Description

A frequent source of frustration for Triumph owners is the stripping of the threads holding the rear hub to the Trailing Arms (TA). The TAs are made of cast aluminum which is both soft and porous and the six studs on each side are threaded at 5/16″-24, which Triumph only rated at 14-16 foot pounds of torque. Anything more then that and you can strip the threads in the aluminum. Some people just drill and re-tap at 3/8″, but you’re still threading a steel stud into aluminum. The better solution is to use a threaded steel insert in the TA that the stud can screw in to, but the problem with doing that is drilling and tapping 12 holes that remain on center and perpendicular to the TA. If you have even one misaligned, the brake back plate and the rear hub won’t fit properly or not at all. More information below.

Trailing Arm Repair Kit for use with KeenSerts, Helicoils, or 3/8” studs is Part

TARK-Master. This kit is ideal for shops or clubs covering all the versions of trailing arm studs.

KeenSerts – also known as key-lock inserts these can be sourced at many places, I’ll use www.McMaster.com and their part numbers as these were used for our testing. However……McMaster only ships parts domestically, so anyone outside of the United States may want to order Heli-coils which are more readily available worldwide or substitute Recoil brand key lock inserts (very similar to KeenSerts) Recoil brand is available worldwide.

Please note that KeenSerts require an “X” drill size and 7/16-14 bottoming tap. There’s some confusion here because a 7/16-14 tap is labeled to use a “U” drill size, BUT the KeenSerts instructions specify the larger “X” drill size. So don’t make the mistake of using a “U” drill. The KeenSerts directions also call for a countersink but you won’t need one when you use this set-up. If you were “free-handing” the tap, the countersink helps to line you up and get you started. The tap guide used here does all of that for you.

McMaster Part#   Description   https://www.mcmaster.com/

92070A337 7 PIECE KIT with TOOL – BLACK-PHOSPHATE STEEL KEY-LOCK THREAD INSERT, 7-PC THIN WALL REPAIR KT,5/16″-24 INT,7/16″-14 EXT T

92070A250
PACKAGE OF 7 ADDITIONAL INSERTS – BLACK-PHOSPHATE STEEL KEY-LOCK THREAD INSERT, THIN WALL, 5/16″-24 INT THRD, 7/16″-14 EXT, 7/16″L,

1413K42
TAP MAGIC CUTTING AND TAPPING FLUID, FOR ALUMINUM, 4-OUNCE CONTAINER (can use WD40)

2521A644
GENERAL PURPOSE HIGH-SPEED STEEL HAND TAP, BOTTOMING, 7/16″-14, H3 PITCH DIAMETER, 4 FLUTE

2901A168
“X” SIZE DRILL BIT

Please specify the kit based on the threaded inserts that you will be using.

Thread Repair

Helicoils

Heli-Coils are also available from many sources but as a former NAPA store owner I’d just recommend you order NAPA part # BK 770-3082. This kit contains 12 inserts, the insertion tool and the tap. It DOES NOT INCLUDE a 21/64″ drill bit or tap lubricant. Additional inserts can be ordered under NAPA part #BK 770-3132.

Please specify the kit based on the threaded inserts that you will be using.

3/8” studs

This kit, TARK-3/8 is for installing 3/8 studs directly into the aluminum rear hub housing, often required for upgrades to rear CV shafts
TARK – 3/8 – Kit for tapping to 3/8-16 for use with larger studs. This kit does not use inserts. This kit can be used when fitting some CV axles and does not use threaded inserts.

Studs can be purchased from your local auto parts store or from goodparts.com in various lengths.

Contents

• One (1) Alignment Jig
• One (1) Tap guide Helicoil
• One (1) Drill guide Helicoil
• One (1) Tap guide Keenserts
• One (1) Drill guide Keenserts
• One (1) Tap guide 3/8 Studs
• One (1) Drill guide 3/8 Studs

Installation

Detailed documents, videos and downloads on installation can be found in Product Support under the Trailing Arm Kit section.

Also see:Trailing Arm Repair Kit – Set-Up | Trailing Arm Repair Kit (TAK) – Contents.

Download: the “Installation Tip” pdf for use with Inserts

Download: the “Installation Tip” pdf for use without Inserts