Complete rocker replacement

[jpnovak]

I thought I would share my work on replacing rocker panels. I was going to title the thread "what I did on my summer vacation" but I have not had any vacation and its still almost 90 deg at 9 pm so I can say that summer is not over for at least 4 more weeks.

I know everyone here wants an early 911. We all know they are lighter, stronger and faster. :twisted: Seriously, Any pre77 911 is susceptible to rust. The rockers are a common place to find that nasty orange/red stuff. Let's take a look at how simple it can be to cut out and replace rocker panels.

Warning: Some material may not be appropriate for Porsche lovers. This thread contains pictures that may need adult supervision.

First, the surgery candidate is my own 71E. I found this car in my neighborhood sitting neglected on the street. It needed someone (like me) to have pity on it and help nurse it back to the full Glory of its previous life. The sport seats, SC brakes and 2.7RSMFI motor were enough to seal the deal. The rust in the rockers was severe. The only thing holding the front and back of the outer rocker panel was the S trim. Ouch! No worries I have a welder and I am not afraid to use it.

here is the starting point. For reference, the car (patient)


the next step is to check for rust. You did do this before buying the car right! Of course, that's how you negotiate a ridiculously low price. As I mentioned before, the outer rocker on the pass side was held on by the trim. Warning Graphic Pictures Ahead:



Yes, that was a huge gaping hole of missing sheet metal. Yes, That is the Heater tube you see. But wait there's more... the driver's side was much better. As you will usually see in some cars, the passenger side is always worse than the drivers. I suppose I heard some argument about road grime in the gutter on LHD cars.



So now that we know what we are facing let's get started. You must remove the front fenders to get to the rockers. That is because the leading edge connects to the vertical fender support just in front of the door. Get out the 10mm socket and start removing all those bolts. Wait! Did you take off the rocker trim first. I hope you did. For those who don't know, the early rocker trim is held on by sheet metal screws. In my case, there were only two left holding metal. Remove the rubber trim strip from the middle and then remove the screws. next, you must remove the thresholds (drill the rivets) and then the carpet trim section. Am I done yet? Almost.

Now that the tub is prepped you can start cutting. Maybe we should discuss the structure first. the rocker panels make up the lateral longitudinal structure. There are three panels that make up this outside structural member. There is an outer rocker and an interior rocker. these are both shaped like a C with the open areas facing each other. through the center is the inner rocker panel. it connects the two C shapes and makes vertical rib. The resulting shape looks like [I], a two pocket structural beam. Lightweight and strong. Between the inner rocker and the interior panel you will find the heater ducting. More on that later.

The forward connection point of the outer rocker is the vertical latch panel. the aft intersection lies on top of the "vertical wheel support". to access the rearward section you will need to cut out a section of the quarter panel and also the lower corrners of the door latch support panel. In my case, this was all rusty and I just kept cutting.

I used a 4" cutoff wheel in my angle grinder. this is the fastest, most efficient way to cut. I find that the pneumatic cut-off wheel lacks enough torque to quickly cut through stubborn sheet metal. To remove the outer rocker you need to make 4 cuts. First locate the seam where the latch panel, and QP overlap the rocker. There is usually a step down where the latch panel meets the top of the rocker. This is a leaded joint so you want to take the proper precautions. this means wear a face mask when you are cutting, lead dust is nasty sfuff. the best way to remove this lead is to heat it up with a propane torch. the lead will just melt off. Catch it with a section of cardboard. When it cools take it to the local battery recycler for proper disposal.

with the lead removed you can now see how the joint comes together. Make a vertical cut just forward of the panel intersection. If you removed the lead properly you might find the spot welds where these panels are connected go ahead and drill them out. It is now time to make the major cuts. the top of the rocker panel is recessed into the seal channel. Pull the seal out and you will find a spot weld every 2 cm or so. That's a lot of welds. the slow way to remove the panel is to drill each and every one of these welds. there is a row on top of the channel and also the backside of the channel. Double Whammy.

