It was never called a Mark 1 when new. It was the 2.4 Litre, announced 28 September 1955, and the 3.4 Litre of 26 February 1957; the name is retrospective, applied once the Mark 2 arrived. It is also the first Jaguar with unitary construction. Underneath: double wishbones, coil springs, telescopic dampers and an anti-roll bar at the front, all on a separate subframe with rubber bushes; and at the rear a live axle on inverted semi-elliptic springs cantilevered into the body frame, located transversely by a Panhard rod. The rear track is about four and a half inches narrower than the front.
Now the brakes, because this is the fact people get wrong. The Mark 1 launched on 11.125-inch drums. From the end of 1957 four-wheel discs became an option — an option, not standard equipment. So a Mark 1 may be either, and you cannot tell from the year alone. Worse, it is not only a brake question: the rear track differs between them. Drum cars 4ft 2⅛in; discs with steel wheels 4ft 2⅝in; discs with wire wheels 4ft 2⅞in. Ask for the chassis number, and a photograph behind the wheel if you can get one. Two other notes: the 3.4 has a larger front grille and a stronger rear axle than the 2.4, and a Borg-Warner three-speed automatic joined the Moss manual and the overdrive option from September 1957. 37,397 built — 19,992 of the 2.4 and 17,405 of the 3.4.
Jaguar Mk1 — specification & changes within the model
- Brakes — drums or discs, and you must ask
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11.125in drums at launch. Four-wheel discs an OPTION from the end of 1957. Not standard, and not tied to a clean date. “All Mark 1s have drums” is wrong.
- And the rear track changes with them
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Drum brakes: 4ft 2⅛in. Discs with steel wheels: 4ft 2⅝in. Discs with wire wheels: 4ft 2⅞in. Figures from the factory manual. The brake choice is an axle question as well as a brake question.
- Suspension
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Front: double wishbones, coil springs, telescopic dampers, anti-roll bar, on a separate subframe with rubber bushes. Rear: live axle on inverted semi-elliptic springs cantilevered into the body frame, with a Panhard rod.
- Engines
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2,483cc XK six (83 × 76.5mm), 112bhp net at launch · 3,442cc XK six (83 × 106mm), 210bhp gross. The 3.4 also has a larger front grille and a stronger rear axle.
- Chassis numbers
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2.4: RHD 900001–916250, LHD 940001–943742. 3.4: RHD 970001–978946, LHD 985001–993460. Engine prefixes BB/BC/BE (2.4) and KE/KF (3.4); body prefixes H and E.
- Transmissions
- Four-speed Moss manual, no synchromesh on first; manual with overdrive; Borg-Warner three-speed automatic from September 1957.
- Where they rust — and it is usually a seal
- Front and rear screen seals and all door seals let water in, which rots carpets, veneer, leather and headlining. Rust traps: front chassis legs, A-posts, sills, the Panhard rod mounting in the offside rear wheel arch, rear spring hangers, floorpans, boot lid and door lower lips.
- Not claimed
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Whether Mark 1 and Mark 2 windscreen glass or glazing rubbers interchange. The Mark 2 screen is documented as wider with slimmer pillars, which strongly implies not — but no source states it directly and we found no part-number cross-reference. Also earth polarity, and the exact date or chassis number at which discs became available.
