1965 Cabriolet Rejuvenation

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Larry Coreth
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Re: 1965 Cabriolet Rejuvenation

#16 Post by Larry Coreth »

Well I have to disagree. Have tried to braze rusty metal ? You will put much more heat into a larger area brazing than you will welding with MIG or TIG done judiciously. As an engineer myself I have gained great respect for the Porsche engineers of 60 years ago and prefer to put the structure back to where it was originally and not for aesthetic reasons !
Yes, I would be worried about the torsion tube twisting since it is no longer held in place by the upright column, plus more importantly the vertical component of the wheel weight now will be attempting to bend the torsion tube about the center brace (where the torsion bar adjuster screws are). BTW tubes are great in resisting torsion but do not do well in resisting bending moments.
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Vic Skirmants
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Re: 1965 Cabriolet Rejuvenation

#17 Post by Vic Skirmants »

I fail to see how the tubes would see a twisting action unless the bearings were seized.

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Mark Dionne
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Re: 1965 Cabriolet Rejuvenation

#18 Post by Mark Dionne »

vic skirmants wrote:I fail to see how the tubes would see a twisting action unless the bearings were seized.
Each of the torsion rods are anchored in the middle of the tube. The two tubes are tied together with a brace, which ideally carries all the force. If not for that brace, the rotational force would be carried back to the ends of the tubes where they are welded to the verticals. To the extent that the center brace flexes, there will be "twisting action" on the tubes. On my car, I assume everything flexes.
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Phil Planck
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Re: 1965 Cabriolet Rejuvenation

#19 Post by Phil Planck »

Mark

Replacement front suspension assemblies are available and not too expensive. I had one delivered to Hershey several years ago(NOS) and I think it sold for around $200. But, I don't know how big a job it is to actually replace that complete assembly. Lots of welds would have to be cut out and precise alignment of the new assembly would be required, possibly in a factory fixture. Hopefully some of the pros can comment on this approach. Looking at your problem, that might be a route to consider.
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Re: 1965 Cabriolet Rejuvenation

#20 Post by Larry Coreth »

Vic,
Mark puts my case exactly. Although this twisting action is very small as I said in my post more important is the bending moment allowed by the loose end of the torsion tube.
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Re: 1965 Cabriolet Rejuvenation - TODO list

#21 Post by Mark Dionne »

List of things to do in Phase I:
- Fix gas tank leak (done with POR-15 kit)
- Rebuild brakes all around (done)
- New leather on seats (done)
- Repair and restore horns and mounting brackets (done--needed for state inspection)
- New floor and longitudinals
- New door sills
- Repair "closing areas" inside fenders
- New battery box area (spare tire area)
- Repair center tunnel and pedal areas
- Repair torsion bar supports
- New front diagonal braces, horizontal struts and surrounding areas
- New brake line and main battery cable in tunnel
- Repair body rust at fuel filler
- New battery, tires, shocks
- New carpeting and sound deadening
- Update brake master cylinder to dual circuit
- Replace steering wheel coupler, restore tie rods
- Treat surface rust in area under fuel tank with POR-15
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Re: 1965 Cabriolet Rejuvenation - measuring longitudinals

#22 Post by Mark Dionne »

On my Feb 24 posting I was wondering about whether the top lip on Stoddard longitudinals was too narrow and would cause problems. I ordered a pair of longitudinals from Restoration Design and got out my sextant, oops I mean micrometer, to measure them. The RD lip is much wider, about 0.800 inches, compared to 0.570 for Stoddard's. Much better.

The Restoration Design longitudinals are heavier gauge. The Stoddards are 0.036 (20 gauge). The left RD is 0.041 (19 gauge) and the right RD is 0.047 (18 gauge). Since I have a Cabriolet, the extra stiffness is very welcome.

