# Rust Removal/Undercoating



## eastcoastjava (Apr 2, 2011)

My 04 sierra has some major rust underneath so i want to remove it and repaint the whole undercarriage with out removing the bed. I don't have access to a sand blaster so i plan on hitting as much of the rust that i can with a wire wheel and 3M pads then pressure wash it. From there using rustoleum rust converter on the whole undercarriage and then spray it with POR 15 in 2 coats. After that i would hit everything with Fluid film. But i do have a few questions

1- Do i need to use a rust converter even though i plan on scrapping most of the rust off with a wire wheel/3m pads, and what about the areas that can scrape?

2-How well does POR 15 work, i have seen other undercoating such as bedliner, Rust Bullet, and eastwood rust encapsulator, also POR 15 says it cant be used in UV conditions?

3-How long can i expect this stuff to last to last?

4- Any recommendations on wire wheels/pads for this, I ask because i literally have to hit all surfaces under the truck ranging from the frame,differential, and control arms so some areas may be difficult to hit?


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## MikeA5150 (Dec 20, 2010)

I used por 15 on the frame of my old truck about 15 years ago and its still holding up fine,its good stuff but the bed was off and I was able to get to all sides. I used scrapers, a wire wheel etc.The bed on your truck is fairly easy to take off. Theres either 6 or 8 bolts all underneath the bed, the rear harness and a wire at the gas fill, I think thats it. Good luck.


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## theholycow (Nov 29, 2002)

Access is bad enough with the bed off. With the bed on I doubt you'll get 50% coverage with your rust removal. Taking the bed off is very easy with a couple strong men (or four average ones)...undo a few bolts, unhook a couple electrical connectors, lift it right off. With no helper it involves a tree or frame and some rigging and it's kinda tough to keep steady.

You'll want a variety of wire brushes. Wheels, cup brushes, end brushes. Knotted, straight/crimped. Drill, angle grinder, die grinder, rotary tool. Everything from tiny to huge. Of course, you won't actually invest in a thousand dollars worth of wire brushes but you'll _want_ them!  Do invest in a variety though.

From what I understand, there's no need to use rust converter before POR15, as POR15 does that job in addition to the job of undercoating. In fact, if anything, with the price of POR15 I'd want to put a couple layers of cheap undercoating over the POR15 to protect it against road debris (and UV in the few spots where the sun can hit it near the wheelwells). I didn't use POR15 because it wasn't in my budget, but the Dupli-Color Rust Fix converter and cans of undercoating I used ended up having less coverage than expected.

You might also consider a chemical rust remover immediately after the wirebrush. Evapo-rust is one brand. Even the most relentless wirebrushing leaves micro-pores with rust in them, and then there's the spots you can't get to so well, and then there's the spots you totally can't reach at all.

However much time you've budgeted for this, double it, and then plan on that not being enough.


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## eastcoastjava (Apr 2, 2011)

I have few questions regarding the bed removal, Will i have to remove the tail gate and tail lights or can those stay on. Also how hard are the bed bolts to find/and have access to same with the electrical connections how many will i encounter and how hard are they to remove. Lastly how hard is it to remove the fuel connection. If i do it this way i might just have it blasted by a friend of my fathers.


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## eastcoastjava (Apr 2, 2011)

theholycow;1600448 said:


> Access is bad enough with the bed off. With the bed on I doubt you'll get 50% coverage with your rust removal. Taking the bed off is very easy with a couple strong men (or four average ones)...undo a few bolts, unhook a couple electrical connectors, lift it right off. With no helper it involves a tree or frame and some rigging and it's kinda tough to keep steady.
> 
> You'll want a variety of wire brushes. Wheels, cup brushes, end brushes. Knotted, straight/crimped. Drill, angle grinder, die grinder, rotary tool. Everything from tiny to huge. Of course, you won't actually invest in a thousand dollars worth of wire brushes but you'll _want_ them!  Do invest in a variety though.
> 
> ...


For a chemical rust remover what do you think about Naval Jelly, i heard that it is effective and i spray everything with that then hit everything with a the grinder/wire wheels, that is if i don't have it blasted.


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## theholycow (Nov 29, 2002)

eastcoastjava;1601161 said:


> For a chemical rust remover what do you think about Naval Jelly, i heard that it is effective and i spray everything with that then hit everything with a the grinder/wire wheels, that is if i don't have it blasted.


No, that's backwards. You do mechanical removal (grinder, wire wheels, sandblasting) *first*, _then_ you use chemical removal (naval jelly, Evapo Rust, etc). The chemical rust remover can't do its job unless you take off the flaky and/or heavy stuff first. The wire wheels can't remove the fine stuff that's well-adhered to the pits and pores, which is why you want to use chemical rust remover and/or rust converter.

I've heard of naval jelly but have not used it.

As for bed removal...

There are 4 sets of 2 bolts. You lay under the truck near each corner of the bed and look up, you'll see them. You need an appropriate sized socket (IIRC 21 or 22 mm, something like that) and a decent length extension. You also need some elbow grease...you might need a nice breaker bar to loosen them before an average DIYer's impact wrench will zip them out, or an impact might just take them right out. If you don't have an impact wrench you can turn them by hand, they're no worse for that than lug nuts, or you can do what I like to do for lug nuts -- break them loose then use a drill to spin them off.

The tailgate is heavy and very easy to remove. You should remove it before removing the bed or you'll need one more man to lift the bed off. Open it, tilt it 45 degrees towards you, and pull up...one side will come right out of the hinge, then you can pull the other side away from its hinge. Rest it on the bumper and pop off the cables.

The lights stay on.

