Relief settings, circuit routing and component rebuilds for the Takeuchi TB250 mini excavator are settled in one place by this 352-page Takeuchi TB250 service manual PDF, factory publication CK7E006. Its hydraulic circuit diagram traces the pumps, control valve and pilot circuit, and the electric circuit and wire harness diagrams map the electrical side of the machine. Disassembly chapters take apart the travel motor's 2-speed mechanism and parking brake, the slew motor's anti-rebound valve and the swivel joint, while troubleshooting charts trace symptoms such as veering to one side back to the faulty component. Set boom and arm relief to 21.0 +1.3/-0.4 MPa. Pilot relief sits at 3.4 ±0.3 MPa. If your undercarriage is up for inspection, the service standards give you the figures for track rollers, carrier rollers, drive sprocket, idler and pin and bushing clearance. Bookmarks keep chapters close, and the pages print cleanly as a working copy.
What's Inside This Takeuchi TB250 Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety | 3-12 | Safety Alert Symbol, Safety Label, Safety Precautions, Cautions When Working, Handling of Seals |
| Service Data | 13-81 | Dimensional Drawing, Specifications Tables, Lubricant and Fuel Chart, Performance Criteria, Tightening Torque, Hydraulic Circuit Diagram, Electric Circuit Diagram |
| Function | 82-105 | Piston Pump, Gear Pump, Control Valve, Pilot Valve, Proportional Control Solenoid Valve, Emergency Shut-Off Valve, Cylinders, Travel Motor |
| Service Standards | 107-109 | Carrier Roller, Track Roller, Drive Sprocket, Idler, Clearance for Pin and Bushing |
| Drive System | 110-118 | Removing the Engine, Removing the Radiator and Oil Cooler, Removing the Hydraulic Pump, Removing the Fuel Tank, Adjusting the Throttle Lever |
| Travel System | 119-123 | Removing the Crawler Belt, Installing the Crawler Belt, Removing the Steel Crawler, Installing the Steel Crawler, Removing the Carrier Roller, Removing the Track Roller |
| Slew System | 124-126 | Removing the Slew Motor, Removing the Slew Bearing, Removing the Swivel Joint |
| Upper Frame | 127-132 | Removing the Upper Frame, Removing the Covers, Removing the Cab |
| Control System | 133-143 | Removing the Lever Stand, Adjusting the Control Cable, Hydraulic Pilot Unit, Blade Lever, Lever Stand, Control Box R, Control Box L |
| Attachments | 144-149 | Removing the Attachments, Removing the Bucket, Removing the Link, Removing the Arm, Removing the Boom, Removing the Swing Bracket, Removing the Dozer Blade |
| Hydraulic Tank | 150-154 | Tank, Pipe Assembly, Suction Filter, Return Filter, Sight Gauge, Air Breather |
| Hydraulic Pump | 155-178 | Shaft, Swash Plate, Cylinder Block, Gear Pump, Housing, Solenoid Valve |
| Control Valve | 179-190 | Tie Rod, Bucket Section, Boom Section, Right Travel Section, Inlet Housing, Arm Section |
| Pilot Valve | 191-225 | Casing, Plate, Spool, Push Rod, Spring Seat, Adjusting Nut, Proportional Control Solenoid Valve, Pilot Valve (Auxiliary), Pilot Valve (Travel), Proportional Control Solenoid, Case, Cover, Plug, Seal, Grease Cup, Damping Spring |
| Solenoid Valve (1-Section) | 226-228 | Plug, Solenoid Valve, Spring, Spool, Body |
| Solenoid Valve (2-Section) | 229-231 | Solenoid Coil, Push Rod, Cap Screw, Checking the Parts, Assembly |
| Cylinders | 232-248 | Boom Cylinder, Arm Cylinder, Bucket Cylinder, Dozer Blade Cylinder, Swing Cylinder, Piston Rod Assembly, Leak Test, Bleeding Air From the Hydraulic Cylinder, Assembly |
| Travel Motor | 249-263 | Hydraulic Motor, Counterbalance Valve, 2-Speed Mechanism, Reduction Gears, Parking Brake, Inspection, Adjustment |
| Slew Motor | 264-282 | Hydraulic Motor, Relief Valve, Make-Up Valve, Anti-Rebound Valve, Parking Brake, Timer Valve, Reduction Gears, Brake Valve |
| Swivel Joint | 283-287 | Thrust Ring, Slipper Seal, Dust Seal, Snap Ring, Backup Ring, Use Limit for Parts, Inspection After Assembly, Assembly |
| Air Conditioner | 288-291 | Removing Upper Case, Replacing Blower Motor, Replacing Evaporator, Replacing Expansion Valve, Replacing Heater Core, Maintenance, Troubleshooting |
| Troubleshooting | 292-351 | Overall Machine, Traveling, Boom Swing, Dozer Blade, Auxiliary Hydraulics, Piston Pump, Gear Pump, Control Valve, Proportional Control Solenoid Valve, Travel Motor, Slew Motor, Air Conditioner, Overall Machine (No Operation Is Possible., Boom, Bucket, Slew and Arm Fail to Move or Are Too Slow.) |
| Engine | 352 | Mounted Engine |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Boom relief valve pressure | 21.0 +1.3/-0.4 MPa | p. 23 |
| Arm relief valve pressure | 21.0 +1.3/-0.4 MPa | p. 23 |
| Engine oil pan capacity | Upper limit 7.4 L, Lower limit 4.0 L | p. 21 |
| Hydraulic hose Union nut (G) 1/8 | 9.8 +4.9 N·m | p. 33 |
| Hydraulic hose Taper thread (R) 1/8 | 11.8 ±1.2 N·m | p. 33 |
| Lubricant quantity | 1.0 L | p. 260 |
| Plug (G3/8) torque | 46 to 51 N·m | p. 261 |
| Proportional control solenoid valve pressure | 0 to 3.4 MPa | p. 336 |
| Engine Oil Capacity (Upper limit) | 7.4 L | p. 21 |
| Hydraulic Tank Capacity | 52 L | p. 21 |
| Engine Coolant Capacity | 12.4 L | p. 21 |
| Travel Reduction Gear Oil Capacity | 0.8 L | p. 21 |
Takeuchi TB250 Common Problems This Manual Covers
Takeuchi TB250 boom, arm, bucket and travel all operate but every hydraulic function has insufficient force
Check the hydraulic oil level first, and slowly loosen the air-bleeding plug to relieve tank pressure before opening anything, as page 152 warns. If the piston pump makes abnormal noise, suspect cavitation: grease suspect suction line joints to find the air leak and check the suction filter for clogging. Then measure main relief pressure against 21.0 MPa (page 17); tighten the setscrew gradually, and if pressure will not rise after 1/4 turn, repair or replace the valve.
