Why not Line-X the undercarriage / cab? / Raptor / Rhino etc

[JWA]

Originally Posted by scuba

Would UV be an issue on the underside of the van?

Not to any significance. Remember I said UV doesn't affect POR-15 in any way other than appearance, a color shift from its as first applied hue.

[scuba]

Ok-- that's great. My draft plan will be to treat with POR-15 the bare / beginning to rust spots, and then consider spraying with fluid film on an ongoing basis.

Follow-up questions:
1. Any experience with whether I should coat over frame paint that's in decent condition with POR-15? (The vehicle is only 7 years old) If I don't, it'll be subject to bad things happening to it on a different schedule than treated parts I'll treat now.

2. Any opinions on attempting to replace bolts with stainless, or at least replace with the appropriate grade steel and treat the heads? Bolt heads seem to be the first to go, and I've removed some seat bolts (not on the van) that were almost gone.

[Orv]

If the underside of the van is seeing significant UV exposure you may need to re-evaluate your driving style.

[Orv]

Originally Posted by scuba

2. Any opinions on attempting to replace bolts with stainless, or at least replace with the appropriate grade steel and treat the heads? Bolt heads seem to be the first to go, and I've removed some seat bolts (not on the van) that were almost gone.

Stainless might be overkill, and for some applications might not be strong enough. I would definitely use anti-seize on anything you remove/replace, though. Painting the heads can't hurt but in my experience the bolts rusting in place and becoming impossible to remove is a much bigger problem.

[Michisurfer]

Great info here, in Michigan and use the van in the winter which leads to lots of salt and whatever is used on the roads in different areas getting all over the under carriage. Van had an under protective treatment (likely Line X but not sure) prior to purchasing it. Not sure how long ago but most of it is peeling off and there is rust behind it. Appreciate everyone's input here- goal is the same as scuba and get something on there (at least a portion of it) to keep it running for another 100K+ (that 7.3L is just gonna keep chugging)

[Lilnuts2]

Originally Posted by Michisurfer

Great info here, in Michigan and use the van in the winter which leads to lots of salt and whatever is used on the roads in different areas getting all over the under carriage. Van had an under protective treatment (likely Line X but not sure) prior to purchasing it. Not sure how long ago but most of it is peeling off and there is rust behind it. Appreciate everyone's input here- goal is the same as scuba and get something on there (at least a portion of it) to keep it running for another 100K+ (that 7.3L is just gonna keep chugging)

Your a Por-15 candidate. I bought a pos flat bed trailer for my construction company, it was rusted and abused. I painted the entire thing with silver Por several years ago. The Por-15 loves rust I have had zero rust issues since. I can't say enough good things about Por and rust.

[Michisurfer]

Originally Posted by Lilnuts2

Your a Por-15 candidate. I bought a pos flat bed trailer for my construction company, it was rusted and abused. I painted the entire thing with silver Por several years ago. The Por-15 loves rust I have had zero rust issues since. I can't say enough good things about Por and rust.

Thank you! I've been using it when I cut holes in the body for accessories etc. Now comes the fun part of cleaning up the metal!

[JWA]

Originally Posted by Orv

If the underside of the van is seeing significant UV exposure you may need to re-evaluate your driving style.

My thoughts too!

Originally Posted by Orv

Stainless might be overkill, and for some applications might not be strong enough. I would definitely use anti-seize on anything you remove/replace, though. Painting the heads can't hurt but in my experience the bolts rusting in place and becoming impossible to remove is a much bigger problem.

This is probably the best advice about bolts and how they rust themselves in place. Remove each bolt carefully, treat with anti-seize and re-install with proper torque if they carry that specification.

Coating a bolt head or any exposed threads could also prove problematic if something like POR-15 is used. That stuff is so tenacious its holding power especially in small openings like threads has it acting almost like welding. If you want to paint bolt heads remove them first, allow enough drying time to fully cure before re-installing.

[scuba]

Originally Posted by JWA

My thoughts too!



This is probably the best advice about bolts and how they rust themselves in place. Remove each bolt carefully, treat with anti-seize and re-install with proper torque if they carry that specification.

Coating a bolt head or any exposed threads could also prove problematic if something like POR-15 is used. That stuff is so tenacious its holding power especially in small openings like threads has it acting almost like welding. If you want to paint bolt heads remove them first, allow enough drying time to fully cure before re-installing.

Good advice.

And will try to keep the rubber side down!

[OurayMark]

Not long after Line-x hit the market I had it applied to my brand new pickup’s bed. The good news is that the line-x and bed still looked almost new after 20 years of heavy abuse. The bad news is that half-ton truck Immediately sat at least an inch lower after the thick coating was applied.
I don’t know what the product typically weighs per ft2 or per application, but in my next pickup (a new 2500) I elected to tolerate scratches and light surface rather than give up load capacity. I can’t help but wonder how much the load capacity of a van is reduced when it is completely coated in a Line-x type product. I tend to push my SMB close to its GVWR as it is.
So as far as “why not” use line-x as an undercoating, its weight and decreased load capacity of the van should probably factor into the decision. (As well as it’s efficacy and other reasons mentioned by previous posters)