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4. Body & Subframe

After a computer wobble (probably my own fault) I accidentally deleted this whole post. Fortunately I still have the pictures but it'll take me a few hours to re-write so, here I go again.

One last, little job on the engine before I bag it up again. The CX500 was not equipped with an oil pressure gauge - just a warning light that comes on should the oil pressure fall below say 5 psi. This usually happens if the engine is so knackered that it runs out of oil, or there is a leak that has been left un-repaired. Odds are that the bike will be driven home anyway finishing off the total knackering of the engine. This light is often referred to as the 'The Too Late Light'. I reckon an Oil Pressure gauge is a must have. Although the Berkeley's dashboard isn't huge, there's room for both an oil pressure gauge and a water temp gauge. 
The original oil light switch screws into an 1/8" NPT thread on the front cover which is connected to the main oil gallery. I used a CBS Aluminium 'T' adapter part number #ADAPT10 with an additional thread in one side and a brass blanking plug in the end. Both the switch and an oil pressure sender can be fitted neatly without too much front projection.

Before I get on to prepping the body and subframe there's something I have to sort out first. It jumped out at me in my early evaluation of the project. 
Here's a sketch of how the subframe is mounted in the body. There are three mounting points on each side of the engine bay. Bonded to the underside of each wing top with a strong fibreglass joint is a 40mm x 40mm steel box section post welded to a plate 'A'. Another plate with two 8mm holes 'F'' is welded to the bottom of the box section. This is where the subframe turrets are bolted.
A rearward-extending section on each side of the rear of the subframe is bolted through the glassfibre floor at the bottom of the aluminium engine bulkhead 'B' . This area has been reinforced with a glassed-in A 75mm x 75mm x 2mm steel angle reinforcing plate across the width of the floor. The two M8 mounting bolts pass through this. So far, so good. I'm happy with the principle and strength. But it's at the front where I have a problem. On each side of the front radiator vent is a bonded-in, steel angle bracket 'C'. One M8 bolt on each side fixes the subframe to the brackets. Now, because the engine is sitting quite high and forward in the subframe. The two 'C' angle mounts are only about 1mm thick steel and although they are embedded in glassfibre, the whole area is not that strong. I reckon torque and inertia under acceleration and hard braking will try to rock the subframe, moving 'C' up and down and trying to rock 'A' to tear it away from the underside of the wing.
My plan is this. There is a 1" square, steel dash frame that reinforces the dash area and supports the steering column (shown in purple). It is welded at the bottom to steel rails in each sill section and it's vertical sides are strongly bonded into the door 'A' posts. I'll drill through the front bulkhead and weld a 25mm diameter x 1.5mm thick round steel tube 'D' , between the dash frame and the upper steel subframe mount. I'll make new, stronger, front, subframe mounting brackets bond them in to the body each side of the front vent, reinforcing the area with thicker GRP. I'll weld another tube to join these new brackets. again to the upper mount box section creating a tubular, partial, space-frame cradle for the subframe.

Here you can see the three nuts and bolts each side that help reinforce the bond between the original front mounting brackets and the GRP flange on each side of the front vent in which they are embedded. A single M8 bolt (out of view in this shot) fixes the subframe to each bracket.

It's difficult to tell exactly how far the brackets extend into the GRP flange but a good start in removing them is to take out the nuts and bolts - no easy task as they too are embedded in the GRP that surrounds the brackets. My Powerfile was able to expose the nuts and with the heat generated, soften the surrounding resin so they could be removed. CBS Stock both the original Black & Decker Powerfile and a compressed-air-powered version. Sorry 'bout the blurry pic.

