Premier 370PK Instruction Manual

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THE FIRST NAME IN QUALITY COUPLINGS
BEFORE GETTING STARTED:
► This procedure should only be performed by a qualified
mechanic.
► Measure the wear on the coupling’s pintle hook. If the
wear is at or exceeds 20% of the cross section, the
coupling is considered Out of Service. Do Not continue.
Premier has Wear Gages to determine wear on our
Couplings and Drawbar Eyes.
► Examine the entire coupling body for excessive wear or
any damage. If any exists, do Not continue, coupling
needs to be replaced.
► Tools required: 1 1/16” & 15/16” sockets, and a flat head
screw driver.
► Safety glasses are required for all of the following
procedures.
► See attached Image Reference Section(s) with photos
and/or drawings to identify various parts.
► Prior to disassembly, familiarize yourself with the location
of all the various parts in the coupling. This will assist in
the assembly process.
DISASSEMBLY
1) The coupling body should be positioned upright with the
latch in the closed position (see Image #2 in the Image
Reference Section.)
2) Locate the 374 Bolt, which resides within the 472 Latch,
and remove the 274A Locknut from the left side. Slide the
374 Bolt out from the right side. Remove the 472 Latch.
3) With the 582A Spring still spring-loaded on the 372B
Locking Pawl, cautiously remove the locking pawl, since
the spring may eject during removal.
4) Remove the 582A Spring.
5) Locate the 375 Bolt, which resides within the 373 Pawl,
and remove the 375A Locknut from the left side. Slide the
375 Bolt out from the right side.
**Do not discard it, you will need to use this 375 Bolt again
for reassembly purposes.
6) Remove the 373 Pawl, 373A Spring and **373B Spacer
(**for 570 models and older model 370’s, 370B’s & 770’s
only). There will either be a **removable spacer (see
Image #1, 373B Spacer) OR a built-in spacer on the
inside right 375 Bolt body hole (see Image #4).
7) IF you are replacing the shoe and its components (279,
379 or 579) then determine your coupling model number
and follow instructions for either A, B or C below:
Otherwise, continue on to #8.
A) FOR MODELS 370 & 770 (using 279 Shoe):
Locate the 274 Bolt, which resides within the 279
Shoe at the bottom of the coupling and remove the
274A Locknut from the left side. Slide the 274 Bolt out
from the right side and remove the 279 Shoe and 266
Spring.
B) FOR MODEL 370B ONLY (using 379 Shoe):
Position the coupling so that you are looking at the
lower back side (see Image #5). Locate the straight
leg of the 376 Spring on the left hand side and push
it to the right, until it has moved past the internal shoe
stop. You may need to push the shoe forward to
allow for clearance of the spring. Turn the coupling
back around to face the front of it. Locate the 374
Bolt residing in the 379 Shoe and remove the 274A
Locknut from the left side. Slide the 374 Bolt out from
the right side then remove the 579 Shoe and 376
Spring from the top of the coupling opening.
C) FOR MODEL 570 ONLY (using 579 Shoe):
Position the coupling so that you are looking at the
lower back side (see Image #5). Locate the straight
leg of the 376 Spring on the left hand side and push
it to the right, until it has moved past the internal shoe
stop. You may need to push the shoe forward to
allow for clearance of the spring. Turn the coupling
back around to face the front of it. Locate the 374
Bolt residing in the 379 Shoe and remove the 274A
Locknut from the left side. Slide the 374 Bolt out from
the right side then remove the 579 Shoe and 376
Spring from the top of the coupling opening.
8) With all parts removed from the coupling body, clean and
370
Coupling
370PK SERVICE GUIDELINES
For coupling models: 370, 370B, 570 & 770

