Right inner fender area rust repair - need advice

[KF6TRG]

Here are pictures of my inner fender, which is visible from under the hood. There is quite a difference between the right and left fenders in this area, and I am aware that there is certainly rust that is not visible. I want to get an assessment from someone most familiar with rust repair in this part of the E9 - must I replace the whole fender? Are there any other repair options? The paint on this car is actually quite good and shiny, and I am somewhat cost-conscious. I will make these repairs regardless of the cost, but I just want to educate myself before I move forward. I am grateful for any wisdom from the good folks of this forum!

 

[ScottAndrews]

Well, saving the paint is probably going to be difficult, but I'd start by scraping al that flaking stuff out of the hood channel, so at lease you can see what you have.

Get a bore scope and examine the "shelf", which is basically a horizontal section that runs along the inner fender under those areas you photographed. Also check the inside of the box structure that has an open hole on the outer side of the inner fender at the rear of the front wheel well.

Looks like one side is worse than the other...

If your fenders are this bad, it is likely your rockers are also bad. That's actually a fairly easy fix. so don't despair...

I suspect repairing this will require removing the front fenders, and that presumably means re-painting the car.

 

[e9Leveque]

These pictures alone won't answer the question. In the front wheel well along the lower rear edge is a panel held on with two bolts. Remove that panel and see whether there is extensive rust that has come down through that fender and into the frame. This is perhaps also a job for a boroscope which you can purchase online for cheap or perhaps borrow from another member. Many of us (me included) have or had some slight rust under the bitumen, but this looks more extensive than just surface rust. The construction of the E9 means that you can see this side easily but not the other side - that's what you're trying to get to. Also check behind the glove box and fusebox - the firewall there separates that currently not visible compartment from the interior of the car. If there's rust in either of those two areas then it means it went from within that compartment downwards to frame and rearward into firewall.
There's a nice document in the FAQ I believe that has diagrams of the places to check for rust. Take a bunch of pictures of those areas and post here and I think you'll get a more thorough response. Right now you're asking people to diagnose something within the body by only showing them a picture of the skin - hard to do.

Looks like Scott and I were typing at the same time, so "what he said"

 

[KF6TRG]

Well, saving the paint is probably going to be difficult, but I'd start by scraping al that flaking stuff out of the hood channel, so at lease you can see what you have.

Get a bore scope and examine the "shelf", which is basically a horizontal section that runs along the inner fender under those areas you photographed. Also check the inside of the box structure that has an open hole on the outer side of the inner fender at the rear of the front wheel well.

Looks like one side is worse than the other...

If your fenders are this bad, it is likely your rockers are also bad. That's actually a fairly easy fix. so don't despair...

I suspect repairing this will require removing the front fenders, and that presumably means re-painting the car.

Thanks, Scott - I do have a borescope and will follow your suggestion.

 

[KF6TRG]

Well, saving the paint is probably going to be difficult, but I'd start by scraping al that flaking stuff out of the hood channel, so at lease you can see what you have.

Get a bore scope and examine the "shelf", which is basically a horizontal section that runs along the inner fender under those areas you photographed. Also check the inside of the box structure that has an open hole on the outer side of the inner fender at the rear of the front wheel well.

Looks like one side is worse than the other...

If your fenders are this bad, it is likely your rockers are also bad. That's actually a fairly easy fix. so don't despair...

I suspect repairing this will require removing the front fenders, and that presumably means re-painting the car.

I am not as concerned about the rockers since that rust seems to be fairly limited - need to inspect more, though! I plan to make the rocker repairs myself, but I need to get a welder that is better for sheet metal (TIG?) and take a welding class.

 

[KF6TRG]

These pictures alone won't answer the question. In the front wheel well along the lower rear edge is a panel held on with two bolts. Remove that panel and see whether there is extensive rust that has come down through that fender and into the frame. This is perhaps also a job for a boroscope which you can purchase online for cheap or perhaps borrow from another member. Many of us (me included) have or had some slight rust under the bitumen, but this looks more extensive than just surface rust. The construction of the E9 means that you can see this side easily but not the other side - that's what you're trying to get to. Also check behind the glove box and fusebox - the firewall there separates that currently not visible compartment from the interior of the car. If there's rust in either of those two areas then it means it went from within that compartment downwards to frame and rearward into firewall.
There's a nice document in the FAQ I believe that has diagrams of the places to check for rust. Take a bunch of pictures of those areas and post here and I think you'll get a more thorough response. Right now you're asking people to diagnose something within the body by only showing them a picture of the skin - hard to do.

