Under body touch up / rust

Falls

Super Moderator
I want to keep the under body from getting all rusty. On my 06 I see rusty area's starting like by some if the weld and off road scrapes.

I dont want to paint it or undercoat it but was going to use some stuff , that when you spray it on those area's it neutralizes & stops the rust and turns it black. The product is not black it comes out clear and goes on clear and turns black a while after it has time to work. I think there are a few different ones out there . The one I used a few years ago on my Vette front frame worked awesome. I did it the first year I had it and 15 years later it look the same black and not rusty at all.


Anyone do this ?

I really dont care how the underbody looks , but would like to nip it in the butt , and do occasional touch up on areas to keep rust at bay . Living here in the winter road salt belt of the U.S. it will just keep rusting until its starts flaking.
 
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Just take a rattle can to it. Rustoleum works best. If you're really worried about it you can look up a product called POR-15.
 
There is a product made by 3M sold at auto parts stores that can be used for underbodies. It sprays out of the can as a black gel, almost like tar. I have heard it works real well, but you have to rough up surfaces first before applying, so its more like a spot treatment. Since I will be moving back to St. Paul this fall, I'm going to try something like that (MN salts roads like crazy).
Falls, lets post pictures of what we do (like before and after) when the time comes to do the work (couple months for me) and try to figure out what works best and maybe get credit for a write up :bigok: !
 
The 3m stuff works relatively well. You could also have rhino lining material sprayed on the undercarriage. A bit of an over kill but I have seen that done as well on the coast.
 
kaneman23 said:
Just take a rattle can to it. Rustoleum works best. If you're really worried about it you can look up a product called POR-15.

FYI, Rustoleum and POR-15 are two totally different classes of product for dealing with rust. Rustoleum is okay if you understand that that the rust will come back. POR-15 (when used properly) is MUCH MORE effective at stopping rust than Rustoleum and many other products on the market. POR-15 is a lot more work but if you don't want to keep revisiting an undercarriage rust problem then POR-15 is the product to use.

About a month ago I visited a friend who has a shop and a lift.
I took before and after photos of the undercarriage of my 4Runner.

Before Photos:

http://www.gti16v.com/images/4rnrb401.jpg
http://www.gti16v.com/images/4rnrb402.jpg
http://www.gti16v.com/images/4rnrb403.jpg
http://www.gti16v.com/images/4rnrb404.jpg
http://www.gti16v.com/images/4rnrb409.jpg
http://www.gti16v.com/images/4rnrb410.jpg

After Photos:

http://www.gti16v.com/images/4rnra70.jpg
http://www.gti16v.com/images/4rnra71.jpg
http://www.gti16v.com/images/4rnra72.jpg

It took me approximately 6 hours to do the whole procedure.
Had this been one of my auto restoration projects it would have taken considerably longer.

BTW, under normal circumstances one should top coat POR-15 with primer and paint if the area is exposed to sunlight.
Since that is not the case with the undercarriage of my 4Runner I chose not to primer and paint the POR-15 and just left it the natural color.

Wish I could have seen the look on the Toyota Tech's face when he serviced my 4Runner a few weeks ago.
He was probably not used to seeing a 3 year old + 4Runner that did not have a lot of rust on it's undercarriage.
 
Last edited:
The stuff I used on my Vette was called X-O Rust ( I think ). It sprayed out clear and stopped the rust and was black after it cured.

Its not like a coating , I dont want to do that , I just want to eliminate the rusty spots from getting bigger and flaky. Maybe do a touch-up every spring & fall. Just dont want it to look like crap after a few years. , not really interested in detailing the undercarriage....lol.

I can see rust around the welds and suck starting and in MANY places of scraped from off road driving.
 
About a month ago I visited a friend who has a shop and a lift.
I took before and after photos of the undercarriage of my 4Runner.

Before Photos:

http://www.gti16v.com/images/4rnrb401.jpg
http://www.gti16v.com/images/4rnrb402.jpg
http://www.gti16v.com/images/4rnrb403.jpg
http://www.gti16v.com/images/4rnrb404.jpg
http://www.gti16v.com/images/4rnrb409.jpg
http://www.gti16v.com/images/4rnrb410.jpg



Wish I could have seen the look on the Toyota Tech's face when he serviced my 4Runner a few weeks ago.
He was probably not used to seeing a 3 year old + 4Runner that did not have a lot of rust on it's undercarriage. [/B]

Holy crap....that's a lot of rust. Is this common with 4Runners?
It looks like you sand blasted under there, then threw salt on it :)

Seriously, our 9 year old Honda CRV has maybe 1% the rust shown in those pics. Is Honda that much better prepping their parts, or is Toyota just that much worse?

I'm sure that type of rust won't cause problems, but it sure doesn't look nice.
 
