[Arne]

Finished re-working the effed-up fuel pump plumbing today. I'm barely satisfied with it now. Worst part is the that the fuel tank itself is pretty beat. If new tanks for Caddys were easily available, I'd probably replace it. Why would someone try to jack up the truck with a floor jack under the fuel tank?

In any case, tomorrow afternoon I'll spend some time picking up and organizing the work space, then drop the fuel lines and start cutting out the passenger floor pan. Wish me luck!

 

[Arne]

Worst part is the that the fuel tank itself is pretty beat. If new tanks for Caddys were easily available, I'd probably replace it.

Hmm. Hadn't occurred to me to check with Heritage on a fuel tank. They have JP Group replacement tanks on the shelf. Probably won't do it right now, but that is tempting...

 

[Arne]

No cutting has happened yet, but I'm getting close.

Spent some time under the truck this afternoon, getting fuel lines out of the way and assessing the best way to approach the job. And after looking it over, I've changed my approach. I had planned on patching from the top, as done in this thread - Replacing Rusted Floor Pans

The key part of this approach is to cut out the seat crossmember to gain access from above, and then weld it back in place after the pan replacement. But after poking around a bit underneath, I think I'm going to go ahead and cut out the entire pan and weld the new one in at the rocker pinch weld, rather than patch bits of it. I actually think that might be easier in some ways, and will be a nicer job in the end.

Should have some time to start cutting and grinding later this week.

Oh yeah, after spending more time underneath fussing with fuel lines and such, it's pretty clear the fuel tank needs to be replaced. One more thing on my list...

 

[Arne]

You'd think a retired guy could find more time to spend playing in the garage. But no, there often seems to be other things that are higher priority.

But today the old pan removal started (finally). Should be able to cut out the rear half tomorrow (crossing fingers).

 

[zeande]

Nice! Looks like it came out clean. Also glad to see the floor support isn't all jacked up. Previous owners had definitely used mine to jack the car, bending it all out of shape.

 

[Arne]

The floor support isn't as nice as it looks in the picture, but I've seen worse. I should be able to re-shape it some prior to welding in the new pan.

 

[Arne]

First test fit. Not bad...

 

[Arne]

All the time I spent staring at the floor and the new pans, thinking about where and how I wanted to cut and weld looks to be paying off. The fit is looking pretty good so far, and I haven't seen anything yet that makes me think, "How am I going to do that?" I'm currently cleaning up the areas where I will be welding, starting with the inside of the pinch weld. Once I get that done, I'll re-fit the pan again and start marking where the final trims and holes for rosette welding will be. I picked up an air-powered hole punch/flange tool yesterday, will start punching holes as soon as I get the final fitting complete. I should have some time to work on it over the weekend, might even get to start the welding before the weekend is over.

Pleasantly surprised that the inner rocker panel is really solid, almost no rust progressed into the rocker. One small (25mm x 25mm) patch is all that is needed there. The center crossmember (that the front seat mount is on) didn't fare as well. The lower edges where it was spot-welded to the floor were pretty much eaten away completely. I'll have to make some angle brackets and weld to both the crossmember and the floor. But that should be pretty simple.

If one is careful, the inboard seat track can be left in place and the pan stitch welded behind it. The outboard track needs to be cut off the old pan and welded to the new. The parking brake cable tubes need to be cut loose from the old floors and re-welded to the new, and several fuel line butterfly brackets need to be transferred to the new pan.

 

[Arne]

I should have some time to work on it over the weekend, might even get to start the welding before the weekend is over.

When will I learn? No, other things got in the way all weekend long. I didn't get back to this until mid-day today. But I was able to finish trimming and fitting the pan today. Tomorrow is not looking good, but later this week I should be able to complete the final prep and begin welding. Really pleased with the fit of the pan for the most part. The rear outboard corner is not as crisply stamped as would be ideal, but it wasn't hard to correct that. Stay tuned...

 

[Arne]

While I—in my inexperience—keep thinking this type of thing should not take as long as it has so far, I'm pleased with how it is going in general. The final fit of the pan itself is complete. I've got the surfaces all prepped, will apply the copper primer next time I get back to it, then fit and weld.

