10

Doctor Preload Bearing Adjustment Tools
Dr. Preload Tool Part
Number
MER415005

Use with Temper Loc
Nut

Axle Applications

TP Trailer

Meritor TP, Dana, Eaton (P22), Propar, Fruehauf

MER614743

TN Trailer

Dana Spicer (D20,D21,D22,DD22,K21,K25,K30),Hendrickson (HN),Ingersoll (A22T),Eaton
(C,C2,CD,CD2,CE,ESA225J,EST,EST225J,EST230J,
ETA230C,ETA225D,ETA225J,H23L,H25R,HCE,HJ,HJE,LA15,T18C,20L77,22L,22R,J,JE,JH,23L,23R,25R), Meritor
(F,H,RL,RQ,TK,TKL,TKLD,TL,TLD,TN,TND,TO,TQC,TQD),Standard Forge (A25,A26, 17,000lbs.,
18,000lbs. trade)

MER415084

MER614743

Dana Spicer (D20,D21,D22,DD22,K21,K25,K30),Hendrickson (HN),Ingersoll (A22T),Eaton
(C,C2,CD,CD2,CE,ESA225J,EST,EST225J,EST230J,
TN Trailer w/ Aluminum ETA230C,ETA225D,ETA225J,H23L,H25R,HCE,HJ,HJE,LA15,T18C,20LHubs
77,22L,22R,J,JE,JH,23L,23R,25R), Meritor
(F,H,RL,RQ,TK,TKL,TKLD,TL,TLD,TN,TND,TO,TQC,TQD),Standard Forge (A25,A26, 17,000lbs.,
18,000lbs. trade)

MER415002

MER614836

FF Steer

Meritor
(FD900,FD901,FD961,FE900,FE903,FF900,FF901,FF921,FF931,FF932,FF933,FF941,FF942,FF943
,FF944,FF952,FF961,FG941) Spicer (1100S)

MER415347

MER614837

FE Steer

Meritor (FE931), Eaton (EFA12FA,EFA12FA,EFA13FS,E12001,FE931,12K,13.2K),
Ford Sifco 12K,Ford 6K

MER415004

MER614973

R Drive

Eaton (P22), Ford, Rainstar, Meritor (TR)

MER415003

MER614723

Axle Spindle Application

11

Temper-Loc Spindle Nuts
• Only Temper-Loc Spindle Nuts Can be used with Doctor
Preload adjustment tools
– Special Chamfered Face to Accommodate the Tool
– Cannot use Stemco’s ProTorq with Doctor Preload
Tools
• Temper-Loc Can replace Stemco Pro-Torq® nuts
(see chart below)
• TN & TP Nuts Approved for Production Meritor Trailer
Axles
Temper Loc Nut
Replacement
Assembly
Replaces
Retainer Ring
Number
Stemco Number
Number

Axle Spindle
Application

Thread Threads Per
Diameter
Inch

Tool Socket Size

Outer Bearing

MER614723

447-4723

MER644723

TP Trailer

3.480"

12

4-13/16" - 8 point

HM518445 / HM518410

MER614743

447-4743

MER644743

TN Trailer

2.625"

16

3-3/4" - 8 point

HM212049 / HM212011

MER614836

448-4836

MER644836

FF Steer

1.500"

12

2-1/2" - 6 point

3782 / 3720

MER614837

448-4837

MER644837

FE Steer

1.500"

18

2-1/2" - 6 point

3782 / 3720

MER614973

449-4973

MER644973

R Drive

3.250"

12

4-3/8" - 8 point

580 / 572

12

Tool & Nut Program Details
• Doctor Preload Tools
– Packaged in a Temper box with a Meritor label
– In the Box:
• Tool calibration certificate
• How to use the tool instructions
• Warranty registration card

• Temper-Loc Nuts & Retainer Rings
– “12-packs” – 12 Nuts, Retainer Rings, and Installation Instructions
• Packaged in a Temper box with a Meritor label
• Bulk Packs Designed for fleets doing conversions

– Single-Nut Pack – 1 Nut, Retainer Ring, and Installation Instruction
• Packaged in a Meritor box with a Meritor label
• Designed For over-the-counter sales

– Retainer rings will be available – can only be used with Temper-Loc nuts
• Packaged in a Meritor box with a Meritor label
• 2 Retainer rings per box

13

Pricing & Warranty Program
• Pricing: (Suggested Dealer Net)

– “12-packs” (part numbers end in “B12”) Up to 16% below Stemco ProTorq
– Single pack boxes Up to 8% below Stemco Pro-Torq

• Warranty:

– Doctor Preload Tools
•
•

1 Year After Sale - Must Register Tool Using Provided Registration Card
The Doctor Preload tool registration card must be completed, with copy of
purchase invoice, and returned to Pete Freeman, Florence

– Temper-Loc Nuts
•

3 Years From Date of Installation (must provide supporting documentation)

14

Sales Support
• Training videos on Bullpen (Jan 2015)
• Demo Stands with Tools and Nuts for Training Trucks (Jan 2015)
• Product brochure – SP-1520 (Dec 2014)
–
–
–
–

What is preload
Fleet testimonials
Product description / features & benefits
Warranty statement

15

Questions?

Quick Start Instructions for Doctor Preload®
FOR USE WITH DOCTOR PRELOAD TOOLS FOR DRIVE AXLES

R SPINDLES
TEMPER AXLE PRODUCTS CORPORATION
ALL PRODUCTS INVENTED AND MADE IN USA!
WWW.DOCTORPRELOAD.COM
NOTE: USE DOCTOR PRELOAD ONLY WITH CONVENTIONAL WHEEL ENDS.
REMOVE ALL BEARING SPACERS FROM PRE-ADJUSTED HUB ASSEMBLIES
BEFORE ADJUSTING WITH DOCTOR PRELOAD. DO NOT ATTEMPT TO ADJUST
A UNITIZED HUB ASSEMBLY USING THE DOCTOR PRELOAD SYSTEM. USE
DOCTOR PRELOAD ONLY WITH TEMPER-LOC® SPINDLE NUTS. To prevent
serious eye injury, always wear safe eye protection when you perform vehicle maintenance or
service. Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving.
Support the vehicle with safety stands. Do not work under a vehicle supported only by jacks.
Jacks can slip and fall over. Serious personal injury and damage to components can result.

Before Starting Bearing Adjustment:
Inspect all wheel end components. Repair any damage to the spindle threads so that the Temper-Loc spindle nut
is able to thread completely onto the spindle.
Prepare the Wheel End for Bearing Adjustment:
Always be sure the hub is fully seated before adjusting with Doctor Preload. Thread the correct size Temper-Loc
nut onto the spindle. Using a bar and socket, tighten the Temper-Loc nut to drive the hub solidly against the axle.
Loosen the nut one half turn. Finally, hand tighten the nut until it first touches the face of the outer bearing.
Six Simple Steps:
1) ATTACH DOCTOR PRELOAD TO THE END THREADS OF THE SPINDLE: Using a downward sweeping motion, guide
the two spring-loaded load arms around two flats of the nut (not over any of the “points” of the nut) while
engaging the keyway locator in the keyway. Use the end tabs on the load arms to control the load arms. Engage
the spindle adapter thread on the spindle with three turns of the star-handle.
Check to be sure the tips of the load arms are properly located around the edge of the backface of the TemperLoc nut and that they make contact with the outer bearing cone. See the diagram below.

Top View of Spindle with Doctor Preload
Mounted and Properly Aligned.

(Continue Instructions on Reverse Side)