JungleJim said:
Holy crap....that's a lot of rust. Is this common with 4Runners?
It looks like you sand blasted under there, then threw salt on it :)

Seriously, our 9 year old Honda CRV has maybe 1% the rust shown in those pics. Is Honda that much better prepping their parts, or is Toyota just that much worse?

I'm sure that type of rust won't cause problems, but it sure doesn't look nice.

My 22 year old VW Golf does not have anywhere near the amount of rust the 4Runner had.
Then again, the Golf had a pampered life when it was owned by the first two owners. (ie not a lot of winter driving)

Not sure if it is common or not. Can tell you that my 4Runner seldom/if ever sees the inside of a garage.
I try to wash the undercarriage in winter but that does not happen very often due to freezing temps.

Left untreated, this kind of rust will be a problem at some point.
Since I tend to keep my vehicles a long time, I chose to deal with the rust sooner rather than later.
 
OP, what did you end up using on your rig for the rust? I wanna do the same but since winter is already here maybe ill wait till spring
 
I use this from AMSOIL on all exposed nuts bolts etc on my underbody

amh_can_300pxh.jpg

AMSOIL Metal Protector (MP) and AMSOIL Heavy Duty Metal Protector (MPHD) are easy-to-use spray-on synthetic products that protect metal surfaces, displace water and silence squeaks. MP cuts through rust and corrosion to restore free movement of “frozen” hardware parts. MPHD lubricates metal surfaces, leaving a dry waxlike film. Neither forms gum or sludge.

AMSOIL MP is the product of choice for drying electrical and ignition systems and protecting electrical equipment from freshwater and saltwater damage. AMSOIL MP is also the product of choice for protecting firearms and other fine componentry. It contains no silicone. AMSOIL MP is compatible with plastic, leather, fabric, fishing line and paint.

AMSOIL MPHD is the product of choice for metal surfaces that require a heavy duty lubricant or are exposed to the damaging effects of salt, moisture or chemical corrosion. It is ideal for hinges, wire ropes and springs, nuts and bolts, motorcycle or bicycle chains, and for undercoating wheelwells and other metal surfaces exposed to water, dirt or road salt.

Performance Features

Protects against rust & corrosion, even in salt water
Displaces water
Stops squeaks
Lubricates metal surfaces
Leaves a dry, long-lasting, waxlike film
Lubricant does not attract dust
Does not sling off
Sprays into hard-to-reach places
Ideal for chains & other heavy-use items
 

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Save your money and don't use Rustoleum it only last about a month with a spary can and about 3 months with a brush on.

Easiest is the 3Mor Duplocolor in a spray can. It will last for 12+ months.

POR-15 and Rustbullet are great and will last years but are tedious and time consuming to apply.

I never tried the Amsoil but I am not one to drink their marketing coolaid.

My experience comes from my family owning 8+ Toyotas all in Massachusetts/RI. I can show you rust/rot photos that will make your head split open
 
I did 2 coats of POR15 a couple weeks ago. I got the starter kit off amazong for under $20. Took a couple hours, but cummon...its a labor of love when you wash, wax n detail your 4runner, right? That takes me a few hours. POR15 is no worse than that and doesnt your undercarriage deserve it?
 
Wouldn't you rather use something that lasts for more than a year?

It still looks good after a year it just needs a guick touch up. It's so quick to do. I think if your in the rust belt no mater what you put on there it is going to need a touch up every year.
 
To all the Rustoleum haters, I've sprayed some undercarriage parts with store-bought spray cans such as Rustoleum and Krylon. 2 years later, guess what? still looking like it was just painted.

I plan on cleaning up the rust in the rear axle area and using these same products. If it flakes off quick- big deal, it was like $20 worth of spray cans. I wouldn't mind using all the POR15, Eastwood, Rustbullet, etc., but they're all so expensive.

Also spraying some WD40 or silicone spray during winter on the underside wouldn't be a bad idea. I also try to wash it every week during the winter since the owner's manual also recommends doing this.
 
To all the Rustoleum haters, I've sprayed some undercarriage parts with store-bought spray cans such as Rustoleum and Krylon. 2 years later, guess what? still looking like it was just painted.

I plan on cleaning up the rust in the rear axle area and using these same products. If it flakes off quick- big deal, it was like $20 worth of spray cans. I wouldn't mind using all the POR15, Eastwood, Rustbullet, etc., but they're all so expensive.

Also spraying some WD40 or silicone spray during winter on the underside wouldn't be a bad idea. I also try to wash it every week during the winter since the owner's manual also recommends doing this.


+1
I clean, apply Rust Converter, then Truck Bed Liner $7 can. Pretty much do the whole rig for $20. If any rust redevelops, the Truck Bed Liner will pop off. Not tar like, drys hard and looks good. Minor touch up every couple years. Keep it simple :-)
 

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