Looks like Scott and I were typing at the same time, so "what he said"

Oh, I understand - actually, I would like to get an in-person evaluation from a shop that is very familiar with the E9, and see how much of this I may do myself. I have owned and done all the work on several BMWs (2002s and one other E9) over many years, so I plan to improve my skills, get an appropriate welder, and take this on. I have a borescope and can get a good image in the "shelf" area in the wheel well. I will post these and ask for input as well. Thank you!

 

[KF6TRG]

Oh, I understand - actually, I would like to get an in-person evaluation from a shop that is very familiar with the E9, and see how much of this I may do myself. I have owned and done all the work on several BMWs (2002s and one other E9) over many years, so I plan to improve my skills, get an appropriate welder, and take this on. I have a borescope and can get a good image in the "shelf" area in the wheel well. I will post these and ask for input as well. Thank you!

Also, zero rust in the area behind the firewall or the interior spaces behind the glove box, and the same area on the driver's side.

 

[eriknetherlands]

From what I can see in the pics, it is not enough to (for me) to tell you how serious it is.
In pic 2747.jpg, the last pic, the rust seems to be limited to an area about an inch wide, and 3-4 inches long. That in itself isn't terrible.

The 20.000 dollar question however is if the rust started on the visible side. If the rust is litterally only on the top sheet or if the rust came from underneath or the side.

For this it starts with a wire wheel: clean it up to see where it extends to.
If you get a clean surface with no rust trails into the seams or holes into the next layer, then call yourself lucky. A (colormatched) spray can paint job will save you a engine bay or full repaint

If you do spot rust going into the seams or downwards then e9 ownership becomes all the more gritty.

Two likely "below" origins: the easier one is the foot long strip along the fender top edge, that strip physically connects the inner to the outer fender. If the rust is just under that strip, remove it, clean it and weld in a new strip (80 euro's at Walloth) It isn't a biggie, and again it can be a (color matched) spray can fix.

The more difficult it gets is when you followed the above, removed the strip, and see it has rust that you still can't reach: going down through the inner fender or further along the edge of it.
Also you might spot rust growing in the vertical seam it shares with the outer fender (that runs the entire length of the hood) fender
Then likely the layer beneath (it's like a union down there) is rusted as well.
Below the innerfender, where the 3 bolts protrude is a 3 mm thick metal plate that holds the strut. It's sandwhiched together over a large area with 20 spotwelds or so, and a zero gap situation with water from the wheel below makes for a good rust trap.
If that is rusted badly it needs to go out, and that means fenders off, thus a half car repaint at least.
I'm sure all cars have some rust there, just how much does yours have? If the rust is serious, it will push the innerfender up as that is thinner metal. The other end of that thick plate connects to the firewall in the aforementioned 2 places: R behind glovebox and L to fuse box.
As you state that those are still ok when looking from the cabin side, i am hoping (from 10.000 miles away) that the thick plate is not rusted soo badly in order to justify pulling it out.

I'd start with the wire brush, and make some pics and post em here.

I'll try to add some pictures later today on how it's build up below. As i have it all apart it's not that difficult for me.

 

[ScottAndrews]

I would absolutely go read @eriknetherlands thread (Fixing that little rust spot...) from one end to the other. He has rebuilt nearly every square inch of his car, and probably knows more about rust, repair, and fabrication than many of us combined.

My car was "nearly rust free" (see 72 3.0 CS 2240344 Restoration), but several folks here suggestd the bore scope and identified potential problem areas.. Sure enough, when I pulled up the carpets and removed the padding and bitumen on the floors, they were perforated, and we had to replace metal part way up the passenger side of the trans tunnel. None of this was visible. I also had a small rust spot at the rear right rocker, which turned out to require removing a lower section of the rear quarter, and a similar lower section of the front fender, and replacing the entire outer rocker piece. Remember, the actual rocker metal is under those trim panels that run along the lower side of the car, under the doors. Remove those and take a hard look both for rust peering through the paint, and also inside the rocker itself (borescope). You will find on my thread a diagram of the complicated rocker assembly. In some areas (around the A and B pillars) there are FIVE layers of metal, and, depending on whether your car has a sun roof or not (thankfully mine doesn't) those areas can rust from the inside out because of the location of the sunroof drains.

On my car the rear floors looked ok, but once we blasted the under side of the car, we found hundreds of small perforations, so that was replaced too.

