Fuel tank plate desaster

[larsmhh]

Hi,
I worked this weekend on my Delorean (#1550) and because I saw a liile corrosion on the fuel tank plate I decided to remove it.
I found this coorosive desaster (Photo).
IMG_20190127_180328.jpg
As you can see, the epoxy coating is bad and loose like chips or a coral surface.
As I read in this community the windscreen water flows down the sink between the windscreen wipers and then flows out of the 40mm hole just above the fuel pump. I think it then must run down the plastic tank and drip down to this plate. I think, this would explain the corrosion.
Thank god the frame looks very different and shows only very little rust.
I will give the plate to a company that wis snad blast the surface and powder coat the metal.
BEFORE that I wanted to discuss with you, if it would be good to drill some holes (i.e. as shown on picture #2) to drain the water from the windscreen easier.
IMG_20190127_180328-modified.jpg

Thank you very much for your help,
best wishes,

Lars

[Jonathan]

I wouldn't drill holes in the middle of the plate like you've shown. Probably a few different reasons why, and some of those might include weakening the structural integrity of the plate itself (and it holding up some of the weight of the fuel tank), additional edges for corrosion to start at, and opening up places for a piece of road debris, however unlikely, to come up and whack a hole in the plastic fuel tank.

My plate looked as bad as yours or worse when I got my car. I didn't attempt to repair it but instead bought a stainless steel one from a forum member selling them at the time. That new plate didn't come with those ribs you see on the sides of the originals. Those were meant to let that water drain down from above by going around the sides. What I ended up doing with my new plate was to purposely use an extra thick washer on each bolt and so built a slim gap between the surface of the plate and that of the fiberglass it was coming up to.

I might try extra washers or something else entirely before drilling holes though. Measure twice, cut once bud!

[Michael]

In hindsight, I think a sunken center with a small hole would have stopped most all closing plate rust issues.

[David T]

As rusty as the plate is, it is still structurally sound. That said, it will eventually rust through. The vendors have plates to sell that they have had made up. While JZD intended the car to last, I don't think even he had planed for or designed it to last 38 years. It's an old car and parts do go bad. Typically the brake master leaks, the brake fluid gets on the epoxy of the frame and the plate. It softens the epoxy, lifting it from the metal allowing moisture to attack the steel causing the rust. Having condensate from the A/C dripping on it also doesn't help.

[larsmhh]

So far, thank you for your postings.
Yes, I also think, the brake master cylinder may have leaked in the past and softened the epoxy. The water from the windscreen AND the a/c will then have caused the bad corrosion.
But that is the cause. What do you think about the effect of drilling (maybe less than in my sketch) holes, maybe just in the front and rear corners?
I would drill holes not bigger than or about 1 inch (25mm) to prevent debris to damage the fuel tank.

Kind regards,

Lars.

[Mark D]

The epoxy damage definitely looks like it was caused by brake fluid. The wrinkled up appearance in the areas that haven't flaked off yet are a dead giveaway. Luckily you caught it before it started rusting through...it looks like mostly surface rust. Nothing a little sanding and POR-15 won't fix.

Here are a bunch of photos from when I restored mine. They aren't in order unfortunately, but you can probably figure out the before and after.

http://dmctalk.org/album.php?albumid=167

I did the following:

Wire brush
120 grit sand paper on an orbital sander to remove more rust and feather out the epoxy along the edges.
Red scotch brite pad to scuff the entire panel.
POR-15 rust preventative paint only on the bare metal sections (2 coats, looks dark gray in the photos)
POR-primer overlapping the POR painted section and epoxy. (2 coats, looks light gray in the photos. High build primer that resembles the thickness of the epoxy. Also helps the top coat bond to the POR-15 below.)
Top coat (2 coats Rustoleum Smoke Gray)

Here's a link to a different thread comparing a few other colors of paint to match your frame. The rustoleum was almost a perfect match on my car to surrounding epoxy that had been cleaned back to its original color to remove brown stains.
http://dmctalk.org/showthread.php?51...lor-Comparison

Drilling a few holes probably wouldn't hurt for fixing drainage issues. I opted to add a thick washer between the plate and the frame at each bolt as others have mentioned. This helps the existing drain channels work more effectively.

[ed uding]

We have the fuel tank plate made of Stainless, simple and solid repair for the rest of your live.
https://www.delorean.eu/catalog/prod...ucts_id=168057


Regards Ed

[dn010]

Considering it's a pain in the ass to get the tank out without the plate even on, I'm thinking you'd probably be fine drilling a few holes here and there.

[larsmhh]

Hi!
I decided to drill 4 small holes (12mm) in the corners of the indentation. So if there will be water in the indention, it can drain... I took a photo of the result:
Präsentation1.jpg
@ Mark D:
Wow, your plate looks better than new after your restoration.
The use of extra washers is a good idea. I will realize this at the assembly.

I was a bit lazy about the big amount of rust on my plate so I asked a powder coater near to my home.
He will sand blast the plate and than powder coat it.
It will take a week, until I will have my plate back.
I will take a picture of the result.
Thank you for the discussion and your replies.
Lars

[David T]

A note of caution, if you change the bolts holding the plate on because you are adding washers and need to use longer bolts, make sure the bolts do not protrude past the welded nuts or you will damage the A/C hoses which lay on them.