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inspect the body for wear and/or damage. If wear exists
or damage is noted, do not attempt to repair. DO NOT
ATTEMPT WELD REPAIR OF ANY DAMAGED AND/OR
WORN PART.
DISASSEMBLY IS COMPLETE
IMPORTANT NOTES TO CLEAN,
INSPECT & LUBRICATE:
► Use only genuine PREMIER replacement parts on any
repairs. Use of other parts, which can have different
specifications or tolerances, may fail to alert you to non-
obvious damage to the hitch which can lead to hitch failure.
► All body holes, part holes and pins need to be thoroughly
cleaned and lubricated with a heavy grease before the
parts are reassembled. If a bushing resides in a part,
lubricate the hole prior to installing the bushing. DO NOT
LUBRICATE PINTLE HOOK WEAR SURFACE.
► Clean, inspect and lubricate latch components every 90
days or sooner if required by the operating environment.
► Clean and inspect the coupling for damage and excessive
wear prior to each and every use.
► Do not over-tighten fasteners as this may cause damage.
ASSEMBLY
1) IF you are replacing the shoe and its components (279,
379 or 579) then determine your coupling model number
and follow instructions for either A, B or C below:
Otherwise, continue on to #2.
A) FOR MODELS 370 & 770 (using 279 Shoe):
Place the 266 Spring over the nipple on the 279 Shoe.
Insert as assembled through the opening at the top
of the coupling and into the cavity at the bottom. The
266 Spring should seat into the concave cavity, which
resides below the pintle base. The 266 Spring must
be slightly compressed to align the 279 Shoe hole
with the bottom body hole. From the right side of the
body, insert the 274 Bolt (right to left) into the bottom
coupling body hole and secure on the left side with
274A Locknut. Rotate the 279 Shoe to verify proper
spring tension (see Image #3).
B) FOR MODEL 370B ONLY (using 379 Shoe):
Position the 579 Shoe so the concave portion of the
shoe is facing toward you and the bolt hole is on the
bottom. Hold the 376 Spring so that the hooked leg
is on the top side, hooking to the left, and the straight
leg is pointing upward and away from you. Slide the
spring over the shoe bolt hole on the right side, while
keeping the hooked leg on the front side. Then push
the hooked leg backward until it wraps around the
necked portion of the shoe, under the concave face
(see Image #6).
From the right side, partially insert the 274 Bolt into
the bottom coupling body hole. Insert the shoe into
the front opening of the coupling. Align the shoe hole
with the 274 Bolt and slide the bolt through to the left.
Secure the bolt on the left side with the 274A Locknut.
From the front of the coupling, use a flat head screw
driver to push the straight leg of the spring backward,
around to the far backside of the internal body stop,
until it is in the rear-most position (see Image #5).
Rotate the 579 Shoe to verify proper spring tension.
C) FOR MODEL 570 ONLY (using 579 Shoe):
Position the 579 Shoe so the concave portion of the
shoe is facing toward you and the bolt hole is on the
bottom. Hold the 376 Spring so that the hooked leg
is on the top side, hooking to the left, and the straight
leg is pointing upward and away from you. Slide the
spring over the shoe bolt hole on the right side, while
keeping the hooked leg on the front side. Then push
the hooked leg backward until it wraps around the
necked portion of the shoe, under the concave face
(see Image #6).
From the right side, partially insert the 274 Bolt into the
bottom coupling body hole. While holding the straight
leg of the spring behind the shoe face, insert the shoe
into the front opening of the coupling. Align the shoe
hole with the 274 Bolt and slide the bolt through to
the left. Secure the bolt on the left side with the 274A
Locknut.
From the front of the coupling, use a flat head screw
driver to push the straight leg of the spring backward,
around to the far backside of the internal body stop,
until it is in the rear-most position (see Image #5).
Rotate the 579 Shoe to verify proper spring tension.
2) Take the 582A Spring and hold it so that the straight leg
is pointing away from you and the hooked leg is on top
hooking to the left.
3) Insert the 582A Spring into the top interior body, aligning
the spring hole with the right side 374 Bolt body hole and
resting the straight leg along the interior body ledge.
4) Holding the spring in position, partially insert the 374 Bolt,
from the right side, into the body hole until the spring rests
on the bolt (see Image #7).
5) Holding the handle portion of the 372B Locking Pawl,
insert the locking pawl into the top of the coupling. While
securing the hooked leg of the spring along the bottom of
the locking pawl catch ledge, align the hole and slide the

