |
| Slow lift or roll back, loss of power | Cold hydraulic fluid | Warm fluid with engine at idle speed |
| Slow lift or roll back, loss of power | Engine speed is too low | Open throttle |
| Slow lift or roll back, loss of power | Oil leaking past control valve | Repair or replace worn section |
| Slow lift or roll back, loss of power | Oil too heavy | Use recommended oil |
| Slow lift or roll back, loss of power | Pump damaged or worn | Repair or replace pump |
| Slow lift or roll back, loss of power | Oil leaking past cylinder seals | Replace seals |
| Slow lift or roll back, loss of power | Dirty return oil filter | Replace return oil filter |
| Slow lift or roll back, loss of power | Faulty relief valve | Clean or replace relief valve |
| Loader and bucket actions too slow | Worn or malfunctioning pump | Repair or replace pump |
| Loader and bucket actions too slow | Stuck relief valve cartridge | Repair or replace pump |
| Loader and bucket actions too slow | Worn pump allowing system pressure to be less than specified | Repair or replace pump |
| Loader and bucket actions too slow | 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 |
| Loader and bucket actions too slow | Worn or binding of mechanical linkage | Repair or replace pump linkage |
| Loader and bucket actions too slow | Bending of linkage or cylinder rod | Repair or replace pump |
| Loader and bucket actions too slow | Loose cylinder piston | Repair or replace pump |
| Loader and bucket actions too slow | Cold hydraulic fluid | Warm fluid with engine at idle speed |
| Loader and bucket actions too slow | Engine speed is too low | 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 and bucket actions too slow | Faulty relief valve | Clean or replace relief valve |
| 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 steering wheel | Broken or worn linkage between cylinder and steered wheels | Check anchor points in steering linkage between cylinder and steered wheels |
| Excessive free play at steering wheel | Leaking cylinder seals | Replace cylinder seals |
| Excessive free play at steering wheel | Large particles in meter section | Clean the unit |
| Excessive free play at steering wheel | Insufficient hydraulic power | Check hydraulic power supply |
| Excessive free play at steering wheel | Severe wear and/or broken pin | Replace the unit |
| Excessive free play at steering wheel | 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 steering cylinder ports | Reconnect lines correctly |
| Engine sounds like it is under load but frees when steering wheel is turned | O-rings in the load sense relief cartridge are worn or missing | Replace o-rings |
| Excessive free play at steered wheel | Leakage of cylinder piston seals or accessory valve between cylinder line or ports | Replace seals or accessory valve |
| Excessive free play at steered wheel | 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 |
| Temporary hard steering or hang-up | Air in system due to low level of oil, cavitation of pump, leaky fitting, pinched hose, etc. | Correct condition and add fluid |
| Temporary hard steering or hang-up | Loose cylinder piston | Replace cylinder |
| Temporary hard steering or hang-up | Thermal shock damage | Replace steering control unit |
| Temporary hard steering or hang-up | Sticking flow control cartridge in gear pump | Replace flow control cartridge or gear pump |
| Erratic steering | Air in hydraulic system. Most likely air trapped in cylinder or lines | Bleed air out of system |
| Erratic steering | Low fluid level | Add fluid and check for leaks |
| Erratic steering | Steering column upper shaft is loose or damaged | Tighten steering wheel nut |
| Erratic steering | Steering control unit meter has a lack of oil. This can happen in start-up, after repair, or long periods of non-use | Usually starting engine and allowing hydraulic oil to circulate will cure the problem |
| Spongy or soft steering | Air in hydraulic system. Most likely air trapped in cylinder or lines | Bleed air out of system |
| Spongy or soft steering | Low fluid level | Add fluid and check for leaks |
| Spongy or soft steering | Steering column upper shaft is loose or damaged | Tighten steering wheel nut |
| Spongy or soft steering | Steering control unit meter has a lack of oil. This can happen in 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 | No flow to steering control unit — Internal steering control unit damage due to "Thermal Shock" | Replace the steering control unit |
| Slip-slow movement of steering wheel fails to cause any movement of steered wheels | No flow to steering control unit — Low fluid level | Add fluid and check for leaks |
| Slip-slow movement of steering wheel fails to cause any movement of steered wheels | No flow to steering control unit — Ruptured hose | Replace hose |
| Slip-slow movement of steering wheel fails to cause any movement of steered wheels | No flow to steering control unit — Internal steering control unit damage due to "Thermal Shock" | Replace the steering control unit |
| Drifts-veers slowly in one direction | Overloaded steering axle | Reduce the load |
| Drifts-veers slowly in one direction | Leaking or kinked load sensing signal line | Correct |
| Drifts-veers slowly in one direction | Worn mechanical linkage | Repair or replace |
| Drifts-veers slowly in one direction | Bending of linkage or cylinder rod | Repair or replace |
| Drifts-veers slowly in one direction | Loose cylinder piston | Repair or replace |
| Drifts-veers slowly in one direction | Severe wear in steering orbitrol | Repair or replace |
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 106 entries.
Parts
13| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 74624 | AXIAL PISTON MOTOR | Motor | Amazon eBay FridayParts $35.59 | |
| D-034 | Right Fender next to Fuel Fill | Service part / kit | Amazon eBay $42.45 | |
| D-147 | On Directional Pedal | Service part / kit | Amazon eBay | |
| D-158 | Cover panel - upper left | Service part / kit | Amazon eBay | |
| D-179 | Right Frame Upright | Service part / kit | Amazon eBay $9.56 FridayParts $20.99 SinoCMP $689.00 | |
| D-189 | Frame Upright - right side | Service part / kit | Amazon eBay $5.00 | |
| D-190 | ROPS front left upright | Service part / kit | Amazon eBay $9.59 | |
| D-191 | Cover panel - lower right | Service part / kit | Amazon eBay $19.99 | |
| D-193 | Right Frame Rail ahead of Exhaust Pipe | Service part / kit | Amazon eBay | |
| D-194 | ROPS front right upright | Service part / kit | Amazon eBay $28.79 | |
| D-195 | Rear Fender-Left of Seat | Service part / kit | Amazon eBay FridayParts $82.95 | |
| D-196 | Left Side of Throttle Control | Service part / kit | Amazon eBay | |
| D-197 | Rear Fender-Right of Seat | Service part / kit | Amazon eBay $9.56 |
Service & wear parts shared with every machine that uses this engine. Confirm the exact part for your serial number.
Available documents
Operator's manual
Common questions
What engine does the Allmand TLB 6235 use?
The Allmand TLB 6235 light tower is powered by the Isuzu 3CD1 engine.
About
Allmand TLB 6235 — light tower. Specifications and parts compiled from manufacturer documents.