How Do You Fix 1-3500 Backhoe Loader With Broken Hydraulics?

Engineered for heavy machinery applications, such as the International Harvester 3500 backhoe loader, hydraulic systems operate by compressing an oil-based fluid through a series of pistons and hoses. Compressing the fluid inside the system generates exponential force, producing sufficient power to move mechanisms weighing thousands of pounds. Hydraulic systems often malfunction from a loss in fluid pressure, resulting from damaged pistons, pumps, seals or hoses. Tp fix a broken hydraulic system, all components must undergo a thorough examination.

Instructions

1

Check the fluid reservoir; the low fluid level will cause decreased pressure in the system, preventing the hydraulics from operating. Unscrew the hydraulic fluid reservoir cap, located on or adjacent to the hydraulic pump, with your fingers. Fill the reservoir to the full line with hydraulic fluid approved by International Harvester for use in the 3500 system. Replace the reservoir cap.

2

Inspect the hydraulic pump drive belt, attached to the hydraulic pump drive pulley. Pinch the top and bottom sections of the drive belt between your thumb and forefinger; tighten the belt if more than one-half inch of play is present in the belt. Loosen the pump-mounting bolts with a wrench. Place a metal bar between the side of the pump and a solid spot on the vehicle frame. Pull the top of the bar toward the pump while retightening the mounting bolts with the wrench.

3

Trace and check all hoses and hose connections for leaks. Wipe the hose fittings with a clean white cloth. Examine the cloth for traces of reddish oily fluid, indicating a loose fitting. Tighten any loose hose fitting with a wrench. Thoroughly inspect all hydraulic hoses for cracks, breaks or tears. Remove any compromised hydraulic hoses, with a wrench, and replace with new hoses.

4

Bleed the hydraulic pump and test the system. Open the bleeder valve on the pump with a wrench. Place the tractor in neutral and start the engine. Move all hydraulic system control levers through two complete cycles. Close the pump bleeder valve with the wrench. Move all hydraulic system control levers through one complete cycle. Piston or pump repair is indicated if any hydraulic mechanisms dont operate through the full range of motions.

5

Examine the hydraulic pump. Start the engine and remove the hydraulic fluid reservoir cap. Look down into the reservoir to see if the fluid is pumping through the system as indicated by the fluid swirling or churning inside the pump. If fluid is not circulating, the pump requires replacement.

6

Disassemble the pistons. Place a drain pan under the hydraulic fluid reservoir and remove the reservoir drain plug with a wrench. Disconnect the hydraulic hose fittings from both ends of the pistons with a wrench. Remove the piston mounting bolts with a wrench and work each piston from the tractor with your hands. Tap the mounting shroud with a rubber mallet, if necessary, to free the piston mount from the tractor.

7

Remove the bolts securing the piston collar to the piston cylinder with a wrench. Tap the piston collar with a rubber mallet until the collar breaks free of the cylinder. Pull the piston and spring from the cylinder with you hands.

8

Place a straight edge against the side of the piston rod to confirm the rod isnt bent. Examine the inside surface of the piston cylinder for gouges or deep or excessive scratches. If either the piston or cylinder exhibits these signs of wear, the entire piston must be replaced with a new unit. Obtain a piston rebuilding kit, containing new piston seals, piston spring and piston rings, for each piston in which the rod and cylinder both pass inspection.

9

Pull the rubber seals from the cylinder with your fingers. Remove the piston rings from the piston with a pair of piston ring pliers. Buff the piston and the inside of the cylinder with fine-grade steel wool. Wipe the piston and cylinder with a clean cloth. Flush the cylinder and position with new hydraulic fluid.

10

Coat the new seals, supplied with a rebuilding kit, with new hydraulic fluid. Install the seals on the cylinder in the same orientation as the ones that were removed, according to the instruction supplied with the kit. Coat the new piston rings from the kit with new hydraulic fluid. Install the rings on the piston with the piston ring pliers.

11

Reinstall the piston into the cylinder, with the aid of the piston ring pliers. Install the new spring, included with the rebuilding kit, over the piston rod. Secure the collar back on the cylinder with the bolts and wrench.

12

Install the rebuilt or new piston on the tractor with the mounting bolts and wrench. Reattach the hydraulic hose fittings to the piston with a wrench. Refill the pump with hydraulic fluid and work all hydraulic system control levers through two complete cycles. Top off the fluid reservoir with hydraulic fluid and bleed the system.