Nuts and bolts removed but the brackets are still in there somewhere. I decided to remove the lower part of the front vent.
..... and this is the tool that did it - my Fein Multitool fitted with a fine tooth straight blade. I then used it to cut out both the brackets with their surrounding fibre glass. You can see the angled ends of the brackets, with their welded nuts.
I'm building this car in a workshop that is also home to my Continental, a couple of my bikes, an assembly area, some stock and a couple of machines, so minimising dust is a big priority. The worst culprit for generating clouds of dust is an angle grinder with a flap wheel. Grinding fibreglass makes a an uncontainable cloud of dust in all directions - definitely a no-no in this workshop. Closely followed by a Powerfile which, at least, has a more controlled stream of dust - most of which can be collected with a carefully positioned vacuum cleaner nozzle.
However, the Multitool works in a different way. Instead of a rotating disc or belt, the blade oscillates to and fro just a few degrees very quickly with minimal dust. The principle was first used in hospitals for cutting plaster casts from healed broken limbs. The blade would easily cut through hard plaster but would not hurt the soft skin beneath. The Multitool can also be fitted with abrasive discs and pads with a vacuum attachment, again, for minimal dust generation.
OK - time for a clean-up. I'm going to be laying-up new fibreglass over old fibreglass which has to perfectly clean and abraded to achieve a strong bond. Sadly most of the inside surfaces of this, almost sixty-year-old car are anything but clean. There is paint over primer over newer GRP over dirt over grease over exhaust soot....... and I won't be happy until it's all as clean as I can realistically get it. Enter - Gun Wash Thinners. This is a fairly crude, less refined sort of thinners which we buy in 25 litre drums. It's a brilliant de-greaser and is really cheap so it makes no sense to use it sparingly. It'll break down most paints, adhesives, underseal, grease and oil. Here I'm using it with a small wire brush from our 'Small Cleaning Brush Set' to get into the nooks and crannies of the surface. CBS Part number #BRUSHPAK.

........ and here, I've laid some thinners-soaked towels on the area to be cleaned. I dribble more thinners on them for 20 minutes or so and the paint layers will just wipe off.

Looking into the upside-down offside wheel arch. It looks a bit of a mess but the thinners has taken off everything that's dissolvable. Whatever is left here is embedded under layers or resin so ain't going anywhere.

My Makita cordless Palm Sander is quite handy for getting into tight spaces and removing high spots from the panels.

Again, upside down, this is the underside of the bonnet reveal and the glassfibre all round the edge is untidy and delaminating. I've already cleaned all the old paint from the left and right sides and I've laid some thinners-soaked towel strips around the back edge to soften the paint there.

On to the new front subframe mounts. This is the nearside front corner of the subframe and the nice and clean GRP area that it'll be bonded to. First step, as always, is to make a cardboard pattern for the new bracket.

The offside bracket, with the bottom corner curved upwards a tad to match the body curvature, is clamped in position. I have to say that the symmetry and accuracy of the body, the subframe and all the mounting points is a credit to both the original Berkeley design and the previous owner. Everything is within a few millimetres of where it should be.

Here are the brackets, made from much heavier material. They're just waiting for an M10 nut to be welded to the end plate for the upgrade M10 fixing bolt. Each bracket has ten large holes for the resin to penetrate through, bonding the new GRP to both sides and four small (6mm) holes for bolts to clamp it all together.

The nearside bracket is bolted to the subframe and I've made this brace from 22mm diameter round tube....

...... that passes through a hole in the forward inner wing to the upper subframe mounting post. The G clamp is just supporting the tube in the correct position.

I welded a stepped hole cutter to a piece of 1/2" diameter steel tube to make a long series drill.

Yeah, I know - but a dampened down cardboard box makes a great shield against wayward welding spatter flying all over the place. But it didn't stop a spark finding it's way to my phone in my top pocket and cracking the screen. BUGGER.

Then another tube from the upper subframe mounting, through a hole in the engine bulkhead to the dash cross-tube. 
I took advantage of the upside-down body to sand down the resin runs on the underside of the dash top and scuttle. You can see a strip of emery cloth laying over the joint. I used this to clean up the weld and abrade the tube where it passes through the bulkhead. I'll have a sealing patch of glassfibre on each side of the aluminium.

I drafted-in my old mate Ray, who welded every one of the fifty or so P4 chassis' we ever made, to weld the tubes in place. We soaked towels in water and wrapped them around the steel to soak away the welding heat before it reached the glass fibre.
Now, I know that these new tubes don't add much in the way of triangulation so it's not a true space-frame section but I'm happy that the three steel subframe mounting points in each side of the glassfibre body are now also joined together with steel. 

Incidentally, you can see the row of Cleko fasteners in this picture that are temporarily fixing the lower edge of the aluminium inner wing to the subframe. These will eventually be replaced with rivets on final assembly, adding some more strength to the structure.
 Guess what? Clekos are available from CBS.

The weld on the dash cross tube was a bit tricky.

Right, all the welds are done and the body has been sanded down flush with the two brackets......

...... ready to lay-up a few layers of GRP, bridging the brackets and body.

Shining a torch up from below helped me identify the position of two of the 6mm holes in the brackets which will eventually take bolts pinching it all together. I drilled and tapped them through and temporarily fitted some stainless studding.

