More Boler Adventures: Repairing the Bargman L-400 lock

Bargman L-400 lock

The Bargman L-400 is the lockset that was originally fitted to all Boler camper trailers (1969-1988) along with the some Trilliums, the Airstream Argosy and maybe other small campers of similar vintage. The Detroit-based Theodore Bargman Company goes way back to the early 1930s, making door locks and other RV parts from the 1940s, and L-400s from the late 1960s into the 1990s (maybe the 2000s). Unfortunately, the L-400 was never what you’d call a quality piece, and so it is that many Bolers have outlived their locks, requiring owners to supplement them through various means, or to simply junk them in favour of something that works.

But we (those who will continue reading) don’t want to throw out our ailing L-400s. We want them to live!

Don’t look to Bargman for help, though, because while the company still exists, it no longer makes the L-400 – or any other locks for that matter – and isn’t interested in supporting owners of them. So the L-400 cannot be replaced with a new or factory “repro” version, and parts are no longer available through RV parts retailers (although one brave soul named Ian Giles has developed and is offering a replacement. Find it at Boler door lock replacement).

At this point, if an L-400 needs repair you have three choices; first, find replacement parts online and take them and your lock to a locksmith; second, find the parts and repair it yourself; and third, replace your L-400 with a non-original lock of dubious fitment. Alternatively, you can search for a new-old-stock (NOS) L-400 online. They do come up, but given the prices, you’d think they were made of solid gold rather than pot metal. Still, if you’re a motivated buyer…

Of course, many vintage trailer owners are keen to keep theirs original, and the only lock that will do is a working L-400 (it’s part of the history, right?). So here’s some L-400 information that may help you fix yours.

Bargman L-400 lock. Interior of paddle handle is wearing away at the tip. Note location of nylon bushing that stabilizes pin

The Bargman L-400 features a distinctive “paddle” handle design, and despite the lock’s generally low quality, many are still somewhat operational. The benefit of paddle handle designs, by the way, is that they fit flush with the exterior, which is certainly desirable on a camper. Despite their shortcomings, many Boler owners (me included) really prize a working L-400 for its period authenticity, and to be fair, the Bargman company likely didn’t envision people using them a half-century on. Consequently, for those who like the original look, finding or fixing an L-400 is a most satisfying occasion!

Making things complicated is the fact that there are two L-400 versions (at least, two that I have found). From the outside they look the same, but inside there are differences. Here we’ll just digress into some lock parts terminology (courtesy of the venerable Master Locksmiths Association’s “Glossary of Lock Terminology”).

Inside the L-400 you’ll find a bolt assembly consisting of a steel bar onto which a bolt is attached at one end. If you’re not sure what a “bolt” is, here’s the Master Locksmiths Associations’s eloquent definition:

The part of a lock or latch which provides fastening or engagement by protruding from the case or forend to engage in the staple, striking plate, link, shackle or other member.

Bargman L-400 lock. The two bolt assemblies. 050 and 051

Got that? For us lay people, the bolt is the bit that sticks out of the door, flat on one side, curved on the other. The L400’s is permanently cast to the stamped metal bar and together they’re called the bolt assembly. If you need a new bolt, you must get a new bolt assembly. They come as one.

Another bit to know about is the shank assembly. It’s the piece that attaches to the handle that causes the bolt assembly to move in and out (find it on the exploded diagram below, parts 10-40-702 and 10-40-716). It’s attached to a spring.

Okay, so the replaceable internal parts of the L-400 that are not common to the two L-400 versions are the bolt assemblies and the shank assemblies. One L-400 model has a Bargman part number 10-40-050 bolt assembly, and the other has a 10-40-051 bolt assembly. The numbers are stamped on them, and they share the same lockbody 10-40-010.

As I say, each version of the bolt assembly has a specific shank assembly and locking mechanism associated with it. What this means is that you can’t replace a 10-40-050 bolt assembly with a 10-40-51 bolt assembly. You have to have the right one, as even if you change the corresponding shank assembly, it still won’t fit the locking mechanism. We know from examining Bargman repair kits that Bargman updated the shank, bolt and locking components in 1984, so the two L-400 variants represent locksets made pre-and post-1984. This means the majority of bolt assemblies for Bolers will be 10-40-050 because the majority of Bolers were built before 1984. Both L-400 versions will fit and work in all Bolers, though. As I say, they are externally identical.