The electrical plugs are at the rear on the drivers side facing back. You'll probably get a good look at them once the gate is off, though you might have to lift the bed a little for clearance to stick your arm in. They come off more easily than most electrical connectors. The truck-side of them is bolted to the frame. There are 2 or 3.

I always forget to mention the fuel filler. When you open the fuel door you can see 3 bolts around the cap. Remove those. There's also a grounding strap on the backside, one bolt, remove that. Take off the gas cap of course. That's it.

I took the bumper off because my bumper was rotted out and I was replacing it anyway, but you can leave yours on. In this pic you can see the connectors, partially obscured by a conduit.









That's a lot of text for what's really a simple and easy job. Do not be intimidated, I know it seems like a big deal because it's like you're taking half your truck off, but it's just so easy. It's less work than rotating your tires, seriously.

I also recommend it any time you need to do work on your fuel pump, rather than struggling with dropping the tank...why lay under it and reach around blind in a tight space to try to disconnect pain in the butt fuel connectors when you can sit on the frame and work on it at bench height! Not to mention seized fuel tank strap bolts and manhandling a tank full of fuel...


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## eastcoastjava (Apr 2, 2011)

theholycow;1601211 said:


> No, that's backwards. You do mechanical removal (grinder, wire wheels, sandblasting) *first*, _then_ you use chemical removal (naval jelly, Evapo Rust, etc). The chemical rust remover can't do its job unless you take off the flaky and/or heavy stuff first. The wire wheels can't remove the fine stuff that's well-adhered to the pits and pores, which is why you want to use chemical rust remover and/or rust converter.
> 
> I've heard of naval jelly but have not used it.
> 
> ...


Thank you for all the info, not trying to sound like an idiot but i am still confused on where the electrical connections are, do you mean below the tailgate right near the rear bumper or are they near the fuel tank?


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## eastcoastjava (Apr 2, 2011)

Now i think i can see the conectors for the electrical,driver side to the right of the back leaf spring?


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## theholycow (Nov 29, 2002)

Yes, below the tailgate near the bumper. When you remove the tailgate, look into the gap below it and you can see them. Yes, driver side to the right of the back leaf spring.

Look at the rear-most crossmember in my photo. It's the crossmember with the tube sticking out for the spare tire jack. On the flat surface facing backwards on the left side there's a cluster of grey plastic. That's the connector. In the photo, the conduit (looks like a hose) partially blocks your view of it.

It's very obvious and simple when you go looking for it.


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## eastcoastjava (Apr 2, 2011)

Yeah i see it now thank you. I just cant wait to do this but i have to do it over spring break because i know this is going to be a time consuming project. How much POR do you think i will have to use, do you think 2 quarts would do the job if i had to apply 2 coats?


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## theholycow (Nov 29, 2002)

No idea about POR15 coverage but I can tell you that I had to use more than expected of the products I used. I also spent far more time than I had planned.

I think you can't start soon. This is a summer project. You can't do it indoors (dust and serious fumes), you can't do it with snow landing on it, and you probably can't apply POR15 in freezing temperatures. (A body shop would have appropriate ventilation systems, I bet, but not your home garage.)


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## eastcoastjava (Apr 2, 2011)

Well, i plan to do it over a week period, i have access to an inside shop with ventilation. And i really don't want to do this in the summer, thats when work really starts to pick up


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## eastcoastjava (Apr 2, 2011)

eastcoastjava;1601299 said:


> Thank you for all the info, not trying to sound like an idiot but i am still confused on where the electrical connections are, do you mean below the tailgate right near the rear bumper or are they near the fuel tank?


I understand that removing the tailgate will reduce the weight but is it necessary. Weight is no problem i have access to a front end loader or a log loader and 3 or 4 guys. Just don't feel like ****in with it.


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## theholycow (Nov 29, 2002)

Leaving the tailgate on won't cause any technical issues that I can think of, though it might be harder to reach the plugs with your hand. Have you never removed the tailgate? It takes less than 20 seconds.


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## mkwl (Jan 21, 2005)

I did this exact same thing to my '03 GMC 2500HD this past fall. I didn't remove the bed, though it probably would have made the job a little easier. I spent a solid day scraping it down, wire wheeling, and prepping the frame. Then put on 3 coats of POR-15, and sprayed the entire frame with gloss black Rustoleum (2 coats- have to cover the POR because it's not UV resistant)... so far so good- my frame was pretty nasty- looks much better now! Hopefully it keeps the frame good for a few years to come... rocker panels and a rear bumper are next on the list for that truck... years of salt and plowing are catching up with it 

Check out the following post- goes over some pics of the after.... http://www.plowsite.com/showthread.php?t=137793


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## eastcoastjava (Apr 2, 2011)

mkwl;1603407 said:


> I did this exact same thing to my '03 GMC 2500HD this past fall. I didn't remove the bed, though it probably would have made the job a little easier. I spent a solid day scraping it down, wire wheeling, and prepping the frame. Then put on 3 coats of POR-15, and sprayed the entire frame with gloss black Rustoleum (2 coats- have to cover the POR because it's not UV resistant)... so far so good- my frame was pretty nasty- looks much better now! Hopefully it keeps the frame good for a few years to come... rocker panels and a rear bumper are next on the list for that truck... years of salt and plowing are catching up with it
> 
> Check out the following post- goes over some pics of the after.... http://www.plowsite.com/showthread.php?t=137793


Did you use the POR there three step process(Marine clean/metal ready/Por15) or did you just put the POR15 on after scraping. Also how much POR15 did you use and did you put 1 or 2 coats of the POR15. Last question would be did you tape off the nuts or did you paint over them with por15. I ask because i think i am going to go over the bolts with spray can Rustoleum rust paint.


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## Zigblazer (Aug 1, 2010)

Any long term update on the POR15?


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