Building a GD427 Cobra Replica

The hand brake of an XJS convertible I found on eBay arrived. Man, it does pay off to buy things in the US these days! For $45,- including transport to the Netherlands, which translates into roughly € 30,- for a used hand brake.

For reference, when you buy this thing at a Jaguar Parts supplier it’ll cost you something like € 130,- (not sure if that would be a new or a used one though) The return-spring and some spacers were not included, so I had to order those separately.

Cleaning the parts and re-assembling was a quick satisfying after dinner job. Like Andy, I too like the clean looks without the plastic handle, perhaps a pressed on piece of stainless steel instead of the plastic?

Having all the parts but one, i did a trial assembly of the differential, brake discs and handbrake calipers. This is relatively straightforward, except for the lower bolt of the brake calipers, which is hard to reach.

The n/s handbrake retraction fork seems a bit too long? Might just be the trial assembly, i’ll figure that out later.

One brake pad location was a bit smaller, making it necessary to shave a tiny bit of the pad. Scraping of the greenish paint turned out to be enough.

Having all the parts in place i tried to determine the necessary shimming to get the brake discs into the midlle of the caliper. It’s not quite clear where you should measure these. There are 4 places on the inside of the caliper which seem to be machined though, so i took those.

Being used to metric it means a little bit of converting back and forth but in the end it looks like i need one shim of ’10 thou’and one of ’20 thou’, o/s and n/s respectively. I’ll just order a bunch and see if on finaly assembly these numbers are still the same.

The ring top-leftish in the picture is a placeholder for the one part missing here, a hinge pin for the handbrake. I think it got somehow lost in the galvanizing sink.

After disassembly i turned the diff on its head and tried to determine the shimming for the diff bracket. Without the actual shims available that seemed to be impossible to do. The GD brackets are drilled to “fit original jaguar shimming” whatever that may be. It seems to imply there is ‘one correct shimming arrangement’here? Would that then directly set toe-in and toe-out properly? Need to read up on that I suppose.

So, there’s a little puzzle ahead on that. I’m not quite sure what the proper shimming order should be to a.) get toe-in/out and other measurements within specs and b.) minimize the number of times i have to lift up the diff (or any other suspension part for that matter).

1. shims behind the brake discs so they’re in the middle of the caliper;
2. shims behind the diff bracket so the GD brackets fit properly;
3. shims behind the drive axle so the camber is within specs.

Sounds about right?

Got my parts back from galvanising today. What a difference a little shine makes! Most of the items were from the donor handbrake calipers, which were in pretty bad shape when i got them.

Using the rivnut tool i bought a while ago, the little covers were repaired with a new rivnut and although i still am missing a bolt and some locking thingies, assembling the caliper was pretty rewarding.

I’m not sure about the inside, the clip i have seems different than what i can find in my manuals. Also the spring on the right seems to be in the middle of the path were the missing bolt should go to hold the covers.

The other caliper should not be a problem.

The galvanising was sort of an experiment; i found a company nearby which asks a flat rate for any ‘box full of metal parts’. They galvanise with blue and yellow finish (blue-ish and yellow-ish i guess). I asked what the limit was for the parts, but they didn’t give me one, so perhaps i should bring the whole set of suspension parts too?

Unable to set a good time-slot apart for the treatment of the donor parts, it needs like a 6 hours slot for all the painting and cleaning, but eager to do something, i started to do some chores on the chassis.

I started with putting all nuts and bolts from the chassis kit loosely in place. This is to see if i got them all, but also thinking that their destination is probably the best place to keep them instead of in a drawer somewhere.

Next up was getting some (more?) wax into the inside of the chassis. Finding a small enough applicator which would also fit the venturi attached to the compressor turned out impossible, so one throwaway aerosol it is then. An easy 15 minute job with nothing to show for. I needed some more…

Still somewhat hindered by the thought of not doing things in order for the build I instead created a storage place for the bottom plates of the car-lift.

While a useful end result, I realised I was just making up excuses and needed a ‘real job’, so, I decided to do the front-brake-pipe run. Here’s the end result:

Gave me good pair of sore thumbs. I can’t attach the p-clips to the chassis yet, as i want to use the same rivets as GD has been using, but I do not have such a rivet gun yet. I feel another tool purchase coming up next week