1G Sending Unit Studs

That for sale thread is getting a little too busy and I think I am going to finally fix this properly so my tank will seal.

From what I can see there are 3 options to fix the tank (that are cost effective):
1) Weld in new bolts to replace the studs (doing with a fuell in the tank is stupid risky)
2) JB weld studs in (did this and there is always one that won't stay put)
3) replace studs with sealed rivnuts

I just thought of number 1 and have everything I need to do that, but not sure I am confident enough to seal up the tank so that I can accomplish this.
I have been talking about doing number 3 for a while and I think this is the safest and most effective of the three. The problem with this is that most rivet tools are right angled which I don't think would let me work with the tank in the car.

RTM is toying with the idea of designing an aluminum ring that more or less mimics the stud area on top of the tank and is itself attached to the tank using some sort of clamping system from the inside of the tank. We think the overall design principal is sound but it would be many weeks (or even months) before anything was available for use.

I realize my post above doesn't respond to your question, but I think some form of welding new studs to the tank is the best overall option.

Bryan, you'd actually be better off with a FULL tank of gas than a mostly empty one, as it is the fuel vapous you should be worried about rather than the liquid fuel itself - not that you shouldn't be careful anyways. Ideally though...you'd drop the tank, empty and clean it appropriately and then weld it...very carefully.

Could you not fill the tank with water, and then weld? That would keep the fuel fumes away, and prevent heat buildup during the welding process, no?

Why not just unbolt the tank? Do it outside the car.

I will be changing my fuel pump in my 1g aswell. Is there enough metal there to just drill holes and thread them and install new studs?

It's sheet metal, so no.

Yeah that's what I had read Sal, but either way I don't feel comfortable with any vapors.

Mike although I would love to do that it just means there is more rusty things that I would be removing and I don't know what my timeline on something like that would be. The one alternative that I can think of is manually pump out the gas, then fill the tank with a bunch of water then drain all the water after welding and put the gas back in. To me that seems like way too much effort though.

We shall see though, I would love to weld it cause I know it would stay and I won't need anything, but I would need to create a device that would keep sparks out, maybe I will see if I can create something like that.

Paul, that sounds like a good idea to me, I would love to test it!My one concern is that you will be missing out on fuel in the tank because it would add extra height to the sending unit.

A few months ago I had to replace the fuel pump in my 1g and was worried I would break studs. At the time I thought the simplest and cleanest solution would be to drill out any broken studs and then have a "C" shaped steel ring made with the correct hole pattern drilled into it. Studs (machine screws with the heads welded on the back side) could be put at any location where there was a broken stud and the "C" shape would allow you to place the whole assembly into the tank with the studs poking up. A couple of flat head screws or even rivets could easily hold it in place before the sending unit got bolted back up
Fortunately I never got to test the idea because I got lucky and none of the studs broke

This. It's sheet metal for the tank and sheet metal for the "flange area" where the studs are located, separated by an air gap. But either way you slice it, it's untappable.

You're correct, the overall height of the sending unit would increase by the thickness of the unit (plus gasket). In this case probably about 1/4".

Actually, if you wanted to do us a favour, you could measure the gap between the top of your sending unit and the underside of the access panel thing. Now that I'm thinking that might be tough to measure but I guess the underside of the sheet metal surrounding the hole is measurable. This info is useful for figuring out how much room there is for fittings attached to the sending unit, etc. Thanks in advance.

Doesn't look like there is enough metal there to tap. We have been thinking about a solution for this problem, but the holdup at the moment is that our idea would require a custom rubber gasket, and not sure who would make those in small quantities at a reasonable price.

As for welding the gas tank, I always thought the proper way to weld it was to empty it and then run the exhaust gases into it from another engine. I think the idea was to have the tank full of carbon monoxide and push out all the oxygen.

Is replacing it not an option?

Ziggy i have a company that makes custom die cutters (think cookie cutters). Essentially blades held on end through a piece of wood so you can make your own gaskets in an arbour press. We use them at work for material test samples.

Looking at $200-$300 for them to make one from the drawing you provide but then you can make your own gaskets all day long.

Not a cost effective one.

I think nick has a good idea, but you would definitely need a way to hold it in place and that would be the difficult part.

What about a using jb weld on the metal peice.


Like drill out the old stud ... Use a bolt with a washer welded to it.. Or a c shaped peice of metal. Then apply jb weld to the washer and pop it up from in the tank and thread on a nut just to hold it in place. Once dry.. Then the nut came come off and the stud will stay there.

Don't put water in your gas tank that is an awful idea.

So to save blowing yourself up welding, use a Pem nut from inside JB weld and a flanged stud from the top, once setup it will never move.Check home depot and you can find enough pieces to get done.
When drilling hold a large socket with a magnet inside to catch filings. Also as jay said with a bolt epoxied from the inside.

https://www.google.ca/search?q=pem+...mp;ved=0CEgQsAQ&biw=1280&bih=674

https://www.amkproducts.com/bulk2.asp?code=7430&title=Studs+-+Round+Collar

could you not grind it flush, drill it out and install some bolts like this with jb weld?