2) SEAT THE BEARING ROLLERS: Tighten the T-handle by turning it clockwise. Load the bearings until the needle
pointer on the Doctor Preload gage reaches the green ‘Roll-in Zone.’ Spin the hub at least 3 full turns in any
one direction to seat the bearing rollers.
The load may drop slightly when rolling in the bearings – this is
normal. If the needle pointer drops out of the “Roll-in Zone”, tighten
the T-handle until it returns to the “Roll-in Zone” and spin the hub
three full turns again. Repeat until the needle pointer stays in the
“Roll-in Zone.” Do not spin the hub again after this step.
The load arms and the keyway locator should NOT be in contact
with the Temper-Loc nut or any part of the hub during this step. If
this occurs, remove Doctor Preload and start over by fully seating
the hub as described in “Prepare Wheel End for Bearing
Adjustment” above. Do not hand tighten the Temper-Loc nut
against the bearing while the needle pointer is in the green “Roll-In
Zone”. Caution: Applying excess force (moving the needle pointer
above the “Roll-In Zone”) can damage the Doctor Preload tool.
3) SET THE BEARINGS: Loosen the T-handle by turning it counterclockwise slowly until the needle pointer on the
Doctor Preload gage reaches ‘Set Drive/Trailer Axle.’ Do not go past the set point; if the set point is overshot,
go back to Step 2 and repeat in order to seat the bearing rollers.
4) LOCK IN THE BEARING SETTING: Hand tighten the Temper-Loc nut to align the furthest possible index dot with
the hash mark on the keyway locator and/or the load arms. When hand tightened, if the hash mark lines up in
the space between two dots, loosen the nut a fraction of the space to align the next dot with the hash mark.
5) REMOVE DOCTOR PRELOAD FROM THE SPINDLE: Completely loosen the T-handle by turning it
counterclockwise until the load shown on the gage drops to zero. Hold the gage-guard handle to support the
weight of the tool, and then loosen the star-handle by turning it counterclockwise. When the tool is detached
from the spindle, gently rotate Doctor Preload until the two load arm tips are positioned over two flats of the
nut and pull straight back so that the load arms and keyway locator will slide back around the nut.
6) INSTALL THE RETAINER RING: First install the EasyView® center tab of the retainer ring in the Temper-Loc nut,
engaging the key in the keyway at the same time. See below. Push in on each end finger tab, one at a time, to fit
each tab into the nut groove.

Retainer Tab entering groove.

Retainer Tab secured in groove.

ALWAYS INSPECT THE FINAL ASSEMBLY. Ensure that there is a yellow retainer ring inserted in the nut. CHECK THAT ALL
THREE EasyView TABS AND THE LOCKING TEETH OF THE KEY ARE FULLY SEATED IN THE NUT. The EasyView notches of all
three tabs must be completely hidden in the groove of the nut. Failure to inspect the installation thoroughly could result
in component failure and bodily injury.
© Jan 2015 Temper Axle Products Corporation
Bulletin # TP10120

Quick Start Instructions for Doctor Preload®
FOR USE WITH DOCTOR PRELOAD TOOLS FOR TRAILER AXLES

TN AND TP SPINDLES
TEMPER AXLE PRODUCTS CORPORATION
ALL PRODUCTS INVENTED AND MADE IN USA!
WWW.DOCTORPRELOAD.COM
NOTE: USE DOCTOR PRELOAD ONLY WITH CONVENTIONAL WHEEL ENDS.
REMOVE ALL BEARING SPACERS FROM PRE-ADJUSTED HUB ASSEMBLIES
BEFORE ADJUSTING WITH DOCTOR PRELOAD. DO NOT ATTEMPT TO ADJUST
A UNITIZED HUB ASSEMBLY USING THE DOCTOR PRELOAD SYSTEM. USE
DOCTOR PRELOAD ONLY WITH TEMPER-LOC® SPINDLE NUTS. To prevent
serious eye injury, always wear safe eye protection when you perform vehicle maintenance or
service. Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving.
Support the vehicle with safety stands. Do not work under a vehicle supported only by jacks.
Jacks can slip and fall over. Serious personal injury and damage to components can result.

Before Starting Bearing Adjustment:
Inspect all wheel end components. Repair any damage to the spindle threads so that the Temper-Loc spindle nut
is able to thread completely onto the spindle.
Prepare the Wheel End for Bearing Adjustment:
Always be sure the hub is fully seated before adjusting with Doctor Preload. Thread the correct size Temper-Loc
nut onto the spindle. Using a bar and socket, tighten the Temper-Loc nut to drive the hub solidly against the axle.
Loosen the nut one half turn. Finally, hand tighten the nut until it first touches the face of the outer bearing.
Six Simple Steps:
1) ATTACH DOCTOR PRELOAD TO THE END THREADS OF THE SPINDLE: Using a downward sweeping motion, guide
the spring-loaded load arms around the nut while engaging the keyway locator in the keyway. Engage the
spindle adapter thread on the spindle with three turns of the star-handle.
Check to be sure the tips of the load arms are properly located around the edge of the backface of the TemperLoc nut and that they make contact with the outer bearing cone. See the diagram below.

