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Line-X Undercarriage - Anyone done this?

ZombieK5

ZombieK5

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As the new garage is slowly getting finished I have started planning some of my next steps. One of the next steps is preparing the tub to go on to the frame. I came across a Jeep body in a YouTube video that had the undercarriage coated with Line-X. I see a lot of pluses and minuses in doing that. One of the big pluses is time. I contacted the local distributor and they said they have done undercarriages for many different vehicles. They said it is a big plus that the body is off of the frame. They said the process would be to degrease the undercarriage, use a needle scaler for any surface rust, spray a rust converter, prime it and then spray it. My plans for the truck do not really include heavy off-road exposure. I also plan to use a gray color on the undercarriage so I can see any oil leakage. Has anybody done this? I searched the forums but I did not find any direct conversations regarding the specific subject.

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I wouldn't do it to my truck, even using "rust converter" that rust will continue to grow, except you won't be able to see it until the pan is rotted out.
 
83ChevyK5Blazer said:
I wouldn't do it to my truck, even using "rust converter" that rust will continue to grow, except you won't be able to see it until the pan is rotted out.
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The tub came from Southern California and is for the most part rust free. There is one rust spot along the windshield frame but other than that there's no structural rust.
 
On a rotisserie i would sandblast the underside+ interior...
Por15 prime the steel or use a marine epoxy coating...... Spray the bed liner on when the primer coat is dry..

Mine never got to the line X stage.... Nice looking + sound deadening... Have seen a Jeep coated top to bottom.
 
I think it's a gamble. That stuff is not chip resistant but it is strong. The first time you get a chip and moisture gets under it will rust and spread. My dad's '79 had the factory undercoating and I'm pretty sure it made it rust out worse because of it. I can put my fist through a bunch of holes in the floor of that truck. LineX is newer and probably better than anything in '79 but I do think you run a risk. My frame and body are also separated at the moment, I'm planning on doing 2k epoxy primer and then a 2K ceramic underneath. You can always touch up paint if it gets a chip or starts to rust through. You won't have that luxury if you get a chip and need to repair anything underneath to stop the spread of rust or prevent it from starting with lineX. If you drive it much you'll get chips. To each their own though.
 
The rust proof factor is only as good as the base coatings on the steel.....ie , Por15, epoxy primer +paint ......

The chip guard, bed liner, old fashioned tar from the 1979, are only an additional layer away from the direct coatings on the steel protecting it from corrosion.

The question or concerns you should have, is will the Line-X bond to the sub surface?????

I have been cleaning on my diesel jeep....new rockers, sandblast inners, floors... Slowly opened up the bottom lip on the doors.... Sandblasted the inside + outside to remove rust + body shop caulking in the seams .... refastened the joints with PorPaste ... Tedious rust repair & prevention.

By accident I sprayed FlexSeal on an old pair of rubber bottom boots to seal the leather to the rubber seam, over my kitchen sink. The over spray was almost impossible to get it off the steel sink....after many months of scrubbing+ washing it went away.

FlexSeal is pricey, but labor costs more to fix cheap repairs. I have been top coating inner panels with the FlexSeal to rubber coat all the edges & isolate salt & water from infiltrating the joints.

Most likey, the. Bottom side will be coated with multiple costs of FlexSeal.

The sandblasted steel bottom will be Acid washed, Sprayed with multiple costs of Por15 paint , when that's dry ,/ tacky to the touch, it will be sprayed with multiple costs of marine epoxy.

What ever path your restoration takes, it will be better than the 1980 era.....most of them were ecoated with multiple layers of steel spot welded together &:a bad coating of asphalt tar on the underside. I can recall seeing 5

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POR 15 is junk, it’s overpriced and peels off in sheets. I apologize now to all the POR15 fan boys on the internet but the stuff is just garbage. Anyone who lives in the rust belt will tell you the only way to stop rust is to coat it with oil (wool wax, engine oil, atf, fluid film etc) or simply park it when the salt hits the roads.
 
