TB10002

TECHNICAL BULLETIN
Subject:

DuraPlate AeroSkirt™ Spring Post Tension Enhancement

Date:

June 18, 2010

Re.:

DuraPlate AeroSkirt™ Spring Post Tension

Priority:

As needed

Units Affected:

All

Background:
Due to variations in supplied components, some DuraPlate® AeroSkirt™ Spring Post Assemblies were
manufactured with less than intended spring preload. In high crosswind conditions this can result in
excessive inward and outward movement of the DuraPlate® AeroSkirt™ assembly. This document
describes the procedure for adjusting the spring preload by installing P/N 21800229, DuraPlate®
Aeroskirt™ Post Tensioning Kits, (one per post), to correct this issue. All repairs must be made
promptly, especially if operating in high crosswinds.

Material / Tool Requirements:
Qty:
8*

Items No.
21800229

Description
DuraPlate® Aeroskirt™ Post Tensioning Kit

* LTL or Pup trailers typically require six since they usually only have six DuraPlate® AeroSkirt™
Spring Post Assemblies IPO the eight used on full size trailers.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 1 of 8

•
•
•

CAUTION
Wear appropriate personal protective equipment (PPE) including, but not limited to safety glasses and cut-resistant
gloves when carrying out this work.
When working beneath the trailer a bump cap is advised.
Follow your company safety procedures in addition to these recommendations.

Inspection & Repair:
Note: If any components of the DuraPlate® AeroSkirt™ are missing or damaged they should be
repaired or replaced prior to implementing this repair procedure. Refer to TB09007, Inspection and
Repair Procedures for DuraPlate AeroSkirt™, available through the Wabash National Warranty
Department, (765) 771-5404 or email us at [email protected].
1. Please read through the entire instruction document prior to beginning the repair
procedure.
2.

3. Open the repair kit packaging and remove one Spring Post Tension Assembly which is comprised
of one (1) Spring Post Tension Bracket, one (1) Spring Post Tension J-Bolt, and one (1) 3/8-16
Nylock Nut.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 2 of 8

4. Insert a 1" hole saw into your drill and set the pilot bit so that it does not protrude more than 1/8"
from the hole saw as shown below. Install a stop collar on the hole saw to limit the drilling depth
to 1/8" as shown:

5. While positioned under the trailer, locate one of the post assemblies and measure up from the
bottom of said post as shown in the illustration below. With the post marked 13-3/4" up from the
bottom edge, drill a hole in the center of the post as shown below BEING EXTREMELY
CAREFUL NOT TO DRILL INTO THE SPRING. If possible, slide a narrow strip of sheet metal
up inside of the post between the spring and the area being drilled with the hole saw to further
insure that the spring is not damaged by the drilling process.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 3 of 8

6. Remove the Nylock Nut, Flat Washer and Tension Bracket and set aside for reinstallation
momentarily.
7. Prepare the J-bolt by wrapping a single wrap of electrical or masking tape around the threaded
end and twist the end of the tape to a point as shown. This will ease the installation of the Spring
Post Tensioning Bracket later in the installation process.

8. Slide the J-bolt into the post as shown below, with the hook against the steel post and the open
end of the J-bolt facing the same side as the spring hook.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 4 of 8

9. Rotate the J-Bolt as shown below to position it for engaging the spring eye or spring hook.

10. With the J-Hook in the position shown below, slide it up and down against the side of the spring
until it slides into the opening of the spring eye or spring hook.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 5 of 8

11. This is a frontal view showing the hook properly engaged with the spring eye to illustrate the
proper position. Note” The DuraPlate® panel is omitted from this view for illustration purposes.

12. With the J-Bolt engaged on the Spring Eye as shown, guide the Spring Post Tension Bracket
over the threaded end of the J-Bolt. The (previously applied) layer of tape around the treaded end
of the J-bolt eases this task by extending the length of the J-bolt below the post, thereby making it
easier to thread it through the bracket. See image below.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 6 of 8

13. Install the flat washer and lock nut as shown with a few drops of oil or light grease applied to the
threads and both sides of the flat washer. Tighten the lock nut until the measurement between the
bottom of the bracket and the end of the J-bolt equals 2.25” as shown below. Do not remove the
spring bolt that goes through the existing chain.

14. Manually deflect (push) the post inward and outward approximately 6” to 10” to verify that the Jbolt is engaged properly.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 7 of 8

15. Repeat the above steps on the remaining DuraPlate® AeroSkirt™ posts to complete this repair. On
a typical 48’- 53’ trailer there will be eight (8) total posts while LTL or Pups will usually have six
(6) post assemblies.

This Concludes the repair procedure, if you have any questions please feel free to contact the Wabash
National Warranty Department, (765) 771-5404 or email us at [email protected].

Labor Hours:
The SRT (standard repair time) is 0.2 hrs per post assembly.

Wabash National, P.O. Box 6129, Lafayette, IN 47903
765-771-5404
[email protected]
TB10002, Duraplate Aeroskirt Spring Tension Enhancement.doc, Page 8 of 8