Grey painted Bargman L-400

You may also find a later-build (post 1984) L-400 distinguished by being finished in a gloss light grey paint as opposed to the chromed versions found on most, if not all, Bolers. The finish is a purely cosmetic difference. Should you come across one of these, it’s exactly the same lockset and dimensions as the chrome version, and will be a perfectly adequate, if not a perfectly original replacement. Then again, you may rather have a correct, working NOS grey L-400 as opposed to a nonstandard replacement that will likely require you to cut into your door to install.

In my journey of L-400 discovery I’ve determined that there are two parts of this lockset that will fail over time. These are the bolt and the paddle handle, and they are responsible for most L-400 problems. Both fail by wearing away over time so that they can no longer make adequate contact with contiguous parts. In the case of the bolt, it wears away so that it no longer engages with the striker plate in the doorframe. The result is that your door won’t lock or stay closed (this is a result of the cheap soft metal used for the bolt. If it had been made of brass, it would have held its shape forever).

Bargman L-400 lock. Failing bolt

Bargman L-400 lock. Badly worn bolt (top) compared with new bolt

Regarding the handle, there is a metal protuberance on the back that is designed to capture the bolt assembly and move it sideways so that the bolt goes in and out of the lockset (again, thus enabling your door to open and stay shut). Like the bolt, the metal on the back of the handle wears away and it simply loses sufficient contact with the bolt assembly. An indication that this failure is imminent is a paddle handle that has a lot of play. It seems completely loose; you can maybe pull it out an inch before you feel the bolt assembly moving, but even then, it may not move much.

In both cases – the bolt and the paddle handle – replacement is the only option if they’re badly worn. To the best of my knowledge, they cannot be fixed. But if you can source NOS replacements for the offending parts, you may get that lock working again.

You don’t have to remove the lock from your trailer to determine if it needs these parts. Look at the bolt sticking out of the door. All worn down at the tip? It’s toast. And operate the paddle handle. If it’s got lots of play and the bolt barely moves, you’ll need one of those, too (they come up on ebay occasionally for about $35.00).

Then there is the key cylinder. They seem quite long-lived, but if the cylinder simply won’t turn, maybe yours has failed (or it could just need some light oil). The good news is that these seem to have more availability than the other L-400 parts (at least, I’ve come across a half-dozen without looking hard). It should go without saying, though, that if you find a replacement cylinder, it needs its key! The keys are not interchangeable although each keyset is not necessarily unique to its cylinder. I suspect that Boler made several cylinder/key combinations reducing, but not eliminating, the chance that your key would work in your neighbour’s Boler.

The keys should come in pairs with a small numbered metal disc identifying them. I had key cylinders PK504, PK 876, PK570 (tellingly, two sets of those), along with the corresponding keys (they’re sold now). More good news is that if you find a complete NOS lockset, it will come with its keys (or it should!). If it doesn’t, it’s likely that a good locksmith could make keys that do the job (but it won’t have the distinctive “B” for Bargman on them). Changing the key cylinder, however, is a not job for those easily upset by small, fiddly, willfully uncooperative devices (I felt my BP go up just thinking about this…).

Bargman L-400 lock. Repair kit

There’s yet more good news, though. As alluded to above, Bargman made repair kits for the L-400. Last year, I purchased one of these on ebay for $75.00 US (about $900 Canadian). Okay, I exaggerate…. a little. But there was also shipping, customs, exchange, handling, brokerage fees, administration, bribes, tips and taxes to consider, which, you know, irks. Anyway, after arranging financing I was delighted to find that the repair kit is a treasure trove of L-400 lock parts that included both bolt assembly versions and a keyset, along with a replacement spring, clips, the two shanks, screws, a useful exploded diagram of an L-400 and a substantial and finely constructed striker plate that in no way can be made to fit the door frame of a Boler. But good on Bargman for making at least one item of lasting quality.