I prefer a different. method. Using your cutoff wheel, angle it so that it fits in the lower corner of the seal channel. this is the point where the top of the rocker meets the seal channel and turns upward to be spot welded. Make a cut in this corner from the latch panel intersection all the way forward to the hinge panel. At the front of the hinge panel there will be a small seam where the lower section of the hinge panel meets the top of the outer rocker. Do not cut the hinge panel. There will be three small spot welds here. you can bust them with a hammer once the rest of the panel is free.

Next, follow the rocker to the point where it meets the vertical fender support. Cut vertically right next to the fender support. If you look down between these two panels you will see that the rocker does not connect to the inner fender well. there is a gap. stop cutting when you reach this gap.

Next, follow the curve of the rocker down until it meets the body. there is another spot-welded seam on the bottom. Using a similar technique, make a cut just above this seam in the corner. Keep going all the way across until you meet the jack tube. Now connect with your first vertical cut and peel the panel away. You should have something that looks like this:


Notice the screen wire and bondo. YUK!! Now you can see the cut line at the top of the rocker and at the bottom. In my case, there was no bottom seam to cut since it was completely rusted. Now you can clean up your mess a bit. Look at this pile of rubble from just one outer rocker.



You have now freed the outer rocker and are staring at the inner rocker. who know's what lies behind. I repeated the process onthe pass side. I even found a surprise rust hole when I got there.



Stay tuned for the rest...

[jpnovak]

Before doing this process of cutting the inner panels I would suggest some chassis support. First, I have the car mounted on the front steering cross member, (steel) and the rear torsion tube. I then placed my floor jack under the sump plate and just slightly lift to prevent preload on the chassis. If this were a targa, I would go one step further and build a brace from the door hinge to the door latch while keeping the top in place.

It is not required but generally much easier to pull the doors off the car for this procedure. The easiest method is to use an air-chisel with a point on the two hinge pins. Spray them first with PB blaster/Kroil and then one quick burst. The pins should just pop out. make sure to catch the door. The factory tool is much more elegant but doesn't make as much noise. You are already annoying neighbors with this work so what's a few blurps with the air-chisel?
Once the outer rocker is cut you can fit the new panel. First I overlay the new inner rocker over top of the old one. Use this as a template to cut. Scribe a line on both ends as a guide. The top and bottom seams are separated by drilling spot welds are just cut and grind back. I use the latter method.





Everything fits fine, time to cut it out.




You will now see the heater tube in front of you. It removes very simply. Compress the front end and pull the heater tube off its metal mount. Then open the clamps and pull the tube forward from the rear metal tube. Now you have a good look at your rockers. Everything looks good on mine so I taped the seams and shot every possible crevice with POR15.



Now you can refit the inner rocker panel, clamp it into place and tack it up. To weld, I drill 5/16" holes around the perimeter. This allows for plug welds that are similar to the spot welds used at the factory. I have a tong-style spot welder but find it doesn't work well on thick panels.



Once the rocker is in place, you can do the same for the jack tube support. My inner and outer rockers came from Restoration Design. I found that the angle on the jack tube support is different than what came off the car. From a structure discussion, the new design is better, it has a more shallow angle and wider base. This however does not match the profile of the early cars. If you are doing a full concours restoration make note of this. I am just building a driver.



Now that its all welded up you are almost ready to finish the project. Once again, tape off the seams and seal with your favorite paint. In my case, POR15. The outer rocker sits on a different spot to check fit before painting over the mounting points.

Next, oil lines...

[jpnovak]

Part of the project for rocker replacement is to mount a front oil cooler. Let's see what can be done to make it look a little more presentable. I needed to add an external cooler. The early cars do not get much airflow through the fender well thanks to the battery box. I could have cut it off but didn't want to do that. The next best thing is a front mounted cooler. It would have been easy to mount the factory hard lines. These are not easy to find and can be expensive. next I could have mounted AN style lines to the outer rockers. The problem is that they sag and look unsightly as they loop across the bottom of the car. My solution, put the oil lines inside the rockers just like they early E and S cars. Hey have I have early E car, I must be headed in the right direction.

