I am a little lost.

I have a '76 which I am proceeding to 'restore'. I will be buying the P335 from RD and I wouldn't have noticed the small qualification on the website "and with modification 1975-76" without following your thread.

I am appreciative of your high lighting this little nuance but am not quite sure where the difference lies and how to remedy it.

It should be the responsibility of RD to guide its customers on how to manage this problem but would appreciate some guidance.

Hope some help will be forthcoming from the community.

I appreciate the 'all for one and one for all' ethic of this community

This project is exacerbated by the fact that we're replacing the rear tail light panel too.
But after a little R&D on Friday I don't think it will too tough to replicate. In the essence of time I won't be able to completely replicate the rolled corner. The circled area.
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I'm going to focus on these two measurements when I create the triangle piece.
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I think I'll contact RD and see if they can chime in and give us there thoughts on the 75-76 modification.

They will say ...yes that what you need to do....

Cary,

Just took a pic of my '74 floor which has been repaired with the RD panel. The difference is quite marked.

Thanks for spotting the difference. I bet I would not have noticed

David

Modifying RD PP335 to replicate the 75-76 rear trunk : Part #2

I start the day with measuring the portion to be cut out. It's kind of a two step process.
First I need to temporarily install the tail light panel supports. This will dictate the finished level of the sloping trunk.
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When we slope the trunk we have another geometric problem. The panel then becomes a smidgen short. I'll elaborate on Part #3 tomorrow. Here's a shot for a teaser.
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The given is the 2" that is the end width of the triangle patch.
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Now on to trimming the panel to go over the side humps. These are a tight fit against the wall.
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I decided to cut out the two humps first. Then make the money cut last.
Right side measurement.
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Left side cut out and lined up.
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Then I set about making the money cut. This is the long cut along the open section of the transmission mount support. I did it wallpaper hanging style, making a double cut.
I held it in place with self tapping screws. I started with the die grinder on the mandrel. I didn't like it, I couldn't feel the lower layer. So I used the air hacksaw, worked great.
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I'll hand the trunk panel off to Super In Law to create the sloped triangles and fabricate the corner extensions/modifications.

I moved on to starting the rear half of the floor pan removal.

It starts with removing the rear floor jack points.
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Pleasantly surprised with the condition under the jack points. They'll get OSPHO'd and primered.
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Mark stopped by and brought several boxes new hardware. We decided that we'll need to order 2 new rear floor jack points. I could work them back to presentable. But the metal would be quite fatigued.

On a sad note note I did find a double layer hillbilly patch on the right rear of the floor pan. Which is ok to do for a quick cover. But DON'T seam weld over the floor pan spot welds. I'll show some detail on how I'll work around it tomorrow.
Punch some new rosette holes and weld them in.
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Cary....you're cruising.
Well done.
I'll be back in the States in late April.
Hope to see you and catch up with all you've been doing.

phrase of the week!

Great work Cary!

I did not see the heat shield that attaches to the btm of the trunk panel. It seems that it would be easy to weld while the trunk panel is on the bench vs upside down when installed.

We're going to install blind nuts on the heat shield and
run domed allen screws in the trunk under the
mat.

Mark's heat shield is in a cart ready to be blasted when I get set up outside again.
The shield has the stand offs still on it. So I would do a 3/16 rosette weld from the trunk if it was to be welded in.

Stand offs will be welded to the trunk floor. Heat shield will bolt to the stand offs.
edited 4/5/16

Measure ten times then cut .............. fairly simple pattern. Only issue was the flange against the tail light panel.
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It's always nice to weld new 18 gauge to 18 gauge.

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I learned we have a few more issues when converting to the 75-76 trunk panel.

Here's corner shot of the factory 75-76 trunk panel. You can see the dipped section in the corner.
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Here's the PP335.
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The X is where the dipped section is. The new one is flat.

The problem I ran into is I can't make contact with the transmission support in the corner.
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Don't drill the holes I have marked with X's. They had to be refilled.
I may try it one time after everything is completely welded down.

The level is dictated by the hump and the bumper support. I need 1/8 to 3/16 ths.

On Mark's visit he added another item to my list . LOL.
He wants me to transfer the hole plugs from the old trunk panel.
I'll give the seam sealer a good soaking with brake cleaner in the am. Then we'll get after it with multiple scrapers.