The repair kit I bought came in a plastic bag tagged Bargman Replacement Parts for L-400 Door Lock.” Another version arrives in a green plastic bag but it only says “Repair Kit” on it, along with the Bargman part number 11-40-302.

Bargman L-400 Repair Kit

Clearly both these repair kits were made post 1984 because they both include the two bolt assemblies. If you see one for sale, just hold your nose and pay.

I’ll get to lubrication in a moment, but first I want to talk about removal, which is a piece of cake. There are two screws in the lock body and two more at the latch where the bolt protrudes. Carefully remove the four screws ensuring that in no way do they make unintended contact with the ground, then pull the inside plate with the conventional lever handle away from the door (don’t worry, it’s not going to explode into a hundred bits in your hand). The main part of the lockset with the paddle handle will then be completely unattached so you can take the screws and the lock to your fully provisioned machine shop with programmable hi-tech lathes, drills and presses, or to the nearest picnic table.

Take a look at the lock. You’ll see a spring, and the back end of the bolt assembly (you should be able to identify the number) and the locking mechanism. If you move the paddle handle, you should see the bolt assembly slide and the bolt move in and out of the lockset body. You may also see that the whole thing is gummed up with old grease, dirt, corrosion and maybe a deceased insect or two. Without going any further you could spray some WD-40 on the works and clean it up with a cloth. Just doing that could help, at which point you could reinstall the L-400, run into the house and yell, “Honey, I fixed the Boler lock!”

Bargman L-400 lock. The works, showing locking mechanism, spring, and tip of paddle handle engaged with bolt assembly.

This is always impressive, especially when there’s noticeable improvement. However, in the case of these locks, it probably requires disassembly and parts replacement, which actually is nowhere near as daunting as you might imagine (then again, I habitually own vintage British sports cars and have therefore built up a tolerance for mechanical absurdities).

First thing to do is take some pictures of your L-400 as a reference for how it’s supposed to look when reassembled. Yes, you’re going to be careful taking it apart and it will seem an easy thing to simply reverse the order when reassembling, but a guide never hurts, especially as there are several parts and C-clips to manage. Notice where things are, and examine the metal protuberance on the back of the handle (mentioned above, which probably has an actual locksmithy name other than “protuberance” but was not singled out by the Master Locksmiths Association. I plan on writing a letter.). As I say, sometimes these are so badly worn that they can’t sufficiently engage the bolt assembly.

Bargman L-400 lock. Handle pin. Punch from this side.

Assuming you’ve acquired a replacement bolt assembly and paddle handle if required, the key (no pun intended) to replacing the bolt assembly is to remove the handle first. This is accomplished by dislodging the pin that holds the handle in place, one end of which is slightly fatter and knurled. You’ll want a punch and a small hammer and you’ll punch from the end that’s not knurled.

A few taps and you’ll see the pin emerge, then drop into your hand (it’s only knurled for about a half-inch). Now, one caveat here… with the handle out of the way, you’ll see that the shank assembly passes through the main lock body and is secured to it with a tiny clip. You’ll have to remove that clip to unfasten the shank, which will permit you to remove the shank, spring and the bolt assembly. Come to think of it, I reckon the operation of the whole darned lock is dependent on that tiny clip. Don’t lose it!

Additionally, take another look at the handle now that it’s removed, and you’ll notice two nylon bushings that stabilize the pin (pictured above). If you’re not re-using the handle, save the bushings as you might need them for your replacement.

With the handle removed, you can slide the old bolt assembly out, clean everything up, add some grease, slide in the new bolt assembly, position its spring and replace the shank. Check for correct operation.

There will be some tension on the spring when you replace the handle, so you’ll need to hold everything in place with one hand, and position the pin to drive it back in with your two other hands. Finally, fitting the tiny clip back on to the shank with the handle in place may be challenging.

Voilà! Almost fixed!

In the event that you are replacing the key cylinder, this would not be the time to do it as you’ll certainly need a massage and a good night’s sleep. However, when you do tackle the cylinder, you will likely be completely mystified as to how removing it could even be possible. Examining the L-400, there appears to be no obvious access point from the lockset body to the cylinder at all.

