Thursday, 7 March 2019

Pedal Box, Brake and Clutch master cylinders

Fitting the pedal box itself was fairly straight forward. All the fixing holes lined up perfectly so with the help of an assistant it was bolted in place in no time at all. Strange thing is that I now seem to have someone claiming that they have built the car...........
















One thing that needed to be thought about was how the brake lights would be operated. The two options are a hydraulic switch fitted somewhere along the brake pipes or a push switch operated by the brake pedal. As my brake lines were all fitted I chose the push switch on the brake pedal.However, the pedal box has no provision for this so a simple bracket was needed to mount it.

So, checking to see how far the brake pedal came back I fashioned a bracket to suit. Fortunately, the switch has a long mounting shaft with two nuts on it so the depth at which it sits in the bracket can be adjusted to suit. (An oversight here meant the whole pedal box had to come out again later....!!)


Brake light switch and bracket.













The bracket was bolted to the pedal box from the back of the box using countersunk screws and all appeared good.














Then the pedal box was fitted to the bulkhead and I could now fit the brake master cylinder and servo and the clutch master cylinder.

Brakes are pretty important...!! So I decided that I wanted to fit new items. So I found a brand new brake master cylinder and servo combo that fits a Rover 200/25/MG ZR. Well, it may do, but it doesn't fit an AK Cobra. The servo and master cylinder combo are too long to fit between the foot well and the offside front wheel arch. So that's for eBay and after some searching I have now got the correct combo comprising a used servo and new master cylinder fitted to the bulkhead and pedal box. (Lesson learnt: not all Rover 25 brake master cylinders are the same......)


Servo and Master Cylinders fitted














I have fitted flexi hoses to the master cylinders to connect up with the brake pipes running along the chassis rail. It took a little while to identify the thread in the brake master cylinder outlets but eventually identified them as  metric M12x1 (3/8 UNF in the Clutch M/C)

Fitting the brake M/C and servo gave rise to the oversight mentioned earlier. The extent to which the brake pedal returns is not determined (of course......doh...!!) by the pedal box but by the length of the brake M/C push rod. So my nicely made brake light switch bracket, even with the adjustment available in the brake light switch, resulted in a 5mm gap between the pedal and the switch meaning that the brake lights would always be on. No good. So to remove the bracket I had to remove the pedal box and to remove the pedal box I had to remove the brake and clutch M/C and servo. (I should have brought some of that 'right first time' culture back from work with me.........!!) Anyway, cylinders and servo removed, assistant recalled, pedal box out, and we're back to square one.

So, rather than make a new bracket, I decided to make a small modification to the brake pedal. At the point where the brake pedal makes contact with the brake light switch I drilled and tapped a hole to accept an M4 Pan head screw. This now makes contact with the brake light switch when the brake pedal is released and provides for further adjustment if ever needed in the future.

So, the very first bit of the Cobra is now working......!!  It's only a brake light switch but it's now fitted and adjusted so that contact is made (and the brake lights will switch on) with the smallest of pressure on the brake pedal.


Pedal Box in place.



There will be a few things to do around here yet. The steering column bush needs to go in and the throttle cable needs to be fitted to the right of the pedal box, plus the wiring to the brake light switch. It's a tight squeeze down there and I hope none of this will have to come out again anytime soon. (is that tempting fate..................??!!)




















Fitting the body

I was a bit worried about refitting the body and aligning it. I had made and fitted a non standard heater box and although I took loads of m...