Should be a fun challenge ..................
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Great Job...did not want you to do more work , Butt the end result will be Way Better...weld on...Jeff

When we slope the trunk we have another geometric problem. The panel then becomes a smidgen short.
From Post #105

When we slope the floor it pulls the base of the spot weld flange out from the tail light panel. Which will not allow me to rosette that portion of the flange without making an ugly mess. So those portions in the middle will be tacked on the top of the flange. Which won't be seen. They'll be finished with sprayed on seam sealer.

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The dark line is the gap.

While I move on to removing the rear portion of the floor pan. Super In Law will be recreating both corners of the trunk. They too have big gaps on the sides and in the corner. So we're going to cut them off and create a new corner.
BEFORE
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AFTER
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The right side was trimmed and ready to be tacked it.

Onto removing the floor. I like to remove the sides and the middle. Then make two middle cuts leaving me 2-3 inches to work with when removing the welds on the center support and the rear fire walls. I'm all about preserving as much of the floor pan flanges that you can.
I don't need to add any floor pan removal pictures. They've been done many times. Ill only elaborate on the tricky parts.

First tricky spot. For some reason they run a couple seam welds right under the inside seat belt bolts on both sides.
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So I cut around the seam welds so I can come back and surgically remove them.
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Time for lunch ................
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Next tricky spot is the seam welds under the seat adjusters.
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Same program, leave the seam welded portion so it can be surgically removed.

Then I remove the e-brake pivot. Pivot pin was bent. Drew alignment marks above to help with installing the replacement.
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I did find some more rust. The bottom of the left inner firewall has been nibbled on by the worm.
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We should be able to patch that bottom portion and flange.

Today's scrap pile ............
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Tomorrow, the remaining portion of the floor under the rear firewall. Could be tricky with the patch that is on the engine side. Long seam weld
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Onto to finishing up the trunk panel. Here's a shot of one of the new corners we created.
Now we're nice and tight on all sides. We should be able to do rosette welds in all but the corner. Corner has too many seams coming together to get a tight enough fit. That's why its always overfilled with seam sealer.
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Then on to installing the 75-76 tail light panel support.
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Decided to fulfill Mark's request while we still had the trunk panel on the table.
We removed the plugs from the old trunk panel. Chisels, brake cleaner and the heat gun. Then tidied it up with the wire cup brush.
I decided to cut up the panel itself and use the old hole as a guide for my air hacksaw.
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Pictures tell it all ...............

Topside
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Bottom
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I start with welding in the poor fitting flange to the tail light panel.
Best I could measure when we lowered the trunk floor we added 3/8" to the needed panel length.
This shot is from under the car. The yellow line should be tight against the bottom panel.
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Like I mentioned earlier the back panel would be tack welded. Do not do any aggressive hammer work on the back panel of the trunk. It will make a mess of the tail light panel on the back.
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I wish I'd bought 3 or 4 of these to hold the flange tight.
https://www.zoro.com/irwin-vise-grip-lockin...275/i/G0317466/
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With the 45 degree angle I don't know if they would have worked. Those are the pivot foot model.

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At the end of the day. The inside of the trunk gets seam sealed. And that portion of the tail light panel is under the bumper.

Mark's pile of stuff ..................

Wow Cary,
Really making progress.
I love that when I'm out of town for 5 days I can come back and see the progress.
As far as the plugs in the trunk, I didn't expect you to actually cut the hole in the new metal and attach the plugs. I thought you would just glue the old ones onto the panel, but you went the extra mile to do it right. Thanks!
Mark

I decided if we were going to return the hole plugs into the trunk. We should cut the holes into the transmission support cover. And weld the spare tire hold down nut back in.
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All dressed up and ready to go ................
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Whoa-la ...............
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From there I went to the back panel and tidied up some of the pre drilled holes that didn't get reused or filled in because it was tack welded instead of rosette welded. When I got home my order from Zoro had arrived. I'd ordered some high quality belts for my 13" belt sander. Hopefully these will work on the tack welds on the back of the trunk.

Short Episode of Tool Whore :
As I weld in replacement panels and create tools. There is a need for magnets. Most everything I have and used are a POS. Until Now.
These bitches work. How long they'll last will be the long term question. $29.
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Got the trunk support prepped and ready to be welded in.
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Stuff :

Mark the 17mm MC is ready for pick up.
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Ken the toe hook items are just about ready to go. I'll refurbish and paint them with weld thru primer.
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Kind of hillbilly. But a quick trip thru the wood stove removed the seam sealer in quick fashion.
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Super In Law pulled these out of the scraps in the scrap barrel.

