Footloose Fabrication

 

Wow aren’t you all lucky to get another update so soon after the last one. This time I have moved onto the pedal box setup and associated fixings, I have made some modifications and deviated again away from the original and build manual. 

First task was the clutch master cylinder and fixing brackets. The clutch pedal and holding bracket fixes from underneath the bulkhead using the same fixings and clamp the horizontal section of the bulkhead between them. This setup is nye on identical to the original Spitfire setup so relatively easy to setup. Great time has been spent mocking and marking from the internal footwell as a want/need to give as much pedal room as possible for my size twelve feet to fit. I want to reduce the risk of hitting/catching the break when I either dip the clutch or try to accelerate. 

Whilst I had some vague markings on my bulkhead paper templates that Mick sent me months ago, I started with these as a base mark, however they have been adjusted slightly to give a good fit all round with acceptable pedal movement from inside. 

As you can see hear the clutch pedal now sits as far to the near side as possible without compromising the travel of the pedal and hopefully allowing full master cylinder movement and thus the longest travel possible on the slave and a good clutch bite as a result. I will possibly have to make some modifications to the fibreglass gearbox cover as a want to keep the clutch pedal so that it’s maximum travel is stopped from the pedal hitting the bulkhead, as opposed to clipping the gearbox cover. Whilst it doesn’t currently hit/graze the cover by the time the interior is trimmed it might rub a little. 

Next up was the same process for the brake pedal and master….. this is where I have made some changes and has been a frigging ball ache to get sorted, but I’m glad to say the hard work is done and just fettling left to do. The majority of spitfires run a single feed master cylinder, exactly the same as the clutch. The brake line is simply split through some fittings to give a feed to the front brakes  and a second feed back to the rear drums.

There is nothing really wrong with the single feed brake system, but my donor Spitfire was a late vehicle which had received some revisions and general technology improvements since the early cars, in the form of a twin feed brake master with PDWA valve (Pressure Differential Warning Actuator) 

I personally feel that a master cylinder giving me primary and secondary feeds is far superior to a single pressure system, so the majority of the braking of the primary’s is fed to the fronts and a second feed to the rears that don’t get such a hard life as such. The PDWA I will come to later but the first problem I had was the depth of the brake master itself. If a single line system was fitted I could fit a master just like my clutch (pictured here) and it would fit within the area no problems, however the duel master is considerably longer so I was going to need to start making some cuts and changes to give me the clearance I needed. 

Firstly I mocked and marked my position for the pedal, as this dictates the master bracket position above it. Same process as the clutch just taking time to make sure everything was aligned correctly giving maximum clearance without compromising safety with the pedal position. Then once the pedal and bracket was in situ I needed to start marking the rear of the firewall bulkhead to make an access area for the bigger master. The cut out needs to be big enough to take the back end of the master cylinder and the fluid reservoir, along with side room for the brake pipes and unions themselves. I simply used my set square agains the bracket and made my markings accordingly on the rear of the bulkhead. 

Once I was happy enough out came the grinder and some cutting was done allowing access for the master and reservoir, however the firewall as such is no longer a firewall as it has a bloody great hole in it. I needed to make a panel that now fits into this void and seals it all off again. I started by making a cardboard template which allowed me to trim and shape it accordingly for a good fit. I had to enlarge the bulkhead hole slightly as I was using the off cut of the bulkhead steel which was 1.5/2mm steel so it was pretty thick stuff. I took my time trimming and cutting the template and then when I was happy with the overall fit I transferred the template onto the steel and starting cutting again. 

I wanted to make the new panel out of a single piece of steel, however I will admit now that I am no sheet fabricator or a welder to be fair. After a a failed attempt making from one piece and bending accordingly I had to surrender and make/cut each side separately and then weld it all together to make one piece. I would like to say this was an easy process but it wasn’t. The sheer tedious cut, measure, cut, tack weld, grind weld etc… became monotonous very quickly but I persevered and after some time I managed to get a fairly good fitting panel that I was happy with. Granted I had to smooth out some roughness with some body filler  but overall it was fairly sound and would work ok. Another detail that I’m working on was the fixings used through the whole build. When fitting the bulkhead I used stainless steel alan head bolts and I want to continue a running theme through the build. It’s attention to details like this that really make some cars stand out from the others so I want to continue trying to achieve this throughout this project also. 

I had ordered some matching imperial alan head fixings for the master cylinder brackets and also now for the new cut out panel fixed with matching head bolts. I gave the new panel a quick primer coat but don’t forget that all of this will be removed again for when the body comes off again, something which is becoming quite daunting with the amount of work going on since it’s initial fit…. Still all for the greater good. 

So now I could trial fit everything and see if this problem with the bigger brake master was sorted. Everything seemed to be ok although it will be a tad tight fitting the secondary brake line, however I should be able to make it work or possibly use a banjo fitting for piece of mind if I can’t get a tight enough bend on the brake pipe. 