To run the oil system I used the following:
AN16 stainless braid hose
AN16 Mocal Thermostat
Setrab 9XX series cooler
M26F -AN16M adapter, BAT, Inc. This fits the connection to the ->71 oil tank
M26M - AN16M adapter. BAT, Inc - This is the same as the case side oil return and fits the hose side coming from the tank.

The first step is to make sure your inner rockers are solid. Check, All new metal now. Next you need to drill some holes for the oil lines to exit. I used a hole saw and the factory location on an early car. The pass side vertical fender support has two impressions that are angled down and to the back. This is the perfect exit for hoses to exit. Here they are painted nice and pretty. the hoses will be installed with grommets not shown (in any of these pictures.



The next thing is to make clearance for the hoses. These stainless braided hoses have a large OD and also a large bend radius. This means you need to make sure that you don't have an off-track excursion when you don't make the turn. OOps I must have been thinking back to my last track day. REally, you must plan to make sure that the hoses fit within the confined space. I did not want to bring the hoses out at the bottom of the fender support. I want them up high and hidden.

Inside the rocker the hinge post has a rather bulbous ending. It is best to notch this for clearance. I made a horizontal cut into the bottom of the hinge post and then a vertical cut about 1/2" from the rocker. Then I cut flat sheet and boxed this section in.
notch hinge posts. Here is the result. Sorry for the crappy picture. My camera doesn't like to focus on the black surface.



Here you can see how the hoses are tucked up under the newly created notch.



Since we are creating spaces for the hoses to hide I needed to cut a relief in the wheel arch support. This panel is commonly called the "kidney" due to its shape. The end of the outer rocker lays down on top and angles in. So, get out the cutting wheel and cut the front and back sides out. NIce window, huh! OK let's add a bit more detail.

I used two short sections of hose to mock all of this up. I mounted to ends to the thermostat. I will used the threaded bung that holds the rear seatbelts in place as a mounting point for the thermostat It goes all the way through to the rear inner fenderwell. First you need to lay the outer rocker in place and mark its mounting point. YOu don't want to cut out the section where you need to weld your rocker in lace.

With the quarter panel and latch panel "releived" you can slide the hose through, bend the thermostat in place and mark the bend. Now make your cuts to make sure the hose fits through. Its a tight fit.





Now that you have made your cuts, painted and preserved the panels its time to run the lines. I attached the lines to the thermostat, taped the ends and pulled from the back to the front. Start pulling through the wheel arch support. Pull until your thermostat monting point aligns. Then make the bend around the hinge posts, through the vertical fender support and out.

I clamped down the hose every 12-15" or so using Adel style clamps. These are also commonly called cushion clamps and can be found at most home centers/hardware stored. I attached two clamps with a single self-tapping hex-head sheet metal screw. The screw is in place between the two hoses. Very secure.






Next the hose has to enter the front trunk. I chose a spot just behind the turnsignal electrical plug. I drilled two hoes with the hole saw about 6" apart and then connected the holes with two tangent cuts using the cut-off wheel. The result is an elipsoid type hole. I then used a hammer handle and block off wood to make the trailing edge of the hole (to the back of the car) bend inward toward the trunk and the leading edge to bend outward to the fender. This makes an easy ingress fo the non-bendable hose. The hole will be covered using a rubber welting strip.



Once the hoses have ended up in the trunk you need something to connect them too. HMM there seems to be some sheet metal missing. I wonder what goes there. The whole point of this project is to have a front mounted cooler recessed into the nose and hidden behind the S spoiler. I will cut an access hole for the air just above the lip to force air through. A duct will be built to duct the air out the bottom of the car.






Next step, outer rockers.

[jpnovak]

ISince you just installed the outer rockers ( or were lucky, right Bill?) you need to prep the seams for the rockers. This means tons of grinding for your plug welds and all other surfaces where panels align. I like to start with good ole' hard grinding wheels. Once the weld is dressed down, switch to an 80 grit flap disc. These will provide a nice smooth, clean surface for welding.

This next part is almost the easiest section. If you did everything right, the outer rocker will just lay down in place.

Check the fit first. The rear should lay neatly on top of the wheel arch support. You can slide a sheet metal clamp inside the bottom of the wheel arch support and grab the outer rocker panel.


