It's more than just the drive shaft. If you look under, you will see an odd plate/bracket looking thing that is below the drive shaft and welded onto the floor pan. Then look above the drive shaft and you will see the tunnel roof. What you will also notice is that the roof is also welded to the floor pan, which goes over that. So that's two layers of metal between you and the drive shaft. And with all those spot welds, things can get sticky. Eventually, I'd like to take that off and properly replace all the spot welds, but I really can't do that now.

So back to the rivets, McMaster has some non-pop brand high strength (also called structural) zinc coated blind steel rivets that I think would be good to use. My question is: what tool would I use to install those? And if I'm replacing spot welds (which I drill out with a 1/4" bit), I'd need 1/4" diameter rivets, but a lot of the standard tools do not come with (or use, from what I can see), 1/4" attachments.

__________________
1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

An air powered rivet gun will set most 1/4" pop rivets.

That sounds like a buck rivet like I was saying before. Is the top of the rivet a dome shape? Does it look like a mushroom in profile?

If its a steel rivet, It may have to be done hot, like red hot so the steel is soft and crushable. Not sure though.
If its an aluminum buck rivet, you put a special end piece into an air hammer that cups the dome shape, and you hold a piece of steel to the back side, something that the rivet will crush against.

Then you hit the dome with the air hammer and it will crush the backside against the steel plate (which someone has to be holding).

I used to work on those cube trucks like UPS trucks, and this was something we were doing all the time. Its pretty amazingly strong if done right, but it would require you to get to the back side.

Why don't you just simply use bolts, nuts, and lockwashers instead? You can always drill the hole for a bolt, put it in and tackweld it from the outside, then just run the nut in on the opposite side. Can you post some pictures of exactly where the hole is so we can get an idea of what you are dealing with?

__________________
This post brought to you by Carl's Jr.

Pop rivets are illegal for body repairs that are considered structural. Any patches must be seam-welded and not buried under tons of undercoating so the MOT chap can see them. Then you can bury them.

__________________
I choose to be happy, even when the Mercedes is being awkward, lol

heres a few pics- shows the difference between pop and buck rivets. I think the same safety laws are also in effect here for the pop rivets. Pop rivets are way weaker than buck rivets.

Versions of heavy steel buck rivets are used on frames of lots of vehicles. I just replaced some cross members on a 98 F150 the other day, which was riveted together with heavy steel buck rivets.

Attached Thumbnails

 

Attached Images

 

__________________
This post brought to you by Carl's Jr.

Solid rivets are indeed way stronger.

I wouldn't however recommend trying to set a steel rivet unless you have some serious air tools. You might get away with a 3mm diameter steel rivet and a standard air chissel type gun (obviously fitted with a rivet head) but you'll need a heavy reaction block on the other side to get it to form properly.

If you don't have the air tools then you'll need space to swing a heavy hammer and the accuracy to hit the rivet and not your fingers or anything else you don't want broken!

Aluminium solids are way way easier to set - mostly they are formed when cold. Some do need heat treatment for preparation and then they have to be used within a specified time frame before they work harden.

What ever you choose to try I'd recommend setting a few test pieces before you do your main job.

Here's what I was talking about:

http://www.mcmaster.com/#blind-rivets-and-steel-rivets/=6th7sy

They are still blind rivets, but steel. I wouldn't bother with the buck rivets. At that point, it'd be easier to weld. I'm trying to find an easier way, not a harder way.

__________________
1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Here's what I'm looking to replicate, more or less.

http://www.youtube.com/watch?v=wefP9BgPpgY&feature=related
http://www.youtube.com/watch?v=BeT4Qz_ugK4&feature=related

__________________
1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Well I'd opt for the rivet nuts - I used to install similar things on the back of Phantoms - they were bloody tough to get out again!

that guy is doing a nice job, but it looks like it will take him forever. I like the holes along the bottom of the rockers, good idea to keep the things ventilated. What level of quality are you shooting for?

I say go for the rivet nuts as well. That guy is restoring that car vs keeping it in daily service while working on it like you appear to be doing.

(I see what you are talking about with the double body panel underneath. If it were me, Id just drill a hole through both, pull the driveshaft out of the way, spot weld a bunch of nuts on the inside of the tunnel, then bolt my new panel down and compress the two stock panels together so I have a sandwich of three panels.)

__________________
This post brought to you by Carl's Jr.

How would I install rivet nuts? What's the advantage of a rivet nut over a standard rivet?

__________________
1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Rivet nuts are usually installed by using a special spanner. One bit attaches to the base of the rivet - the bit that will stay on the structure you are riveting - and another integrated spanner / socket fits on the top bit that is designed to shear off at a pre-determined force. You just wind them up until they go "dink".

The benefit of these rivets is that they are very strong. With this design much harder metals can be used as you are effectively utilising a screw thread and nut that deforms when broken - it is a bit like getting a very tight bolt and nut that has been peened (or staked) into place all in one go. Other rivet designs rely on softer metals that are deformed during the process of riveting so they are not as inherently hard or strong.

Certain heat treating processes and designs have been thought up to get around this problem (of having the necessity of a soft metal to enable formation) such as systems that need to use big forces (i.e. hydraulically actuated tools) and alloys that harden over time after heat treatment.

Is that too much information?

Alright, if I still want to use rivets, it seems like rivet nuts is the way to go. Found two different tools online:

http://www.skygeek.com/ats-rnt01.html

http://www.jcwhitney.com/assorted-mandrels-for-thread-sert-tool-kits/p2008058.jcwx?skuId=221749&TID=8014524F&utm_source=Google_Product_Search&utm_medium=CSE&utm_content= product-815291&zmam=15972153&zmas=21&zmac=141&zmap=815291#

Those look good?

I liked the idea of the steel structural rivets, but those are expensive and look like they require expensive tools to install the size I need, as well and possibly not even being good enough.

__________________
1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Well if they work they work - looks good to me. Only I'd check with the supplier of the rivet nuts to make sure that you've got the best option for the rivet nuts you are buying. (These tools look slightly different to the ones I've used before) But for an "investment" of 10 to 30 USD for a special tool that seems to me to be a small outlay compared with the MB spring compressor I've just bought, or even the W123 rear wheel bearing socket I've also just got on order...

Take the advice of the supplier / manufacturer

I use hard Aluminum pop rivets on all panel repairs on my 84 123 and 84 126
I have an inverter stick welder that will do nice welds on 20 ga (.035) metal with 3/32 rod at 25 amp reverse. But I prefer rivets. There are solid rivets on the market that are blind. They are have a powder filled filled lower stem that will expand when it explodes and are set off by heat on the head from a 300 watt soldering iron. Only problem is the $1.20 each price.
I have used pop rivets for 10 years now and the replaced fender skirts on the 123 are still holding. I will try to post some pics and instructions here.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom