(?) Repairing tailgate rust?

[tinius]

Has anyone tried to repair the typical tailgate rust at the lower left and right corners of the glass?

Here's the way it looks now. The right side isn't as bad.
http://farm9.staticflickr.com/8493/8407371154_3a193d14d0_c.jpg

This isn't my tailgate, but a photo from a forum in the UK.
http://farm9.staticflickr.com/8214/8437684333_ab184e3cbd_c.jpg

Any tips or photos? I have a painted, no-rust tailgate metal shell, but I would like to try fixing what I have before moving all of the trim and electrical to the new gate and trying to adjust it for fit.

Has anyone worked with the POR-15 (http://www.por15.com/SUPER-STARTER-KIT/productinfo/SSKB/) products, specifically tried to fill and paint over them?

I would also like to stop/fix rust around the gas filler. Tips, commiseration, etc. welcome.

Thanks,

[RVAE34]

You can't catch a break with that can you, Stephen? Por 15 is pretty nasty stuff. Thick and dries really hard. It's generally used on areas you don't see but that area is a bit hidden so it might work..

I might be interested in that tailgate shell if you don't end up using it.

Have you tried a body shop to see what they would charge? I may try fixing mine from your old car myself as I have done a lot of paintwork. But on your old car, I feel I can just grind it down, etch prime and shoot again without having to replace any metal. Your photo looks like you need to remove a small section and weld in new like the second image you posted.

[noodlesandsam]

POR 15 is nasty. Get it in silver if that is your car color. I have the same issues with mine. Wear lots of old clothes, and gloves.

[cwise12]

I'm having the same problem. The metal around the glass is also rusting pretty badly, right at the bottom where it sits in that groove the tailgate itself makes.

I've been looking for replacement tailgates, but I wonder if it can actually be repaired long-term or of any measures to stop the rust would be very temporary...

[noodlesandsam]

It's temporary. You're in Mass? My 540iT spent the 197k there. The tailgate is a mess, and the last owner had it fixed at least once. Maybe twice. The rest of the car is super clean. I'll try to post pics at some point. I'm looking for a clean tailgate.

[geargrinder]

It's temporary. You're in Mass? My 540iT spent the 197k there. The tailgate is a mess, and the last owner had it fixed at least once. Maybe twice. The rest of the car is super clean. I'll try to post pics at some point. I'm looking for a clean tailgate.

Hmmm. I wonder if i know your car. Billy suspension all around and no tailgate trim?

To other posts, yeah that spot is super common. Its amazing its not mentioned more i thought i was the only person who could see 80% of tourings not from arizona or newmex seem to have at least a tiny bubble... Left side always first and more common, right side rarer.

RE: POR yeah that stuff is nuts and awesome but its not really a finish surface thing. Agree it would be great for the unseen parts of hatch as long as trim covers it up mostly. For a better finish in a delicate area you CAN thin it. POR pretend you need their super extra special thinners but IIRC its really xylene. Maybe a dash of something else but i used HW store xylene w no issues. Yes it does come in silver but you need to top coat it with paint anyway (though obv silver under silver would be ideal). Part of what makes it awesome for rust prevention is that it cures reactively using atmospheric moisture so unlike paints it will "suck up" all the moisture under the coating to prevent creeping rust from continuing. Last POR tip - if you really want to make it near perfect you clean up the rust a bit first, then use a phosphoric acid type "rust remover" "naval jelly" etc product. This converts any lurking rust underneath. Then POR it. Unbelievably hard and effective long term rust resistance. Oh and due to the moisture cure, doing it on a dry summer day can actually be a pain as it will take forever. Imagine the exact opposite of house paint. Likewise on a moist day it will cure really fast. I had some pieces stay wet all day on a nice summer day, finally took em in my humid basement and boom - reaction started to kick and hardened right up. And yeah - dont spill it on anything you dont want to be permanently POR'd. Sh1t is SERIOUSLY permanent.

[jstern]

Just a point of interest. The tailgates rust from the inside out because of a poor seal (factory poor design fault IMHO) where the wiring harness goes from the outside to the inside of the tailgate. If you lift the window and remove the plastic covers on the left and right sides, you will see where the harness goes through.

My son's 99 Touring's tailgate was very rusted. I bought a complete tailgate (from a 2001 525iT-same color) from LKQ for about $500 and installed it. I used the wiring harness from the car removing the one that came with the tailgate-of course it was hacked off where the wires came out of the roof. Everything plugged in and worked fine except for the window.

http://forums.bimmerforums.com/forum/showthread.php?t=1942128

The window is rarely used so disabling it was a good temporary, if not permanent, solution. Since I saved all the electronics from the old tailgate, I'll probably transfer the window electronics from the old tailgate in the warmer weather-the 'new' latch has a different part number from the 'old'.

I made sure to seal the holes on both sides where the harness goes through the tailgate very well with silicone sealant. This should prevent the replacement from rusting out like the old one did.