Top View of Spindle with Doctor Preload
Mounted and Properly Aligned.

(Continue Instructions on Reverse Side)

2) SEAT THE BEARING ROLLERS: Tighten the T-handle by turning it clockwise. Load the bearings until the needle
pointer on the Doctor Preload gage reaches the green ‘Roll-in Zone.’ Spin the hub at least 3 full turns in any
one direction to seat the bearing rollers.
The load may drop slightly when rolling in the bearings – this is
normal. If the needle pointer drops out of the “Roll-in Zone”, tighten
the T-handle until it returns to the “Roll-in Zone” and spin the hub
three full turns again. Repeat until the needle pointer stays in the
“Roll-in Zone.” Do not spin the hub again after this step.
The load arms and the keyway locator should NOT be in contact
with the Temper-Loc nut or any part of the hub during this step. If
this occurs, remove Doctor Preload and start over by fully seating
the hub as described in “Prepare Wheel End for Bearing
Adjustment” above. Do not hand tighten the Temper-Loc nut
against the bearing while the needle pointer is in the green “Roll-In
Zone”. Caution: Applying excess force (moving the needle pointer
above the “Roll-In Zone”) can damage the Doctor Preload tool.
3) SET THE BEARINGS: Loosen the T-handle by turning it counterclockwise slowly until the needle pointer on the
Doctor Preload gage reaches ‘Set Drive/Trailer Axle.’ Do not go past the set point; if the set point is overshot,
go back to Step 2 and repeat in order to seat the bearing rollers.
4) LOCK IN THE BEARING SETTING: Hand tighten the Temper-Loc nut to align the furthest possible index dot with
the hash mark on the keyway locator and/or the load arms. When hand tightened, if the hash mark lines up in
the space between two dots, loosen the nut a fraction of the space to align the next dot with the hash mark.
5) REMOVE DOCTOR PRELOAD FROM THE SPINDLE: Completely loosen the T-handle by turning it counterclockwise
until the load shown on the gage drops to zero. Hold the gage-guard handle to support the weight of the tool, and
then loosen the star-handle by turning it counterclockwise. When the tool is detached from the spindle, gently
pull Doctor Preload straight back, and the load arms and keyway locator will slide back around the nut.
6) INSTALL THE RETAINER RING: First install the EasyView® center tab of the retainer ring in the Temper-Loc nut,
engaging the key in the keyway at the same time. See below. Push in on each end finger tab, one at a time, to fit
each tab into the nut groove.

Retainer Tab entering groove.

Retainer Tab secured in groove.

ALWAYS INSPECT THE FINAL ASSEMBLY. Ensure that there is a yellow retainer ring inserted in the nut. CHECK THAT ALL
THREE EasyView TABS AND THE LOCKING TEETH OF THE KEY ARE FULLY SEATED IN THE NUT. The EasyView notches of all
three tabs must be completely hidden in the groove of the nut. Failure to inspect the installation thoroughly could result
in component failure and bodily injury.
© Jan 2015 Temper Axle Products Corporation
Bulletin # TP10121

Quick Start Instructions for Doctor Preload®
FOR USE WITH DOCTOR PRELOAD TOOLS FOR TN AXLES*

TN-AH* Tools for TN SPINDLES
*For Use with Certain Aluminum TN Spindle Trailer Hubs
TEMPER AXLE PRODUCTS CORPORATION
ALL PRODUCTS INVENTED AND MADE IN USA!
WWW.DOCTORPRELOAD.COM
NOTE: USE DOCTOR PRELOAD ONLY WITH CONVENTIONAL WHEEL ENDS.
REMOVE ALL BEARING SPACERS FROM PRE-ADJUSTED HUB ASSEMBLIES
BEFORE ADJUSTING WITH DOCTOR PRELOAD. DO NOT ATTEMPT TO ADJUST
A UNITIZED HUB ASSEMBLY USING THE DOCTOR PRELOAD SYSTEM. USE
DOCTOR PRELOAD ONLY WITH TEMPER-LOC® SPINDLE NUTS. To prevent
serious eye injury, always wear safe eye protection when you perform vehicle maintenance or
service. Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving.
Support the vehicle with safety stands. Do not work under a vehicle supported only by jacks.
Jacks can slip and fall over. Serious personal injury and damage to components can result.

