body and interior What Do Good Rockers Look Like?

[Andrew Havens]

I hear the rockers (or is it rocker panels?) are a common rust issue. I haven't been able to find a good explanation or picture of what a "rocker" is, where it rusts, and what a good one looks like. I think mine has been repaired before (poorly), so I'm trying to find an example of what mine should look like. What should a good rocker look like and where does it commonly rust?

[Mike Self]

"Rocker panels" are the pieces that are at the very bottom of the body, and on a 2002 run between the trailing edge of the front fender to the leading edge of the rear wheel opening, below the doors.  On a 2002 there are actually three pieces that make up the rocker panel:  

   1.  an inner rocker panel (also called the sill), visible as the vertical sill below the door opening and below the quarter panel upholstery in the back seat area.  This part is structural.  Serious rust here can make a car a parts car.

   2.  an outer rocker panel.  This is the part you see on the outside when you look under the door.  

   3.  the rear quarter panel--just aft of the door opening you'll notice a vertical seam on your rocker panel.  In front of the seam you're actually seeing the rocker panel; aft of the seam what you're seeing is actually part of the rear quarter panel; the "real" rocker panel disappears behind the quarter panel sheet metal.

 

A "good" rocker panel is one with no rust!  It usually begins at the aforementioned seam when water penetrates the seam sealer and starts rusting in the 3/8" space between the quarter panel and rocker panel sheet metal.  The second place rocker rust begins is immediately aft of the seam between the front fender and the rocker; it spreads from these two spots until the whole rocker is rusted out.  

 

outer rocker replacement panels are readily available, and so long as the rust hasn't seriously spread to the inner (structural) rocker it's a cosmetic repair.  

 

I'm sure folks can post pictures of good and also rusty rockers.  I think some rusty ones have been posted in the past couple of days.

 

cheers

mike

[Ian]

Rusty outer rocker, at front of door.

 

Same corner, from inside:

 

Corner after rust cut out of inner and outer rocker:

 

While allowing for easier viewing of the curb while parallel parking, I recommend patching the hole...

Edited March 17, 2014 by Ian

[KFunk]

 

I'm sure folks can post pictures of good and also rusty rockers.

 

 

Sorry, I had to do it. 

 

[Ian]

That's excellent!  They might be a bit older than our rockers

[Andrew Havens]

Thanks Mike and Ian. Those were really helpful. Those photos speak a thousand words. I'm starting to understand. So the rocker panel is not just a single spot but actually the entire underside edge from one fender to the other? Ian are those pictures of the front passenger side? Would you happen to have any photos of the rear passenger side? I wish I could find a diagram. I was hoping the Haynes manual would have a diagram of how those pieces were originally fit together by the factory, but I can't find any such diagram.

[Tommy]

Project blogs are a great resource. One example mine here http://www.bmw2002faq.com/topic/71426-goodfellas-streetmachine/

 

Should give you an idea what you may find. But maybe you're lucky and it's not quite that bad.

 

  Tommy

Edited March 18, 2014 by Tommy

[LarsAlpina]

Rusty outer rocker, at front of door.

 

While allowing for easier viewing of the curb while parallel parking, I recommend patching the hole...

 

Ian,

 

your outer rocker panel looks quite well in still untouched conditions as it seems. The hole you worked on was in the outer A-pillar panel. A-pillar is formed like an "L", the shorter leg of which continues underneath the front part of the outer rocker panel. Two layers of metal here to reinforce the front original factory lifting points. On many cars already whelded in that area (two layers of metal = potential rust spot) people only replaced the outer rocker part (red) and "forgot" the underlying A-pillar section (yellow). That is the reason why today the factory lifting points are mostly considered weak: The 1mm metal of the outer rocker panel alone can´t deal with the weight of the car, second underlying A-pillar section is needed to make this point sound. Red line on my photo shows where the outer rocker panel is put up on top.

 

 

Same with the rear lifting points except there you have three layers of metal: lower section of the rear side panel (yellow), underneath is the end of the outer rocker panel (red) and from above comes the crossbeam of the rear outer wheel arch supporting the lifting point (green).

 

 

Other than Mike I disagree that rust on the outer rocker is only cosmetical and not structural. Only the complete closed profile of inner AND outer rocker panel provides the strength needed. In case of an accident the inner rocker panel alone will simply fold like an accordion if the closed structure with the outer rocker does not reinforce the area because of rust issues.

 

@Andrew: Have a look at the Walloth&Nesch website and click through the picture pages. On the lower part of each site you will find detailed pictures of nearly every single body panel still available (some aftermarkets for repair issues and others OEM BMW for complete replacements): http://www.wallothnesch.com/karosserie-blechteile/bmw-1502-2002-turbo/katalogbild-41-01.html

Might help to explain which part is what on your car.

 

Regards, Lars.

[Ian]

Good point, thanks for the clarification.

[MitchaPaLoOza88]

On 3/17/2014 at 11:17 AM, Ian said:

Rusty outer rocker, at front of door.

 

Same corner, from inside:

 

Corner after rust cut out of inner and outer rocker:

 

While allowing for easier viewing of the curb while parallel parking, I recommend patching the hole...

 

I know this is an old post, but I am in the same situation. Just correct me if I am wrong but it looks like you used two patch pieces to fix this. correct? One sheet metal patch for flat hole that is on the interior wall. Then another sheet metal patch that goes around it, ending the A pillar and then butting up to the beginning of the rocker.

[Ian]

Correct.