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A few rocker/rust repair questions


ChuckR

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Hi finally getting around to replacing my rockers and dealing with other rust spots. I had a few questions as we've never done this before:

1 - we have good BMW repair panels - the rockers are black, I assume it's primer, should we coat the inside with POR15? 

2 - the rear wheel arches on the car have small rust spots, wondering if we should replace the entire arch as that bump out detail / profiles could be off? or just put in small patches?

3 - I have two good replacement fenders that need paint, should the insides be painted off the car?

4 - there is no #4 but as things progress, I may have more questions...

 

Thank you, Chuck

 

 

IMG_8847.JPG

1969 Colorado Automatic (converted to 4spd)

1982 528e
1972 BMW R75/5

chuckrouthier.com

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Tough one. My gut is that those rust holes aren't severe enough to replace the entire arch. If there aren't any rust holes in the remainder of the arch, then I would keep the original: cut out the rust, clean and protect thoroughly.

 

I've not replaced an entire panel but it feels more intrusive of an effort to match it up. I'm a believer in keeping the original metal if at all possible. 

 

Depends of course on your skill and available time, of course. 

 

Interested to hear what others have to say on this. Not an easy one.

 

Cheers,


Jason

Edited by JsnPpp
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1973 2002tii (2764167), Baikal, Rebuild blog here!

In the past: Verona H&B 1973 2002tii (2762913); Malaga 1975 2002; White 1975 2002

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Remove all the paint to confirm the limits of the rust.

 

If your rot is only limited to what you have shown, I suggest only cutting and welding those areas that need repair.  This minimizes warpage due to welding heat.  Here are a couple of pictures where I replaced a small section of fender lip on the '67 2000CS.

 

Here, i cut the new material and clamped it up over the rotten area.  Trace around the new material, then cut out the rotten section with a slitting disk.

 

IMG_8811.thumb.JPG.57237a05a37d2048acae828124ef3883.JPG

 

Place the new material into the void and secure with magnets, (available from Eastwoods) and super handy.  

 

IMG_8812.thumb.JPG.e6f9d78762c511697c71550ec84f8913.JPG

 

Here's Barney laying down the stitch welds (small spot-type welds) along the seam.  Constantly moving around and never letting too much heat build in one area.  Expect to stitch weld and grind at least 2-3 times before the seam is completely filled.  Be careful to grind only the tops of the weld and not the surrounding metal too much. 

 

IMG_8813.thumb.JPG.8fd1dd2dac8b405165992bea578b4125.JPG

 

Finished patch should look something like this.

 

IMG_8814.thumb.JPG.7f7dc18a23c6d4cfd8b6b6734c05c107.JPG

 

It worked for me... 

 

We also repaired a HUGE section, but only did that to fix what others had poorly done before us...

Look here on the build thread:

Best of luck!

 

Ed

 

 

Edited by zinz
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'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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We typically shot everything with etching primer after things cooled off, just to keep things from developing any rust down in the pores of the welds.  This particular car was completely stripped and bead blasted prior to paint.  Immediately afterwards, everything was shot with epoxy primer.  

 

All the nooks and crannies were sprayed with etching primer. 

 

The rockers were completely exposed on this car, so we treated all that with rust stop, then etching primer, followed by Eastwood's frame rail etching primer... comes with a long plastic tube and a nozzle that sprays in 360 degrees.  That coats all the interior surfaces.

 

Welds on the floor pans were wire wheeled and coated with POR15.  We also use POR15 paste to smooth over welded seams under the car to give a cleaner looking finish.  POR15 was used in rust prone areas under the car.  Didn't use it on exposed sections of the car too much, as I remember.  

 

Ed

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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6 hours ago, ChuckR said:

the rockers are black, I assume it's primer, should we coat the inside with POR15? 

The rockers are black only on squarelights; roundies came from the factory with body-color rockers, but it's your call.  I kinda like black rockers 'cause they tend to lower the car a bit (especially light-colored cars) and are easy to touch up when they get grungy.  Regardless of color, shoot 'em with schutz (gravel/anti-chip guard) before the final paint.  As for the insides:  when I replaced the rockers on my car, I accessed the rockers' back sides via the small holes in the inner rocker (sill) inside the car.  You can see one of the holes (sometimes covered with a plastic plug, sometimes open) by removing the back seat cushion.  Those holes extend forward all the way to the cowl; pull the carpet away and you'll see 'em.  You can spray a rust inhibitor (the waxy stuff Ziebart uses) through those holes and get 99% of the rocker's backside if you're patient and thorough.  

 

6 hours ago, ChuckR said:

the rear wheel arches on the car have small rust spots, wondering if we should replace the entire arch as that bump out detail / profiles could be off? or just put in small patches?

