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Adapter Assembly Instructions

It is recommended that you watch the adaptor assembly videos @


Items you will need:

* Strap wrench

* AN wrench (Available on Autoplumb Website)

* Silicone Adhesive

(Please use Permatex Ultra Black Gasket Maker or equivalent “ silicone adhesive”) Use only Adhesive type gasket maker. Do Not use regular silicone.

Silicone adhesive is not used as a sealant. It is used to provide lubricant for the seal to smoothly and fully engage the taper during assembly. After curing it adds additional strength and rigidity to the assembly.

First, Disassemble the Adapter.  Apply the assembly tape (shipped inside of the Adapter) to the Adaptor ring. Viewing the ring from the back, wrap the tape clockwise.  Next make certain that the back of the bead on your water neck to the face of water neck measures 5/16” or less. Trim the face of the water neck if necessary.

Thoroughly clean the water neck.  As seen on the Assembly video at place the adaptor ring onto the water neck as shown.

Lubricate the shim with a small film of grease. Coil the shim onto the water neck.

Apply silicone adhesive generously to the entire seal.

Slide the seal onto the water neck, “Important” with the chamfer facing out toward the end of the water neck. Distribute any excess silicone from the end of the water neck up against and around the outer edge of the seal. Apply a small amount of lubricant to the threads of the Adaptor Body.  Place it and hold it firmly up against the face of the water neck. Thread the ring onto the Adapter body and hand tighten the ring as tight as possible. Use the AN wrench and strap wrench to tighten the assembly, go slowly and tighten as tight as possible. The Adaptor Ring should meet flush or within .075” of the Adapter body. Lacquer thinner is safe to clean the Adapter. Make certain the Adapter is square and in line with the water neck.  Allow to set several hours, overnight if possible before disturbing.

After being allowed to set up your adaptor will be firmly attached to the water neck but is still removable and reusable. NOTE: When assembling Hose ends to the Adaptor, “ALWAYS” support the Adaptor with a wrench before tightening or loosening a hose. Do not over tighten. Re-check connections after initial warm-up.     

**Special Instructions.

Installation on Water Necks without a Bead/Barb

LS Water Pumps

-20AN Hose Assembly

Barb Adapter Assembly

**Special Instructions  for Water Necks without or for the removal of the bead:

Autoplumb adapters are designed to fit over the raised bead. It is recommended that it remain on the water neck whenever possible. In some cases a water neck has no bead or due to space   restrictions or appearance concerns users have chosen to remove the bead. This procedure has proven to be safe and effective. There have been no reported failures. It is left up to the sole discretion of the installer to remove it.       

Caution: a minimum of 1” of water neck length is required to be able to install the Adapter.

Follow all instructions as stated previously, with this addition. When installing the rubber seal push it past the end of the water neck leaving approximately 3/8” of water neck exposed. Using the silicone adhesive apply a generous bead around the water neck in front of the seal effectively creating a bead. Place the Adapter body onto the water neck and hold it by hand firmly and squarely against the end of the water neck. Apply lubricant to the threads and screw the adapter ring onto the body and hand tighten as tight as possible. While holding the Adapter firmly against the face of the water neck use you’re AN wrench and strap wrench to tighten.  There should be no threads showing and the ring should be flush or within .075” of the Adapter body. Make sure the Adapter is square and Do not disturb for 24 hours.


LS Water Pumps:

Most all LS pumps have 2 beads on the water neck. For space and appearance purposes it is ok to remove the outer bead (Recommended). Cut squarely up to and as close as possible to the second bead . Do not remove the second bead. There should be no more than 5/16” left from the back of the bead to the face of the water neck.

Take a look at the LS pump on the Adapter assembly video at


-20AN Hose Assembly:

I recommend that you watch the -20AN hose end assembly video at before attempting the assembly process. To prevent damage to your hose end it is important to have a correct fitting AN wrench and a set of AN aluminum vise jaws. Both these items can be found on our website. As you will see on the video you should place the sleeve all the way up to the face of the vise jaws where the sleeve is the thickest. This prevents the jaws from denting the hex of the sleeve.  Also toward the end of the tightening process turning gets really difficult. Using a heat gun on the sleeve at this point will greatly reduce the pressure of turning and greatly reduce the chance of damage. If you have any questions please give me a call, I would be happy to help.


Barb Adapter Assembly:

It may be necessary to remove a small amount of OD off the barb to allow the hexed ring to go over the barb. Install the hexed ring and o-ring over the barb. Liberally coat the assembly with Permatex Ultra Black Silicone Adhesive. Screw together and let set 24 hours.


For more assembly assistance call Joe @ Autoplumb 405-823-7149