Do you happen to know who first coined the phrase
"A right bloody game of soldiers" ?
No, me neither.
However, I can tell you what he was doing at the time. He was cutting, forming and fitting brake and clutch lines to an AK Cobra chassis.
A few things to know.
The brake lines are 3/16 inch pipe. The clutch line is 1/4 inch pipe. It means you will need flaring and bending tools suitable for both sizes. I do suggest you spend a little money here. The cheap flaring tools that are 'Silver' in colour are of limited quality. This one however did a sterling job for the 3/16 flares.
A flaring tool for the 1/4 pipe is the type that only goes DIN single and double flares of the type that is shaped like a cocktail glass. You'll need that for the 1/4 clutch pipe so be aware of the unions and joints need to be of a type that works with this type of flare.
There are flaring tools available that will form a bulb type flare but they seem to all have a three figure price tag.
The AK manual has a bit of variance to the actuality regarding the number of joints you need.
What I used:
Brake lines;
2x 3-way 3/16 connectors. (or 3x if you intend to use a pressure switch for the brake lights)
2x 3/16 male-to-male inline connectors
8x 3/16 male union connectors
8x 3/16 female union connectors
3/16 inch brake pipe
Clips etc.
Optional inline pressure switch which activates the brake lights.
Clutch line;
1/4 inch clutch pipe
2x male-to-male inline connector 1/4 (for the clutch pipe up to the master cylinder, and one for the clutch pipe to flexi hose connection on slave cylinder)
Master cylinder adapter: 3/8" male to 7/16" male (1/4" hole). This screws into the clutch master cylinder and enables connection to the 1/4" pipe.
4x 1/4" female unions.
The end of the clutch pipe that connects to the flexi hose could be terminated with a male or female type. I used a female type so it connects to the male-to-male inline connector.
The clutch pipe is the middle one of the three 'tails' you see in the photos in the manual and in the video tour. Terminate the clutch pipe around the beginning of the cut out in the nearside inner chassis rail. This will have a flexi hose to connect to the clutch slave cylinder.
I started with the front offside connection. It is but a short length. In fact with both ends on only just long enough to use the flare tool. To get the tight bend I used a pair of hand held pipe benders that were useful when navigating the tight internal corners within the chassis tubes.
The 3-way union is then placed on the pipe and the hole for drilling marked.
The resulting fitting sits a little way off the chassis rail so the gap is filled with spacers.
I used small plastic clips which are neater and IVA compliant. Just drill a slightly undersized hole so it is a nice tight fit (giggety).
The long run from the rear 3-way to the front is pinned at a line that will allow room for the return fuel hose and clips to run just above it.
Take note of where to bring the pipe up onto the top surface. The video tour in the AK members area is very useful to see where to run the pipes.
At the front where the clutch line runs alongside the brake pipe I used dual clips so I didn't have to drill more holes than necessary. I had clips that were for dual 3/16th inch but I drilled one side out to allow for the 1/4 inch clutch pipe. I have not used rivnuts for this which seem to be de rigeur elsewhere. The fuel tank is allegedly held up with bolts drilled and tapped into the chassis rails so 4mm tap'd hole with screws is easily adequate to hold these pipes in place.
The clutch pipe was a right sod. It is thicker and harder to bend. Don't use the small bending tool as the pipe comes close to kinking. Took me three attempts and therefore all of 25ft length to get it right. Other folk on their blogs seem to deal with this as easy as making a cup of tea. I found it a challenge, but satisfying when finally I had them all formed and installed the way I was happy with.
Here are the finished runs.
Note where the clutch pipe ends.
I still have my wooden cross braces on castors. They are so handy for moving the chassis around.
The slave end of the clutch pipe was terminated with a female union onto a male-to-male connector. The flexi hose made up by Merlin attaches to the other end of the male-to-male.
The slave cylinder end is terminated with a banjo bolt connector.
This pic shows the clutch slave fitted so the bleed screw is at the top. Which is fine when you are working on it now, but hard to get at later on when the body is fitted and you need to access it from underneath. You can fit it with the bleed screw facing down to make access easier from below, but be aware you may have trouble getting all the air out. Normally we want the bleed screw at the top to get all the air out
Bleeding and testing
Brakes:
I have created a temporary mount for the pedal box and brake master cylinder.
With this rig I can test the master cylinder as well.
Bleeding the lines is quite laborious and requires a fair amount of brake fluid. After bleeding all four the brake pedal was still soft. To check the master cylinder I blanked of the rear outlet. I could have blanked both but after just blanking the rear the pedal was hard. Use a short piece of pipe crimped at one end.
For the master cylinder, once you get a hard pedal, hold it for several minutes. It should stay. If it sinks, the master cylinder is no good and needs new seals or replacing.
All union joints were sound, no leaks at all. So all the flares must be good.
Last thing is to blank off the master cylinder outlet pipes and crimp the temporary pipes down to the real brake pipes just to keep fluid in and dirt out. They will stay like this until ready to connect up again after the body is on.
Brake Light Switch
If using a pressure switch, attach a three way union to the back of the wheel arch cover. Connect a pipe from the master to the top, screw in the switch to the middle outlet, and when the body is fitted connect the third outlet into the pipes on the chassis.
But, don't fit it like this.
When you get the AK wiring loom, you'll find the wiring for the brake light switch is bundled with the loom leg that supplies the offside lights. The wires for the brake light switch and the fluid low light will appear on the other side, so I had to turn the switch around for the wires to connect.
So after the body is fitted and is never going to come off again, we can connect the clutch line and the two brake lines from the master cylinders.
Servo Vacuum Hose
While on the subject, there is a matter of the brake servo vacuum connections.
The servo unit will hopefully come with a plastic right angled elbow connector that pushes into a rubber grommet in the servo. This needs a hose up to the rear of the LS3 engine where we find the vacuum port (big black stub tube next to the oil pressure sensors).
Using the proper Rover 25 part (for it is a Rover 25 servo as recommended by AK) we have a 8mm diameter stub pipe that will have to connect to a 13mm diameter stub pipe on the LS3 vacuum tube.
So, inline in the hose we need a one-way valve and a reducing joiner. All this is available from Car Builder Solutions. Natch.
Plated Steel Reducer - SRED128
Non-Return valve - NRV8A
13mm ID Vacuum Hose - VACHO13
8mm ID Vaccuum Hose - VACH08
Make sure the Non-Return valve has the arrow pointing towards the engine, you want to be able to suck from the engine side.
The 8mm hose I have has no markings. I think the nice IVA man will want to know it is kosher and not a piece of garden hose so keep the receipt and any off cuts that does have a marking.