Manual Section: Overall machine p. 295Right or left track will not travel at all while the other hydraulic actuators still work
Operate the boom (right travel, P1) or arm (left travel, P2) to rule out the pump and main relief. Release hydraulic pressure before disconnecting any hose (page 9). Gauge the travel pilot hose for 0 to 3.4 MPa with lever angle, then check for 21.0 MPa supply at the control valve discharge port following page 300. Remove the counterbalance valve plug and push the spool; it should move smoothly about 6 mm.
Manual Section: Traveling p. 299One track travels slower than the other and the machine veers to one side
Check crawler belt tension and clear any foreign matter caught in the belt. If spool operation is normal, swap the P1 and P2 discharge hoses; if veering flips sides, repair the pumps and replace the hydraulic oil or filter. Release internal pressure before breaking any line (page 9). Next swap the right and left travel main relief valves. With swivel joint and counterbalance valve clean, the travel motor reduction gears are the suspect.
Manual Section: Traveling p. 3012nd speed travel will not engage when the travel speed switch is pressed
Check the gear pump and clean the line filter if clogged, then measure pilot relief pressure against 3.4 ±0.3 MPa (page 23). Test the fuse, check 2nd speed switch continuity with a tester, and stop the engine before checking relay voltage at the solenoid, as page 304 directs. Release pressure before disconnecting the swivel joint hose (page 9), then look for 3.4 MPa supply with the 2nd speed switch on.
Manual Section: Traveling p. 304Slew turns the upperstructure slowly or lacks force compared to the specified slewing time
Time a slew cycle against the performance criteria first. Release hydraulic pressure before disconnecting any hose (page 9), then confirm 0 to 3.4 MPa slew pilot pressure and 19.6 MPa spool supply at the control valve, following page 307. Measure both slew relief valves against 19.1 +2.2/-0 MPa (page 23); adjust, or repair the valve if pressure will not rise. Then check the slew brake check valve and slew drive reduction gears.
Manual Section: Slewing p. 310Upperstructure slews in one direction only and right or left slew is not possible
Release internal hydraulic pressure before removing any valve (page 9). Swap the left and right slew relief valves; if slewing returns, repair or replace the relief valve. Inspect the check valves in the slew brake valve for foreign matter or sticking, since a contaminated check valve returns oil to tank. If those pass, suspect the pilot valve spool or the control valve spool on the dead side, following page 308.
Manual Section: Slewing p. 308Frequently Asked Questions
Why are the boom, bucket, swing, and arm slow or not moving?
If these functions are slow or fail to move, first check the gear pump that supplies hydraulic pressure to the pilot valve. Ensure the line filter is not clogged and clean it if necessary. Also, verify the fuse in the power supply circuit for the pilot solenoid valve and check the limit switch by moving the lever stand to the driving position. p. 297
How do I troubleshoot auxiliary hydraulics when proportional control is not working?
To troubleshoot proportional control, first check the operation of other actuators to isolate the fault. Then, inspect the proportional controller (see page 4-93 for disassembly). Finally, check the proportional control solenoid valve by fitting a pressure gauge to the hose disconnected from the control valve; if the pressure is between 0 and 3.4 MPa depending on the lever angle, the valve is normal. p. 336
What are the replacement specifications for engine oil and the oil filter on the Takeuchi TB250?
The engine oil pan requires Diesel engine oil (API: CD class, ACEA-E3, E-4 or E-5). The capacity is 7.4 L for the upper limit and 4.0 L for the lower limit. The oil should be changed every 250 hours after the first 50 hours of operation. p. 21
What is the procedure for bleeding air from the hydraulic cylinder?
After reassembling hydraulic devices, bleed the air by running the engine at low-idling speed for 10 minutes. Then, extend and retract each cylinder 4 or 5 times without reaching the stroke end while at low-idle. Finally, run the engine at high speed and repeat the extension/retraction 4 or 5 times, then return to low idle and extend/retract each cylinder 4 or 5 times up to the stroke end. p. 154
What is the tightening torque for the hydraulic pump fixing bolts on the Takeuchi TB250?
When installing the hydraulic pump, the fixing bolts must be tightened to 102 N·m. Additionally, apply molybdenum disulfide grease to the spline before installation. p. 115
What exactly do I receive with this Takeuchi TB250 Service Manual?
Instant PDF download. You get the full 352-page searchable Service Manual immediately after payment. Open it on your laptop, tablet, or phone right in the shop.
Is this Takeuchi TB250 Service Manual printable?
Yes. Print a single page or a chapter for your own shop use, on letter or A4.
