Stemco Pro-Torq Installation and Torque Specs

Stemco

Bearing Adjustment

This video demonstrates the 2-1-1 Installation Process for the Stemco Pro-Torq spindle nut, including proper torque spec and back off procedure.

When the Pro-Torq 2-1-1 adjustment procedure is followed, wheel bearing end play adjustment of 0.001 – 0.003″ can be achieved. Acceptable end play is 0.001″ – 0.005″.

Wheel End Warning

Failure to follow proper wheel end procedures can cause a wheel-off situation, leading to bodily injury or death.

We do our best to ensure the most accurate and current installation information is represented on the Trailer Technician site. However, you should always consult the manufacturer to confirm the correct process and torque specs. 

Training Video

  • Title: 2-1-1 Installation
  • Source: Stemco
  • Run Time: 4:38

Bearing Adjustment

Pro-Torq and Zip-Torq Installation Procedure for Hubs with Manually Adjusted Wheel Bearings

Step 1

Remove the Keeper From the Nut

When using Pro-Torq, use a screwdriver to carefully pry the keeper arm from
the undercut groove on each side until the keeper is released.

Step 2

Thread the Nut Onto the Axle

Thread the nut onto the axle until hand tight against the bearing.

Step 3

Seat the Bearing

With wheel hub assembly:

  1. Using a torque wrench:
    1. Tighten the nut to 200 ft-lb. Spin the wheel hub assembly at least one full rotation.
    2. Tighten the nut to 200 ft-lb. Spin the wheel hub assembly at least one full rotation.
    3. Tighten the nut to 200 ft-lb. Spin the wheel hub assembly at least one full rotation.
  2. Back the nut off one full rotation.

Step 4

Adjust the Bearing

With wheel hub assembly:

  1. Using a torque wrench:
    1. Tighten the nut to 100 ft-lb. Spin the wheel hub assembly at least one full rotation.
    2. Tighten the nut to 100 ft-lb. Spin the wheel hub assembly at least one full rotation.
    3. Tighten the nut to 100 ft-lb. Spin the wheel hub assembly at least one full rotation.
  2. Back the nut off one face mark (according to chart).

Final Back Off

PRO-TORQ PART #ZIP-TORQ PART #BACK OFF
TRAILER AXLE FASTENER
447-4723, 447-4724, 449-4973400-4723, 400-49731/8 turn
447-4743400-47431/4 turn
STEERING AXLE FASTENER
448-4836, 448-4838, 448-4839, 448-4863, 448-4865, 448-4864400-48361/4 turn
448-4837, 448-4840400-48371/3 turn
DRIVE AXLE FASTENER
449-4904, 449-4973, 449-4974, 449-4975400-49731/8 turn

Step 5

Install the Keeper (Skip this step if using Zip-Torq)

Orange side facing out:

  1. Insert the keeper tab into the undercut groove of the nut and engage the keyway tang in the axle keyway. Insert keeper tab with the orange side facing out.
  2. Engage the mating teeth.
  3. Compress and insert the keeper arms, one at a time, into the undercut groove with a screwdriver.

For Steering Spindle Nut:

448-4836, 448-4839, 448-4840, 448-4863, 448-4864, and 448-4865

  1. Align the flat of the keeper with the milled flat on the spindle and insert the single keeper tab into the undercut groove of the nut. Insert keeper tab with the orange side facing out.
  2. Engage the mating teeth.
  3. Compress and insert the keeper arms, one at a time, into the undercut groove with a screwdriver.
NOTE: Recommended practice is to replace the keeper each time the Pro Torq nut assembly is removed for maintenance purposes.

Step 6

Inspect the Installation

Failure to follow this instruction could cause the wheel to come off and cause bodily injury. When using Pro-Torq, make sure that the keeper tab and keeper arms are fully seated into the undercut groove. Inspect keyway tang to ensure it does not contact the bottom of the keyway. If contact exists, immediately notify a STEMCO representative.

This procedure will consistently produce a bearing setting of 0.001″ to 0.003″ end play.

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