From what I have seen, the floors are almost always rusty (condensation collects on cold nights, and ends up under the bitumen on the floors, and the tin-worm has its meal...). On my car the heat from the exhaust, and condensation from a bad drip seal on the AC unit rusted out the front inner floor badly (you will see this in my thread).

I removed the outer rocker on my car to find that the intermediate rocker, B-pillar base, and A-pillar base were rusted, but not structurally, so my "nearly rust free" car was still fairly rusty!!

If you are going to do this DIY, I'd highly recommend spending time studying this forum. Unless you are an Ultra DIY man like Erik, you will probably find that some of these jobs are just too difficult, and it's best to engage pros (I sure did, and, after 4 car restorations, I'm a pretty hard core DIY guy! ).

For the rockers, I'd recommend getting an electric spot welder, and follow Erik's advice on prep and such. A 120 Volt MIG welder will probably serve you well for most other jobs. Remember that metal warps with heat. It is easy to burn through thin sheet metal, and even easier to warp panels by welding too much at a time. Most panel repairs involve many short welds followed by cooling air ("welding cool" as @sfdon calls it.. )

There are lots of coupe folks down in the LA area. If you don't already, get to know them, and follow their advice on shops to help with major repairs.

Here are some pics of my right side rocker that had literally a 1.5 inch round rust spot bubbling under the paint at one end. The painted part is the lower rear quarter panel, the rusted sharp bits are what was left of the outer rocker, and the rusty but sound parts are the lower C-pillar and the intermediate rocker beam. Note in the middle pic I have cut away most of the lower quarter panel, and exposed the outer rocker (this is what you see at the door opening under all the trim... it dives under the front fender at the front of the door, and under the rear quarter at the rear of the door). I have cleaned it up here, but you can see rust perforations all the way up to the B-pillar... :

Here is a pic withthe entire outer rocker pulled off. The zig zag piece is the intermediate rocker beam. You can see the large rusted areas at the front of the door and the rear of the door. Those are the bases of the A and B pillars, which weld to the intermediate beam. The shiny little dots are the remnants of the spot welds. There is a special drill you use to drill out a flat spot the same diameter as the weld.

 

[KF6TRG]

From what I can see in the pics, it is not enough to (for me) to tell you how serious it is.
In pic 2747.jpg, the last pic, the rust seems to be limited to an area about an inch wide, and 3-4 inches long. That in itself isn't terrible.

The 20.000 dollar question however is if the rust started on the visible side. If the rust is litterally only on the top sheet or if the rust came from underneath or the side.

For this it starts with a wire wheel: clean it up to see where it extends to.
If you get a clean surface with no rust trails into the seams or holes into the next layer, then call yourself lucky. A (colormatched) spray can paint job will save you a engine bay or full repaint

If you do spot rust going into the seams or downwards then e9 ownership becomes all the more gritty.

Two likely "below" origins: the easier one is the foot long strip along the fender top edge, that strip physically connects the inner to the outer fender. If the rust is just under that strip, remove it, clean it and weld in a new strip (80 euro's at Walloth) It isn't a biggie, and again it can be a (color matched) spray can fix.

The more difficult it gets is when you followed the above, removed the strip, and see it has rust that you still can't reach: going down through the inner fender or further along the edge of it.
Also you might spot rust growing in the vertical seam it shares with the outer fender (that runs the entire length of the hood) fender
Then likely the layer beneath (it's like a union down there) is rusted as well.
Below the innerfender, where the 3 bolts protrude is a 3 mm thick metal plate that holds the strut. It's sandwhiched together over a large area with 20 spotwelds or so, and a zero gap situation with water from the wheel below makes for a good rust trap.
If that is rusted badly it needs to go out, and that means fenders off, thus a half car repaint at least.
I'm sure all cars have some rust there, just how much does yours have? If the rust is serious, it will push the innerfender up as that is thinner metal. The other end of that thick plate connects to the firewall in the aforementioned 2 places: R behind glovebox and L to fuse box.
As you state that those are still ok when looking from the cabin side, i am hoping (from 10.000 miles away) that the thick plate is not rusted soo badly in order to justify pulling it out.

I'd start with the wire brush, and make some pics and post em here.

I'll try to add some pictures later today on how it's build up below. As i have it all apart it's not that difficult for me.

Thank you for your excellent advice!

 

[KF6TRG]

I would absolutely go read @eriknetherlands thread (Fixing that little rust spot...) from one end to the other. He has rebuilt nearly every square inch of his car, and probably knows more about rust, repair, and fabrication than many of us combined.