There are two other differences. The Stoddards have a diagonal cutout underneath the hinge post area. The RD one probably will need a similar cutout, but will be stiffer if I can avoid it. In this picture, you can also see the difference in the widths of the top lip for the door sill area.
Left side Restoration Designs part is on top, right side Stoddard on bottom.
Left side Restoration Designs part is on top, right side Stoddard on bottom.
The Stoddard longitudinal has quite a bit more metal at the rear where it mates with the inner longitudinal/floor. That's a complicated area and I hope there's enough metal on the RD one. See the black triangle in the picture, which is the extra Stoddard metal. The short side of the triangle is about 2.7 inches.
Stoddard (black) is underneath the RD Longitudinal.
Stoddard (black) is underneath the RD Longitudinal.
Edit 3/2: I also got a "rear closure" ("Front of rear wheel well") sheet metal piece from Restration Design. The one that I previously got from Stoddard seems better. The RD one just has two straight-line bends while the Stoddard one has compound bends made in a press. I've already welded half of the Stoddard one to the car and the edges lined up well.
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Re: 1965 Cabriolet Rejuvenation - Tools and Such

#23 Post by Mark Dionne »

Tools and Such

Angle Grinder

The most indispensable tool while doing sheet metal repair is the electric angle grinder. Mine has nearly a full horsepower and spins at 12,000 RPM. With a cutoff wheel, which is about 1/16th inch thick, you can plunge a cut with one hand into a hard-to-reach panel with little clearance behind the cut. With a wheel like the Norton RapidStrip 04015 you can remove rust down to shiny new metal. Use 1/4 inch wide wheels for bulk grinding. You should really not use the side of the grinding wheel--if you thin it down too much it might disintegrate.
Angle grinder with Norton RapidStrip.
Angle grinder with Norton RapidStrip.
The DeWalt XP cutoff wheels are the best I have found. They are more expensive but they outlast 3-4 ordinary ones. The Norton RapidStrip 04015 wheels that I mentioned are much better than other "non-woven abrasive" wheels I have tried; I have found them only at Sears.

This is probably the most dangerous tool you will use. The need for eye protection every single second is immediately obvious. After half an hour with this thing inside a wheel well without hearing and breathing protection, I felt so terrible I nearly threw up. You also want to be wearing heavy leather gloves. When using a wire brush or stripper, if you catch a metal edge the wrong way the tool can be violently ripped out of your hands in a millisecond. Dropping the grinder while it is running can be very bad. Other dangers are disintegrating grinding wheels, kick-back and fires from sparks. Be extremely careful!

Creeper

I'm not using a rotisserie so I'm lying on the floor a lot. A creeper is basically a type of skateboard, and getting on and off the creeper is about as hard as using a skateboard. While you're getting on it you must crawl on the hard floor and hurt your knees.

I use an old piece of closed-cell half-inch backpacking foam plus an old couch cushion. I could take a nap on there if I wanted. Edit: If you use this foam, start by marking one side "DIRTY" and keep that side always down.
creep.JPG
Edit 10/11/12: Someone responded that working on the floor must be much harder than working under a lift. I'm not sure this is true. If you get the height of the car right (I raised it about 6 inches), when you are lying on the floor the work is "right in front of you" as opposed to trying to reach over your head which is hard on your neck and shoulders. The main difficulty with being on the floor is getting down there and back up repeatedly. Think ahead and have the tools ready.

I did come up with the idea for an invention that would help: a creeper with a voice activated brake on the wheels. You could lock it when you got into working position and also when climbing on and off.

Welding

I spent a lot of time looking for good welding instruction. This set of 5 videos is the best I found:
http://www.youtube.com/user/midnightoilgarage/videos

I bought some sheets of 19 gauge (1mm) steel from Shapiro Metal Supply on eBay. You will need pieces of this at places on the car, so get it early for practicing welding.

In addition to the usual assortment of clamps, I got a pair of Hobart 770562 Long Locking C-Clamp Pliers. These have 9-10 inches of depth and were really handy for the "closing areas" at each end of the longitudinals.

Welding Helmet

I started with a generic brand auto-darkening helmet, but I was getting headaches. I suspected that it was not darkening fast enough so I got a Lincoln Viking helmet for close to $200. The headaches have gone away and I also get much better visibility in the non-dark state.

More than once, welding sparks made it inside my helmet. This gets one's attention. I now wear close-fitting safety glasses inside the welding helmet. In fact, I wear safety glasses all the time while working on the car, ever since a drop of POR-15 almost fell in my eye.

Respirator

I use a 3M model 7500 respirator with 2097 filters while welding, grinding and painting. It is much more comfortable than those white cloth or foam things, which also cause my glasses to fog up. I'll bet if I wear it enough my allergies will disappear too.

Reference Materials

If you are restoring a Porsche 356, you need Ron Roland's new (2010) book Restored By Hand.

