Mounting roof rail with expansion bolt instead of bolt and nut

borabora

Well-known member
I am if wondering anyone has ever succeeded or heard of someone succeeding in mounting a roof rail through the existing roof holes using some type of expansion bolt that does not require threading a nut from the inside of the van? As you may have guessed, I bought my van with existing wood paneling and would love to avoid having to remove it along with some cabinets just to add a roof rack.
This must be relevant for passenger van Sprinters unless they all come with a roof rail installed already.
 

Kajtek1

2015 long/tall limo RV 2.1l
Beware the Sprinter body is build with very mild steel.
I was quite surprised how easy wood screws and wood hole cutters go via sheet-metal .
I would not risk any anchors that will have 20 lb pulling strength.
I heard others are using rivet-nuts, but better use good quality stuff.
 

borabora

Well-known member
Beware the Sprinter body is build with very mild steel.
I was quite surprised how easy wood screws and wood hole cutters go via sheet-metal .
I would not risk any anchors that will have 20 lb pulling strength.
I heard others are using rivet-nuts, but better use good quality stuff.
I believe the anchor holes are reinforced (not just roof skin) and there is a "tube" welded to the hole. If they had put a thread in the tube, there would be no issue...
 

Aqua Puttana

Poly - Thread Finder
There have been discussions about VHB tape used in conjunction with some fasteners for roof rails and similar parts. Searching VHB tape should get you started.

vic
 

OrioN

2008 2500 170" EXT
If you want to be entirely leak-proof, use an epoxy adhesive, no fasteners. If you are using the OEM rails, you will need to cut off the jam studs. That is how the factory skylights and windshield is bonded. Less expensive than VHB.
 
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borabora

Well-known member
I was hoping to avoid having to glue it on. Maybe have to drill through the paneling and find a creative way to cover the holes.
 

Aqua Puttana

Poly - Thread Finder

sparkplug

Well-known member
I'm planning on using rubber well nuts in combination with some sika flex 512

That said I'm also not planning on having any weight on them. They're really only for attaching a removable tarp/awning and possibly a WiFi antenna
 

Eric Experience

Well-known member
Bora
You do not give the model of your sprinter but most have threaded holes. they are usually an M8 thread, I have had some heavy loads on those rails, the ambulances have all there flashy and noisy things held on those rails, no problems with a piece of canvas. Eric
 

borabora

Well-known member
Bora
You do not give the model of your sprinter but most have threaded holes. they are usually an M8 thread, I have had some heavy loads on those rails, the ambulances have all there flashy and noisy things held on those rails, no problems with a piece of canvas. Eric
Oh, wow, that's news to me! I have a 2016 2500 2.1l tall roof. I knew there was a "tube" but since installations include a nut to be applied from the inside of the van I figured the tube is not threaded. If it is threaded I'd feel perfectly comfortable to use bolts with some threadlock but no nut at the bottom. If anyone can confirm the threading on my model I'll be a happy camper.
 

borabora

Well-known member
Why no adhesive ?
Because it tends to lock you into one installation. Changing things out can become very difficult or even impossible. I just read from Eric's post that there maybe a thread -- that would be good enough for me.
 

Aqua Puttana

Poly - Thread Finder
There are many plastic hole covers available.


vic
If you abandon the thought of fender washers, the access hole size can be minimized.

As an example, these would work.

Small custom made parts from galvanized flat bar stock is another option.

:2cents: vic

Added:
Because it tends to lock you into one installation. Changing things out can become very difficult or even impossible. I just read from Eric's post that there maybe a thread -- that would be good enough for me.
I believe that any threaded points would have a plug or cover of some type. Are there any visible plugs or marked areas?
 

borabora

Well-known member
If you abandon the thought of fender washers, the access hole size can be minimized.

As an example, these would work.

Small custom made parts from galvanized flat bar stock is another option.

:2cents: vic

Added:

I believe that any threaded points would have a plug or cover of some type. Are there any visible plugs or marked areas?
Yes, there are plugs and I know how to remove them. From installation videos I surmised that the holes are reinforced and "tunneled" but not threaded. But that was an assumption and now I learn that the "tunnel" might be threaded. If that is the case I'd feel comfortable using high quality bolts with thread lock and no nut at the bottom.

I don't understand how fender washer can help -- mostly probably because I have never heard of them. I looked at the picture but don't understand how they can come in...?

If I need to put a nut on the bolt from the inside then my plan would be to drill a small hole through the factory hole on the top to mark the spot in the cabin and then use a hole saw to make a larger hole from the inside to apply the nut. Then cover the hole with a plug of some sort...
 

Aqua Puttana

Poly - Thread Finder
...

I don't understand how fender washer can help -- mostly probably because I have never heard of them. I looked at the picture but don't understand how they can come in...?

...
If you have threaded parts designed for the purpose the point is moot.

Fender washers distribute loads better. For roof rails they are probably not needed. I guess I was crossing over to securing L track or other load type systems.

vic

Added:
Those are not fender washers. Fender washers are oversize washers which provide more bearing surface. The washers I linked to would provide a bit more bearing surface than a standard cut washer, but would insert sideways into a smaller hole in the headliner.

Again. Standard cut washers will be fine for a roof rail.
 
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Shawn182

Active member
I would not use RivNuts since the sheet metal is so thin but PlusNuts would have more than adequate grab IMO.

Bora
You do not give the model of your sprinter but most have threaded holes. they are usually an M8 thread, I have had some heavy loads on those rails, the ambulances have all there flashy and noisy things held on those rails, no problems with a piece of canvas. Eric
NCV3 does not have threaded inserts under the plugs, it is just a hole that requires a mechanical fastener on the other side.
 

borabora

Well-known member
I would not use RivNuts since the sheet metal is so thin but PlusNuts would have more than adequate grab IMO.



NCV3 does not have threaded inserts under the plugs, it is just a hole that requires a mechanical fastener on the other side.
Thank you! Crap -- I was hoping for threading and problem solved.
I'll research PlusNuts -- I have never heard of them.
 

borabora

Well-known member
I just realized from another thread that you sell roof rails. Are they currently available and are they standard sized so that other accessories besides your mega solar mounts fit into the rails?
Besides epoxy or VHB do you have an opinion on using rivnuts or plusnuts or peanuts for NCV3 144 to avoid the hassle of getting access from below??? I'd appreciate the feedback.
I would like to mount a single 325 watt panel (all I need) using the roof rails and probably a homemade crossbars. I want to have an option add other stuff as may be necessary but the rails won't have to support a dance floor.
 

OrioN

2008 2500 170" EXT
I just realized from another thread that you sell roof rails. Are they currently available and are they standard sized so that other accessories besides your mega solar mounts fit into the rails?
Besides epoxy or VHB do you have an opinion on using rivnuts or plusnuts or peanuts for NCV3 144 to avoid the hassle of getting access from below??? I'd appreciate the feedback.
I would like to mount a single 325 watt panel (all I need) using the roof rails and probably a homemade crossbars. I want to have an option add other stuff as may be necessary but the rails won't have to support a dance floor.
Ours are clones of the OEM's. They have bolts that are press-fitted in the extrusion which are matched to go through the body holes, and fastened from below the roof.

We currently do not have stock.

If it were me, only mounting a single panel, do not want or have access from below, I use the 8020 1575 t-slot and epoxy it to the roof. Inexpensive, very easy to install, and gives you more 8020 options and mounting solutions for cross rails.
 

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