Bargman L400 Door Lock Replacement Kit

~ Installation Instructions ~

Thank you for purchasing the Camping Treasures Lock replacement kit.  This kit is designed so the average person can replace the original Bargman L 400 and Lyster 20-213 / 20-214 on their vintage trailer with a modern Bauer lockset.

This kit was specifically designed to replace the Bargman L400 on a 13′ Boler.  Although great care was taken to design our kit it should fit most trailers with smooth flat inner and outer surfaces on the door. Doors with profiles molded into the surface may need some modifications to the door or spacer plates may be required for some applications.  Use the following instructions as a general guideline.  ideally your current door thickness should be between 1⅛” to 1⅜” thick.

If you have any questions, trick or tips please contact me

Lock Installations Overview video

Detailed Installation Instructions


The original Bargman L400 Door Lock


The Camping Treasures Door Lock Replacement Kit

IMPORTANT: Read and understand all instructions before starting

The following items are included in the Lock Replacement Kit

1 – Bauer Door lock, packaged (White or Chrome)
1 – Inner Aluminum Adapter Plate
1 – Outer Aluminum Adapter Plate
1 – Aluminum Striker Plate
2 – #8-32x½” Pan Head Machine Screws (door jam screws)
4 – #8-32x¾” Pan Head Machine Screws (standard screws to attach inner latch plate on thicker doors)
4 – #8-32×1” Pan Head Machine Screws (may need to attach inner latch plate on thicker doors)
2 – #10-24x¾” Flat Head Machine Screws (to attach striker plate to door frame)
2 – #10 Flat Washers (to attach striker plate to door frame)
2 – #10-24 Nuts (to attach striker plate to door frame)
6 – ⅛” Aluminum Rivets
1 roll – Butyl Sealing Tape
1 pair – Disposable Gloves
1 – Dust Mask

NOTE: Due to the global supply shortage, the dust mask and disposable gloves identified in the instructions we will not be included in our kits until further notice

*2 additional striker plates are included that are usually not used for installing this kit in a Boler but may be needed if using this kit on another application

You will need to supply the following tools and supplies

  • Screwdriver, Phillips, Robertson (square) and Slot
  • Safety glasses
  • Paper towels or rags
  • Petroleum free solvent such as;  Methyl Hydrate or Methyl Alcohol, Acetone, Mineral Spirits, Brake Cleaner
  • Painters masking tape
  • Pencil or fine marker
  • Drill with 1/8”, 3/16″ and  5/16” drill bits
  • Jigsaw with fine metal cutting blade, or similar hand saw
  • Tape measure
  • T-square
  • File
  • Pop rivet gun


Painting the Aluminum Adapter Plates

The aluminum Adapter Plates supplied in the our kit are supplied unpainted, you can leave them, polish them or paint them
In these instructions the adapter plates have been painted white

To Paint:

  • Sand the surface lightly with 320 grit or finer sandpaper or a Scotch-Brite Pad
  • Prime with an etching primer or primer specifically designed for aluminum
  • Paint with a quality paint.


Unpainted Adapter Plate with Chrome Lock

Painted Adapter Plate with White Lock

Remove the original lock

  • On the original lock remove the 2 screws attaching the interior plate and handle, then pull the handle and plate straight out, some minor “wiggling” that may be needed to free the shaft.
  • Remove the 1 or 2 screws on the edge of the door holding on the trim plate above the latch bolt.

  • Along the door edge place some masking tape and mark the location above and below the latch bolt assembly on the edge of the door, this will be used later when installing the new lock set

  • Remove the original lock assembly, the outer half of the original lock set will be sealed to the door with butyl tape or sealant.  From the inside apply steady pressure on the edge of the lock assembly closes to the hinges to slowly release the butyl tape seal.

  • With the lock removed measure the thickness of the door to ensure it is 1⅛” to 1⅜” thick.  

NOTE: Only if the door is less than 1⅛” thick then proceed to the last section in these instructions
NOTE: If total door thickness including adapter plates measures greater than 1½” the interior handle may not engage the latch fully causing the interior release to not operate.   