If you want a photo of how some sheet metal goes together, see Preston Brown's photo gallery. He has hundreds of great photos of all the phases of his restoration project, and an interesting diary over nine years.
Last edited by Mark Dionne on Thu Oct 11, 2012 8:45 pm, edited 2 times in total.
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Mark Erbesfield
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Re: 1965 Cabriolet Rejuvenation

#24 Post by Mark Erbesfield »

Mark, great thread and love the narrative how to for those that want to learn. I can attest to wearing all the safety stuff, my sinuses are a mess if I am lazy and virtually perfect if I am deligent with the respirator. I also agree with you about the grinder, I had one come out of my hands with a wire wheel attached and in the blink of an eye it chewed through two shirts and cut into my chest, not to mention the flying needles. But even with all the dangers, this is lots of fun.
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Matthew Devereux
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Re: 1965 Cabriolet Rejuvenation - measuring longitudinals

#25 Post by Matthew Devereux »

Mark Dionne wrote:...The Stoddard longitudinal has quite a bit more metal at the rear where it mates with the inner longitudinal/floor. That's a complicated area and I hope there's enough metal on the RD one. See the black triangle in the picture, which is the extra Stoddard metal. The short side of the triangle is about 2.7 inches.
I just finished installing a pile of RD metal including floors, longs, perimeter, heater tube supports, front foot well and front struts. I didn't end up using the front closing panels that I bought. I was shy on metal at the rear of the longs too which required butt welding a piece onto it. To be quite honest I had done a lot of reconstruction in this area so I wasn't sure exactly what it was supposed to look like so I didn't say anything. Otherwise their metal fit fairly well although there was generally an excess where it really wasn't needed.

ps some of my favorite tools were a plasma cutter and an assortment of vise grip clamps. A close second was a right angle pneumatic die grinder with about 100 3" 36 grit pads :)
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Re: 1965 Cabriolet Rejuvenation - The Restoration Reality Sh

#26 Post by Mark Dionne »

For the one front closing panel I have done, I just cut horizontally about 3-4 inches up and butt welded in a piece of 19 gauge. I formed a lip at the inside end and plug welded that to the new perimeter metal. After the outer longitudinal goes in I will bend up the outer few inches of the bottom edge.

I also had to add metal to my Stoddard rear closing panel, a crescent about 6 inches long and about 1/2 inch at the widest. I'm not sure if this could have been avoided by better fitting of the closing panel. Ron Roland recommends fitting the outer longitudinal before doing the closing panels. In my case, I wanted to repair the front closing panel before cutting out the old outer longitudinal, because I did not want to weaken my cabriolet frame more than necessary. On the other side of the car, I will do the rear closing panel after removing the old rusty outer longitudinal.

I had to cut out a bit of my Restoration Designs outer longitudinal at the hinge post area, and remove a small slice at the rear inner bottom where I also had to hammer on it a bit.

In his book, Ron Roland suggests leaving some chassis repairs on open-top cars "to professionals." That scared me but I'm going ahead anyway, with extreme caution. My car has had a large repair patch, about 4 ft square and nearly 1/8 inch thick, holding the front together. I'm cutting out small pieces at a time. I've been supporting the car at several points, but initially it was not easy to find metal that was strong enough to support.

At the moment, I'm nearly ready to install the left outer longitudinal. I have a scissor jack under the area of the hinge post. With no jack, the door needs a little extra push to latch. With a small load on the jack, the door closes perfectly. Certainly nothing dramatically bad has happened yet, even though there's a frighteningly small amount of metal holding the left side of the car together. The plan is to give the jack a little extra load, weld the new longitudinal, and see what happens.

Will Mark's Porsche end up bent in the middle? Stay tuned for the next episode of The Restoration Reality Show.
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Matthew Devereux
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Re: 1965 Cabriolet Rejuvenation - The Restoration Reality Sh

#27 Post by Matthew Devereux »

Mark Dionne wrote:For the one front closing panel I have done, I just cut horizontally about 3-4 inches up and butt welded in a piece of 19 gauge....

I had to cut out a bit of my Restoration Designs outer longitudinal at the hinge post area, and remove a small slice at the rear inner bottom where I also had to hammer on it a bit....
I did the same just patching the front closing panels after the longs were welded in.

