Please critique this underbody

[JQ02]

25 minutes ago, TobyB said:

earlier cars have the trunk floor glued to the outer quarter

Interesting. Thanks. Seems like BMW did make the last couple years a bit sturdier. I wonder how much was making corrections to prior shortcuts and how much was regulatory. Prolly all the latter.

 

It's not clear to me how the trunk floor is attached to the quarter. I'll be finding that out.

 

I appreciate your feedback.  Hopefully this addition to the thread will be helpful to someone else someday. I feel like I hijacked it. 

Edited April 30 by JQ02
updated comment about sturdiness

[HobieDog]

On 10/26/2017 at 8:47 PM, ray_ said:

 

 

But, look closely at the rockers.

 

By look, I mean with a screwdriver and a hammer.

+100000 on the hammer 

 

this was on my car, which was advertised as having “solid rockers”.  I guess they meant “solid Bondo”

 

 

[JQ02]

2 minutes ago, HobieDog said:

this was on my car, which was advertised as having “solid rockers”.  I guess they meant “solid Bondo”

 

I hadn't thought of solid as a relative term 🤷‍♂️

 

I definitely am wishing that I started from a $6-8k basket case / barn find / stalled project. I had found the one in Colorado that would have been a way better (cheaper) starting point and I would have known what I was getting. Too bad I'd already started and it was 1700 miles away.

[popovm]

2 hours ago, HobieDog said:

+100000 on the hammer 

 

this was on my car, which was advertised as having “solid rockers”.  I guess they meant “solid Bondo”

 

 

 

 

As someone who is in the middle of major rust repairs and is getting punchy, this made me lol. I feel your pain. 

[HobieDog]

On 4/30/2024 at 6:58 PM, popovm said:

 

 

As someone who is in the middle of major rust repairs and is getting punchy, this made me lol. I feel your pain. 

Yeah man, those are not particularly fun surprises to find!  We laugh because we must not cry, right? I picked around with the hammer just enough so that I knew what metal I needed to order from W&N all in one-shot, but otherwise just focused on one section at a time.  Started at the drivers a-pillar and worked counter clockwise around the car, head down and feeding discs into the grinder and wire into the welder 😊.  I saved the floors for pretty much last.  I knew that if I got too carried away tearing absolutely everything apart at once I would end up feeling discouraged.  Easier to focus on one section at a time, get it buttoned up and have a nice burst of motivation from that before moving on to the next.

Keep muscling through it and good luck! 

[popovm]

2 hours ago, HobieDog said:

Yeah man, those are not particularly fun surprises to find!  We laugh because we must not cry, right? I picked around with the hammer just enough so that I knew what metal I needed to order from W&N all in one-shot, but otherwise just focused on one section at a time.  Started at the drivers a-pillar and worked counter clockwise around the car, head down and feeding discs into the grinder and wire into the welder 😊.  I saved the floors for pretty much last.  I knew that if I got too carried away tearing absolutely everything apart at once I would end up feeling discouraged.  Easier to focus on one section at a time, get it buttoned up and have a nice burst of motivation from that before moving on to the next.

Keep muscling through it and good luck! 

 

Thanks, same to you! Finishing up the passenger floor pan this weekend. Going to drive it for a while before tackling the trunk. Gotta use up the gas in the tank to make things easier, right? 😄

[VWScott]

On 10/26/2017 at 1:53 PM, Adamha said:

Any under carpet pics? Floor around pedal box? Frame rail near pedal box from inside? Rear shock towers/trunk from inside? The front portion of both rockers look like they need a closer look.

 

The real problem is the rockers and frame rails can rust from the inside out. One needs to poke at them with a probe to see if they are soft. They can look good in pic's but be very soft from the inside out.

 

How is the rust around your front and rear window seals? Easily covered with a quickie respray. How are the door bottoms?

yeah that whole under the carpet thing was a bad day for me!

[JQ02]

On 4/30/2024 at 3:40 PM, JQ02 said:

On 4/30/2024 at 3:15 PM, TobyB said:

earlier cars have the trunk floor glued to the outer quarter

 

 

So, the newer ones do, too. I think it was the boxed section that was tack welded and then the trunk floor is glued to the quarter. I cut out most of the rust. Still more detail to clean up before thinking about welding.

 

[popovm]

1 hour ago, JQ02 said:

 

So, the newer ones do, too. I think it was the boxed section that was tack welded and then the trunk floor is glued to the quarter. I cut out most of the rust. Still more detail to clean up before thinking about welding.

 

Is that boxed piece cut in half in this pic? I am going to need to rebuild that section on my 76 too. I am not sure how bad it is but this intel on that section is great to have ahead of time. Have anymore pics? 

[JQ02]

10 hours ago, popovm said:

Is that boxed piece cut in half in this pic? I am going to need to rebuild that section on my 76 too. I am not sure how bad it is but this intel on that section is great to have ahead of time. Have anymore pics? 

Good luck @popovm  I've been thinking about how to fix this. My current thought is to just put a piece over top of the area and lap weld it above and below. Or weld above and seam below.

If you want to preserve the boxed section to have it look original - which I think is an invitation to re-rust.

 

It looks like from the factory, they literally tacked the box on from the bottom by drilling holes through the trunk floor and spot welding the perimeter.

 

The 'flange' for the box is what was tacked on. There was a tiny bit of the box remaining on the front side and a little more on the back, but it's mostly gone.

 

I google searched bmw 2002 underside and found this pic (and a couple others) on the forum that someone else posted and said they found with google images:-D  Here's a close up of just the boxed section.

 

Hope this helps. I'm happy to look at your pics and see if I can help further.

 

Here's how mine looks now, so it's no longer much of a reference. Note that looking through the mostly rectangular hole is the inside of the quarter and a bit of my garage floor on the left. Beyond the rectangular hole is another rust hole that goes all the way to the edge of the trunk floor and reveals the glue / sealer that had attached the trunk to the fender.

below view

 

Edited May 3 by JQ02
pasted in same image twice instead of closeup of good box

[popovm]

@JQ02 amazing, thanks for all of that! Yeah, recreating that underside piece may not be worth it. I’ll have to decide when I get to that part of the car. 

[bergie33]

Here are some pics I got from someone on this site, but I cannot remember who.  They chose to duplicate the original boxed area, but I don't think it's totally necessary.

 

 

 

 

 

 

 

 

 

 

 

 

[JQ02]

12 minutes ago, bergie33 said:

Here are some pics I got from someone on this site, but I cannot remember who.  They chose to duplicate the original boxed area, but I don't think it's totally necessary.

 

That's nice work. Seems like overkill, but I guess if you're looking for factory original. I'm not. 

This forum is so great.

[VWScott]

I just did this about 2 months ago.When I took  out the tank that shelf was toast as well as most of the box beam underneath. I cut out all the rust and fabbed a little box slightly shorter than the original and welded it to the nub that remained.I also welded it to the shelf that went on top of it.It was stiff as a board.Hope this helps.

[JQ02]

1 hour ago, VWScott said:

I just did this about 2 months ago.When I took  out the tank that shelf was toast as well as most of the box beam underneath. I cut out all the rust and fabbed a little box slightly shorter than the original and welded it to the nub that remained.I also welded it to the shelf that went on top of it.It was stiff as a board.Hope this helps.

 

Nice work. Actually, I guess a value of the box is stiffness given that the trunk floor is glued to the quarter panel. Hmm. Maybe a capped bit of square stock or at least an L is not a bad idea.