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374 Bolt into the locking pawl hole, until the bolt is flush
inside the locking pawl.
6) IF you have a coupling body model without a built-in
spacer, then follow the instructions below: Otherwise
continue on to #7.
A) Rotate the 372B Locking Pawl backwards (while
making sure that the straight leg of the spring remains
on the interior body ledge) until the 472 Latch can be
inserted.
B) Insert the 472 Latch next to the locking pawl, align the
holes and slide the bolt through until the bolt head is
flush against the body. Secure the bolt on left side
with the 274A Locknut. Skip to #9.
7) Rotate the 372B Locking Pawl backwards (while making
sure that the straight leg of the spring remains on the
interior body ledge) until the locking pawl catch ledge
clears the built-in spacer on the inside body hole. Then
slide the 372B Locking Pawl to the right so that the locking
pawl catch ledge rests below the built-in spacer (see
Image #8).
8) With the 374 Bolt flush inside the 372B Locking Pawl hole,
insert the 472 Latch next to the locking pawl, align the
holes and slide the bolt through until the bolt head is flush
against the body. Secure the bolt on left side with the
274A Locknut.
9) If the 582A Spring is installed correctly, smooth increasing
spring resistance should be felt when rotating the locking
pawl backwards to the open position. If no resistance or
binding is felt, the spring and/or parts are not installed
correctly. Reassemble correctly.
10) IF you have a coupling body model without a built-in
spacer, then follow the instructions below: Otherwise
continue on to #11.
A) Rotate 372B backwards until you clear the interior body
hole.
B) Align the 373B Spacer with the right side’s interior
body hole for the 375 Bolt. Insert the new 375 Bolt
from the right side until the spacer can rest on it.
Release 372B and it will be held in position behind the
373B Spacer (similar to Image #8). Skip to #12.
11) Insert the new 375 Bolt from the right side until it is flush
with the built-in spacer.
12) Take the 373A Spring and hold it so that the straight leg is
pointing downward on the left side, and the hooked leg is
on top hooking to the right.
13) Holding the spring in this position, partially slide the ‘used’
375 Bolt, from the left side, into the top body hole and rest
the spring on the bolt (see Image #9).
14) Rotate and hold the 372B Locking Pawl backward and
insert the 373 Pawl into the top of the coupling. Keeping
the hooked leg of the spring on the bottom catch ledge
of the pawl, align the pawl with the ‘used’ 375 Bolt and
partially slide it through the pawl.
15) From the right side, slide the new 375 Bolt through the 373
Pawl, causing it to displace the ‘used’ bolt out of the left
side.
16) Confirm that the bolt head is flush against the right side
of the body and secure the bolt on left side with the 375A
Locknut.
17) To check for correct installation, rotate the 372B Locking
Pawl backward, then rotate the 373 Pawl backward. They
should each have a smooth increasing spring resistance
when rotating them backwards to the open position. If no
resistance or binding is felt, the spring and/or parts are not
installed correctly. Reassemble correctly.
18) Once the coupling is assembled it should be opened
and closed several times, testing for smooth and correct
operation. DO NOT use the coupling if it does not operate
properly. Call for assistance.
ASSEMBLY IS COMPLETE
NOTE: Use only new Grade-8 fasteners torqued to SAE
specifications when mounting the assembled coupling to
its mounting structure.
WARNING:
Do NOT bind-up (jackknife) any application, as stresses can
cause damage to the hitch, drawbar eye, other components
or any combination of them. Jackknifing may result in failure
of products or components, resulting in detachment of the
trailer while in use.

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IMAGE REFERENCE SECTION
IMAGE #2
IMAGE #3
IMAGE #1
274A:
372B:
373:
373A:
**373B:
374:
375:
375A:
472:
Locknut
Locking Pawl
Pawl
Spring
Spacer
Bolt
Bolt
Locknut
Latch
582A:
*266:
*271:
*274:
*274A:
*279:
Spring
Spring
Thimble
Bolt
Locknut
Shoe
370PK Parts Kit Includes:
*Not included in parts kit, available individually
375
374
274A
373
372B
373A
375A
*271
*266
*279
*274 *274A
**373B
472
582A
**373B Spacer is only for use in older model coupling
bodies. Newer models have a built-in spacer.
- Do not weld on any coupling assembly
- Always use Grade-8 fasteners properly torqued
- Do not apply lubricants to the coupling hook
- Air service chamber must be Type-24 or Type-30 with 90-120 PSI air supply
- Clean & inspect coupling for damage & excessive wear prior to each and
every use
- Lubricate all coupling components at a minimum of 90 day intervals
- Do not bind-up (Jackknife) any application as stresses can cause damage
to products or components, resulting in failure and detachment of the trailer
while in use
IMPORTANT GUIDELINES that apply to all Premier Air Adjusted Couplings