On the front, use a small C clamp to hold the rocker to the vertical fender support.



You must reinstall the door and check to make sure you have a consistent gap across teh bottom. If you weld it in crooked you will need to cut it back out. Shimming the door will not be an option. My door gap was off at first. I needed to bring down the front. This was accomplished with a BFH.



Once you are satisfied with the fit, scribe some reference marks and remove the panel. ONce again, drill your perimeter holes for the plug welds. I drill the bottom seam and then the back of the seal channel on top. Do not drill the top of the seal channel. these will be welded by drilling through the interior seat support that sits on top of the rocker seal channel. If you are this far into the project, you understand what I just said.

Make your perimeter welds. Now step back and enjoy your work. At the ends it may be necessary to massage the panel to lay flat with your BFH and a drift. you want tight seams to weld to. I just made a lap weld at the end rather than the spot welds. The welds will support the panel to make fitting a bit easier. keep the BFH in hand so that you can align the panel right after welding the previous section. The still hot panel will bend very easily.





Did your door gaps work out? I hope so.

Next up, latch panels and QP patches. The fun never stops.

[jpnovak]

Now that your rockers are in place there is some filler work to make the car look whole again. My door latch panels were in sad shape. On my targa I was able to just make patch panels. This car is different. I opted to buy the full latch panel to save fabrication time. I ordered these from Stoddard along with the outer rockers. No other reason than they were in stock.

Here is the hole I needed to patch.







I planned to only use the lower section to repair the car. first offer up the panel to the car. I scribed a line on the back side to approximate my cut. the first thing was to shorten the panel. A quick pass with the cut-off wheel makes the panel fit nicely.



next fit the panel to the section to be mounted. Notice that the rib that attaches to the seal channel does not fit into the seal channel.


While the panel is in place scribe a line on the back side. You want to use this to trim the panel so it fits within the seal channel.



I used a grinding wheel to quickly mill down the surface. Its much faster than the cut-off wheel and makes the curve better. Keep test fitting until the panel fits in place.



Now you need to trim the car's latch panel to fit the patch. Scribe a line across the paint. make the cut to the bottom of the line. cut all the way to the inner fender well so the patch panel fits flush. This is where time and patience pays off. Spend the time to grind the panel so that it fits snugly.



Now you have the panel trimmed and fit, you need to align the gap. this is a butt-weld section that will be metal finished and invisible.



Now you are ready to weld. Pull the the panel back out and drill some holes for the plug welds in the seal channel. you have done this before, the process is the same as I described higher in the thread. Now go to town with the welder. remember, the butt-weld will take less heat than the plug welds. I like to tack the seam on the latch panel, then tack the section where it lays on the rocker, then start on the plug welds using a drift to flatten the metal before each weld. This way the panel fits tight. Once the tacks are all in place, finish weld the piece.



Once the welding is done, dress the welds down. I still used a 60 grit hard wheel to knock the welds down and then a flap wheel to finish them off. You have had lots of practice with the welder and your seam should be nearly invisible.

[jpnovak]

Did you check the door gap? I hope so, Here is my end result.



Now go repeat on the other side.



Next QP patch. Its really getting good.

[jpnovak]

OK lets start with the patch for the quarter panel. this should be the last step in your rocker repair. If you cut well you should be able to patch back in the section you removed when this process started. If your car is like mine, it was so badly disfigured you are replacing lots of metal.

The first thing we need to do is fabricate a panel. I realize that not everyone has some of these tools. Here is a tip if you don't. Trace the fender curve on cardboard. Take this and a $20 bill to your local HVAC duct building place. Go near lunch and ask if anyone can make a panel at lunch using scrap. hand them a $20 and say you'll be back for more. Tell them you want the curve to match and use 20G cold-rolled steel. you will be happy with your return. Plan ahead and make the panel big enough that you can cut and do both sides of the car.

OK here is my panel fab. I was lucky enough to get a combo slip-roll shear-press brake from work. Someone tried to shear over capacity and broke the leg. Let's just say it was going to be scrapped and that the shear doesn't work. The slip roll works just fine.