My car was "nearly rust free" (see 72 3.0 CS 2240344 Restoration), but several folks here suggestd the bore scope and identified potential problem areas.. Sure enough, when I pulled up the carpets and removed the padding and bitumen on the floors, they were perforated, and we had to replace metal part way up the passenger side of the trans tunnel. None of this was visible. I also had a small rust spot at the rear right rocker, which turned out to require removing a lower section of the rear quarter, and a similar lower section of the front fender, and replacing the entire outer rocker piece. Remember, the actual rocker metal is under those trim panels that run along the lower side of the car, under the doors. Remove those and take a hard look both for rust peering through the paint, and also inside the rocker itself (borescope). You will find on my thread a diagram of the complicated rocker assembly. In some areas (around the A and B pillars) there are FIVE layers of metal, and, depending on whether your car has a sun roof or not (thankfully mine doesn't) those areas can rust from the inside out because of the location of the sunroof drains.

On my car the rear floors looked ok, but once we blasted the under side of the car, we found hundreds of small perforations, so that was replaced too.

From what I have seen, the floors are almost always rusty (condensation collects on cold nights, and ends up under the bitumen on the floors, and the tin-worm has its meal...). On my car the heat from the exhaust, and condensation from a bad drip seal on the AC unit rusted out the front inner floor badly (you will see this in my thread).

I removed the outer rocker on my car to find that the intermediate rocker, B-pillar base, and A-pillar base were rusted, but not structurally, so my "nearly rust free" car was still fairly rusty!!

If you are going to do this DIY, I'd highly recommend spending time studying this forum. Unless you are an Ultra DIY man like Erik, you will probably find that some of these jobs are just too difficult, and it's best to engage pros (I sure did, and, after 4 car restorations, I'm a pretty hard core DIY guy! ).

For the rockers, I'd recommend getting an electric spot welder, and follow Erik's advice on prep and such. A 120 MIG welder will probably serve you well for most other jobs. Remember that metal warps with heat. It is easy to burn through thin sheet metal, and even easier to warp panels by welding too much at a time. Most panel repairs involve many short welds followed by cooling air ("welding cool" as @sfdon calls it.. )

There are lots of coupe folks down in the LA area. If you don't already, get to know them, and follow their advice on shops to help with major repairs.

Here are some pics of my right side rocker that had literally a 1.5 inch round rust spot bubbling under the paint at one end. The painted part is the lower rear quarter panel, the rusted sharp bits are what was left of the outer rocker, and the rusty but sound parts are the lower C-pillar and the intermediate rocker beam. Note in the middle pic I have cut away most of the lower quarter panel, and exposed the outer rocker (this is what you see at the door opening under all the trim... it dives under the front fender at the front of the door, and under the rear quarter at the rear of the door). I have cleaned it up here, but you can see rust perforations all the way up to the B-pillar... :
View attachment 227123

View attachment 227125


View attachment 227124

Thank you - very helpful!

 

[HB Chris]

Alex, I have a guy…….

 

[KF6TRG]

Alex, I have a guy…….

Thanks, Chris -I would like to know more!

 

[Fritzie]

Before

And after removing some part -

but, your car might be better!

 

[KF6TRG]

Thank you so much! This is very helpful

 

[eriknetherlands]

@Fritzie : that last pic! It's missing sooo much metal!
That's not a small job to tackle.

I am humbled by your desire to fix it.
.

 

[KF6TRG]

I agree! Inspirational, to be sure.

 

[D Calkins]

Oh, that is scary. Glad to see your taking care of it properly.

 

[Fritzie]

@Fritzie : that last pic! It's missing sooo much metal!
That's not a small job to tackle.

I am humbled by your desire to fix it.
.

In the meantime another e9 project come across to me. Even worse than this project, so I decided to make an Celette complete with an e9 Celette tower set. Lot of work to make them to fit the original bmw alignment drawing. Here are a few pictures. The tower set I made has 9 towers to keep the chassis aligned during large replacements of parts.
So I’m busy with that project first. By the way, the bad previous welds and restoration you see at the left of this front picture - right side of the car - will be cut out completely! Of course

 

[eriknetherlands]

Thank you for your excellent advice!

Here the promised pics, were the "union" construction is already very well visible on the pics from @Fritzie , here's a specific pic of the foot long strip that you may want to remove as a second step (if the rust doesn't disappear with a wire wheel alone).