This car is no longer the lightweight buzz-box it used to be. Even with the subframe removed it took three of us to lift and flip it over again, right side up. It's incredibly strong and rigid. 
I've laid up several layers of GRP on the top side of the brackets, around the welded tube and the studs, which I masked with tape to keep the threads clear of resin. I made two, reinforcing, sandwich plates from 3mm steel. Here's the nearside one, sitting on top of the layers of cured GRP. 
Of course it would be quite difficult to achieve a perfect face to face joint between the GRP and steel so........

I mixed a blob of this stuff to fill the gaps and bed the plate nicely in position. It's commonly known as 'Fibrefill' and is a ready-mixed paste of glass strands and resin. It's brilliant for gap-filling and bridging holes. Available, of course from CBS - Part number #FIBREFIL.

I wound the nuts down 'finger tight' to squeeze out the excess Fibrefil and settle the plate. Then spread it around with my finger to smooth the joint edges. You get a few minutes working time, depending on ambient temperature and the amount of hardener you mixed in.

I cut some 3" diameter discs of matting and glassed four layers around the tubes on both sides of each panel the tubes passed through. More strength and sealed against rain and fumes.

I guess it's fortunate that much of the work done by the previous owner has been done to a pretty good standard. My usual modus operandi is to strip a project right down to bare materials and the last nut and bolt before starting the complete rebuild. But with the Berkeley it's neither necessary or practical. I can see that the body modifications and reinforcing are mostly good and strong and do not preclude any further modifications I choose to do. But still, I can't seem to get going on the project. I feel that I'm still having to go backward before I can go forward (if that makes any sense).

That red paint has come off and I think this too would qualify as a backward step. I reckon the previous owner just wanted to get some colour on it to see the overall effect of his work so far. It's only Cellulose paint so it almost falls off with the good ole' Gun Wash thinners and a Scotchbrite pad. 
Looks like a screen shot from the TV serial-killer series 'Dexter'.

The beige, Filler Primer beneath the Red is much better - probably Two-Pack. It's a good, heavy coat - just as I would have applied and it's pretty resistant to the Gun Wash.

That's got all the red off. What's left is reassuringly good. I can see no cracks or crazing, the flat areas are flat and the curves are smooth. It's a good place to start.

I've cleaned most of the crappy grey primer from the aluminium pedal bulkhead and inner wings. The riveting is neat and nicely spaced and the GRP-to-aluminium bond is very good with no visible delamination - not an easy thing to achieve. You can see the two large holes in the bulkhead. The top one is for the steering column and the lower one for the driveshaft (on it's way to the rear wheel). The small hole is for the gearshift cable. On the left of the bulkhead (on this picture) are two vertical steel angle pieces riveted to the bulkhead. These are mountings for the brake master cylinder and pedal box. There's a neatly-made little depression in the offside inner wing that'll provide a little clearance at the side of the master cylinder. Nice.

I love my Makita battery tools and here's my latest addition - a Detail Sander for rubbing down in tight areas. It's a tad heavy for my dodgy wrist but OK to use for short periods. I adapted the vacuum dust extractor attachment with a 4 metre length of 25mm plastic convoluted ducting. It works pretty well keeping the old dust down.

Repairing or blanking unwanted or over-enlarged holes in fibreglass isn't just a case of filling them with filler. This example is one of the bonnet hinge holes. My plan is to have hidden hinges so these have to go. I ground away a concave depression on the back of the hole half way through the thickness of the GRP. I cut several small discs of matting and laid them up in the hole with resin.
I then ground away from the front of the hole to meet the new matting half way through and laid up more GRP from the top. It's a bit laborious but it's a permanent repair that won't crack,come loose or fall out. If you still want a hole it can be redrilled the correct size in the correct position.