I have a coupe so I was not faced with the same chassis twisting risks as you although I took precautions. I would certainly listen to what Ron Roland says about having to fix twisted cars. From what I recall these were cars that were weld repaired while on a rotisserie. IMHO (and a relatively inexperienced opinion) the same risks would apply to any open car not supported and leveled properly. Check critical measurements and door fits often. Install support braces where possible. Just make sure everything is very true before welding. I like Ron's method of supporting the car at the suspension points since this will be its normal position. I fab'ed up some of those odd looking drum stands which worked well.

If you are doing this work on jack stands you deserve some kind of a medal. :) I have a 4 post lift and could not imagine how much harder it would have been doing this job on the floor.
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Re: 1965 Cabriolet Rejuvenation

#28 Post by Larry Coreth »

Matthew, Amen !
30 years ago when I replaced the floor and associated sheet in my speedster while on jack stands, because that's all I had at the time, I took great care to be sure the car was straight and level as I welded it all up. I think I spent more time measuring and double checking than I did welding. I used the shop manual chassis dimensions as my guide, yet when all was said and done, the drivers door still had an 1/16" more gap then the passenger side ! Needless to say an open cars is susceptible to sagging and twisting than a coupe but even they are not immune to this problem depending on how much sheet metal is replaced.
So a couple of words to the wise, “Proper prior planning prevents piss-poor performance”. Use the dimensions on the chassis drawings they will help greatly.
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Re: 1965 Cabriolet Rejuvenation - Torsion Bar Support part 2

#29 Post by Mark Dionne »

On my February 26 post I described my severely rusted left front torsion bar support. I looked at it some more and decided to try welding to the remnants of the old welding bead where the sheet metal was joined to the thick tube wall. I first ground down the bead to a fairly thin edge that would be easier to weld.

I carefully shaped a piece of 19 gauge steel to match the tube bead and the rest of the cleaned-up edges of the old support. I laid out the rest of the vertical sides of the "box" I would be creating for the bottom of the support.
first.JPG
Here the lower edges have been bent with a 1/4 inch radius in my jury-rigged press brake. The excess was cut off, the corners were notched, and one of the side bends of the box is being made with the press. The top die in the press is a 1/2 inch aluminum rod. The bottom is just a 90 degree notch in wood.
press2.JPG
The notch for the rounded corner took a few tries to get right using scraps. Note that all this work needs to be carefully fit to the car within about a millimeter at each step. Each rounded bend (1/4 inch radius) uses about 1/8 inch less length of metal than a square corner would use, so take that into account.

Here are the finished bends.
bent.JPG
Next I made the bottom of the box, which has the mounting point for the sway bar. To form this, I clamped 2 blocks of wood and drilled a 1.125 inch hole through the split. Then I used a 1.125 dowel in the press. Leave extra metal to weld later to the diagonal "K" support.
bottom.JPG
The cutout for the sway bar in the side piece took some careful Dremel work. Once the rounded edge is cut, you have to be careful not to accidentally bend the side piece.

I added 8mm nuts for the sway bar clamp and welded it up. I cleaned up with the angle grinder and the Norton Rapid Strip.
welded.JPG
Here it is welded into the car. I stuffed a wet rag into the hole to keep things cool, and took it slow. The old bead was easy to weld to. All the welding was MIG.
installed.JPG
Prior to welding, I treated the inside of the old metal with POR-15. The inside of the patch was epoxy primed and painted. I considered putting drain holes in the bottom of the piece, since it's a place where water accumulates and makes rust. Maybe I'll do that later.

It's nice to get past this milestone! Stay tuned for the passenger side torsion bar support--it's in worse condition! (See May 28 post.)

Here's the "before" picture again:
porsche024.jpg
Edit: I've learned two new things: 1) In the original, the sway bar "nuts" were formed by a steel strap about 1/8 inch thick and 5/8 inch wide that wraps over the semi-circular cutout making a nice strong clamp. 2) According to the shop manual chassis measurements, the centerline of the sway bar should be 4mm in front of the centerline of the two torsion bars. (April 6, 2012)
Last edited by Mark Dionne on Wed Dec 18, 2013 11:00 pm, edited 4 times in total.
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Re: 1965 Cabriolet Rejuvenation

#30 Post by Larry Coreth »

Mark, Nicely done !
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