  • Thoroughly clean the area ensuring that all sealant has been removed.
  • It is best to use a petroleum free solvent that does not leave any residue, these include:
    • Methyl Hydrate or Methyl Alcohol
    • Acetone
    • Mineral Spirits
    • Brake Cleaner

NOTE: read and follow product precautions

NOTE: wear protective gloves when handling solvent chemicals

NOTE: many solvents are flammable, use with caution, dispose of rags in a safe manner

  • Apply masking tape to the inside and outside of the door to protect the fibreglass surfaces and for marking the cut lines where the new lock set will be installed


Marking the Opening

  • Hold the inner adapter plate (the plate with the bent edge) tight against the inside or the door and door edge with the notched edge of the plate lined up with the marks you made of the tape locating the original latch bolt.  You want to align the outer edges of the adapter plate cutout with the marks from the original latch bolt assembly.  Refer to picture.

  • With a marker or pencil draw around the inside of the new lock cut-out

  • Using a 5/16” drill bit, drill holes through the door at opposite corners to mark the new opening.  As an option you can also drill 4 holes to mark all the corners

    NEW!!! Use the drill jig included to drill the holes as straight as possible, in the corners and 90 deg to the door surface.

  • Using a T-square along the edge of the door draw a line along the bottom of the lower holes to align the outer adapter plate
  • Hold the outer plate against the door so that the line you just drew aligns with the inside lower cutout on the adapter plate
  • Mark along the bottom of the adapter plate, then use a “T” square against the edge of the door to draw a line along the marks you just made along the bottom of the adapter plate,
    this is to make sure the lock set is square to the door edge,

  • Place the outer adapter plate on the door and align the bottom of the plate with the lower line you just made.
  • Using a fine marker or pencil marker draw around the inside of the lock cutout.
    NOTE: if the corner marking holes don’t line up perfectly don’t worry, these will be covered by the plate

Cutting the Opening

NOTE: Fibreglass dust can be very irritating to your skin and eyes and very hazardous to breath.
Protect yourself, wear long sleeve clothing, disposable gloves (included), dust mask (included) and eye protection

  • The best jig saw blade for cutting fibreglass is one that is designed for cutting ceramic tile (a grit blade) but a fine tooth blade designed for cutting metal also works well on fibreglass.
  • Operate the saw at a slow speed to control the dust and prevent “splintering” of the fibreglass
  • If the door surface is smooth on the inside you can cut from the inside but if there is any profile or contouring on the inside of the door you need to work from the outside smooth surface of the door
  • With the jig saw cut along the marked lines

  • Test fit the new lock assembly and adjust the opening as needed being careful not to make the opening too large.
  • Some trimming or fitting of the fibreglass on the edge of the door may be needed around the latch bolt.

  • Make sure that the two small tabs on the latch housing do not bind, use a file if needed to adjust the opening.
  • Test fit to make sure the latch fits tight on the outside surface of the door

  • Some trimming or fitting of the fibreglass on the edge of the door may be needed around the latch bolt, as seen in this installation

  • As shown in the pictures make sure the latch bolt can move freely, file any fibreglass that may interfere with the movement of the latch.

Installing the Lock Assembly

  • I always recommend test fitting the lock assembly with the plates to make sure everything lines up correctly.
  • Apply the butyl tape on the back side of the outside adapter plate.  The tape should be applied about ¼” from the edge with the joint where the two ends meet located at the bottom of the plate.

  • Remove the masking tape if applied to the door and clean the surface with rubbing alcohol.  When dry, press the outside plate firmly into position making sure the cutout aligns and the plate is square to the edge of the door.  (do not drill or install pop rivets at this time)

  • To install inside adapter plate, hold it in place by starting the two #8-32 flat head machine screws into the latch bolt end of the lockset a few turns.

  • Install the inside door lock handle and assembly, ensure to align the inside latch and install 4 screws, do not tighten yet.

    NOTE: 2 sets of #8-32 machine screws are included with the kit to connect the inner latch handle plate to the the latch assembly (¾” long and 1″ long), if the ¾” long screws are not long enough to engage the screws then use the 1”

  • When tightening the 4 inside screws make sure the plastic arm on the inside plate fully engages the latch release lever on the door lock assembly. Gradually tighten the 4 screws in a criss-cross pattern until snug, do not over tighten.
  • when the screws are tight test the inside handle several times to make sure the latch works freely.  

NOTE: On thicker doors it is possible that if the inside latch arm is not fully engaged it can flip over the release lever making it impossible for the door to be opened from the inside without removing the inside assembly and manually pulling the release lever.

