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Assembly Guide: PA B-18, B-24, B-31 Gear Box Assembly

Updated: Mar 11

This is a step by step guide to assemble the PA General Pump B-18, B-24, and B-31 Gear Box.

You can download the PDF here. Or you can follow along in the post below.

Assembly Guide PA B-18, B-24 and B-31 Gear Box
Download PDF • 35.40MB

Step 1: Remove the 4 bolts from the Pump Bearing Cover.

  • This install will show a General Pump TS Pump install to a PA B-18, B-24, B-31 Gear Box for reference.

Step 2: Install and Set the O-ring Into Small Gearbox Plate Flange (Pump Side)

  • Place the proper size O-Ring into the slot on the flange.

  • Press and set by hand. Make sure the O-ring is smooth and not pinched or twisted.

  • Inspect that the O-Ring has been properly installed into position before proceeding.

Step 3: Put Flange On Pump (O-ring Down)

  • Place the pump in the Shaft Up position and flip the flange over slowly placing it over the pump with the O-ring installed facing down to the pump.

Step 4: Apply Seal Washers to Bolts and Secure Flange to the Pump.

  • Apply Seal Washers to the 4x m8 bolts.

  • Apply thread lock. A minor amount is needed.

  • Secure flange to the pump.

Step 5: Install the Gearbox Seal to the Flange. (Large O-ring)

  • Take the provided large O-ring and install it on the outer lip of the gear box flange as shown. Make sure it is nice and smooth and free of crimps or spins.

Step 6: Install Gear on Pump Shaft

  • Slide the Gear on the Pump Shaft.

  • It should slide on EASY AND SMOOTH.

***If the Gear does not go on with ease, check the key way to make sure the key is fully seated.

Step 7: Secure Gear In Place With Black Set Screw

  • Apply Thread lock to set screw

  • 4mm Allen Wrench

  • Hand Tighten the set screw. This set screw just needs to be installed hand tight.

Step 8: Install the Main Gear Box Cover

  • Carefully check alignment when placing cover over the seal

  • Check the alignment all the way to closure

  • Check the cover alignment again to ensure no pinching or marks will apply to the seal.

Step 9: Install Compression Washers

  • Install compression washers to 4 m8 bolts.

  • Crown of Washer Convex Up

  • Make sure the compression washers are properly installed

  • Apply thread lock to the 4 bolts as shown.

Step 10: Tightening Bolt Process

  • To Start, hand tighten the bolts to secure the gear box cover to the pump flange.

  • The instructions from the manufacturer say that the bolts can be set at 20-22lb we have found that less is needed to ensure the bolts won't shear off over time. We recommend using locktite and applying 15-17lb max on a torque wrench for best results over time. We believe that the shearing is happening due to torque and weight resting on the bolt. When applied at 15lb we have found 0 issues.

  • We found that in a vice, these bolts provided by the manufacturer will start to collapse and break between 27-30lb of torque. This is why we think too many people are shearing off bolts.

Here is a quick video assembling the gearbox by hand. Please use a torque wrench to ensure the bolts are sheared off inside the pump or gearbox.

Step 11: Install Sight Glass To Cover

  • Hand Tighten the Sight Glass.

  • Use a Wrench to give it 1/4 turn more.

  • USE CAUTION not to over tighten the sight glass.

Step 12: Install The Oil Drain Plug

  • Hand Tighten the oil drain plug.

  • Then use a wrench to give it 1/4 turn tighter.

  • Like all drain plugs.... DO NOT over tighten it!

Step 13: Fill Gear Box With 80w-90 Gear Oil ONLY

  • Fill Oil in the gear box SLOWLY until the level is EQUAL with the Red Dot on the center of the Sight Glass.

  • Check again after oil settlers to ensure proper oil amount is used.

  • 80w-90 Gear Oil is what we recommend. We use STP.

After this step.


You have successfully assembled your PA Gear Box!

If you need directions to install your Gear Box and Pump to the Machine. Check out our Installation Guide Here


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