Supercrew Rear Door Seam Rust

[Yinzcity]

19 Lariat supercrew with 32,000 miles over the great salt plains of southern Michigan. Noticed some rust starting at the bottom seam of both rear doors, passenger side worse than driver side. Both front doors still look fine. A little rust visible, but paint bubbling indicating more hidden. From the little I could see with a borescope through the drain holes, the inside of the seam doesn't have any rust so seems to be coming from the outside in? A bit disappointed at seeing this at only 4 years in. Any other salt belt owners seeing this on their doors yet?

Sponsored

 

[grammat95]

I just checked my 21' and it doesn't appear to have any rust in those areas yet. I've got 55k miles and my truck is also blessed with Detroit road conditions.

 

[Glocker]

Ouch!

 

[myothercarizahearse]

IIRC isn't the paint/rust covered to 5 years 60k miles?

 

[Yinzcity]

IIRC isn't the paint/rust covered to 5 years 60k miles?

The consensus online is they'll only fix it if it's rusted fully through a panel. I don't see this making it that far in a year though so I'm probably out of luck.

 

[myothercarizahearse]

consensus online

always 100% correct/wrong


sometimes right 100% of the time?

can't remember now

 

[AnimalMother]

Absolutely in the same boat as OP. Driver's side passenger door had what looked like a little bubble. Poked it and a one inch or so section of paint flaked off. Went round to the inside and mine looks like yours below and behind the rubber trim/seal.

Applied some rust converter and will paint. I'm most worried about the outside getting worse. Considering the new rocker panel guards that apply to the lower half of the door panel. Maybe the dealer will give me a discount ?

As mentioned, I highly doubt I'll get anywhere on rust related warranty with them.

Very disappointed. Have had 3 F150s in the past 15 years (no running boards) and paint has never been an issue on these country roads.

I'm not sure if sacrificial running boards would have prevented this or not. Seems more like an issue with the actual paint as opposed to any damage.

 

[Canadian Ranger]

I used to undercoat professionally.
A person has to undercoat the day the buy the vehicle. You can't wait a month or a year, then it's too late, especially if you live in the salt belt.
I can guarantee you the rust inside the door in those spots is even worse. Find someone in your area who undercoats with Fluid Film. Get it sprayed now, and again in Oct./Nov.. Cross your fingers that stops it from getting worse.

 

[miraculon]

This has happened on every Ford I have ever owned. My 2011 Flex had it, not rusting through to the outside though. I also sprayed it with Fluid Film in the last few months (before I decided to trade it in on the Ranger). It also happened on the Mazda 626 I used to own.

 

[Yinzcity]

I'm not sure if sacrificial running boards would have prevented this or not. Seems more like an issue with the actual paint as opposed to any damage.

I have the factory steps on mine that do block some of the spray along with mudflaps. They probably help some with spray, but not completely. This seems to be more from water entering the door from the top and sitting in the crimped seam between the 2 sheets of metal. Fluid film or some other oil sprayed in the interior of the door would have probably worked when the vehicle was new, but probably too late for it now.

 

[Trigganometry]

If you do decide to repair this yourself this works for the US Navy and it has always worked for me. Wire brush off all the rust and loose paint you can. Then treat the exposed surfaces with Naval jelly. I do that twice! It is passivating the rust and lifting off all the free iron (main cause of rust) rinse off with water and let dry completely. Then paint with something like POR15. Then paint with body color and call it a day. Rust should never return.

 

[Blmpkn]

Maine here, mine are starting to rust at the seams as well. 2021.

 

[IdahoRanger]

Use a lot of salt here too so I was almost afraid to look but mine are okay. Dirty as hell though.

Passenger rear

Driver rear

 

[Blmpkn]

Use a lot of salt here too so I was almost afraid to look but mine are okay. Dirty as hell though.

Passenger rear

Driver rear

Look at the fronts ? that's where mine are starting lol

 

[IdahoRanger]

Look at the fronts ? that's where mine are starting lol

Look good all around.

Sponsored