Emergency help on installing seat/cargo needed

ok so I have my sprinter 2500 cargo 2006 scheduled to have a 3 person seat installed on 1/2, I got a 3 person bench seat, the 3 proper anchors, the bolts and backing plates... but I stopped by my mechanic to schedule the appt. and first thing he said was " problem is that it sits right on top of the frame, if you drill into the frame it will never pass inspection again", I knew the fuel tank would have to be lowered on the driver side, but didn't realize it lines up right on the frame rails. what should I tell him ? is it ok to drill through the frame ? I don't see how else they could mount, there are no holes visible as its a cargo, but when i ripped out the floor as you will see in this pict, there are spaces of bare metal where the seats would sit.... any help is greatly appreciated, anything I can tell my mechanic to help him will save me money for sure.... ( looking to install seat in the first position just behind driver seat...

thomasrobert23 said:

ok so I have my sprinter 2500 cargo 2006 scheduled to have a 3 person seat installed on 1/2, I got a 3 person bench seat, the 3 proper anchors, the bolts and backing plates... but I stopped by my mechanic to schedule the appt. and first thing he said was " problem is that it sits right on top of the frame, if you drill into the frame it will never pass inspection again", I knew the fuel tank would have to be lowered on the driver side, but didn't realize it lines up right on the frame rails. what should I tell him ? is it ok to drill through the frame ? I don't see how else they could mount, there are no holes visible as its a cargo, but when i ripped out the floor as you will see in this pict, there are spaces of bare metal where the seats would sit.... any help is greatly appreciated, anything I can tell my mechanic to help him will save me money for sure.... ( looking to install seat in the first position just behind driver seat...

Click to expand...

There is a slight possibility that the anchor nuts for the seat receivers are already there. I recall comments of some people being able to grind off the tack welded OEM stubs to allow them to be used.

Can't alter the frame? It may depend upon the State Regulations. I have seen a couple vans modified for wheelchair service where very long bolts were installed centered through Sprinter frame sections to attach L-track mounts. A suitable heavy backer washer was used against the frame section.

There is a MB upfitters document which may give you something to provide ideas for your installer.

vic

thanks Ill look into that

sounds like quite an emergency.

How and where in the world would a van be inspected so thoroughly that they would crawl underneath or remove the seat brackets to see if the frame had been drilled into?! I live in the People's Republic of California, and even THEY are lax that they glossed over the rear seat LAYING ON THE FLOOR in my Transit cargo van and registered it as a passenger van.

krisinak said:

sounds like quite an emergency.

Click to expand...

he he - in my house "emergency" is only allowed to be used in case of blood or fire (maybe chest pains)

(where ARE you? That helps us feather our "inspection" answers to suit)

If you're mounting the seats in the Official Locations (marked by tiny pinholes in the wooden floor to tell you where to cut to install the seat anchors) then YES the anchor Nuts are already in there. They may have a drop of weld metal in them obscuring the hole, but a tap with a punch and a quick pass with an appropriate tap to clear the threads will leave you with a good, safe anchor. No frame drilling needed.
(if memory serves, there are even access holes on the sides of the frames at those points, so that MB could put the nuts in place at the factory.)



(approximately)
--dick

thanks I am in NY, emergency to me as I have a 5 year old that I cannot legally drive in it so am extremely stressed about getting this bench in asap. I agree when he said that about inspection I was thinking I just won't bring it to you, no one else would know to look.... there are no markings on the white metal floor for holes, and the underneath was under coated which is great for winters, but tough for seeing the frame thanks for all your help, hopefully on the 2nd I can drive my son

Looking (harder) at your photo, i'm surprised you can't *see* the fitting for the anchors at the spots i've circled (plus the other ends of the anchor slots).

If they are just open holes (like it looks at some of the ends), then you will need to put reinforcing plates underneath (you can make/buy plates with a hole through and a nut welded on)
The plates don't have to be too big, but they do need/want to spread the load out a bit inside the frame.



If you could take a close-up photo at any of the red-circled spots, it would help.
There have been threads (back in 2006/2007) with detailed photos showing the as-delivered "plugged" holes ... before and after the owner cleared them out. I'm using the search bar to try to find some...

--dick

Well, i found one of the old threads about adding seats, but no the photos (he had them on another server, and they're now gone)
https://sprinter-source.com/forum/showthread.php?t=4432

Unfortunately, he *added* reinforced nuts, he didn't make use of anything that MB had put in there originally...

So i'm still digging through the dusty archives....
(in another thread surlyoldbill wrote of only needing a Dremel to remove the small welds holding bolts that were placed into the nuts)
Your photos show that that's not your situation.

