Jaguar Mark VII & XK 120 Factory Service Manual, Part 1 | 1945–1960

Jaguar’s English-language Part 1 factory service manual covers Mark VII and XK 120 maintenance and repair. The additional XK 140, XK 150/S, Mark VIII/IX, Borg Warner automatic-transmission, and Laycock de Normanville overdrive manuals named on the opening compilation pages are not included.

Bookmarks and Wiring-Diagram Detail

Navigation and small labels: Embedded bookmarks link to sections and many component topics; PDF text search is unavailable. Small cable numbers and wire-color keys on the checked XK 120 wiring diagrams are readable with zooming.

One printable PDF contains 457 pages, including five opening pages and four inserted wiring-diagram pages, one of which is repeated.

XK Engine, Drivetrain and Chassis Service

The selected coverage below outlines major workshop tasks. Further topics include sliding-roof drain servicing and speedometer-cable replacement.

• Engine repair: Step-by-step instructions for engine removal, dismantling and reassembly, cylinder-head service, decarbonizing and valve grinding, with valve-timing and clearance adjustments.

• Fuel and cooling: Twin S.U. carburetor overhaul, jet centering and synchronization, electric fuel-pump servicing, thermostat checks, and water-pump dismantling and reassembly.

• Clutch and gearbox: Borg & Beck clutch servicing, hydraulic clutch-cylinder repair and bleeding, gearbox dismantling, internal inspection, reassembly, and selector-cover overhaul.

• Axles and propeller shafts: Separate Salisbury and E.N.V. rear-axle procedures, differential and pinion adjustments, axle-shaft servicing, and Hardy Spicer universal-joint work.

• Steering and suspension: Burman steering-unit overhaul, linkage adjustments, torsion-bar settings, wishbone servicing, rear leaf-spring work, and shock-absorber maintenance.

• Brake systems: Mark VII Girling vacuum-servo servicing and early/later XK 120 Lockheed brake procedures, including cylinder overhaul, shoe adjustment, and hydraulic bleeding.

• Lucas electrical equipment: Ignition, charging-system and starter diagnosis, component servicing, wiper fault tracing, and XK 120 wiring diagrams with cable-color keys.

Jaguar prepared this manual for its distributors and dealers undertaking major servicing, dismantling, and reassembly.

Engine Overhaul and S.U. Tuning

The engine chapter separates complete overhaul from component work with the engine still installed. Bearing fits, crankshaft regrinding limits, piston selection, valve guides, seat inserts, and tappet adjusting pads accompany the procedures. Cylinder-head and timing-gear exploded views show the assembly relationships.

Timing and lubrication cautions: The head-refitting instructions warn that incorrect camshaft phasing can bring inlet valves into contact with pistons. The oil-feed notes identify an incompatible combination of C.5846 banjo bolts and C.2333 pipe banjos that can cut off or severely restrict camshaft lubrication.

The S.U. H.6 material includes piston-to-dashpot checks, float-level setting, and auxiliary starting-carburetor adjustment. Sectioned carburetor views support component identification. Engine-tuning checks cover compression, ignition advance, and mixture setting, helping distinguish engine or ignition faults from carburetor adjustment problems.

Gearbox Variants and Rear-Axle Setup

Gearbox scope: Detailed instructions and illustrations apply specifically to S.H. and J.H. units. Construction and interchangeability notes explain the S.L. and J.L. versions, including their shorter mainshaft and different rear-cover arrangement.

The axle chapters provide bearing-preload, pinion-setting, backlash, and tooth-contact checks. Salisbury’s “Tooth Contact Indication” illustrations support gear-mesh assessment; its tool list identifies the SE.104 gear-carrier stretching fixture and SE.107 pinion cone-setting gauge, helping plan the equipment required for axle work.

Brakes, Suspension and Coachwork

Brake differences: Later XK 120 coverage includes self-adjusting front brakes and the tandem master cylinder, with a separate chassis-number table. Drop Head Coupe references belong to this brake coverage; the main coachwork procedures distinguish Super Sports and Fixed Head Coupe bodies.

Steering and bodywork: Drop-arm/rocker-shaft alignment-mark views and torsion-bar gauge drawings accompany the chassis procedures. Coachwork coverage extends to body removal and mounting points, door adjustment, window mechanisms, and windshield removal and refitting.

The “Air Conditioning Equipment” section covers hot-water heaters, blower units, controls, and demisters.

Always verify lifting points and use proper supporting stands before heavy chassis or drivetrain work.

A Preview of Valve Clearances and Engine Assembly Data

For cold inlet-tappet inspection, the Mark VII specification is .004 in. (.10 mm.); the XK 120 specification is .006 in. (.15 mm.). Crankshaft end clearance for both models is .004–.006 in. (.10–.15 mm.).

Cylinder-head refitting data specify 650 lb. ins. for the fourteen large dome nuts, within the manual’s gradual tightening procedure and illustrated sequence.