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.