The following items must be noted when disassembling.
① Prepare necessary tools: hex wrench 2~22mm, open-end wrench, socket: 17, 19, 22, 24, 27, 30, 36, 41, 50, 55, etc. (unit: mm), medium-sized adjustable wrenches, screwdrivers (flat blade), hammers, circlip pliers, copper rods, torque wrenches, etc.
② Thoroughly clean the outside of the oil pump before disassembly.
③ Clean the working surface as well.
④Make corresponding marks on each joint part of the oil pump housing so that the correct position can be found during reassembly.
⑤ The components of the front and rear pumps should be stored separately and should not be mixed together.
⑥ Thoroughly clean all components inside the casing with detergent or gasoline.
⑦ Check and analyze all faults to determine the most fundamental cause of the fault. Note: Please refer to Figure 4-99 for the labels in the following items. Disassembly is as follows.
①Choose a suitable working position (it is best to place it on a workbench covered with rubber mats to prevent components from being bruised).
② Use detergent to clean the pump surface thoroughly again.
③ Remove the oil drain plug (468) and drain the oil from the pump housing (both the front and rear pumps must be removed).
④ Mark the joint surface between the regulator and the pump body, remove the screws (401, 406), and remove the regulator, as shown in Figure 4-104.
⑤ Remove the pilot gear pump.
⑥Remove the screws (401) that fix the swashplate support (251), oil pump housing (271) and valve block (312).
⑦ Place the oil pump flat on the workbench, with the regulator seat surface facing downwards, and separate the oil pump housing (271) from the valve block (312), as shown in Figure 4-105.
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⑧Pull the oil cylinder block (141) out of the oil pump housing (271), directly pull out the transmission shaft (111), and at the same time pull out the piston (151), setting plate (153), spherical bearing (156) and hydraulic spring (157), as shown in Figure 4-106. During this process, do not damage the sliding surfaces such as the cylinder block, spherical bearing bush, wrap angle and swash plate. Mark the piston and each plug hole. When assembling, it should be carried out in its original position.
9Remove the screws (406) and the front cover (261), insert the screws into the cover and pull out the pin holes. This will make the cover easy to disassemble, as shown in Figure 4-107.
⑩ Remove the screws (406) and the rear cover (262).
⑪Gently tap the flange part of the swash plate support (251) on the side of the oil pump housing to separate the swash plate support from the oil pump housing (271), as shown in Figure 4-108.
⑫ Remove the corner plate (211) and swash plate (212) from the oil pump housing (271), as shown in Figure 4-109.
③ Use a plastic or rubber mallet to hit the end of the drive shaft (111, 113) and remove it from the swash plate support, as shown in Figure 4-110.
⑭ Remove the valve plates (313, 314) from the valve block (312), as shown in Figure 4-111.
⑤ If necessary, the stop blocks (534, 535) and servo piston (532) must also be removed from the oil pump housing (271) With tilt pin (531), remove bearing (124) and splined rack coupling (114) from valve block (312). When removing the tilt pin, use a clamp to prevent damage to the pin head. It is important to note here that do not loosen the nut (808) and the adjusting screws (953, 954). If loose, the oil flow setting will change.