I used the same method to repair holes, cracks and damage to the lower half of the front air inlet before I re-bond it in place.
The previous owner had bought a pair of clear plastic headlamp covers from the owner's club. They're vacuum moulded from 2mm thick Lexan, which is strong, shatterproof and quite flexible compared with the ones on my original car back in 1970. If I recall correctly, they were moulded from much thicker, maybe 3/16" to 1/4" thick 'Perspex' which was not at all flexible. The were held in the headlamp cut-outs with 'H' section, rubber windscreen moulding and were a pig to install.
I'm not sure if these newer covers are still available so I thought I'd make a mould from one of them as insurance if I ever need replacements. The covers were made on a Vacuum Moulding Machine (which we just happen to have). They start as a flat sheet with a thin, removable film on both sides. I wrapped masking tape all round the edges to seal them against stray resin and I sprayed wax mould release on both sides. I cut an oval shaped hole in a cardboard box to support the cover. The two-part moulding resin is mixed equally by weight and quickly because it goes off in just a minute or two. I reckoned two litres total would fill the mould.
My guess was spot on. Two litres filled the cover to the brim.
.........and within five minutes the resin had cured enough for thenew 'buck' to 'fall' out leaving the waxed cover (mould) undamaged and in perfect usable condition. I wanted to get the it out as soon as possible because of the exothermic reaction of the curing resin. It gets almost too hot to touch and I didn't want the heat to soften and deform the original cover.
Rather than risk damaging one of the replacement clear covers I moulded six on our vacuum moulding machine from 2mm ABS. I'll use them to make templates and bucks to mould the reveal ledge around the headlamp opening.
It's probably fair to say that most Berkeleys have suffered a 'front corner collision' or two at some time in their lives. My first one certainly did when I pulled out in front of a Transit !
And this one is no exception. The previous owner had rebuilt the offside front corner and the nearside also looks suspiciously un-original.
My intention is to form a narrow 'shelf' all around the inside of the hole so that the cover will sit flush with the surface, secured with a few small countersunk screws and screw-cups - just like on our Ferrari 'P4 replica'.
But first I have to get the shape right with a combination of measuring, templates and simple judgement. The flat section at the bottom has to be sorted.

The nearside is too thin around the rim in several places which had led to an uneven edge to the hole.

......likewise, the off side. It was damaged and delaminating in this area so there's no alternative but to grind away, first the outside layer, feathering back to good GRP, then .....

........ lay-up a few layers of new GRP then .....

.......... grind away the old glass inside until you reach the new lay-up on the outside then glass a few new layers on the inside. CBS stock Glassfibre kits with everything you need to get started, in 500ml and 250ml sizes. Part numbers: #GRPL and GRP2
I've repaired all the damaged areas and thrown on a bit of paint to help me check the height and blending. Now it's time to tackle the reveal shelf for the headlamp covers which will be a much easier task if the body is upside down. So, over it goes again. I was surprised that this different perspective highlighted more work to be done on the shape of the holes. At this stage the hole shape is refined pretty-much my eye and judgement. I made up this sanding block from a piece of 50mm aluminium tube and some 60 grit abrasive paper.
Bear in mind that some of these piccys were taken with the car upside down.

The plan is this: I'll trim one of the mouldings slightly oversize so that it can be taped in place over the outside of the hole. I'll then cut a double-thickness ring of two mouldings stuck together with double-sided tape, that will lay on the first moulding, flush with the inside of the hole. There are two mouldings in this picture - one untrimmed and a trimmed one that I've put masking tape on so I can see the trimming marks. The mouldings are not symmetrical end to end - there is a subtle difference top and bottom. It's quite a subtle difference but I found the optimal trim line for the best fit and curve matching with the bodywork.

I've trimmed the outer moulding so that it overlaps the hole by about 6mm all round.
It's important that it's touching the rim all round too.
These are the two mouldings cut from the exact same area of the dome. Two identical rings will be cut from these and stuck together with thin double sided tape.
Here's one of them.
Here's the double thickness ring sitting flush in the reveal. I found it easier to cut it into numbered sections and fix each one to the outer cover with double sided tape. I keyed the whole area around the inside face with my powerfile. I covered the inside face with masking tape as a mould release as I wasn't sure if the fibreglass resin would bond to the ABS moulding making it impossible to remove when the resin had cured. It didn't stick so I didn't bother with the tape on the other side.
I cut the CSM (Chopped Strand Matting) a little oversize then in half, staggering the cuts at each layer. Smaller pieces are it easier to apply - especially one-handed.
Six layers of matting and resin for starters should make about three millimetres thickness - plenty strong enough for the job. I can always build up more layers later if necessary.
Here it is from the outside with all the moulding parts removed. Don't forget the body is upside down and we're looking up at the headlamp hole. There's plenty of waste for trimming but this'll have to wait until it's right-way-up again. The little masking tape number tabs are still on the the surface but they'll come off easily enough.
One of the reasons you rarely see sharp edges on glassfibre cars is that it's quite difficult to achieve - especially back in the pioneering days of glassfibre in the early 60's. Brushing the first gel-coat resin layer into a sharp corner is easy enough but trying to get matting and resin to lay tightly in that corner and bond completely to the gel-coat is not so easy. Voids often form where the matting doesn't fill the corner completely leaving a void and a thin gel-coat edge that can later get damaged and break away exposing the void. There are two channels with sharp edges running the length of the Berkeley floor pan - I guess to reinforce the large flat panel. Along the channels edges are several such damaged areas. They're easy to fix. I just grind away any loose or thin gel-coat with my Dremel.........
..... and fill the void with filler to be rubbed down flush later.. It's a bit anal - underneath the car, never to be seen by anyone, but I know it's there and it's one of the many things that bug me.
Time to refit the lower half of the front air vent. I first bonded it in place with a few dobs of Fibrefil on the edges then laid-up several GRP layers in the corners. Remember, we're still upside down here so this job is much easier.

