Sealing up rocker panels...more harm than good?

[Get2theBimmah]

Hey guys - question posed for you...should I seal up the rocker pinch welds under the car?

 

My subframes are out, chassis is stripped down to bare metal.  My body guy replaced both rear quarters and in the process before installing the new ones back on the car, he prepped and undercoated the inside of the quarters and the shell itself where they cover. 

 

I just POR15'd the rest of the rocker pinch welds to the front of the car as well as getting in the little crease where the belly of the chassis meets the rocker.   After that dries I wanted to seam seal both of those seams the entire length of the car.  I know there's drains for the rockers themselves, but for a non sunroof car how crucial are they?  My thought process (which is probably flawed) is that I wanted to seal out debris and moisture from entering through those areas under the car.   Of course the adverse effect is that any moisture that does enter will essentially be trapped.  Which will do more harm, leaving them open to the elements below the car or sealing them shut and trapping in whatever enters over time?

[Hans]

I would leave the drains clear and seal whatever else you can. I'd focus more on areas that are splashed by front/rear tires and any obvious mud traps. I sprayed inside the rocker cavity with thin undercoating in a garden sprayer.

[Simeon]

5 hours ago, Hans said:

I would leave the drains clear and seal whatever else you can. I'd focus more on areas that are splashed by front/rear tires and any obvious mud traps. I sprayed inside the rocker cavity with thin undercoating in a garden sprayer.

 

This. Concentrate on trying to coat the internal surfaces with something and then leave the vents clear. Ideally you want a circulation of air through the cavity. 

[TobyB]

Keep the drains clear.

 

From the inside, spray the entire inner rocker with a 'body cavity' wax- Waxoyl, 3m Rust Fighter, Fluid Film, etc etc.

Get it everywhere, bottom insides of the doors, bottom insides of the fronts of the rear quarters, over the wheelarches, 

in the trunk, up your nose, everywhere.  Even in the roof.  (I missed that spot, and have paid for it)

 

Let it drain out the drains.  In the doors, in the rockers, at the bottoms of the fenders.

 

Clean them occasionally, as it'll try to seal them up, too.

 

A car is a little microclimate, and you are a big bag of mostly water that leaks out at an alarming rate.

 

As you condense on the cold outer shell, the water'll run downhill as far as it can go.

 

You don't want oceans in the low spots...

 

Oh, edit, the lip around the base of the hood and trunk are low spots, too-

you REALLY want to fill those, AND let the excess drain, so it doesn't seal the holes.\

 

t

 

Edited December 3, 2018 by TobyB

[Hans]

What Toby said. I used Waxoyl, don't know if its still available. It is however still in/on my CS after 35 years. You want something sprayable. Do up  inside car's nose section too . A and C pillars. The bottom of my car was sprayed with something like bumper guard, but that should be sprayed as well.  Forget the concours - think about preserving the car. Garden sprayer for  enclosed sections, big hand sprayer for open areas.

[Mike Self]

Since you have the interior out of your car, you'll see a row of holes in the inner rocker panel, inside the car and normally hidden by the carpet.  Pop the plastic plugs off the holes, and you have a nifty set of access ports to rust proof the inside of the rockers--the space between inner and outer rockers.  And be advised that the quarter panel has its own section of rocker that covers the outer rocker panel (thus the vertical seam on the rocker just aft of the door opening).  This forms a narrow space that can only be reached from inside the car, under the quarter windows (with the upholstery panel removed).  That's another place to spray your rustproofing liquid. (Waxoyl, Bilstein 2002, Rus-Free etc)

 

But as was stated previously, don't plug the drain holes.  The factory put 'em there for a reason, and it wasn't to induce rust (they did that with the sunroof drains).

 

cheers

Mike

Professor of Iophobia

[xr4tic]

Anyone have some pictures that point out all these areas to spray into?

 

I just replaced the drivers side frame rail, floor pan, and a chunk of the inner rocker.  I bought some Fluid Film to spray in there, but would really like to know other areas I can spray.

[Hans]

Lophobia a real problem in this neck of the woods.

 

See above for other places. Inside the frame rails for sure, rockers front to back, rear wheel arches from inside trunk and backseat, ....look at pics of rusty 02s for inspiration.

[02ManyBimmers]

https://www.eastwood.com/eastwood-internal-frame-coating-14oz-aerosol.html

 

[zinz]

I also used the Eastwood internal frame coating on my 2000CS.  It seems to work very well, with very good coverage.  Using the techniques described above by Mike and others, one can reach most all the nooks and crannies with the extended nozzle.  

 

Ed

[Hans]

I found the garden sprayer with a rigid pipe was more controllable in the enclosed areas.

[Mike Self]

7 hours ago, Hans said:

Lophobia a real problem in this neck of the woods.

That's "Iophobia" -- a real word that means (of course!) "fear of rust."  Originally saw it on a poster of arcane phobias, and after a lot of looking finally found it in a medical dictionary.  That was the title of the first story I ever did for the BMW CCA Roundel, back in 1984...

 

mike

[Hans]

i have to take meds after the salt truck goes by. The ones from Scotland work the best.

[Get2theBimmah]

Thanks for the tips guys! Toby those are good points made and you've all helped tremendously.  I've gotta look for those access points from the inside with everything removed Mike.  I shot the inside of my frame rails with the eastwood coating already and was planning on hitting the rocker internals too.  Definitely a good realization to hit the "low points" as they will collect moisture as well.   

[irdave]

13 hours ago, mike said:

That's "Iophobia" -- a real word that means (of course!) "fear of rust."  Originally saw it on a poster of arcane phobias, and after a lot of looking finally found it in a medical dictionary.  That was the title of the first story I ever did for the BMW CCA Roundel, back in 1984...

 

mike

 

Mike, you know they have shots for that now, right?  Have for a while...

 

Awesome that that was the title for the first story.