This article introduces how to disassemble the swing motor of Caterpillar 325, 320L, 320N, and 320S excavators

 2023 CAT ET 2023A 2023C & 2019C Full Service Download and Installation Service

①Clean the outer surface of the motor and blow dry with compressed air. Before cleaning, block all inlets and outlets to prevent foreign matter from entering.  

② Remove the oil drain plug and drain the oil in the housing.

  ③ Place the motor on a clean wooden frame and mark the valve body and housing with relative marks.

  ④Remove the brake valve (note that this valve is an optional part). 

 ⑤ Remove the relief valve and disassemble the valve body. 

 ⑥After removing the blockage from the valve body, pull out the spring and valve core. Be careful not 

to operate the valve core seat. 

 Caterpillar 18 Digits Factory Password Calculator One-Time Calculate Service

 ⑦ Loosen the bolts, remove the valve body from the housing, and remove the valve plate from the 

valve body. Be careful not to drop the valve plate and damage it. 

 ⑧Remove the brake spring from the brake piston.  

⑨ Use the brake piston assembly tool to pull out the brake piston from the housing. When pulling out, 

the bolt groove of the brake piston can be used. 

 ⑩ Place the motor horizontally, pull out the cylinder block from the shaft, and remove the plunger, 

pressure plate, ball bushing, front pad and sliding plate. Be careful not to damage the sliding parts of 

each component when disassembling.

  ⑪Fold off the friction plate and separation plate from the housing. 

 2 Use pliers to remove the locking ring. Then remove the front cover from the housing. When 

removing the front cover, be careful not to operate the oil seal.

  ⑬ Use a plastic hand hammer to tap the shaft lightly to disassemble the shaft and housing.

14. Use a copper rod hammer to gently tap the rolling bearing shell to remove the skid plate. 

1⑤ Carry out the following disassembly work if necessary. a. Remove the limit ring and pad from the 

shaft, and remove the inner ring of the rolling bearing. b. Remove the oil seal from the front cover. For 

reuse, do not damage the oil seal. c. Use a thrust shaft puller to remove the rolling bearing from the 

valve body. d. Disassembly of the relief valve.  

⑯Disassembly steps of the relief valve. a. Remove the plug, bushing, spring and spring seat from the 

valve core. b. Place the valve body downward and remove the slide plug, valve stem, spring, spring seat

 and valve head. But do not touch the adjusting screws and fastening nuts. If damaged, replace them in 

groups.  

17. Assembling the relief valve. Disassembly should be carried out in the reverse order. Pay attention 

to 

the following points before assembly. a. Repair damaged parts during disassembly and prepare spare 

parts. 

 b. Clean all parts with clean oil and blow dry with compressed air. 

 c. Apply hydraulic oil to the sliding surfaces, bearings, etc. and keep them clean. 

 d. Replace the O-ring and oil seal. 

 e. Use a torque wrench to tighten each bolt and plug to the specified torque.