Previously I mentioned the pressure differential warning actuator (PDWA) This is is a device fitted on duel brake circuit cars which splits the brake fluid feed between front and back wheels with a sliding valve and an electrical switch. This devise basically would notify you of a fault with a dash warning light if you were to loose brake fluid from either the front or the back cylinders. The valve would slide to isolate either the front or the back brakes depending where the fluid loss was coming from and the loss of pressure would activate the warning light switch. After much evening reading and researching I have decided to do away with this PDWA however I want retain the fluid level switch for safety reasons… it’s better to be notified of a fluid loss buy the float switch as opposed to pressing the brake and nothing happening. In all my years of driving I have never suffered instant and total loss of brake fluid, even in my early minis with drum brakes all round so I’m happy enough to just leave this PDWA out when I make my brake lines up. I found a brake level float switch from CarBuilderSolutions that fitted my brake reservoir perfectly so this will now act as my brake fluid warning light, if I develop a leak and start to loose fluid. This switch can also be wired into a hand break switch so duel purposes hand break and fluid level, this would also be IVA compliant as it is the same setup as on the Cobra when I built that.

Last up for this update was the accelerator pedal fitting. This was the hardest of them all simply because of its location, and I didn’t have the comfort of having a top bracket to guide its position. I located the accelerator as far to the offside as possible without restricting its travel on the chassis outrigger and allowing for cable access from above, then when I was happy enough I marked and drilled the two fixing bolt positions. This was difficult to get correct as it’s difficult to bend your spine in five different directions at once whilst holding the accelerator with one hand trying to centre punch the holes with your free other hand. All in all a tad tricky but I’m confident that the pedal positions are as good as I can get them considering the narrowness of the product itself. I treated the pedals also to some bling as such when I was down there…. It would have been rude not to, devils in the details. 

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. 

Bulkhead Ballache!

I’ve been making some progress with the front bulkhead over the past week or so. Mick had sent me some scale templates for the steel bulkhead which needed to be cut to shape and fitted to the body tub. I was concerned about going just straight for the cutting without checking all measurements and fitting first. It’s not possible to tell from the paper template how good the fit will be, and each body tub will be slightly different in terms of resin thickness. So I opted to make a scale template out of hardboard first as this would be rigid enough to mock into position and relatively quick and easy to cut. 

I started each faced section separately and simply held together with masking tape which allowed to fold for each section different angle. Then just systematically working my way through each bit, until I had a full template of exactly fitting bulkhead that could be used to mark the bent sheet steel and then cut with a little more confidence. This turned out to be a tad tedious however it was essential to get a good fit, and with hindsight was a really good idea. The paper templates were close, but I have made many many alterations to taylor fit my body. 

 Attention to detail was also needed here as to how the fitting was going to be finished. I opted for nice button headed socket caps which will be spaced equally around top section, with a panel bond on the side sections and bolted onto the lower chassis outriggers.

The bulkhead will really firm up the body flex when fitted and it will be on and off the chassis many more times before the final fit. Mick should inform people in the manual that this is a ballache of a task to complete, with many many trial fits and adjustment needed before I was anywhere near happy, and I’ll be honest it was not really a very enjoyable task….but I’ve broken its back now (and mine also) so it’s definitely all getting pushed along stage by stage. 

One problem I had potential envisaged was the ability to remove the gearbox at a later date and not being able to slide it back from the engine because of the bulkhead. So I opened the bell housing area of the bulkhead wide enough so that I can slide freely through the bulkhead which will allow access to the bell housing bolts etc… 

I spent a great deal of time cutting and trimming the steel and further time again with a flap wheel smoothing off the edges and tidying up all the cuts. I have decided that I will be painting the bulkhead for the final finish, but I still have many more cuts and holes to drill first for the clutch master cylinder, break master cylinder, pedal boxes, accelerator cable, steering column etc… etc…

Another little task to tick off was the front chassis body supports. These will also take the radiator bracket fittings which I’m hoping I will be able to weld on with access through the front nose hole. The two body brackets were manipulated into shape and trimmed accordingly then with the body removed (again) I welded them to the front chassis legs. I had some primer and texture 2k paint left over still from painting the chassis so I set about just lashing on a bit to stop it being exposed to the moisture. I also touched up a few bits of the chassis that have taken a bash during the corse of the build so far. 

Another job ticked off was to fold down the top flange of the offside chassis rail. This is to give a little more room for my feet to fit on the peddles when driving. I noticed this was done on Paul’s car when I saw it, and he said what a massive difference it makes. The build manual also suggests to fold it down to aid comfort when driving, so now was a good time to get it done, and I could also touch up the damage it made to the paint finish at the same time. 

Last task for this update was to drop the body back on the chassis, which I’m getting quite good at now on my own. I’m still miles off a final fit, but a good solid chunk of the front is now sorted. The rear bulkhead I’m using some 2mm sheet steel and I’m hoping with it not being bent, then it should be easier to fit than the front was. I’m opting for steel as I’m going to really try to beef up some solid mounting points for the seat belt harnesses. I want to get similar style harnesses as I used in the Cobra, because they are really comfortable in use and they look totally bad ass with the rotary release clip… I’m still miles of that point yet mind, but it’s all in the plan for the final product. 

The bulkhead looks great fitted with socket cap screw heads equidistant round the top sections. I haven’t secured the bottom lip yet or bonded the sides as the tub will be off and on again a good few times still. The bulkhead sits really close to the back of the engine which surprised me. It’s not a problem, but just not how I had envisaged how it was going to fit. Still plenty of room for movement under throttle if needed and now it’s fitted it opens the door for loads of other jobs I can be getting on with. 

Starting to look like a car now! Wahoo!