Trunk support welded in ..................
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Trunk all finished up ..................
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Came back from lunch and went on a pin hole hunt in the upper trunk and back panel. Using a flash light to back light, its amazing what you'll find.
I'm real happy with the belts that I bought from Zoro for my 13" air belt sander.
Here's a shot of the finish I'm getting.
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Every thing was going ok until I went after a pin hole the area that I called out in
Post# &4.

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Dammit ............ blew a hole to start with. Then went underneath a did some work with a wire brush. Just started to disintegrate.
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Haven't bought a seam roller yet. So I can't recreate a large area.
Took a gander into trunk of the parts car. Might be usable. I'll cut the section out and see what I have ............

Super In Law refurbished the toe hook pieces that we're getting ready for Ken. Then he tidied up the stand offs on the exhaust heat shield. It's all ready to get bead blasted tomorrow.
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Thanks Cary! That kit will be exactly what I need if I ever do track time and need to have the car safely towed! Please PM me with what I owe you for your efforts, and we can work out shipping with Mark.

Beautiful work!!!

Ready to go ................ I'll send you a PM. Not really yellow. Lights
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Started the day pulling out the plasma cutter.
Cut this section out of the parts car.
PLAN A :
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Went with smaller section.
PLAN B :
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Saved PLAN A for the future.
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We have a break in the weather here in PDX so we pulled out the refurbished HF blaster tank. Tore the whole thing apart and cleaned out all the hoses and valves. Then bought a new 5ft longer commercial grade hose. She ran like dream.
Blasted the exhaust shield and the left door sill I pulled out of my stash.
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Then onto finishing the removal of the floor pan under the firewall.
I start with those seam welds under the seat belt bolts. No real issues. Just cut them out with cut off wheel on the mandrel. Then peeled the remaining pan off with Rick's screwdriver spot weld removal method. Rolling the removed material with a pair of lineman's pliers like an old style sardine can.
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While systematically removing the hillbilly patch. I pulled out a couple holes in the long while locating and removing spot welds under the long seam welded patch.
Area is nice and solid so a patch should be an easy deal.
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But I did find a rust degradation hole right on the bottom rolled edge of the long.
We'll see if we can recreate that radius and make a long patch so we can remove most of the degradation.
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Here's a couple shots of other issues that I'll need to deal with.
1. About 1/2 the bottom edge is gone.
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2. I don't get it. Just like the end of the hell hole. They left the old rusty portion of the lower firewall behind the patch.
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The yellow arrow indicates where they seamed the patch in two pieces. I might be able to peel back the rusty portion up to the seam

We'll be taking a couple day break so we can paint the frame bench I bought in January.
I'll add that update on my rustoration thread
Then I'll dive into the wheelhouse rust.

Thanks Cary,
I'll be back in late Sunday and will come out to see you.
Thanks for everything!

Bump

Back to the task at hand ..................

After giving the wheelhouse a complete inspection you'll see the the white lines I drew out. These are the cut lines ..................
Always keep in mind, less is more. Only remove what you absolutely have to.
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All cut away other than the double layer that sandwiches the tail end of the outer long.
Interestingly when you look down into the long you can see clean steel. It seems the rust was caused by the moisture retained in the mouse nest.
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Off comes the outer layer.
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Then the inner box.
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Here's the same area on the backside of the new piece. The long tucks into the rounded section and gets spot welded together.
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I stand corrected on my original statement. What I needed to do was remove the stand offs from Mark's shield and mount them to the floor pan. I was too focused on the floor pan recreation. All I could think about was it being in the way every time I took the pan out for fitting. And making sure it wasn't in the way of getting a good shot epoxy at a later date. Yes, this would have been easier on the bench.
I think I'll have Super In Law create 6 new stand offs, just a smidgen bigger to accommodate the blind nuts. I'll create a template for the stand offs off my car.

Now where was I ? I fell asleep with the computer on my lap.

With the wheelhouse opened up I have a better picture of the damage to the long. Not going crazy like I did on my car. LOL.

The outside will need a bottom patch. Looks like I can keep it inside the floor pan seat.
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I'm cutting up to the heater tube because experience says I won't be able to weld the pitted metal. It's thick enough, but you cant get enough of the rust out of pits for a good weld.
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Now on to the inner box where all the damage started. This will take some delicate surgery to remove the inner box without damaging the outer long. I think this will take my entire pile of die grinders, cut off wheels and the Dremel to get the job done.
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This piece will have to built in two three pieces and welded. The issue is, can we create the ribs without a seam roller. MacGyver (Super In Law) says he can. Hmmm.
I'm thinking Tool Whore will have to dip into the saving account and order a bead roller. Looking at Woodward Fab at Summit and Eastwood. Leaning towards the Woodward. You can order the additional dies as you need them.

