For those whose rust warranty has lapsed, the following is how I have handled cosmetic rust in prior lifetimes:

If you can access the rusted area, you need to get the rust removed almost down to a molecular level. Otherwise, the rust will return. Sanding will NOT remove down to the molecular level.

Once you have been able to get most of the rust removed with sandpaper or a wire brush/wheel, you need to treat the area with either diluted phosphoric acid or diluted hydrochloric (muriatic) acid. I personally prefer the diluted phosphoric acid, but hydrochloric acid works well too. When you are not seeing the acid solution turn redish while it is being applied (iron oxide - otherwise known as rust being released) to the metal, the metal is ready to be painted. While applying the diluted acid, use a paper towel to absorbe the runoff acid. If there is pitting of the sheetmetal, and it is in a visible area, you are looking at having to fill the pits. I like to use liquid solder - it fills the pits and bonds well in the bargain. It also can be worked if necessary.

Dry the metal with a compressed air source. Once you have dried the metal, DO NOT TOUCH IT! Touching transfers oil from your skin to the metal and you have negated all of the preparation you have done before touching the bare metal. I prefer a rust resistant primer, such as zinc chromate, but zinc chromate is out of favor due to hazardous materials concerns. Get the best rust resistant primer you can legally purchase. POR is a good product; but you may not be able to get it other than by mail. After applying the primer according to the manufacturer's instructions, I like to let it dry at least overnight before applying the color coat.

After thoroughly drying the rust-resistant primer, you can either go straight to a color coat or apply an additional primer coat before the color coat. Depending on where the rust is occurring, the paint can be applied with a brush or sprayed on.

This is the Cliff Notes version of repairing an area of sheetmetal that has suffered cosmetic rust. The sooner you catch rust, the better. In a worst case, you are looking at welding in replacement sheetmetal. And realistically, when you have to weld in replacement sheetmetal, you are at the start of a viscous circle where the metal around the weld area starts to rust. Hope this helps.

 

Found evidence of rust on my drivers' side....only small areas....but present none-the-less...

 

WOW dude, thanks for that DIY very informative. ...I have a question.... where can one procure the above listed phosphoric or muriatic acid?

 

I noticed this thread has reached "sticky" status

 

but I found this thread from a link on Motoringfile. The floodgates are open...

 

No rust on my 05, the door sills are painted under there.

Was water buildup though.

 

I have an '02 MC (May build). I'm very nervous given my car's history that it will be damn nasty under there. Will have to check...

BTW...found this thread from NEMINI

 

Yeah my '05 had no rust under the weatherstrip (both sides) and it also is completely painted. But there definitely was trapped water inside the strip and on the rocker seams.
Looks like ill be pulling up the weatherstrip at least once a week and wiping it dry, just to be sure... Atleast until Mini/BMW solves this problem!

 

Cool thread - apprently the rust is only on a handful of 2002's (I guess all of us with 03s, 04s, 05s and this problem don't know what year our cars are) and this thread is full of "mass hysteria".

Edited to add I double checked my registration and I DO have an 03! Someone call motoring file and tell them to extend the mass hysteria to 03 owners too..........

 

IIRC, I received a notice of rust warranty extention from MINI USA after I bought my 2004 MCS... Anyone else recall this?

 

I received that same notice.
I vaguely remember reading that it had to do with thin paint coverage in the door jamb area... though I thought it to be more in the hinge area.

 

Any pool supply store or Home Depot carries Muriatic acid for sure.

Checking my '02 build '03 now...

 

If you check the active ingedient of most any 'rust converter' at your paint/home improvement store you'll probably see phosphoric listed. Biggest difference in the products is the use or not of a 'binder'. Some are liquid, some a gel. Since you want the acid to sit on the rust for a bit, gel may be better in this application.

 

The problem with using muriatic acid is that you have to dilute it further. And there is no standard for strength (ph, moles, normal - all chemistry terms that are beyond the scope of this thread/post) of "muriatic" acid - so you can not follow a given dilution protocol. If you use muriatic acid at full strength, you will have to go through a neutralization process after the rust has been etched out, which is a further layer of complexity. My preference as I stated in my original post is for diluted phosphoric acid. Many hardware stores that have a paint department should carry pre-packaged diluted phosphoric acid for rust removal. Another source if you are located near one is a marine hardware supply store. In the S.F. bay area there is a store called West Marine that has all kinds of marine strength goodies (stainless steel locks, stainless steel hardware, and, and, and...). West Marine is located in a number places, so that might be a first place to check if one is located near you.

 

Very true (about gel binders), depending on the extent of the rust. However, some binders are not friendly to paint and would need to be removed/neutralized before application of the paint. If you don't do the removal/neutralization, the paint will loosen and then the rust starts all over again. Only, this time, you thoght you solved the problem and don't check and with the passage of time, a hole develops and your car has rust cancer.

 

Regarding the 05s, my MCSa with a 3/23 build date came with a 144 month (12 year) unlimited mileage rust warranty. I don't know when the warranty was extended to 12 years, but to give that long of a warranty (even if it is only for penetration/hole developing), there must be some sort of galvanizing that is done to the body panels.

 

as I recall - but I don't have the bottle b4 me here - all of the rust converters I've used such as POR's metal ready, and naval jelly, need to be removed before painting with the the product (I use POR-15) - typically by 'rinsing thoroughly with water'. That's part of the 'full process' - the product binds to metal and rust, not acid residue - and one doesn't want to get any of them on parts or finishes that they don't want treated.

And that can be an advantage of buying a 'system' like POR or EASTWOOD as the instructions cover using the products as a set of linked steps. Somewhere I saw a review of POR and EASTWOOD that went beyond doing it following the instructions, but also covered the reults when the process took some shortcuts...interesting stuff.

and oh btw - buying a can of each step of POR for this small issue seems like real overkill. Sand or wirebrush it and hit with some rust-o-leum and know it is an area to watch is probably good enough. I'd only use the fancy stuff cuz it is already in the garage fm the 79

 

I think that it is not only a handful... the % has been fairly high and this is only people who pay attention to NAM etc....most of the Mini owners I know don't even know what NAM is or any online Mini board for that matter......let's not "freak" but let's not ignore and/or diminish the probability

 

Let's see how Mini USA's sterling customer service and always helpful and fair dealership service network deals with this.

In the past, they've been very upfront about known issues such as the wiring harnesses and the car fires. Why should we expect anything less than full cooperation from them?

Then we can plan on mass hysteria.

 

I will cross you off of the mass hysteria list then.

 

Spider X, thanks for this thread. I have an 05 cabrio and will check.

I do dry the door jams after every wash - but those who live in rainy areas will get extra water in the jams every time it rains. Clearly - it's not sensible to dry the jams after every rain.

MINIUSA better fix this quick...

BTW - I use a cheap vaccum/blower to blow extra water out parts difficult to get to after a wash...maybe that would help dry out the jams better. It was only $15 at Home Depot...

 

Just checked - no rust or lingering water on either side- everything is painted over.

Note: car is covered at night and may help keep water out...

 

I too have rust. I was trying to figure out whats causeing my check engine light, and thought i would take a peek

 

yep, just went and checked... rust for me too. Time to send my service advisor an email with a link to this thread.

 

Has anyone checked to see if there is any rust between their door panels?

I have read several posts about water seeping through the windows and corroding speaker wires....I am now concerned about rust developing inside the doors.