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IMAGE REFERENCE SECTION
IMAGE #4
IMAGE #5
IMAGE #6

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IMAGE #8
IMAGE #9
IMAGE #7
IMAGE REFERENCE SECTION

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(1) VERIFY THAT BOTH COUPLING’S AND
DRAWBAR EYE’S RATED CAPACITIES MEET
YOUR APPLICATION(S) REQUIREMENTS.
(2) DO NOT OVERLOAD COUPLING OR DRAWBAR
EYE.
(3) INSPECT COUPLING, LATCH AND DRAWBAR
EYE FOR CRACKS, BENDING DAMAGE OR
EXCESSIVE WEAR. DO NOT USE IF ANY OF
THESE CONDITIONS EXIST!
(4) CHECK FOR GAP BETWEEN CLOSED LATCH
AND TOP OF HORN OR COUPLING BALL.
DO NOT USE IF GAP IS 3/8 IN. OR MORE.
(5) MAKE SURE COUPLING IS LATCHED AND THAT
LATCH WILL NOT OPEN.
(6) PRIOR TO USE, ALWAYS CONNECT SAFETY
CHAINS OF ADEQUATE STRENGTH FOR
LOAD(S) BEING TOWED.
(7) DO NOT BIND-UP (JACKKNIFE) ANY
APPLICATION AS STRESSES CAN CAUSE
DAMAGE TO THE COUPLING, DRAWBAR EYE,
OTHER COMPONENTS OR ANY COMBINATION
OF THEM. JACKKNIFING MAY RESULT IN
FAILURE OF PRODUCTS OR COMPONENTS,
RESULTING IN DETACHMENT OF THE TRAILER
WHILE IN USE.
(8) DO NOT APPLY LUBRICANTS TO THE COUPLING
HOOK OR DRAWBAR EYE LOOP, AS THEY
CAN COVER UP POSSIBLE DAMAGE AND
ACCELERATE WEAR.
(9) ALWAYS ABIDE BY ALL APPLICABLE STATE AND
FEDERAL REGULATIONS GOVERNING SAFE
AND PROPER TRANSPORTATION.
(10) NEVER STRIKE ANY OF THESE COMPONENTS
WITH A HAMMER OR ANY OTHER DEVICE.
(11) ALWAYS VERIFY PROPER OPERATION
OF LATCHING SYSTEM AND COUPLING
COMPONENTS PRIOR TO DRIVE OFF.
(12) NEVER USE A COUPLING THAT YOU DO NOT
FULLY UNDERSTAND HOW TO PROPERLY
OPERATE AND VERIFY SECURE LATCHING OF.
(13) NEVER REPLACE ANY PART IN ANY OF
PREMIER’S ASSEMBLIES WITH NON-PREMIER
COMPONENTS. DOING SO WILL VOID ALL
WARRANTY AND POTENTIALLY COMPROMISE
THE UNIT’S INTEGRITY, WHICH COULD RESULT
IN PROPERTY DAMAGE, SERIOUS INJURY, OR
DEATH.
ATTENTION !
End Users must read and follow this information.
DISTRIBUTORS & OEM’S: Please ensure that your customers
are made aware of the following information on this page.

WARRANTY: We warrant all Premier products to be free from defects in material or workmanship for one year. We
will repair or replace, at our option, any Premier product which our examination reveals to be defective, provided that
the product is returned to our factory, at Tualatin, Oregon transportation prepaid, within one year of purchase
by the first retail purchaser. Our warranty does not extend to products which have been subject to misuse, neglect,
improper installation, maintenance or application, nor does our warranty extend to products which have been
repaired or altered outside of Premier’s facility unless the repair or alteration has been expressly authorized in
writing by Premier. This warranty is in lieu of all other warranties, express or implied, and excludes warranties
of merchantability, fitness for a particular purpose and otherwise, and in no event will Premier be liable for
incidental, special, contingent or consequential damages.
DISCLAIMER: Although great care has been taken to ensure accurate information throughout this document,
Premier Manufacturing Company must reserve the right to alter any information contained within. These changes
include but are not limited to: Dimensional changes, load capacity and availability of any part or assembly.
© 2010 Premier Manufacturing Company
All rights reserved. Any reproduction of the photographic images or any other portion of this document, including but not limited to the photocopying, or retention and/or storage
in a retrieval system of any kind, is strictly prohibited without prior express written permission from Premier Manufacturing Company.
PREMIER MANUFACTURING COMPANY
THE FIRST NAME IN QUALITY COUPLINGS
800-255-5387 [phone]
www.premier-mfg.com
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WARNING!
Important
Installation Instructions:
Do NOT attempt install
without rst reading all
attached instructions.
Installation must be
performed by a qualied
mechanic only.
370PK Service Guidelines
01/2010