 

[zeande]

Looking forward to seeing you get those pans in, since that seemed like your biggest challenge on this project. Hopefully it will be smooth sailing once that's done!

 

[Arne]

Yes, the pans are the biggest part remaining. It will be all downhill after I finish the pans.

 

[Arne]

The passenger side pan is now about 2/3 done. Still have some welding to do on the underside, need to weld in the outboard seat rail, and build and weld supports for the seat mount crossmember.

Welding from underneath is tricky, as I'm sure many of you already know. My welding skills keep improving, but about when I think I'm getting the hang of it I run into a slightly different situation and I get another cobbled-looking weld. Oh well. That's what grinding wheels are for...

I should have some time to work on it over the weekend, hope to finish the welding and get to priming and seam sealing. Then undercoat and re-installing the fuel lines. Finally will re-hang the door (which I took off to ease access for the work).

Then I can put the battery back in, start it and turn it around do it all again on the other side.

 

[Arne]

More progress today. I've got a little more I want to do on the pinch weld, and also need to weld in the outboard seat track. The rest of the welding is done. Then dress all the welds with the grinder, prime, seal and undercoat.

Pretty pleased at this point. With the floor welded in and both the lower support and seat crossmember attached, the floor is tight and solid. Massive improvement.

Going to need more gas soon, and maybe a spool of wire as well.

 

[Arne]

Forgot the picture...

 

[Arne]

Calling the passenger floor pan done today. All welded in, cleaned up the welds, everything looks good and is solid. Tomorrow I'll pick up some more primer, seam sealer and undercoating to finish up this side. The truck should be mobile again fairly soon, and I can see how it really runs with the new-to-me air flow meter.

And then I will do it all over again on the other side...

 

[racingti]

Arne

Awesome story!! Enjoying every post. Keep up the great work.

Word of advice. Being a 16v guy, I can say this with confidence. If your latest Motronic fix doesn’t work, scrap it. It can be a finicky system in a stock car at best and that has every part it came with from the factory. (I know you have had a good experience with your Jetta 16v.). It came from an in-between time. Mechanical fuel injection transition to electronic FI but before OBD EFI.

You eluded earlier to being open to CIS-E. Do it!! It is simple, runs well, and easy to tune with far less wires and sensors. With your demonstrated skill to diagnosis the Motronic injection, CIS-E would be a breeze. Motronic can run well (sometimes), but you said it was a rough wiring. CIS-E is closer to the stock injection, easy to diagnosis and dependable. I think I would rather run a Digifant injection or ABA injection swap over Motronic.

There will be plenty of people that will hate on CIS-E but you can’t hate a system that is simple and works. I have run it for years.

What ever you decide, Keep up the good work. Glad to see a Caddy saved. We are all enjoying the read of the trials and progress.

 

[Arne]

Well, I've got enough invested in the Motronic by now that I'd probably prefer to keep it. We'll know more on that within the next week or two, once I get it reassembled enough to drive it.

I'm loving the project so far. No, it's not going 100% smoothly, but they never do. The addition of the welder right here in my own garage has changed how I approach things. I've bailed on a prior project due to rust not much worse than this, because I'd have to have paid someone for hours of repair work. So this truck is benefiting from me acquiring a new skill. Same with the Mk3 seats - I could not have made those seats work without access to a welder.

So far, so good. Thanks for the encouragement!

 

[Butcher]

A good shop should have a welder. I do not use my often, but if you do not have one, there are plenty of things you cannot do. I recently purchased a used lathe.

I recently worked on someones Mercedes and some hack could not install a set of brake pads correctly. All 4 holding pins were coming out. I tried to install them, but the cheap Chinese junk were not machined right to fit. Off came the pins and within a few minutes, they were machined to fit.

My next few toys on the list is a plasma cutter, mill, and a backhoe. I bet I could disassemble an interior real quick with that.

Keep up the good work!

 

[ToddA1]

Unless you cut a lot of thick plate, put the plasma cutter at the end of the list. I have one and it’s probably been years since I used it.

The welder is a different story. I almost consider it to be a garage necessity.

-Todd