The rear suspension was removed for better access for the wheelhouse repair. I was going ask for Rick's guidance on doing a trick repair of the wheelhouse. Trimming the outside off the new wheelhouse and sliding it behind the suspension mount. Just not confident I could get the welds that I'd be happy him. So the mount will be coming off.

Suspension added to the cart. Mark stopped by to drop of a couple additional RD pieces and pick up Ken's toe hook. He added prepping his cars for WCR to the work list. One oil leak, one D-Jet tune up.
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Prepping for surgery................... Make pot of coffee
Step one, remove outer layer of long. Peeling off only the outer layer didn't work. Either too much rust or too much coffee. Measure the seat belt plate to best determine where the bottom edge might be.
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Like my dad used to say, Do As I Say, Not As I Do............
I cut first. Ran into the bottom edge of the plate............. Dah
I wonder why. Two beer lunch ............
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Here's where I ended up on the outer cuts.
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Inner box ends 60mm from center of seat belt bolt.
I'll edit tonight and add a shot of after I cut the upper edge 3/4" higher as to not have the stacked seams.

Onto to the inside.
This is a bit more difficult because of the metal degradation, tough to find the spot welds. Just slow work with chisels. Peel up with chisel until you run into a spot weld. Grind down the weld from the top until it will pop free.
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I took it out if two pieces. Bottom, then the wall. As you can see the outer long is in great condition. I went into the engine and ran an 1/8 bit thru the spot welds that were easy to locate on the shiny side. Then ran the Rotacut thru the inner box to weaken them enough to pop free.
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At the end of the day I gave it a good soaking of OSPHO to dry overnight.
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I moved out of the way so Super In Law could finish the work on his patch patterns.
I moved on to removing the left door sill. Nothing to much to document. You do need a torch to loosen and remove the brazing.
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Only additional work I picked up on the sill removal was the rust between the sill flange and the door post brace/box.
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This is a tricky area to work on. On the couple I've worked on the metal has thinned and is pretty soft. Don't let this be the place you try out your new welder. You'll be in tears and your welder will be For Sale on Craigslist.

While I was working on the car MacGyver was working on his rib fabrication tooling.
First one was too big. Version #2 looks to be a nice fit.
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Basically he chiseled out a channel in a piece of oak from the scrap pile for the form. Then found a piece of solid stainless steel for the press.
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Then he squished them in the press. He says he can create about six inches with each pressing. No Bead Roller Yet .............
This tooling will be used many times in the future.
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Piece one and piece two being aligned. This is where we ended the day. We'll start today with the third piece and welding it together.
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Super In Law spent the day fitting, welding, trimming and grinding the inner box.
At the end of the day it's just about ready to go.
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Looks like we'll be bringing the old 90 amp Craftsmen MIG from home. At times we need two welders. It will work fine on new metal to new metal. Not enough adjust-ability for the new to old welding.

Need to do a little refurbishing on the sill I pulled out of my stash.
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New magnets are almost to strong for welding ......... sitting on the solid u-channel, the MIG would studder when I got too close to the magnets.
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Yes I did refill the rosette holes. Once again it would have created gigantic rosettes.

Then I moved on to the holes in the door post support.
It must have been my lucky day.
All three holes welded up without any issues. Being paranoid I did back off to only two blips, instead of my usual three.
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Along the way I did find one more little rust pin hole.
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After some fiddling and fitting shes already to go .................
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Left tail needs a little more polish. A couple spots could use a little more welding to level out. I'll get that finished up in am. Then I'll get out the torch and braze in the joints.
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I love this thread.


Nice work Cary.

Super in Law.......that is great soft tooling for the ribbing work. Lost art along with steel rule die making.

Quit your day job.

At the risk of being the asshole... Dude, more heat, less wire. You seem to like grinding. Had to poke fun, but wouldn't if I didn't have huge respect for what you are doing. Seriously amazing project.

No harm, no foul. All input is good. I've had better luck the last couple years using the Millermatic mode. So the wire is on autofeed. I have a lot less blow thrus. So in order to go hotter. I need to weld faster. Less time in the same spot.

I'll tinker with a little more of a 90 degree angle and a little more heat. But I forgot to mention that I'm always concerned about distortion that is caused by more heat. Especially if I'm trying to weld good metal to old metal that is a bit pitted. Like the above shot of the tail of the door sill.

Super work!