Hard to find those small enough, but to use KISS drill out use self tapers don't need studs....done

We dont need to keep em small.. If were gonna redesign the whole mounting system... Can we not upgrade to bigger then stock studs.

Yeah mine are slightly bigger, you don't want to drill the sending unit so you can't go too much bigger.
I like John's idea, I might go see if I can find both of those.

Tyler I think that is a better option than just using the screws at it would stop it from spinning much better than normal nuts.

The knurled stud idea (like the wheel stud pictured above) would be fine if the metal it was being pressed into was thick enough. It isn't, it's very thin sheet metal. I suppose a hole could be "pushed" through the metal so as to simulate a certain thickness and that could be used. I would think that would involve a specialty tool of some kind.

Agreed. I would drop the tank and do it properly. Very easily done on a 1g, and it would be a great time to replace that rusty old filler neck. There is also a 24mm drain bolt at the bottom of the tank in case you guys didn't know.

I'm not into hack jobs on DSM's. Do it once, do it right

Ok I am going to give the rivnut option a try. Does anyone have a rivet gun/tool that I can borrow.
As long as it doesn't look like this, it should work.

DIY tool.... http://www.carolinarovers.info/croc-stuff/tips/259-make-your-own-rivnut-tool

I have had no end of issues using a rivet gun to do rivnuts... Always seem to snap the rivnut when compressing... might also be the rivnut quality itself... .

Now that is a simple solution that should work well enough to get a few installed. Might need a longer bolt and spacers to get the wrenches away from the tank a bit.

Good to know! I will go pick up some rivnuts and see if I can find the tool.

So the line is secured with a nice amount of zip ties for now, but here is how it is currently routed. (This is not my car, I just made the line in green where I placed mine)




And it follows the OEM fuel line all the way back. The way I routed it, I just had enough hose to reach all the way back.



First, I bent the sending unit back.

Then, I drilled holes for the groud wire, low level light wire, fuel level wire and the pump power wire, soldered more wire onto each to extend them, fed them through the holes and then epoxied the holes shut.

As per the studs, I drilled holes into the fuel tank and drilled out the broken nuts/bolts out of the sending unit, then; Put a bolt pointing upwards> thin nut holding it> the gasket> the sending unit> bolts on top to hold it down> tightened them.

No fuel smell inside or outside the car as of now.

Where did you get the thing nuts from?
Any pics of your car?

I'll go snap a picture in a bit.

Found the bolts and nuts in the basement. I can measure them though.

Came close to having a perfect solution. Server mounting clips.



Had a few in the basement as well, but they were too small unfortunately. There might be different sizes on ebay though.

Here is where I ran my line. Zip tied to the original line/brake lines. A little close to the exhaust? Maybe, but I'm still alive.









For my studs:




No fuel smell in the car as of yet, just the smell of burning clutch. YUM!

I would be more scared of that control arm rubbing it then the heat from the exhaust doing anything.....

I should mention, I made absolute sure that the control arm is out of the way before I lowered the car. There's no rubbing or pinching of moving parts. Stuff rubbing or pinching is one of the things I am paranoid about.

Thanks for posting!
Nice work Stephan, got any more hardware you can send my way?

How come you didn't run it the stock way, on the other side of the control arm?
Did you have any luck removing the stock lines?

Sure can. I will let you know next time I am near.

I was going to run it through the stock location, but after trying for a long time in the cold and snow, I decided I'll reroute it later in the spring.

Didn't remove the stock line yet, as it is one of a couple lines which are supporting the new fuel line.

I was able to chop out all of my old line except for the stuff that runs between the firewall and the cover for the lower control arm, it's super tight in there, and the old lines are not very flexible.

Thanks man!

Judging by those pictures, that metal (particularly the head of the stud that sits between the two layers of sheet metal) may be thick enough to drill and tap after all.

There are lots of solutions to the problem of broken studs for the 1g AWD sending unit. For future reference, here's one of them:
https://www.rtmracing.com/xcart/product.php?productid=18982&cat=0&page=0&featured=Y

This certainly isn't the cheapest option, nor the easiest, but we feel it is a legimate one.

For those keeping score at home, in my opinion, the BEST solution is to replace the tank with new, and second on the list is to remove the entire "stud ring" and weld in a new version of one. But short of those two solutions, we think this one ranks right up there.

Very nice fix and a very good price, RTM making life easy

Ugh... Everytime I see this post light up in yellow.. I get butterflies in my stomich!

Keeps reminding me that I gotta do my 1g in the spring.

Yup, I feel sorry for all you 1g types anytime the subject of the sending unit (or the clutch pedal assembly) comes up. I used to be a 1ger myself, so I understand. Whenever I need to feel superior (which is rarely 'cause I pretty much feel that way perpetually), I remind myself that the 2g AWD sending unit does not use studs and the 2g clutch pedal assembly doesn't use the same lame-ass design as the 1g.