Before Starting Bearing Adjustment:
Inspect all wheel end components. Repair any damage to the spindle threads so that the Temper-Loc spindle nut
is able to thread completely onto the spindle.
Prepare the Wheel End for Bearing Adjustment:
Always be sure the hub is fully seated before adjusting with Doctor Preload. Thread the correct size Temper-Loc
nut onto the spindle. Using a bar and socket, tighten the Temper-Loc nut to drive the hub solidly against the axle.
Loosen the nut one half turn. Finally, hand tighten the nut until it first touches the face of the outer bearing.
Six Simple Steps:
1) ATTACH DOCTOR PRELOAD TO THE END THREADS OF THE SPINDLE: Using a downward sweeping motion, guide
the two spring-loaded load arms around two flats of the nut (not over any of the “points” of the nut) while
engaging the keyway locator in the keyway. Use the end tabs on the load arms to control the load arms. Engage
the spindle adapter thread on the spindle with three turns of the star-handle.
Check to be sure the tips of the load arms are properly located around the edge of the backface of the TemperLoc nut and that they make contact with the outer bearing cone. See the diagram below.

Top View of Spindle with Doctor Preload
Mounted and Properly Aligned.

(Continue Instructions on Reverse Side)

2) SEAT THE BEARING ROLLERS: Tighten the T-handle by turning it clockwise. Load the bearings until the needle
pointer on the Doctor Preload gage reaches the green ‘Roll-in Zone.’ Spin the hub at least 3 full turns in any
one direction to seat the bearing rollers.
The load may drop slightly when rolling in the bearings – this is
normal. If the needle pointer drops out of the “Roll-in Zone”, tighten
the T-handle until it returns to the “Roll-in Zone” and spin the hub
three full turns again. Repeat until the needle pointer stays in the
“Roll-in Zone.” Do not spin the hub again after this step.
The load arms and the keyway locator should NOT be in contact
with the Temper-Loc nut or any part of the hub during this step. If
this occurs, remove Doctor Preload and start over by fully seating
the hub as described in “Prepare Wheel End for Bearing
Adjustment” above. Do not hand tighten the Temper-Loc nut
against the bearing while the needle pointer is in the green “Roll-In
Zone”. Caution: Applying excess force (moving the needle pointer
above the “Roll-In Zone”) can damage the Doctor Preload tool.
3) SET THE BEARINGS: Loosen the T-handle by turning it counterclockwise slowly until the needle pointer on the
Doctor Preload gage reaches ‘Set Drive/Trailer Axle.’ Do not go past the set point; if the set point is overshot,
go back to Step 2 and repeat in order to seat the bearing rollers.
4) LOCK IN THE BEARING SETTING: Hand tighten the Temper-Loc nut to align the furthest possible index dot with
the hash mark on the keyway locator and/or the load arms. When hand tightened, if the hash mark lines up in
the space between two dots, loosen the nut a fraction of the space to align the next dot with the hash mark.
5) REMOVE DOCTOR PRELOAD FROM THE SPINDLE: Completely loosen the T-handle by turning it
counterclockwise until the load shown on the gage drops to zero. Hold the gage-guard handle to support the
weight of the tool, and then loosen the star-handle by turning it counterclockwise. When the tool is detached
from the spindle, gently rotate Doctor Preload until the two load arm tips are positioned over two flats of the
nut and pull straight back so that the load arms and keyway locator will slide back around the nut.
6) INSTALL THE RETAINER RING: First install the EasyView® center tab of the retainer ring in the Temper-Loc nut,
engaging the key in the keyway at the same time. See below. Push in on each end finger tab, one at a time, to fit
each tab into the nut groove.

Retainer Tab entering groove.

Retainer Tab secured in groove.

ALWAYS INSPECT THE FINAL ASSEMBLY. Ensure that there is a yellow retainer ring inserted in the nut. CHECK THAT ALL
THREE EasyView TABS AND THE LOCKING TEETH OF THE KEY ARE FULLY SEATED IN THE NUT. The EasyView notches of all
three tabs must be completely hidden in the groove of the nut. Failure to inspect the installation thoroughly could result
in component failure and bodily injury.
© Jan 2015 Temper Axle Products Corporation
Bulletin # TP10122