Two Piece Stay Rod Installation Instructions {5070, 5070} Caterpillar

Well Pump

WS223 (S/N: SR31-UP)

WS223 SS (S/N: BM31-UP)

WS223 XD (S/N: SR41-UP)

WS255 (S/N: SR51-UP)

WS255 SS (S/N: BM51-UP)

WS255 XD (S/N: SR61-UP)

WSP223 (S/N: FNJ1-UP)

WSP255 (S/N: FNK1-UP)

Introduction

This Special Instruction is intended to give information on installing the two-piece stay rod for certain well stimulation pumps.

Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.

Also ensure that you are following all safety precautions while you are performing the procedures outlined in this document.

Safety Section

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Personal injury can result from oil under high pressure. DO NOT allow high pressure oil to contact skin. Wear appropriate protective equipment while working with high pressure oil systems.

Installation Procedure

Note: Stay rods must always be replaced as an assembly (1 stud and 1 sleeve). This is how the stay rods are packaged and sold from Caterpillar^®.

Note: The stay rods are designed to last the entire life of the power end, stay rods should only be replaced if they are damaged.

Note: Cat two piece stay rods should never be torqued into the nose plate.

Note: Loctite 263^® Threadlocker is used only to keep the stud from turning while the fluid end is being installed. Once the Loctite is broken, the stud should spin out freely.

1. Before installation of the new stay rods, carefully clean thread bore and surrounding surface area on the power end nose plate.

2. Inspect thread bore for damaged threads, thread separation, and cracks. Damaged threads or cracks will require further inspection and repair criteria, contact the Dealer Solution Network (DSN).
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   Illustration 1	g06315309

3. Apply Loctite LB 8009^® Heavy Duty Anti–Seize in the back 19.05 mm (0.75 inch) of the threaded bore on the power end nose plate.

4. Install the stay rod stud and thread approximately 38.10 mm (1.50 inch) into the threaded bore to achieve an overall exposed length of 450.85 mm (17.750 inch).
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   Illustration 2	g06315310

5. Apply Loctite 263 Threadlocker to the last 3 threads to 4 threads of the stay rod stud.
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   Illustration 3	g06005369
   (A) Exposed length dimension (1) Stay rod

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   Illustration 4	g06315318

6. Finish installing stay rod stud (1) until the overall exposed length dimension (A) is obtained.

   Note: The minimum exposed length dimension is 438.150 mm (17.250 inch)and the maximum exposed length dimension is 439.738 mm (17.313 inch).

   Note: There will be exposed threads on the stay rod stud that are not threaded into the nose plate after dimension (A) is obtained.

7. Apply a liberal coating of 129-1966 Multipurpose Grease or equivalent to the stay rod stud to prevent corrosion and possible premature failure.

8. Install the stay rod sleeve over the stay rod stud.

9. Repeat Step 1 through Step 8 for all the remaining stay rod assemblies. Use a straight edge or a level to check length consistency.

10. Position the fluid end on the stay rods and slide the fluid end onto the stay rods until the fluid end bottoms out on the stay rod sleeve shoulders.
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    Illustration 5	g06315315

11. Apply Loctite LB 8009 Heavy Duty Anti–Seize on the 44.450 mm (1.750 inch) threads prior to installing the 44.450 mm (1.750 inch) stay rod heavy hex nuts.

12. Install the two outer–most heavy hex nuts on both sides and hand–tighten. Screw all remaining heavy hex nuts in and hand–tighten.
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    Illustration 6	g06005478
    Triplex Unit WS223

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    Illustration 7	g06005507
    Quintuplex Unit WS255

13. Using a hydraulic tensioning tool or torque wrench, torque all hex nuts to 3254 N·m (2400 lb ft). Refer to Illustrations 6 and 7 for the correct torque sequence.

    Note: These nuts MUST be kept tight. Under–torqued nuts will lead to thread fatigue failure of the stay rods.

Removal Procedure

1. Remove the fluid end, refer to Disassembly and Assembly, UENR3290 or Disassembly and Assembly, UENR6796 for additional information.

2. Remove the stay rod sleeve. The stay rod sleeve will not be reused when installing a new stay rod.

3. Using a pipe wrench, loosen the stay rod stud with minimal force.

   Note: If the stud starts to bind, using more force will likely gall the threads and cause the stud to get stuck.

   If the stud is binding, lightly tap the end of the stud (closest to the nose plate) with a dead blow hammer as you twist the stud back and forth. This should allow the stud to unbind and easily be removed.

4. Remove all the old anti-seize and Loctite from the female threads of the nose plate.

5. Repeat Steps 2 through 4 for all damaged stay rods being replaced.