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Last year was the first full year of using my Tornado GT40 on the road and on the track, the car was built in 1995 and has now covered some 16,000 miles many of which have been on circuits around Britain and France such as Castle Combe, Silverstone, Oulton Park, Val de Vienne etc.
This year we are again going to La Mans in June and hopefully Spa and the Nurburgring later in the year plus various action days and rallies etc. in this country.
The cars brakes are adequate for normal road use and will stand up to several laps on race circuits before starting to fade and getting very hot, after all the Granada brakes were originally intended for fairly light use compared to the hammering they take on a GT40.
Some months ago I decided to try and improve things somewhat by fitting larger disc brakes and calipers. After visiting the racing car show at the NEC and contacting several manufacturers of braking systems including AP Racing, Brembo, Alcon and Willwood I decided to go for the latter mainly because they were slightly cheaper than the others and also more importantly seemed easier to fit.
About 7 weeks ago I went to Rally & Marine Design in Faversham, Kent who are the sole import agents for the American braking systems. I received a warm welcome upon arrival and was shown around their premises which although fairly small are packed with parts of all descriptions for most makes of car both European, American and Far East models.
As far as I am aware, Rally and Marine Design is the only manufacturer who actually produces two kits for GT40 models and has them in stock at all times. Dave who runs the place is an ex Ford development engineer who did his apprenticeship with them, so he knows what he is talking about which is quite reassuring.
The kit parts I picked up are stock items> The front kit is BK32 which contains the 32mm thick x 320mm diameter vented and curved vaned discs, top hats, Superlight IIA 4 pot racing calipers, mounting brackets, Ferodo 3466 hard pads and all the nuts and bolts to assemble the items on the car. The fitting is extremely easy and could easily be completed in 3 hours as there is no machining or manufacturing of brackets required.
One point I should make is that if you have 15in wheels then you will have to remove the stick on weights from the inner rim if you have this type and get the wheels rebalanced using knock on weights as the wheel to caliper clearance is only some 4mm.
The rear kit is part number BK32A which again contains discs of 320mm x 25mm thickness these are plain vented discs, 4 pot Dynalite calipers, Ferodo 3466 hard pads, top hats, mounting brackets, nuts and bolts.
The rear kit is a little more difficult to fit as the rear uprights will need modifying, this involves removing the packing piece which is welded to the upright in order to line the Granada caliper up with the disc, this is not required new brakes. It took me some 30 minutes per side to make the modification. The top hat will also require machining as the inner small lip on the casting will need removing to fit the Ford hubs.
The hand brake was the last item requiring attention as the cables were left hanging with nowhere to go. I therefore purchased from Rally & Marine Design two spot mechanical calipers (LH & RH) which could be used without modification to take the Granada hand brake cables. The main difficulty was to mount the caliper as there seemed no easy way to fit them and use the original cables.
The answer was to get Ken Saunders to make me two steel brackets to suit the calipers and also fit onto the raking uprights, after two attempts at making cardboard templates I arrived at a suitable design and gave it to Ken who set about making the brackets which were a little complicated due to the location they had to be bolted to. The brackets I hasten to add fitted without any modification at all. After removing the hub assembly and drive shaft to give access to the upright, I drilled the upright to take the brackets and bolted them to the upright using M6 bolts and nylock nuts. I then refitted the discs, hubs, calipers and drive shafts.
Once the brakes were bled I decided to try the car out on the road and bed the brakes in. All seemed well except for the pads rattling and a lot of pedal travel.
I pulled into my drive and applied the hand brake which worked fine. I opened the garage doors, jumped back into the car, released the hand brake, selected first gear but nothing happened. The car refused to move.
After opening the rear body section up I realised that the hand brake leavers would require coil springs to assist in the release of the hand brake calipers as they werejemmed on.
I duly purchased a set of springs from Halfords at a cost of £4.49 and fitted them, all now seems well. The chattering pads however had me puzzled and after some 4 - 5 hours of tinkering I still had the same problem even after bleeding the brakes again and making various adjustments. I then decided to contact Dave at Rally & Marine Design to ask if he had come across this problem before. He was very helpful and asked if I checked the brake line residual pressure which when the brake pedal is released should be no less than 21bs. Upon checking I found I had no residue pressure at all and this was allowing the brake caliper pistons to retract too far thus allowing the pads to move.
The answer lay in two small valves which have to be installed in the brake line as near as possible to the master cylinder. They have the affect of releasing the hydraulic pressure back to the master cylinder when the brake pedal is released except for the last 21bs which keeps the pad virtually in contact with the disc at all times and prevents the pad from moving and rattling.
Apparently all GT40s should have these valves fitted because the master cylinder is virtually at the same height as the calipers which allows the fluid to drain back. In most production road cars the cylinder is mounted at as high a location as room dictates.
You may be thinking of fitting an improved braking system so I've listed below the likely cost of the modifications which are trade prices but are available to club members if you ask.
Above is a drawing of the rear caliper mounting bracket I required which may vary from car to car, however specials can be manufactured if required by Rally & Marine Design and this is included in the above prices.
If you want more details ring either myself or Dave at Rally & Marine Design on 01795 531871.
Mike Osborne
158a Eden Vale Road
Westbury
Wiltshire BA13 3QG
Great Britain
Tel: 01373 827331
email: 106256.2270@compuserve.com
email to sundt@pncl.co.uk
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