Box truck leak

[RedMF40]

I have a box truck on a E350 Ford chassis I use for work. It’s been through a lot of storms with no problems but lately there’s a significant leak into the cab where it meets the box. Just take off the old caulk and clean the area then reapply or is there more I should be looking at? Thanks for any suggestions. Gerrit

 

[300jk]

I have a box truck on a E350 Ford chassis I use for work. It’s been through a lot of storms with no problems but lately there’s a significant leak into the cab where it meets the box. Just take off the old caulk and clean the area then reapply or is there more I should be looking at? Thanks for any suggestions. Gerrit

Not sure what type of caulk your using but maybe you could try a LAP sealant like they use on rv’s. Liquid applied plastic. I have used both the regular and self leveling on our camper with great results.

 

[RedMF40]

Not sure what type of caulk your using but maybe you could try a LAP sealant like they use on rv’s. Liquid applied plastic. I have used both the regular and self leveling on our camper with great results.

Thanks, I needed to know what people use. I just said “caulk” because it seemed like it would be something like that.

 

[showcrop]

"Flex Seal" could work well.

 

[Jim.ME]

A sealant caulk like NP1. There are roof repair tapes made for RV. box truck, etc., roof repairs. ZIP tape will last for several years on a trailer roof. A place that sells/ leases/repairs OTR box trailers will often have a sealant they recommend/use. Whatever you use the area needs to be cleaned, degreased, and dry before applying the chosen product (at least any I have used).

 

[caterpillar guy]

JimME has it that trailer roof tape is good stuff and seals well. Does have to be clean and dry to work though.

 

[jon f mn]

Those are usually something rubber I believe. Sort of like an inner tube but with no way to add air. The cab and box will move some what independently so most calls and such won't work. Ask at a camper or commercial truck repair place for what they use.

 

[john in la]

3M makes several sealers like this made specifically for what you are trying to do.
Some stay flexible some get hard. Some can go over bare metal some need a special primer under them. Some are one part some are 2 part but require a special mixing gun to apply them.
Sorry I don’t know enough about them or your conditions that I feel safe picking the right one for you.

 

[BarnyardEngineering]

"Flex Seal" could work well.

Flex Seal is reportedly not UV resistant and quickly degrades in full sunlight.

 

[BarnyardEngineering]

Thanks, I needed to know what people use. I just said “caulk” because it seemed like it would be something like that.

That's what most people would use, too. Clear household silicone. Totally wrong for the application. Houses don't rattle down the road at 70MPH on a daily basis.

Years ago I used a product called Dicor which is an RV sealant. Very sticky stuff. Household silicone won't stick to smooth metal. Dicor needs to be chiseled off.

 

[RedMF40]

"Flex Seal" could work well.

I consider the flex seal products a temporary Bandaid, not a long-term repair. Just my impression, never actually used any.

 

[RedMF40]

Thanks for the replies. I looked online at some products, have a better idea what to use. On Monday I’ll call the shop that works on my truck—they specialize in medium to large commercial vehicles and their service person is happy to help with DIY questions. Here’s a visual of the sealant that’s on there now. It’s flexible like silicone.

 

[Jim.ME]

Hard to tell just by looks, but it looks like a polyurethane to me. NP1 is a very good polyurethane sealant. The biggest part of the task is going to be removing the old and getting it clean, if you want to do it fully correctly.

 

[RedMF40]

Hard to tell just by looks, but it looks like a polyurethane to me. NP1 is a very good polyurethane sealant. The biggest part of the task is going to be removing the old and getting it clean, if you want to do it fully correctly.

Yes, I plan to remove the old sealant. I have a good assortment of scrapers and razor blades that should help with the job. Too wet out to do anything right now and I want to have the new sealant on hand before starting the job.

 

[Tony in SD]

Not sure what type of caulk your using but maybe you could try a LAP sealant like they use on rv’s. Liquid applied plastic. I have used both the regular and self leveling on our camper with great results.

X2 on the Self leveling RV roof sealant.

 

[glennster]

Yes, I plan to remove the old sealant. I have a good assortment of scrapers and razor blades that should help with the job. Too wet out to do anything right now and I want to have the new sealant on hand before starting the job.

if you have a sawzall, there are many scraper blades available that make the removal much easier. also there are scraper blades for the multi tools that work well.

 

[Ray,IN]

Eternabond sealing tape is used widely by the RV industry and on commercial flat roofs.
As with any sealing product; follow the prep and application directions exactly for the best results.

 

[TN 2N]

I consider the flex seal products a temporary Bandaid, not a long-term repair. Just my impression, never actually used any.

i have used FLEX SEAL SPRAY outdoors and temporary Bandaid is a generous description!

 

[RedMF40]

I called the place that works on my truck this morning. They said if I find something that works, to let them know. They were no help as far as recommending a sealant. I'll look into the products others mentioned here.

 

[showcrop]

i have used FLEX SEAL SPRAY outdoors and temporary Bandaid is a generous description!

I don't see that the aerosol has much chance of working. I use the brush on. It is very thick. Follow instructions.