Hood hinge pocket rust

[firstdiesel]

Hi all,

Well, I decided to tackle the both hood hinge pocket areas which I knew to be leaking. I have read everything I could find on the forum, and it is very informative. However, none of them looked to be quite as bad as mine.

Chad has a great write up and I wish mine would go that smoothly, but alas, someone else decided to do a sub par fix and it only made matters worse.

Here are some pictures of the previous repair attempt and some of what I found.

[firstdiesel]

There is some on the battery box area, but not as bad as I've seen others.

The inside is not so good either, really not good!

The front firewall area next to the drip area is showing sky, and the area near the spring mount is open enough to have rusted the metal going to the A pillar (I think that's what its called. It holds the front door on the car.) area all the way to the rocker. Oddly enough I don't see any serious rust on the top of the rocker looking inside.

[firstdiesel]

So here is my question. Is the sheet metal inside the A pillar, not the A pillar itself, able to be cut and patched so that I can clean up the inside and properly prep the area for POR15?

You can see the rust starting to come through in the oval section of the picture, and in the picture of the "upper inside" view, the right hand portion is opening into the A pillar area.

The A pillar looks to have some surface rust, but when I assaulted it with a long screwdriver it just flaked off a little. It didn't give way at all, no holes and no flexing. I could cut away the sheet metal, prep the rust, coat with POR15 and then patch the cut area with metal and JB Weld since I don't believe it to be structural.

Anyone else tackle something like this? I saw the rust fix on the SD, but he doesn't have hinge pockets, luckily.

No structural rust anywhere on the car! Rockers are solid, jack points, floor pans all look good. Some minor surface rust to deal with in a couple areas, but then I will need to get it painted and I don't have the cash for that right now.

[Graham]

1stD,

Did you read the threads in the Bodywork forum? Stretch started one and there are pictures of my hinge pockets toward the end of his thread. Just as bad as yours!

http://www.peachparts.com/shopforum/body-repair-restoration/286079-w123-hood-bonnet-spring-pocket-refurbishment.html

Then there is the epic thread f the rust repairs I had done last fall:

http://www.peachparts.com/shopforum/body-repair-restoration/326615-300d-w123-weld-repair-rusted-chassis-floorpans.html

This is a link to pictures the shop posted on line:
http://www.lastchanceautorestore.com/gallery_completed/gallery.php?vid=1985_Mercedes_300D

Once springs were out of the way, I glassed the hinge pockets using POR-15 as the resin. I put in multiple layers. Then I did same from the other sides - From inside footwell up high where the hinge pockets had rusted through and also on the outside back between the fender and the footwell sidewall. Those areas would have been easier with the fenders off, but I was bale to reach in to first paint with OR and then apply patches.

Of course, I had a lot of other rust, largely caused by the water that got in through those hinge pockets. Last Chance Restoration did a good job of fixing that.

In the end, I spent about $3k, but our 300D is once again our main driver. It looks and runs just great. My wife chooses it over our E320 W210! She finds it comfortable, just like an old pair of slippers!

[firstdiesel]

I have definitely read those threads! Very helpful.

Seriously, Last Chance did a great job. You're right, lot worse than mine!! Of course if I didn't do this now, I'd be heading down that road for sure.

Some of it I can patch the way Chad did and the rest will be the fiberglass cloth and por15. But, the A pillar thing is what concerns me. At least a third of my pocket is missing and the part that leaked in went in places that are impossible to get to without cutting.

Yeah, I'm hoping that stretch checks this out and can give some feedback as well. He'll tackle any project, but I have to be careful, I rebuilt my entire transmission twice because of his threads!!:-D

One question I do have is that if I use the cloth-por15 route, and do a couple layers, do you think it will stay water tight or could I end up with hidden water? That blue stuff was backed by aluminum plating which left huge open spots to hold water. Made it worse than leaving it open in my opinion.

[Smoker]

On the 240 mine was really bad, had rusted a fist sized section from the top of the pocket there on down into the fenderwell.

After I did the POR15 and glass, I use eastwood seam sealer. Some folks don't like seam sealer but in my experience with rust repair as long as you don't trap water or create areas for water to pool with the seam sealer it can really help keep water out. I spread it in with nitrile gloves on and use a finger, just a thin coat to seal the seams.

[cooljjay]

I have a nasty pocket of rot under my battery tray......I did a very professional job fixing it.....I sanded the rust down, killed it all.....and filled the few holes going into the cabin with silicone.....some bondo, can of spray paint and it will match that of a macco job

Seriously though, I think as long as the rust is stopped, and it hasn't compromised anything structural.....the easiest and simplest way to keep the water out of the cabin/pockets is the best solution.....smoker's idea is a good one!

[Graham]

Originally Posted by firstdiesel

One question I do have is that if I use the cloth-por15 route, and do a couple layers, do you think it will stay water tight or could I end up with hidden water? That blue stuff was backed by aluminum plating which left huge open spots to hold water. Made it worse than leaving it open in my opinion.

POR doesn't wet out the glass like polyester or epoxy resin does. So it is possible to have pinholes. I don't recall how many layers of glass I used in those hinge pockets, but more than two. Then every time I was working on something else, I used whatever was left to slather the hinge pockets. Sometimes I thickened the POR with microballoons (which I just happen to have). Gets it more to the consistency of POR Putty and it then stays where you put it. You do need to try and sand a little before overcoating so as to get a good bond. In the end, I used seam sealer on most of the repairs, more to just feather them in than anything. Can't recall if I used it in the hinge pockets but no reason not to as a final coat.