Bargman L-400 key cylinder with keys.

Without exaggeration, this took me days to figure out. Perhaps this technology is an everyday part of the locksmith world, but it sure isn’t part of mine and honestly, I think even British automobile engineers would be impressed at the devilish level of obscurity and challenge built into this lock when it comes to removing the L-400 key cylinder. That’s assuming the L-400 wasn’t deliberately designed to prevent owners from fixing them (which, let’s face it, could be the case). But assuming Bargman isn’t completely malicious, there really is only one way to change this cylinder, and the solution, as with many things in life, is to approach it from the rear.

The cylinder, as you can see in the images, contains a number of brass discs (or plates), one of which is taller than the others. Viewing from another angle, you can see a tiny circular component beneath the tall one, which is a spring. By pressing on the tall disc it can be made flush with the cylinder body. Here resides the solution to the cylinder’s removal.

Bargman L-400 lock. Note the flash of brass at nine o’clock. That’s what you have to push in to get the cylinder out.

Your task, should you accept, is to fashion a very thin metal probe (I used a long, skinny nail…) to fit in the miniscule space between the failed key cylinder and the lock body and manipulate it in such a way as to push the disc into the cylinder, freeing it from the slot in the lock body that holds it in place (it’s another three-handed job). Thus achieved, the old key cylinder will willingly slide out. This, in and of itself, is cause for champagne and a large party because, well… why not? You got the damned cylinder out!

Bargman L-400 lock. Key cylinder internal spring

But wait, as they say, there is more, and this is the time and place where character is truly built because getting the new cylinder in is actually harder than getting the old one out. Really, it’s ridiculous. I would suggest meditation or at least the rest of the champagne as preparation.

Here’s some important advice, though. First of all, it can be done. Secondly, don’t make the mistake of putting the lock in upside-down (it will happily fit that way). If you do, it’ll still work, but you’ll have to put your key in upside-down to lock the door, which will become an idiosyncrasy of your particular Boler that will have future owners scratching their heads as they obsessively contemplate revisiting your excellent if flawed work on the L-400.

One more thing. I mentioned earlier the presence of a nicely constructed striker plate. There are two striker plates supplied in the repair kit, actually… one for the doorframe and one for the door, through which the bolt protrudes and which you use to help secure the lock into door.

Door striker plate that comes with Bargman repair kit. Won’t fit your Boler!

OE Boler striker plate of dubious quality, but it fits so hang on to it!

Note that neither of the striker plates supplied in the repair kits fit Bolers. Here are pictures of the nice useless Bargman striker plate, and next to it the cheesy jerry-built “original equipment” striker plate that’s in my door, likely fashioned by our friends at Boler back in the day. As I say, this plate is an important component as it enables you to secure the front of the the lock to the door with two short screws. A nicer plate would have been appreciated and I guess if you know what you’re doing with metal, you could make a better one. But important note to self: If you do get a NOS lock or repair kit, don’t toss your Boler’s original striker plate!

Well, that’s about it, folks. That is my data dump. I think I’ve pretty much got the measure of the humble Bargman L-400.

Now tell me there’s another way to get that cylinder out…

Update: Now that I know how to do it, replacing the key cylinder is not such a difficult task (for me, though, a good set of reading glasses helps). Fact is, using a flashlight to peer into the space between the cylinder and the lockbody, you can see that brass disc, and if you use a skinny enough nail with a nice point on it, or maybe a super-thin mini screwdriver, you can fairly easily push the disc in, and the cylinder just drops out. Replacing with a new cylinder is likewise straightforward. Just drop it in, insert your nail or equivalent and push the disc it into the lock whereupon it’ll willingly move into place.

Holy Grail. NOS Bargman L-400 lock with keys.


Skip to comment form

    • Norm on May 17, 2018 at 8:48 pm
    • Reply

    Paul, THANK YOU! not only for providing the ability for us to swap out a lock on our boler handle, but for the fantastic humour along the way! I had to read the article several times, just so I could stop laughing and pay attention to what I was actually doing.