Chickntrk said:
This ^ 110%

I have never seen one thing coated in line x in PA that didn't start to rust underneath it.
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My 85 toyota has line-x’d bed, (done before i bought the truck). Poorly prepped I’m sure and has rusted underneath. Wish it didnt have it
 
CT-BLAZER said:
??? Are your facts documented? POR15 doesn't release details....
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Polyurethane may or may not be the correct term. It is a moisture-cured urethane, like Rust Bullet and various other products that have already been discussed (mostly bashed) here in the Body Shop forum (where this thread should probably be).

The web is full of stories of POR-15 peeling off in sheets with more rust underneath than when they started. You just have to dodge all the posts by fan boys who just got finished applying some and dig the shine. http://www.spiuserforum.com/index.php?threads/why-you-never-use-por-15-ever.4204/
 
jimmyleetn said:
I think it's a gamble. That stuff is not chip resistant but it is strong. The first time you get a chip and moisture gets under it will rust and spread. My dad's '79 had the factory undercoating and I'm pretty sure it made it rust out worse because of it. I can put my fist through a bunch of holes in the floor of that truck. LineX is newer and probably better than anything in '79 but I do think you run a risk. My frame and body are also separated at the moment, I'm planning on doing 2k epoxy primer and then a 2K ceramic underneath. You can always touch up paint if it gets a chip or starts to rust through. You won't have that luxury if you get a chip and need to repair anything underneath to stop the spread of rust or prevent it from starting with lineX. If you drive it much you'll get chips. To each their own though.
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I had originally planned to do the epoxy primer underneath and with the advice above, I'll probably stick with that.

What was your solution for accessing the undercarriage of the body? I'm debating whether purchasing a rotisserie is a good thing or if there is a cheaper alternative.
 
Blue85 said:
Polyurethane may or may not be the correct term. It is a moisture-cured urethane, like Rust Bullet and various other products that have already been discussed (mostly bashed) here in the Body Shop forum (where this thread should probably be).

The web is full of stories of POR-15 peeling off in sheets with more rust underneath than when they started. You just have to dodge all the posts by fan boys who just got finished applying some and dig the shine. http://www.spiuserforum.com/index.php?threads/why-you-never-use-por-15-ever.4204/
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I don't think POR15 is polyurethane. I too have read the bad stories on the internet but I've had nothing but good experience with POR15. My frame is currently sitting in the driveway, fully exposed to the elements, and it's been there for for at least a year and a half. I painted it with POR15 and it is still holding solid. It has faded which is known issue however there is no peeling cracking or signs of failure. I had an old truck with a steel bumper that I covered in POR15 that maintained its Integrity for five plus years until I sold it. A lot of the success or failure of POR15 comes down to preparation.

I'm pretty sure I'm going to go with epoxy primer at this point
 
POR15 is junk, it was nice 30 years ago because there wasn't alternatives but today it's totally outclassed.

Unless you have an absolutely pristine underbody, I would not bed line it. There's too many body panel seams that moisture can get it from behind and has no where to go with bed liner. It's also very hard to remove or touch up if needed.
 
ZombieK5 said:
I had originally planned to do the epoxy primer underneath and with the advice above, I'll probably stick with that.

What was your solution for accessing the undercarriage of the body? I'm debating whether purchasing a rotisserie is a good thing or if there is a cheaper alternative.
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I sent you a dm. We're probably going to get off topic. I didn't want to hijack the thread.
 
I keep dreaming that someone will make a functional set of undercarriage plastic shields. Keep spray/mud from the tires reaching the majority of the nooks and crannies, mainly for the rear.

Once stuff gets into places like the taillight pillars, its not coming out with a simple rinse. But a plastic wheel well filler and plate from the rear wheel well to the bed end would help a ton.

My truck basically never sees deicing fluid or salt, but still rotted out the wheel wells from mud getting stuck where I couldnt see to wash it off.
 
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