Before doing a partial patch, make sure the section you're leaving is absolutely rust free.  I had to do that job twice as the section I didn't replace originally developed rust, so be very thorough.  BTW, for small rear fender lip repairs, sections cut from a derelict front fender work very well as patches.

 

6 hours ago, ChuckR said:

I have two good replacement fenders that need paint, should the insides be painted off the car?

Not a bad idea...what I did before installing the new front fenders:  I painted thoroughly around the parking light housings (I used Sherwin-Williams industrial anti-rust paint), especially between the upper side of the housing and the underside of the fender top.  That's a great place to accumulate dirt, and difficult to clean.  More importantly--I stood the fender on end (trailing edge on the ground) and poured anti-rust paint into the crevice formed by the fender skin and the bracket used to attach the fender to the body.   Let it dry for a couple of days, then paint your color paint over it.  That crevice is nearly an inch deep at the bottom and is the cause of that rustout line along the fender's trailing edge that you see on many 2002s.  My '69 is on its third set of front fenders, but those have been on for 20 years with nary a rust spot. 

 

mike

'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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Great info, thanks to all responding. Mike, I like the rocker in body color, I was referring more to the inside of the rocker - before we spot weld it - should I apply rust preventative paint, POR15, whatever, I am going to coat the inner rocker with POR15 - it's pretty clean.

thanks Chuck

 

1969 Colorado Automatic (converted to 4spd)

1982 528e
1972 BMW R75/5

chuckrouthier.com

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I posted some pics in a blog I did on the work my car had done this summer.  

 

In this section I relay what the folks at the shop did in terms of coatings, etc.  You might find the whole thing interesting, if you haven’t looked at It.  The job started as just rockers, but...

 

02ing since '87

'72 tii Euro  //  '21 330i x //  '14 BMW X5  //  '12 VW Jetta GLI

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27 minutes ago, saaron said:

 

In this section I relay what the folks at the shop did in terms of coatings, etc.


wow... that is top quality 

 

Ed

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'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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That's awesome, thanks for sharing, helpful. I had a few more questions if you don't mind.

 

1 - found some holes in the footwell near the rocker, but there is also some 'pitting' not too bad, do I need to cut that out as well? Or can I coat it?

 

2 - there back part of the rocker has a few vertical sections that has some rust under, I need to cut those off to get to the rust, are those critical? do I need to fabricate something to put back?

 

thank you, Chuck

 

IMG_8862.JPG

IMG_8864.JPG

1969 Colorado Automatic (converted to 4spd)

1982 528e
1972 BMW R75/5

chuckrouthier.com

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If you decide to use ANY paint or POR15 type product....make SURE you rough up the black factory primer with at LEAST a red Scotchbrite pad, for proper adhesion! +1 on using epoxy primer during the repair process, to preserve any clean / non-rusted bare metal that you reveal. 

I'm excited to watch your progress on this, Chuck!

 

Paul

Paul Wegweiser

Wegweiser Classic BMW Services

Nationwide vehicle transport available

NEW WEBSITE! www.zenwrench.com

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That rust area above the jack stand doesn't look to bad but you'll need to clean it up and then use a ice pick or awl to probe the rest of the area fairly hard to make sure the rest is sound if it is you could just use the por putty on that small hole IMHO if you open any other holes you'll should to patch it. 

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Mine had rust in that same place.  The shop did what Son of Marty said - ended up cutting that metal piece fairly high up to get to actual metal.  

 

Yours might not be as bad.  The pics of that area are the last pics in this blog section.  "Drivers Side Part 2" has the whole thing going back together.

 

 

Edited by saaron
adding more info

02ing since '87

'72 tii Euro  //  '21 330i x //  '14 BMW X5  //  '12 VW Jetta GLI

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4 hours ago, Son of Marty said:

you could just use the por putty on that small hole IMHO if you open any other holes you'll should to patch it. 

+1 on POR putty--I've had very good success with the stuff, patching up to 12-14mm holes--the larger ones using a piece of fiberglass window screen to bridge the hole. 

 

Here's how:  poke back around the hole 'till you find sound metal (surface rust is OK, just not thin or perforated), then ding down the edges 'till they're slightly below the surrounding surface.  Cut a patch out of fiberglass window screen that will overlap the hole by 5-6mm, then butter the edge of the hole with the POR paste and press the screen into the paste 'till it oozes out through the screen  (wear gloves; POR stains skin 'till it wears off).  Once it's dry, take more paste and work it into the screen, insuring you leave no voids or holes; let the new application dry.  Trim off excess screen around the edge with a razor blade.  If it's in a no-show area (like the floor) just sand to smooth things out, and paint.  If it's where it'll show, sand things smooth, make sure you haven't sanded through the POR, then give it a skim coat of filler, prime and you're ready for paint. 

 

I repaired rusted holes on the rear fender lips on my '87 E30 and primed, but never finish painted.  No new rust after three Ohio winters...that's good stuff.

 

mike

'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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