If you guys repair your rust holes, make sure you clean and reseal these holes very well.:)

[Der Krieger]

POR-15 is a combination of chemicals (http://www.por15info.com/msds/POR-15MSDS.pdf) that convert the iron III oxide (red 'rust') into iron II oxide (black - not rust) that does not further corrode. It is also an epoxy that covers the converted rust so moisture can't reach the metal surface. If you remove the bubbling on the surface to present a relatively smooth surface after application, it will be paintable and quite presentable when you're done. The link above is to the MSDS to address your concerns about exactly what is "nasty" about it - and what precautions you should take.

[tinius]

Just a point of interest. ...
If you guys repair your rust holes, make sure you clean and reseal these holes very well.:)

My plan is to grind away and remove all of the rust I can see, then seal the area with POR-15 silver. They claim it will stop the rust. Then I will use body filler to re-build the area, then sand and repaint. Then replace the rubber pass-through.

Will body filler adhere to the POR-15?

With the metal covered with POR-15, body filler and paint, I hope that even if water sits there, it will not continue to rust and show.

I may be a dreamer...

[geargrinder]

POR-15 is a combination of chemicals (http://www.por15info.com/msds/POR-15MSDS.pdf) that convert the iron III oxide (red 'rust') into iron II oxide (black - not rust) that does not further corrode. It is also an epoxy that covers the converted rust so moisture can't reach the metal surface. If you remove the bubbling on the surface to present a relatively smooth surface after application, it will be paintable and quite presentable when you're done. The link above is to the MSDS to address your concerns about exactly what is "nasty" about it - and what precautions you should take.

There is SO MUCH wrong with that post.

POR-15 itself doesn't contain any phosphoric acid. The company sells a SEPARATE naval jelly type phosphoric acid product called Metal Ready. But you can buy anybody's - theres is nothing special although I'm sure it's fine quality too.

And POR-15 itself is not epoxy. It is Reactive Polyolefin. OK maybe their secret formula contains some epoxy functionality or blending i dunno but if so that's the add-in not the primary chemistry.

Not to say its not great stuff (and I already SAID pretreating w phosphoric was a good practice) but otherwise that post is very wrong about the details.

[Der Krieger]

There is SO MUCH wrong with that post.

POR-15 itself doesn't contain any phosphoric acid. The company sells a SEPARATE naval jelly type phosphoric acid product called Metal Ready. But you can buy anybody's - theres is nothing special although I'm sure it's fine quality too.

Who said anything about phosphoric acid? That is not the only way to treat rust nor is it the only way to convert the iron ion.


And POR-15 itself is not epoxy. It is Reactive Polyolefin. OK maybe their secret formula contains some epoxy functionality or blending i dunno but if so that's the add-in not the primary chemistry.

Yeah; I 'shorthanded' it for ease of understanding because I didn't want to do a whole f*cking chemistry lecture here. How about, "It forms a hard protective coating." Does THAT satisfy your sensitivity for "wrong"? Maybe if you'd actually read the MSDS that I linked, you'd see there are no polyolefins in it at all. They're isocyanates.


Not to say its not great stuff (and I already SAID pretreating w phosphoric was a good practice) but otherwise that post is very wrong about the details.

I don't see that you added a whole lot that was RIGHT ...

Oh, look! A smiley for you! :finger22

[geargrinder]

LOL. knew I'd get the angry denial and "hey when I said epoxy I meant like something that is like epoxy" classic interwebs "just because my actual specific words were wrong doesn't mean I'm not right" defense. Next up is usually editing your post so you can deny.

But instead of givin you the finger I say have a fine day my friend and I hope you have a more cheerful day tomorrow.

[Der Krieger]

LOL. knew I'd get the angry denial and "hey when I said epoxy I meant like something that is like epoxy" classic interwebs "just because my actual specific words were wrong doesn't mean I'm not right" defense. Next up is usually editing your post so you can deny.

But instead of givin you the finger I say have a fine day my friend and I hope you have a more cheerful day tomorrow.

Had I wished to ninja edit the post, I would have. However, I have more integrity than you think. UNLIKE you, I also post with a real name. I notice that when YOU are wrong about the chemistry, it apparently doesn't matter. It only does when I do. I hope I can remember to simply ignore you in the future.

[geargrinder]

However, I have more integrity than you think. UNLIKE you, I also post with a real name..

LOL. dats a good one. And i have no idea what bearing it has here, but, FWIW...

I go to no particular lengths to hide my identity, here or on other forums. Lots of members know my details and i freely share them if there is any reason too. Anybody with half an ability in google would know exactly who i am. Also, uh.. gee "Der Krieger" i have no idea how that is "a real name" vs any other screenname here. It must be 99% of members here use a screenname that is not their actual legal "Joe Smith" name. Who cares. Jumping on that bizarrely as if it was anything and gives you "Der Kreiger" some moral high ground seems in right keeping with your attitude jumping into this thread to make erroneous corrections to previously posted correct answers with an attitude of superiority. Whatever. Block user "Der Krieger".