The first spread of filler. I'm using-up the last of an old tub so it's a bit stodgy. Still OK though. I've ground away around the front and inside joint line about 3mm deep and filled the joint with Fibrefill.

If you're after fast removal and shaping of filler on a curved surface here's the tool for the job. I've used a short length of 75mm aluminium tube and glued some good quality 24-grit abrasive cloth to it with our fantastic Medium Duty Aerosol Adhesive.
Part number #ADHAEROMD
It works brilliantly. But beware - 24 grit abrasive is very aggressive and removes a lot of material very fast. I used it here in combination with a flat sander with 60 grit abrasive. Try to buy good quality abrasive sheets - the cheap stuff doesn't last long.
Many years ago, my old mate Roger, who, along with his magic filler-spreader, painted many of our P4's, gave my an invaluable tip for forming smooth flowing curves with filler. 'Close your eyes and trust your hand', was his mantra. Try it yourself. Caressing a curve with the flat of your hand will give you a much better idea of highs and lows than your eyes ever will.
This coarse rasp will get into sharper corners.
Time to apply some primer. At this stage, it's not necessary to rub down through the grades to get a perfect, paintable finish. The purpose of filler primers is to seal the surface, fill small scratches and provide a uniform colour that you can rub down to indicate highs, lows and surface imperfections.
CBS sell several aerosol primers for all materials. For the small patches that I'm repairing and modifying on this little car it's not worth firing up the compressor and mixing paint, so I'm demonstrating three of these aerosols on separate areas of this front panel. All details and specifications on these products and more can be found in our catalogue or online.
On the left is (grey) POR15 Self-Etch Primer - Part No: ETCHAERO @ £18 + vat.
Centre is (beige) E-TECH Filler Primer - Part No: FILPRIME @ £4.50 + vat.
Right is (yellow) AUTOTEK Filler Primer - Part No: FILPRI @ £4.50 + vat.
They're all excellent products but I'm choosing to go with the Beige E-TECH on this job - just because it's a fair match for the existing primer.
For visual confirmation of surface highs and lows I use a Foam sanding block like this 60 grit one here. You can squeeze it to match concave curves and remove the paint from the highs, leaving paint in the lows.
For final filling of minor imperfections up to 1mm deep I use this one-part 'Stopper'. It's almost liquid in consistency and I use old plastic business cards to spread it. I'll rub it down with 240 or 400 grit Wet and Dry on the palm of my hand.
I've filled and levelled the underside of the bonnet reveal so, looking from the top, you'll see a consistent 8mm thick edge all around.
Here's one corner finished and primed.
Time to enter the wonderful world of 'Choppies' - mid-way between 'Fibrefill' and 'Mat & Resin'. A 2 Kg bag of 8mm 'choppies' will set you back just a few pounds and will mix into resin to form a coarse GRP paste which is perfect for ........

...... reinforcing the inside returns of the front wheel arches. The add-on wheel arches were originally designed for a Mk1 Escort and are pretty good in strength and shape - except for the edges, where there are a few small cracks. I ground out the worst cracks on the inside and built up the edge thickness with the choppie resin. It's quite easy to apply and spread evenly with gloved fingers.

I left an overlap of a five or six millimetres to dress back later. You can see here that the width of the original return wanders a few mm around the arch. When I have the new, choppie reinforcement layer rubbed down to a consistent width all round the arch, I'll fill the original arch out to meet it with Fibrefil. On the right is the finished return.
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