A slip roll works by having three rollers. The middle roller moves in and out changing the radius between the other two. A hand crank moves the metal in and out causing it to roll into shape. Here is the metal between the rollers.



Keep rolling, tightening the radius and checking your work. you will end up with a panel that looks something like this...



Now check to see how it fits. Mine fits like a glove. This panel would have convicted OJ.





Once again we need to fit the panel to the car. The first thing you need to do is make sure the door fits. Just like the seal channel the outer side under the door will fit. Close the door and scribe a line where the panel sticks out. don't worry, it will be easy to find. Especially if you walk by and catch your knee on it. Ouch! BTW, Is your tetanus shot up to date? I cut more than 1/4" off the panel to get the door gap right.

Offer the piece up and scribe some lines. you need to cut the QP on the car to fit the patch piece and also scribe a line on the back side to fit your door gap. This is the same procedure I used to fit the latch panel patch. Here are the two scribe lines.

Panel in place:


scribe line:



Scribed and cut:



Now that the panel fits, time to do some welding. Again, this is a sheet metal butt-weld and a fillet where the corners meet. Turn down the power some so you don't burn through. Tack the three "corners" and then the middles. Keep splittting the distance until your welds are about 3/8" apart. Then stitch the beads together.





once again its time for the grinder. I really need three grinders. One for the hard wheel, one for the flap wheel and one for the wire brush. This would be easier than changing all these wheels. Of course, then I would need a bigger extension cord.

[jpnovak]

Once agian, check your door gaps often. The goal is to metal finish and be as close to perfect as you can.



My gap is not too bad. I will need to have a little filler here. You can see where the gap is not perfect. The small section is the correct gap. I will need to build up the rest. Another important part is that if you lay a straight edge across the door and new panel that they lack perfectly parallel and flat. Also, If you know how much lead goes on these panels from the factory the amount of filler I need is insignificant.

I hope that everyone reading this learned something. I am not an expert/professional body repair person. I am just a guy that likes playing with Porsches and welders and grinders and.. Well you get the idea.

I hope I can also inspire someone to fix the car themselves or have the car fix. There truly is some marvelous engineering that made the 911 the icon that it is today. Keep putting them back on the road!

[azasadny]

Jamie,
Incredible work there! You've inspired me!

[LakeCleElum]

Subscribed!!!!!!!!!!! I have a '69 that needs all this........

[jpnovak]

Art, that was the intention of this thread.

Go ahead Bob and start cutting.

[Morrie]

So, when do I get to take it out and beat on it again?

;-)

MorriE

[scottb]

I'm subscribing just to see how it all turns out. Jamie, your work and write-up are incredible!

[ianc]

I can only aspire to produce a thread of this quality myself one day.

However, due to galvanization, I probably won't need to.

Very interesting and inspiring read. Great work!

ianc

[jpnovak]

Morrie, I am sure it will get driven once the welding is finished...

The goal to finish is mid-Oct. The new owner, I am building this for my Dad, will take delivery and head across the south to Rennsport III in Daytona. I hope I can get it all finished in time. This project will include paint and interior too. good thing the car is mechanically sound. Oh and It's pretty darn quick!

[elflamo]

Jamie,

I'm in he middle of replacing the left rocker. Behind the jacking point, there are two panels, seems the overlap of the inner rocker and the rear wheelhouse metal. If you cut out metal for the entire length of the replacement rocker, am I correctly understanding that this overlap no longer exists? Did you overlap weld to the wheelhouse metal or buttweld to it? Will the lack of the original overlap reduce the strength of the jacking point - or not, as I noticed that the replacement panel is quite thick.

Thanks for your info

Dennis

[Trident]

Great thread..Thx..I think I can do it..

[khamul02]

My question is how do you treat the inner sections that are welded and you do not have access too? If those welds aren't painted/undercoated won't that be just another great spot for rust to start all over again.

[dtw]

Tom - For the rocker you're getting ready to do, there is an access hole. It is near the front, on the horizontal plane. You can get a schutz gun with various wands and directional sprayer attachments, which you can snake into the hole and spray your sealant of choice. I am partial to POR15.