Without actually seeing the A-pillar or door frames, hard to comment. I had some places that I could not get to, like inside the rockers. I sprayed those inside with rust treatment like Fluid Film. I am going to do them again and again jusy s they won't rust from inside out.

By the way - You probably need to grind out that blue stuff and get back to what is left of original metal.

Good Luck with it!

[firstdiesel]

All those are good ideas.

Pulled the "blue stuff" out and the pocket is worse on the driver's side. Looks like it is a bondo kit with aluminum plate backing. Very poor choice of patchwork.

It didn't get to the parking brake bracket mount point, but it did get to some of the hood release cable opening. Just the bottom where some of it forms the lower drain point.

I know that it seams to be a por15 and cloth, or patch, but is there any reason to not use epoxy or polyester resin and then por15 over that?

[Graham]

Originally Posted by firstdiesel

I know that it seams to be a por15 and cloth, or patch, but is there any reason to not use epoxy or polyester resin and then por15 over that?

The advantage I see of using POR first, is that you encapsulate the rust that is already there. It is easier and probably better to stay with just one product. Don't worry about the pin-holes. If you apply a few coats of POR once glass is in place they will get filled. If you are still worried, coat with seam sealer.

[Diesel911]

Here is some pics of rust repair done with a Polyester Cloth that is thinner than Fiber Glass Cloth but otherwise similar and JB Weld Epoxy.

[Stretch]

I think people need to be careful with the JB weld epoxy filler / fibre glass / metalised filler route.

I think people need to realise that from the 1960s all Mercedes cars have been built with monocoque / unibody constructions. This means the structural integrity can not be thought of in terms of "structural" or "non structural". Some parts of the structure are stiffer and thicker but if you remove too much of the structure you end up with a fragile egg shell.

For me good quality welding of new metal is the only option.



I understand that for others this causes a dilemma - it caused a dilemma for me - I had to go off and learn to weld. Pain in the arse!


Although this next bit of advice will almost certainly make more work...

...I think that before anyone decides to treat anything with POR-15 they should get an angle grinder and a wire brush attachment and push this up against the area of concern. If your wire brush attachment travels quickly into the car and you are covered in a cloud of rust dust you will most certainly be upset. It is not nice - but you need to face reality of the situation - rust is not strong - papering over the cracks with filler will not fix the problem. Epoxy does not stick to rusting metal for long - neither does POR-15.

[Graham]

Originally Posted by Stretch

. Epoxy does not stick to rusting metal for long - neither does POR-15.

Mostly good advice Stretch. In short, don't repair any parts that contribute to the stiffness of the vehicle with epoxy or POR. They just don't stick well enough. There are structural adhesives that could be used in place of welding but mostly beyond our DIY capability.

POR-15 does bond to rust. That is what is intended for. To use epoxy, you need to get to bare metal i.e sand blast. For POR and similar, you do need to remove loose scale and rust first. I have a repair that I did on my 350SL trunk tool storage area bottom that you cannot tell is not steel and I did that in 1990! It had completely rusted out.

I think POR is an ideal solution for the bottom of the hinge pockets which I doubt are structural. But not for the A-pillars or surrounding sheet metal.

One problem with weld repairs, is that it is not always possible to get at both sides of the weld. The hidden side gets oxidized and then rusts. Don't know how many times over the years, I had rust repairs done on my old cars and then saw rust appear in a year or so adjacent to the repair. There are weld through primers these days, but not always possible to apply them (such as inside rockers.

Nothing is easy!

[Stretch]

Originally Posted by Graham

...
POR-15 does bond to rust. That is what is intended for...

I respectfully disagree Graham.

I haven't been using the POR-15 for long - only about four years. BUT buyer beware - don't believe what's written in big letters on the tin - following the instructions (also on the tin in small letters) and you'll get to see a different story. POR-15 can not cope with anything more than very very light surface rust. You can indeed paint it straight onto rust and it will look like it is doing a good job for a while. But as it cures POR-15 goes hard. Knock it with a hammer and if there is rust underneath it will come off in great big chunks.

So to those people who don't want to use an angle grinder and a wire brush attachment your repair won't be that good. You really do need to clean and clean the surfaces as much as possible to end up with a good result.

Originally Posted by Graham

...

I think POR is an ideal solution for the bottom of the hinge pockets which I doubt are structural.

Sorry Graham I disagree again - that part of the body looks to me like it is designed to be super stiff and light. It looks to me like it is additional stiffening to the bulkhead and therefore plays an important role in the protection of occupants in a head on crash.

Originally Posted by Graham

...

One problem with weld repairs, is that it is not always possible to get at both sides of the weld. The hidden side gets oxidized and then rusts. Don't know how many times over the years, I had rust repairs done on my old cars and then saw rust appear in a year or so adjacent to the repair. There are weld through primers these days, but not always possible to apply them (such as inside rockers.

Nothing is easy!

I too have seen many a repair go sour like that. I'll be spraying the internal parts of the cavities I weld with Dinitrol. I hope it does what it says on the tin!

[Smoker]

Have to agree with Army, I use quite a bit of POR15, but never over rust. Strip it all down, use the proper metal ready prep on the clean metal, then put on POR15.

Tried it the other way on a Saab Sonett. After less than a year was able to peel strips of intact POR15 off of the happily rusting car.

As to the strength/crash role of the firewall and pocket area, honestly don't know. Obviously the glass is weaker than steel, hope I never find out if it's critical