Attaching L-track to Sprinter - what to expect?

Inertiaman

Well-known member
What did you decide to use and where did you source your plusnuts?
My post you quoted was somewhat early in my fastener eval. Further study of galvanic corrosion, and the relationship of mass of anode vs cathode, implied that my concern was largely unjustified. Zinc plated is still preferable to stainless w.r.t. galvanic corrosion w/ aluminum, and also cheaper, so I eventually settled on relatively standard zinc-plated, hex key flat head bolts. I bought most of them from McMaster-Carr. One example is p/n 91263A565 but I bought various lengths. These had ideal head sizes for my track. Head size is the one thing that can really kill you when installing L track; if the head is too large relative to the track hole, and/or the countersink angle doesn't match, the head can stick up and inhibit movement of any L track anchors through that section.

Most of my placements had access for washers/locknuts behind. For the long runs about 12" below roof, I used full length 1/8" plated steel backing plates. Based on the specs for the bolts, plus the backing plate, that particular L track should meet/exceed reqs to use for shoulder strap anchors. I anticipated possibly having removable one-person seats, and these track could provide the upper anchor for shoulder mounts; otherwise, I wouldn't have bothered with the full steel backing plate (although it wasn't difficult to use). On other track locations, I just used zinc plated fender washers.

Handling the nuts and washers behind the various van wall structures can be tedious. It helps to refine a method w/ specific tools, for example a ratcheting closed end wrench helps to blindly hold and position the nuts.

I did use rivnuts in the C and D pillars to mount 14" vertical L tracks that provide 4 adjustable locations to mount my bed rails. Each "corner" has 4 bolts/rivnuts across the 14" track, so very strong and redundant. Also used rivnuts in some floor locations. Bolts installed w/ loctite and 5 years / 80k miles later I've never had anything loosen.

Hope that helps.

EDIT - oops, forgot to mention I sourced all rivnuts from McMaster-Carr also. Worth noting they carry a unique rivnut called an "Aligning Rivet Nut" which can accept an off-axis bolt; these were critical for installing a plumb L-track onto the curved C pillars.
 
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I'm not Inertiaman.

It doesn't need to be all or nothing.

If I were installing L-track again I would use a combination of thru bolts and pop rivets or rivnuts. The through bolts with large backing washers would be installed where access is convenient. The pop rivets would fill in where access was not.

Keep in mind that the Mercedes OEM length of L-track is installed using only 3 ea. fasteners per length. Those 3 ea. fasteners are not just attached to body metal like rivnuts or pop rivets would be. They are fastened into reinforced areas, as are the OEM tie down rings.

A few proper thru bolts combined with pop rivets will make a strong installation.

:2cents: vic
Is there any reason you would advise against the use of machine screws to fasten L-track in areas where a backing plate cannot be implemented?

Thanks a lot as always for your contributions to these threads!
 

Inertiaman

Well-known member
Is there any reason you would advise against the use of machine screws to fasten L-track in areas where a backing plate cannot be implemented?

Thanks a lot as always for your contributions to these threads!
Do you mean sheet metal screws? Machine screws have threads that would need a corresponding female thread to fasten into. Its not a formal nomenclature, but generally a machine screw is just a small bolt. In this case, @Aqua's "thru-bolt" and a machine screw are the same thing: 1/4" male threaded bolt/screw. It might mate to a loose nut, or a fixed rivnut, but its essentially the same bolt in either case.

I would be hesitant to use sheet metal screws to mount L track, even for non-critical, low-load use cases. At a minimum, I would place rivnuts to receive 1/4" countersunk cap head screws/bolts. In some areas, as @Aqua noted, its actually easier to use a thru-bolt and a backing washer and nut. For example, many locations on the lower wall assembly have reasonable "backside" access to place nuts/washers. Or the long horizontal run at the roof/wall seam, where one can finesse a nut behind w/ some practice.
 
Do you mean sheet metal screws? Machine screws have threads that would need a corresponding female thread to fasten into. Its not a formal nomenclature, but generally a machine screw is just a small bolt. In this case, @Aqua's "thru-bolt" and a machine screw are the same thing: 1/4" male threaded bolt/screw. It might mate to a loose nut, or a fixed rivnut, but its essentially the same bolt in either case.

I would be hesitant to use sheet metal screws to mount L track, even for non-critical, low-load use cases. At a minimum, I would place rivnuts to receive 1/4" countersunk cap head screws/bolts. In some areas, as @Aqua noted, its actually easier to use a thru-bolt and a backing washer and nut. For example, many locations on the lower wall assembly have reasonable "backside" access to place nuts/washers. Or the long horizontal run at the roof/wall seam, where one can finesse a nut behind w/ some practice.
Hey thanks a lot for the response.

And for catching me on the wording, you’re right I meant sheet metal screw.

I ended up mounting my L track Just below the window “well” which as you noted allows plenty of space to reach behind with a washer and nylock nut.

Even better than a riv nut !
 

jason09

Member
I did use rivnuts in the C and D pillars to mount 14" vertical L tracks that provide 4 adjustable locations to mount my bed rails. Each "corner" has 4 bolts/rivnuts across the 14" track, so very strong and redundant. Also used rivnuts in some floor locations. Bolts installed w/ loctite and 5 years / 80k miles later I've never had anything loosen.
Hey Inertiaman, Thanks for the tip on the Riv-Float nut option for angled placements! Just ordered 20 from MacMaster-Carr, so they thank you too :)
Do you have any tips or photos on how you fastened the vertical L-Track with clamps while working with it to get the proper hole placements?
 

Jbeauv

Member
Man I just received my L-track from U.S. Cargo control. I wish I paid a little more attention, apparently they drill holes like every 4 inches……snap
 

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