Building our AC Cobra 289 LeMan

We had a few small jobs to get done to finish of the rolling chassis.

Change the Rear Axle shims

We realised once we got the wheels on the chassis, that there was too much play in the rear wheel baring. After removing the wheels to measure the end float we discovered the original shims we put in when building the axle back in February (read here) were 0.009 ” too big. So we striped the rear hubs to replace the shim, giving a final end float between 0.001- 0.003

Prop shaft safety loop installed

I’d received the prop shaft safety hoop from Gerry so we thought we’d fit that. It comes in two parts. The support bracket bolts to the chassis with 2 bolts, then four holes need to be marked up and drilled so the hoop can then be bolted to the support bracket.

Rear brake pads

We had the rear pads to put in. This is a fairly simple job. We painted a layer of copper grease on the rear side, this to prevent brake squeal. Then took the retaining pins out to slide the pads into the rear calipers and then secure again with the retaining pins.

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This one was just a small job, but following on from installing the brake lines and our post on 4th June, we decided to upgrade the plastic P clips we used to hold the brake pipe in place with better quality stainless steel, rubber insulated P clips. We also used new rubber sealer washers underneath the clips to properly seal the strew holes and prevent any water getting inside the chassis in the future and causing damage. Less importantly, as you won’t see them when the body is back on the car, but aesthetically the clips also now match the style of the P clips used on the near side for the fuel pipe.

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We put in the handbrake lever and prop shaft. These were quite easy to install. We had to source the bolts for the prop shaft, which we got from a Landrover dealer Mark knows, and are from a Landrover Defender. Next we’ll have to fit the prop shaft safety loop.

The handbrake was installed using counter sunk bolts then we connected the handbrake cable to the hand brake lever. We’ll leave the adjustment until later.

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We decided to get on with installing the brake pipes. We ordered the brake pipe kit from Gerry with the Hawk kit containing all of the pipe and fittings. The build manual shows the rough route for the pipes.

Running the pipe in

First thing was to run the pipe down the offside of the chassis. We fitted rubber grommets into the ready made holes in the outrigger and piercing holes through them as we ran the pipe through. We then carefully measured the postions for the P-clips to hold the pipe, 7.5 inches apart. We then drilled the holes and used galvanised self tapping screws to secure them. P-clips are provided in the kit to suit the 3/16” pipe. We actually found there wasn’t quite enough in the pack, so we had run around town looking for a place that sold them in this size. In the end Halfords had some.

Connecting the rear calipers

Then we had to connect the pipe to the rear calipers, running the pipe carefully into place. This took a little time and was a bit of a fiddle, connecting and then disconnecting again to get the bends in the pipe just right. We bent the pipe carefully using our hands, ensuring that the pipes didn’t get kinked, but once we had the rough shape we used a vice to get the bends really neat and tidy. We also used a flaring tool to flare the end of the pipe that fit inside the brake pipe unions.

Connecting up the front calipers

Next was to run the front brake lines in. We started by fitting the front 4 way adaptor. This is held on by the small threaded bar that comes welded to the chassis. There is one on both sides of the chassis depending on it being a RHD or LHD car. The offside one is used for RHD cars. We secured it in place with a M6 nut. We then put the flexi hoses in, connecting the front calipers to the 4 way adaptor via a short piece of brake pipe (flaring both ends). The offside was quite easy to connect BUT running the brake pipe around to the nearside proved to be a bit more difficult as the engine was in the way. So we jacked the chassis up onto axel stands to gain access to the front cross member from underneath. In hindsight, this would have been easier to do before the engine was installed, but nevertheless we got there eventually. We actually used the same holes to mount the clutch pipe brackets at the same time making the final job very neat and tidy.

We won’t be able to connect the whole system up yet until the body is back on and the master cylinders pedal box are installed but we have done most of the work now.
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Unfortunately we haven’t spent much time on the build in recent weeks due to holidays, Marks university work and other things taking priority. We have spent some time ordering lots of new parts though and Mark has done a few bits and bobs. We are planning to get more build time over the summer and make some really solid progress.
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Here’s a little update from recent weeks.
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Firstly, we have now replaced the old rusty bottom ccntre bolts through the base of the differential with the shiney new ones we were waiting to arrive.
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Having built up the rear calipers back in April, Mark has now also installed them onto the rear axle again. Attaching with 2 bolts and then lock wiring them in place. Then connecting the handbrake cable to the handbrake calipers. Other than a bit of tinkering, thats the back axle complete. Even though it has been a bit of hassle and time getting all the parts together, it has been a great learning curve, and we are now really pleased with the way it has turned out.

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The rear calipers arrived back all zinc plated and all shiny. They have done a great job. Mark spent some of Saturday building them with his new apprentice, little Phoebe (showing off her new spanner skills)! First picture show the original condition, coming off the donor axle, then the next stage after sand blasting and cleaning and then following on the pics show the stages of re-assembly after zinc plating. Now they’re ready to be refitted to the back axle which we’ll do the next weekend we get free to work on the car.

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The front brake calipers have arrived. Originally, Me and Jon talked about which front brake to go for and after a conversation with Gerry at Hawks, we decided that the standard MGB brake may not be man enough considering the spec for the rest of the car. As we have gone for the Jaguar rear axle (where the brakes are very good) and also using a Ford 302 V8 engine (producing about 340 bhp), using the standard MGB front brakes would mean a chance that the back end could lock up as the front brakes would be less powerful than the jaguar rear brake. So Gerry gave us 2 options:

1. to up grade with Austin Princess front brake calipers or

2. to upgrade to more expensive 4 pot aluminium calipers, which Hawk could supply. He also suggested that if put together with an in line servo would balance out well with the rear jaguar brakes.

We decided to go for the aluminium calipers, and i am glad we did. I have to take my hat off to Gerry the quality of them is very good as you can see from the pictures.

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