    Now that I have my lock functioning again, I’m going to go have a beer and celebrate.

    thanks Again

      • on May 25, 2018 at 5:06 pm
      • Reply

      Hey, Norm, my pleasure! I, too, had a beer and celebrated!

        • Daryl on November 19, 2018 at 3:05 am
        • Reply


        Thanks for the great article. Helped me rebuild mine big time! One question for you. When you turn the key (my lock cylinder spins freely with the key) the tab the cylinder it is supposed to move on the lock mechanism is broken off. Is the lock mechanism available as a replacement part? It was not in my rebuild kit. Thanks for all the help

          • on November 19, 2018 at 12:25 pm
          • Reply

          Hi Daryl, glad the article helped! There should have been a lock cylinder and a pair of keys in the repair kit. At least there was in both of the kits I found. I also found a couple of cylinders on Kijiji. Otherwise, unfortunately, they’re not available and I have none left.

  1. Hi Paul,
    It turns out that Trillium also used the L400 lock. I just bought a wreck of a trailer and it didn’t have keys. I thought pulling the cylinder should help me get a replacement. with a little help from your post and some lock picking skills I had. Ive got the cylinder in my hands and now I need to find a locksmith who can make me a key.

    Thanks for explaining in detail how to get it apart. I had a much easier time because of your helpful instructions.

      • on June 29, 2018 at 3:58 pm
      • Reply

      Glad to be of assistance, John. I’ve got a couple of key/cylinder sets, so let me know if you need one.

    • Matt Burch on July 20, 2018 at 4:24 pm
    • Reply

    Just need a new lock core and key!!!!!????? Can anyone help
    me secure my brought back to life 1982 17’ Boler?!!!

      • on July 28, 2018 at 5:57 pm
      • Reply

      I’ve got a cylinder and key. Send me a note at

    • Carlin on September 25, 2018 at 11:27 am
    • Reply

    Hello! I have a 1976 Boler 1300. The Original Bargman L-400 still functions perfectly – however. The Dead Latch is so warn out that it has developed a concave and the little bit of play when locked is enough to let the door clear the strike plate – I have taken it around town to see if a welder could build up the end of the dead latch to the point that I can then file it back down to the original shape to no avail – does anyone have a suggestion? I’d really like to avoid replacing the whole lock being that it is original and still “works”.

    Many Thanks,

      • on September 25, 2018 at 11:35 am
      • Reply

      Hi Carlin, I may have one. I’ll email you.

        • Frances Stowe on August 31, 2021 at 5:42 pm
        • Reply

        I did not get a key for the 17′ I just purchased (the previous owner did not have a key), any chance you can cut new keys if I find someone with a key?

    • Anke on October 22, 2018 at 2:57 am
    • Reply

    Hello Paul,

    Do you still have a cylinder and keys for the L400 left? I recently got myself a 17ft Boler; it needs some TLC (which will keep me busy for a while) but the original lock still works I think. The only thing is – I don’t have a key. If I could replace the cylinder with a new one, I could keep the lock. Many thanks for considering!


      • on October 31, 2018 at 6:56 pm
      • Reply

      Hi Anke, you’re in luck. I have one left. I’ll email you…

    • Colleen on October 22, 2018 at 5:08 pm
    • Reply

    Paul-it’s folks like you who make the internet good!! I have a Trillium with an L-400 lock, but no key. I ordered a replacement cylinder, and without your instructions, this would have been wayyyyyyy to daunting to take on.

    Of course, after cleaning up the lock and attempting to take the old cylinder out, I tried the keys from the new cylinder just on a whim, and lo, it worked! So lucky! I better go play the lottery today…

    Anyway, many thanks for a such a fun and thorough lock anatomy lesson!


      • on October 31, 2018 at 6:47 pm
      • Reply

      You’re welcome! Thanks for the kind comments, Colleen.

    • Rob Gilmour on December 23, 2018 at 5:18 pm
    • Reply

    I’m also looking for cylinder and key. Any chance anyone has one for sale?

    • Sandy on January 3, 2019 at 1:59 pm
    • Reply

    So do u have any replacement kits available at this time ? Or where we can find one for the L400 Bargman

      • on January 10, 2019 at 11:52 pm
      • Reply

      I don’t have any kits, unfortunately. I’m seeing them occasionally on Ebay, so put a “saved search” on Bargman L-400.

