Fabrication Fun

 

So back with another update and this one has been a real pain in the arse to be fair. I have deviated slightly from the advised manual in regards to the rear bulkhead. I have replaced the rear bulkhead with a sheet of 2mm steel as opposed to the advised marine plywood. Plywood has no place in a car of this nature in my opinion, it’s not durable it will be prone to moister and structurally will not hold up well if the unfortunate happens. Because I’m deviating slightly from the manual, it creates further problems that need to be sorted, but I’ll get to that later on. The bulkhead panel was made in the same fashion as the front, with tedious amounts of trimming and trial fitting on a sheet of hardboard, before I could be confident with the cut of the steel. The steel I got was a tad too short, so I will have to make a couple of filler panels for the bottom outer corners. It has however left a nice little gap currently that will probably be utilised for the brake line runs along the outer chassis rail and the fuel line also, so not all bad. 

When I was happy with the shape/fit I then welded on the two plates (after measuring and marking) that take the rear radius arm brackets. These I welded to the bulkhead rear face however I had to make some spacers from off cut steel as the bracket mounts sit lower than the bottom of the bulkhead sheet steel and they need to sit flush with the lower face of the chassis outriggers.A bridging piece was needed so they will pull square on and I had plenty of bits of 2mm steel so these were quickly cut and welded on to the lower half of the plates. 

This whole process of constant fitting, removing, trimming and fitting again is a real pain in the arse. It’s vital for a good fit and all part of the process but it’s a frigging chew on and starting to piss me off a bit now, I’ll be glad when Im past this stage and onto more enjoyable tasks.

The rear bulkhead was fitted back into position (again) and this time I was now able to drill a couple of holes into the rear chassis outriggers and fix the bulkhead with some sturdy bolts, in preparation for the holes for the radius arm brackets. With all these fixings on the lower edge, and with the planned tubular support brackets that will be fitted to the boot side of the top bulkhead this will create a nice strong structure for the seat belt mounts also hopefully, further on in the build…. Stronger than plywood that’s for sure. The edges of the bulkhead will be bonded with some PU sealant which won’t be seen either as the interior trim will be covering it all and the boot trim from the other side also. 

Next I was then able to measure and fit the radius arm brackets, but because I’ve deviated from the build manual slightly I needed to be confident in my measurements and allow the angles of the radius arms to do their job. 

I used a ratchet strap fixed to the front end of the chassis and round the rear vertical link that allowed me to get the vertical link into a better position for alignment of the support arm and bracket position. The radius arms are a posh adjustable unit as fitted to higher performance spitfires and GT6 they will also allow a huge amount of adjustment for the tracking of the rear wheels when finally fitted without the need for shimming etc…

I then drilled the two holes and fitted the bracket and adjust the arm to somewhat how it needs to be. It needs to obviously have clearance for a full swing within the travel of the suspension and then it can be locked off with the two bolts to stop it adjusting itself under tension and movement. This was very satisfying to finally get some bits back to how they should be the same as when they left the original Spitfire many many months ago. 

Next on the list was to build the rear brake drums up. I had order all the parts a week or so back it was relatively straightforward fitting them and very enjoyable to see the handbrake bracket working effectively when the drum was fitted. It safe to say the handbrake efficiency will be far superior to the Cobra when I built that. I still need to make all the brake pipes and rear flexible pipes but I’ll save that for another update later on. The rear brake cylinders and lower adjusters are all new obviously, it would have been stupidity to reuse the original units but it was very straightforward fitting them all and reminded me very much of working on my first mini back in the day, very simple mechanics, relatively effective and simple to maintain… awesome!

I have noticed also that at least three of the rear wheel studs are a tad sketchy in regards to the thread condition. I’m intending to fit knock on wire wheels for the final wheel, and have seen how some people have changed the wheel studs to Land Rover units for a better thread diameter and all round stronger stud. I’ll have to do some research as to exactly what and how people are using this upgrade and if it will interfere with my hub adapters for the knock on wheels, so some homework for me there. And then I’ll have to take all these brake bits off again no doubt to fit the new studs. 

I have to still fit the rear handbrake cable. It fits to the upper fulcrum pin you can see pictured here, however I have some repair work to do first. The cable had a spring fitted that fixes to a little bracket just below his pivot arm, but mine have worn through and have no hole anymore for the spring to fit. I have made some replacement brackets that I have welded onto the backplate of the rear drum and these should be good enough to fit the spring too. The spring is needed to fully disengage the rear brake shoe from the drum when it’s taken off as you don’t want the brake shoe to drag on the drum as this will obviously create drag but also excessive wear on the pad itself. So with all these bits done it was on with the brake drum and jobs a goodun…. Until it all comes off again. Haha

The rear handbrake cable was made up again with all its fittings and clevis pins and was fitted back through its support guides. I need to purchase the main pivot compensator as I stupidly left mine on the old body tub when that went the distance. I will also need to find a scrap body to take a prop shaft tunnel cut from, as this is not going to be easy to fabric from scratch so I think I’ll opt for the easy route on this one. I did initially plan on having the handbrake external to the already tight cockpit area, but I think with the seat fitting position it will make any linkage setup nye on impossible to work…. We shall see mind. It would be pretty cool to have one external like on a vintage Bentley or Rolls Royce. 

 I have a fair bit of tinkering to do still with all these bits, but the bulk of the hard graft is pretty complete now. One step closer to final body fit I suppose… the thought of having to remove the body again now is not very exciting, however it’s a needs must in order to progress. I can start focusing on the front bulkhead again now and more so the pedal box setup and fitting. This is going to be interesting to say the least as the space is tight and narrow, but we’ll see what we can accomplish soon.