  • Tighten the two flat head machine screws above and below the latch bolts.

  • Double check the door latch and deadbolt operates freely from both the inside and outside handles.

Installing the Striker Plate

The reason aluminum is used for the striker plate rather than steel is because over time the aluminum will wear rather than the steel in the latch bolt.  The aluminum striker plate is very easy and inexpensive to replace when compared to replacing the door latch assembly.


  • The kit includes two chromed striker plates that come with the door lock assembly, these are designed to fit an inset door with a flat door jam. The kit also includes a flat aluminum striker plate that works best on most 13’ Boler’s or trailers that have an overlay door or lip around the door opening.

  • The first thing to test is if the original striker plate allows the door to close completely and engages the latch properly.
  • In just about all cases the original striker plate will not engage the latch and the supplied flat aluminum striker plate will need to be installed

  • If the latch bolts do engage the original striker plate then remove the plate
  • Remove the original striker plate by drilling out the pop rivets
  • Use a screwdriver or small pry bar to remove the striker plate

  • Place masking tape along the door jam, extend the deadbolt and mark the position of the top and bottom of the latches. Use these marks to centre the striker plate when installing

  • In most cases the fibreglass door jam needs to be trimmed slightly to allow the latch bolt and deadbolt to full extend. 

NOTE: This pictures shows how the latch should look after trimming

  • Place strips of the remaining butyl tape on top of the masking tape and extend the deadbolt

  • Gently close the door and press the latch and deadbolt into the butyl tape, this will leave an indent which shows how much the edge of the door jam needs to be trimmed

  • Mark the masking tape where the dead bolt and door latch extended to
  • Use a round file on the top and bottom mark, then use the jig saw to cut the remaining fibreglass between where you filed
  • You will find that the door jam usually has to be trimmed about  ¼”

  • The flat aluminum striker plate is installed on the outside of the door jam by centering it with the latch bolts, use the marks you made on the masking tape as a reference
  • With the door closed measure the distance from the edge of the door jam to the side of the door, position the striker plate so it does not hit the door but the latch bolt if fully engaged (usually the striker plate sits slightly less than a ¼” proud of the edge of the jam
  • Drill two – 3/16” holes through the fibreglass, Start by drilling one hole then install the flat head machine screw through the striker plate and door jam, then install a washer and nut on the back side and snug it up.  Then align the plate, drill the second holes, install the machine screw, washer and nut and tighten both machine screws.

  • Test close the door, and adjust as needed.

  • Attach the outside plate by drilling through the 1/8″ holes in the plate and into the door
  • Install the four aluminum pop rivets
    NOTE: we have updated to plate to use four rivets, the image shows a prototype plate that only uses two rivets

  • Repeat the operation on the inside plate by drilling through the two 1/8″ holes in the plate and into the door
  • Install the two aluminum pop rivets

  • Remove any excess butyl tape that has squeezed out
  • Clean the area with a cloth or shop rag dampened in solvent

Your new lock assembly is complete

17′ Boler & Trailers with Profiled Doors

The inner panel of the door needs a smooth level surface and the door thickness at least 1 ⅛” thick.  The inside of the 17′ Boler has a raised profile where the original Bargman L400 mounts.  To install the Camping Treasures Door Lock Kit on these doors follow the general instructions above, then after the opening has been cut through the door position the inner plate and draw a line along the left edge.  Remove the lock and plates and using a Dremel tool with a small cutoff wheel carefully cut along line and along the ridges even with the door surface (wear the dust mask when working on fibreglass).

Cut along the marked line shown in red

This picture shows the finished installation on a 17′ Boler where the protruding profile on the door has been removed to allow the inside plate to sit flush on the door this reduces the overall door thickness to the required dimension of between 1⅛” to 1⅜” including the adapter plates.

If your door is less than 1⅛” thick there may be the need to cut a spacer plate to increase the door thickness or fill  gap.  A spacer plate can be installed on the interior surface of the door either between the adapter plate and the door surface, or between the adapter plate and the interior latch handle assembly, depending on your situation.   You can make the spacer plates from any material, options include thin plywood or wood strips, plastic or acrylic, leftover laminate flooring, etc.  Use the inner adapter plate as a template to mark the spacer.