    • William Urie on March 13, 2019 at 6:34 pm
    • Reply


    I’m another one in need of a Bargman L-400. I have 1977 Surfside (similar to a boler). I need a bolt assembly and key and key cylinder. thank you for your help. Bill

      • on March 13, 2019 at 7:04 pm
      • Reply

      Hi Bill, I’ll keep and eye out for you. They’re getting harder to find, with people asking for stupid money on eBay. Frustrating!

    • Cory mcmillan on May 21, 2019 at 2:47 pm
    • Reply


    I’m trying to find a bolt replacement for the Bargman to no avail. How can I find this Ian Giles fellow? And is he still making replacements?

      • on May 21, 2019 at 6:15 pm
      • Reply

      Hi Cory, find him here:

    • Derek Klotz on May 31, 2019 at 5:23 pm
    • Reply

    Hi Paul,
    Thankyou for taking the time to explain the workings of the L400. I had it easy getting the lock cylinder out: the back cracked off at the retaining clip. And, of course the little spring that activates the clip went into orbit. So, now I’m looking for a cylinder and keys. Are you aware of any available?

      • on May 31, 2019 at 6:50 pm
      • Reply

      Not right now, Derek. One was on ebay recently as part of a repair kit. Keep an eye on Ebay!

        • derek klotz on June 22, 2020 at 10:03 pm
        • Reply

        Hi Paul,
        Well its a year later and I didn’t find a Bargman lock cylinder. However, I’m trying a few substitutes that fit the lock barrel but don’t have the right double cam shape on the back. I need to understand how the cam interacts with the lock mechanism both clockwise and anticlockwise. I have the original L400 (bolt 050). The lock mechanism is very different from the photos in your article. It’s hard to read but the part # looks like 10-40-090. The lock mechanism flops up and down loosely and I’m wondering if it was supposed to be tensioned in some way. As it is now, if the cam pin at the bottom rotates up into the locking mechanism, the bolt is released but as the cam reaches the top position, the locking mechanism is disengaged, falls down and the bolt is locked again. Any guidance you could give on how this should work would be much appreciated.

        best regards,
        Derek Klotz

    • Scott on September 16, 2019 at 12:45 am
    • Reply

    Thank you for accurate, yet funny, explanation and directions. I recently corrected the sagging door on my 1978 Trillium and it became immediately apparent that the bolt was so worn that you could open the door with it locked. I removed the bolt and took it to a local welder I know and he cut further back in the hard steel and welded a 1/4″ spacer which gave me room to shape the end of the striker. Locks like a charm now. I always like it when you can salvage something so it’ll last longer. Cheers, Scott

    • Donnell Bonds on July 4, 2020 at 9:49 pm
    • Reply

    Great Article.
    Just wondering if my L400 can be repaired?
    Backing Plate has a small crack around the bottom screw.
    Lock wont lock and the inside lever for locking is missing whatever held it on.
    would the repair kit rebuild this lock?
    Sincerely, Donnell

    • Derek Klotz on July 28, 2020 at 7:10 pm
    • Reply

    Hi Paul,
    I replied with another question this June 2020 to your 31 May 2019 answer about the Bargman L400 locking mechanism. (I’ve successfully customized a patio door wafer lock to replace my broken cylinder in the meantime). I’m still puzzled about the looseness of the locking arm.

    Perhaps I should have started a new comment rather than send a reply. If you could take a look I would really appreciate it.

    best regards

    • SF on June 18, 2021 at 8:33 pm
    • Reply

    You may be interested to know that the Beachcomber fiberglass trailer also uses this lock set. And after reading your instructions, I will be using tape to keep my door shut as I lack any useful skills! LOL

    • chris andrade on January 7, 2022 at 10:56 pm
    • Reply

    Im curious if you are still answering these posts? This page is extremely helpful and thank you. I ran into a trailer that has this lock but its missing the cylinder. It sat in a shed for 30-40 years and looks brand new. Works perfect. Just determing if the cost of a cylinder and keys is worth it. Thanks for your time.

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