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G15 brakes+


Exploded view front brakesG15 Technical Guide - brakes

Early cars (up to chassis 298) should have standard Spitfire discs. Later cars used the same discs turned down to a diameter of 223mm to clear the calipers.

Up to chassis number 298, Girling calipers as used on the Mk 1 and 2 Spitfire, Herald 1200 and Vitesse 1600 were fitted.  Later cars used Avenger (all models and no other car) calipers, which have a larger bore and piston.

Some Girling Type 14 calipers have different lug thicknesses -- eg. 14L MK2 needs to have the dust shield removed in order to centralise them on the disc.

The rear brakes have always been standard Imp.  The handbrake cables appear to be standard Imp but 10" shorter.

For cars up to chassis number 297 the master cylinder bore is 0.625" from the standard Imp, the same as the clutch. For cars after chassis number 297 the cylinder bore is 0.7". In general, go for the 0.7" cylinder.

The pedal box on early cars (number not known) was a modified Imp box with extensions welded onto the driver's end of the box supporting a second, Ginetta made, pivot. The pedals were cut off and welded to sleeves turning on this new pivot and operating the cylinders via four flat pushrods. This has the effect of moving the brake and clutch pedals closer to the driver. Several dimensional variations from car to car exist so check your car before starting work. The body moulding for the pedal box changed on later cars so the standard Imp box could be used.

Useful part numbers

Master cylinder seal kit 0.625" SP1963
Master cylinder seal kit 0.7" SP2076
Wheel cylinder seal kit SP2027

Solid brake pipe schematic (opens in new window).

G15 Technical Guide - suspension

Triumph Spitfire with Ginetta shock absorbers. 1.9" springs approx. 100lbs. Period replacement Spax shock absorbers are generally useless. There were two heights of turret during production and Spax listed them the wrong way round. Springs weakened and curved, rubbing against the shock absorber.

Exploded view of front suspension (pdf file)

Current solution: Fit Protec shocks (cheaper from Ginetta Heritage than direct from Protec) and 2.25" 120lb 8" springs. This clears the angle drive. 140lb springs used for race. For bushes use standard Spitfire wishbone bushes or Superflex.

Anti roll bar

Ginetta special — see drawings (pdf file)

Morris Minor end bushes.  Centre bushes are special.

front suspension

Imp rear shocks. 3" 350lb springs which bent and weakened with use. 11" long. Originally had wooden packing spacers underneath. If the top mounts are round you can fit some 450lb standard Imp springs which are bigger diameter. For racing use 550lb 8.5" Monte Carlo springs. Protec adjustable rear shocks are recommended.

Exploded view of rear suspension (pdf file)

G15 Technical Guide - steering

Standard Spitfire rack — early ones and some Herald ones are 'quicker' than late ones. With wider wheels a 'lock stop' may be needed on each side to limit range or wheels may rub on body — MOT failure. Jubilee clips work.

The column is shortened Imp with an alloy bottom bush by Ginetta. Use the felt top bush rather than the plastic one. From Speedy Spares, Shoreham.

Relieve the UJs on the lower steering shaft so that they don't foul at extreme angles.


Fit the UJs at 90° to each other.

Achieve as straight a steering column run as possible by loosening the upper column and pulling the steering wheel slightly towards the driver.

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