72 front bumper connection

[malcolm2]

There are 4 captured nuts (2 on each side)under the cab door threshold that the bumper bolts thread into. When I removed my front bumper one nut broke loose. They are attached, welded i assume, inside the cavity. How on the hell do i fix this?

Window seals allowed water in. It rusted thru the bottom of the door and then the threshold. Filled the cavity and rusted the nuts. My take on this ugliness.

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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[70Crew]

I had to do a similar repair. Google “rivnut”.
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1970 Crew Cab

[busdaddy]

If you don't want to open up the dog leg or inner skin you can hole saw that out, weld a new nut on the part you cut out (or a new piece) and weld the "hole" back in.

Or put a Riv-nut in there, not nearly as good a repair but I don't know your personal level of "good enough".
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[malcolm2]

My 1st thought to cut it out. That way i could get a tiny look at the inside rust and cleaning and coverting and coating in there.

I was thinking cutting the side, but i like the hole saw idea.
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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[aeromech]

I've installed a lot of rivnuts but I don't think they are the right way to go for mounting a bumper. They rely on the body being squeezed and when you put a lot of torque on them they can spin. A bumper is too heavy and hanging out on the end of an arm. I think you'll need a weld repair to do this right. Pictured is the tool and 6mm rivnuts. You'd need 10mm rivnuts I think and most likely a different tool because hand squeezing a big rivnut takes a lot of force

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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[busdaddy]

That looks like the side step mount to me from here, so 8mm bolts. But if you are set up for welding already it's best to cut it open and replace the nut.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

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[malcolm2]

[malcolm2]

Lots of 5 star reviews on this one. Many from Car People. Looks like you can apply much more force with the longer handles. I will read up on it. Truthfully, I could do this 1st. If it ever failed, I could go the welding route.

https://www.amazon.com/dp/B073VK3B7S/ref=pd_luc_rh...merReviews
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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[aeromech]

Yes, much better. Since it's only the 8mm bumper side support bolts I think the rivnut would work. The weight of the bumper itself is not supported by these so I'd give it a try.

The greatest majority of the rivnuts I install are for the pedal pan so you might want to use it there too.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[malcolm2]

maybe I'll buy that rig but add the $20 set of SS nuts.
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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[mikewire]

Interesting timing on this post...I'm about to mount my rear bumper (and hitch) with the same issue - the captive nuts in the frame gave way and there's no way to mount the right (passenger) side into the frame, short of opening the frame up. My Bus is also a 1972.

I'll be using that exact rivnut tool from Amazon, but with stainless steel rivnuts, (M10 x 1.5) with bolts, and lock washers.

I have most of it layed out, ready to go...and I am going to produce some content on this bit of work for a YouTube channel I've created for documenting working progress on my Bus.

Please post up your progress, and when I have mine done, I'd be glad to share it with you and the group here.

BTW, on the regards of safety and rivnuts...I'm not planning on towing anything with my hitch setup, and if anyone were to hit the bumper with any modern vehicle at a moderate rate of speed, it's not going to help much. As far as I'm concerned, this is pretty much just a cosmetic appearance repair. I'm interested in hearing others thoughts (and other possible solutions) too.
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-Mike

@countdowngarage
@bigskyeuro

1972 VW Kombi 9 Passenger Deluxe w/ 2.0L F.I. VWAC swap
1965 VW Beetle Deluxe Bahama Blue

[malcolm2]

A bit of an update. As much as I liked the idea of using a hole saw to cut the hole out, weld the nut in then replace it.... I now see how they really beefed up the nut bracket. Not sure what the very best way would be to repair but it might include some cutting out from the top and actually welding the a fresh nut back in. Oh well, RivNut tool is on the way and I am doing it that way.

But here is some of my cutting today. Gives you a view inside. Truthfully the Riv nut wedged on the bracket and the dogleg should be a nice and tight sandwich.

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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[mikewire]

Nice! Great picture of the inside dogleg; shows exactly what you're dealing with. I'm sure there's others (present and future) with the exact situation.

Please keep us updated with your progress!
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-Mike

@countdowngarage
@bigskyeuro

1972 VW Kombi 9 Passenger Deluxe w/ 2.0L F.I. VWAC swap
1965 VW Beetle Deluxe Bahama Blue

[malcolm2]

Used a stainless steel one. Still need to do some top coat painting under the driver and in the wheel well, but I think this will do it.

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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)