This thread: https://sprinter-source.com/forum/showthread.php?t=8481[/url] has another approach.
ECU has posted that he added a 2-wide seat using the factory anchors, but i can't find where he described the work.
...ahh.. i'm finding dribs and drabs... https://sprinter-source.com/forum/showpost.php?p=372997&postcount=8
...he speaks of having nuts welded up so that he "wouldn't have to drop the fuel tank" ... which must interfere with the forward points of the forward seat. The nuts were welded to the floor from the top.
added: i finally found ECU's "how i did it" thread: https://sprinter-source.com/forum/showthread.php?t=5470

Then there are the totally whacko installations (but note the wide-support-area nuts used under the floor)
https://sprinter-source.com/forum/showthread.php?t=36197

Someone who moved the seats back a foot or so... https://sprinter-source.com/forum/showthread.php?t=28123

And then there was the added-seat-legality thread: https://sprinter-source.com/forum/showthread.php?t=29940

Another "how i did it": https://sprinter-source.com/forum/showpost.php?p=82873&postcount=14
... which is part of this thread: https://sprinter-source.com/forum/showthread.php?t=9876

Another: https://sprinter-source.com/forum/showpost.php?p=4626&postcount=4

--dick
p.s. this post is going to keep growing for a while... ... done

Mine did not have nuts. I drilled from above and did not hit the fuel tank. You only need to drop the tank to get to the nuts so you can put a wrench on them
I screwed up in putting in nutserts. So I had a shop weld in bolts. Solved having to drop the tank. Don't think I went in the the frame rails.

thanks for all the input, here are better picts, there is no sign of the holes being there, which is weird that whoever did the underlayment at the factory left the strips for seats, it does appear to line up at least on the passenger side with the frame rail, I am just going to have to convince my mechanic to drill through and use long bolts, I would rather the seats be anchored to to frame than the thinner floor metal in the case of an accident....

Why not get an endoscope or USB camera and stick into the chassis rail to see if the nuts are already in place. if they are all you have to do is drill in the right spot!

Keith.

good idea keith I will see if I can do that

The trick with "long bolts" is to put a (thick pipe?) *spacer* inside the frame to carry some of the load to the bottom of the rail.



Part of the seat's job is to protect the occupant from cargo flying forward from the rear... so it's got additional load considerations.

You are correct that just welding a nut to the sheet metal floor is nowhere near equivalent to the original MB seat anchor design.

Here's the "short bolt" approach. In both long and short cases the "washers" can be welded to the pipe or nut



In MB's case, they weld the nut to the frame rail so that it doesn't drop when you remove the seat anchor bolt.

--dick

For a very safe retrofit, I think a single piece of 1/8-1/4" steel, 1.5-2" wide, for the entire length of each floor mount, with the nuts welded to the underside would be ideal. All 3 positioned correctly to match the floor mounts above, and the beauty is that the strip/nut combo could be fastened in place by a few small bolts through the sheet metal, so the floor mounts could be installed/removed without having someone under the van holding a wrench.

Not sure how you'd get that configuration inside the frame if needed, though.

edit: The strip/nut combo goes UNDER the sheet metal, like the factory nuts

thanks, I just ordered an iPhone endoscope camera, for 37$ I am sure I will think of other uses for it, but will be good to be able to peer into the frame in case its already drilled, can't hurt..... I will be sure to post the final results that we end up having to do, I just know the more knowledge I can give my mechanic it will save me the hours of him trying to figure it out, hopefully

My observations.

As has been mentioned, the OEM seat receiver nuts (or are they plates with special threaded receivers?) which are contained within the frame structure are not just against the sheet metal. The area is re-enforced.

It is similar to the OEM cargo load D-rings. It looks like the D-ring fasteners are secured to the sheet metal. Closer inspection will show that there is a spot welded plate at each D-ring attachment. That provides proper depth of thread engagement and backing.

I was hoping to find the same OEM cargo D-ring plates hidden behind the plastic trim on my passenger van. No such luck. It is only body sheet metal. I'm quite certain it is similar for the seat receivers, unless you uncover some OEM "nuts".

vic

In my passenger van, the row with the 2-seat had a place for a floor mount to use a 3-seat. Once I cut the floor vinyl, there was a plastic insert in the already-cut plywood floor. Under that, there were two bolts in the mounting nuts, with a stitch weld holding them. I used a grinder to remove the weld and unscrewed the bolts, and could then put a floor mount in that spot. It seems that cargo vans are not pre-fitted for floor mounts as far as the sheet metal is concerned, but if they have a ply floor it may be marked for the floor mount cutouts.

just to update, I got an endoscopic camera and looked inside the frame rail, there are no holes or nuts for the seats, looks like they will have to drill through, I will post a final update ( hoping ) that my mechanic can pull it off....