Description

Citroen Twelve, Fifteen 1956 Repair Manual – Factory Procedures for the Front-Wheel Drive

Citroen Twelve, Fifteen 1956 Repair Manual – if you are wrenching on a Traction Avant, you already know that generic aftermarket garbage will leave you chasing phantom leaks and stripped threads. This is the actual factory document printed in October 1956 by Citroen Cars, Ltd., Slough, England, covering both the Twelve and Fifteen models from 1938 to 1950. 116 pages of illustrated procedures, with torque sequences you can trust because the factory engineers wrote them for the mechanics who built these cars. No guesswork, no reprints of faded photocopies. You get the original index, the same diagrams that sat on the bench at the Slough plant.

I have torqued enough head bolts to know that a missing sequence number or a wrong value means pulling the head again. Page 5 shows the cylinder head nut tightening order – not a generic pattern, the actual sequence for the Twelve and Fifteen engine. The manual also covers replacing a valve seat or guide (page 9), fitting pistons into barrels (page 17B), and setting timing wheels (page 19). Every step comes with a factory illustration number. You follow the picture, you get the job done right.

Engine Assembly: Longitudinal and Cross Sections (Pages 7–8)

The engine section alone runs from page 1 to page 22B. You get the full assembly drawings – longitudinal and cross sections – so you can see exactly how the oil baffles align and where the sump gaskets seat. The manual warns about sump gasket precautions on page 17: those early engines leak if you rush the sealant. There is also a dedicated page for checking the oil pump adjustment (page 13) and water pump bush replacement (page 14). If you are rebuilding a Twelve or Fifteen cylinder head, the valve spring testing specs on page 12 tell you the free length and load. Do not rely on aftermarket data for those; the factory values are metric, but you can convert them to inches and pounds using the conversion chart you should already have in your toolbox.

Cylinder Head: Sequence of Tightening Nuts (Page 5)

You want a head gasket that seals the first time? Use the sequence on page 5. The factory drawing shows which nut to snug first, second, third, and the torque value – given in the manual as kilogram-force meters. If your torque wrench reads foot-pounds, multiply by 7.233. That is not my opinion; that is how you apply the original spec. The manual also includes a simplified method for the toggle adjustment on the clutch (page 24A) and the crown wheel and bevel pinion (page 35A) – both are time-savers when you are working on the gearbox.

Gearbox and Differential: Factory Adjustment Procedures

The gearbox section (pages 25–36) covers the synchromesh fitting, differential bearing extraction, and crown wheel adjustment. Page 35 walks you through the full adjustment of the crown wheel and bevel pinion – backlash and contact pattern – with the specific tools listed on page 32. You need a stand for dismantling (page 25) and an extractor for the coupling flange (page 27). The manual does not assume you own every special tool; it shows you how to fabricate a bar for keeping the opposite flange in position. That is real-world shop thinking from 1956. If you have a later Citroen with automatic transmission, the Citroen BX Workshop Manual – Automatic Gearbox & Drive Shafts covers the hydraulic circuits, but for the Twelve and Fifteen you need the mechanical gearbox specs in this manual.

Front Axle, Torsion Bars, and Steering

Pages 37–61 are dedicated to the front axle. Torsion bar fitting (page 40) requires correct preload; the manual gives the seating procedure with the silentbloc orientation. The vertical section through the hub and swivel (page 41) shows you the ball-race arrangement – essential when you are pressing out the stub axle. Brake back plate assembly (page 49) includes the flaring procedure for the adjusting cams (page 51) and the method for checking concentricity of brake linings (page 61). The steering section (pages 62–67) covers rack and pinion gear holding in a vice and track rod length adjustment. If you need a deeper dive into later front-drive systems, the Citroen 4HP20 Service Manual – Factory Transmission Guide covers the 4-speed automatic used in XM and Xantia, but the Twelve and Fifteen manual is the one for torsion bar alignment.

Rear Axle and Alignment Checks

The rear axle section (pages 67A–79) shows you how to raise the axle, remove torsion bars, and check camber and toe-in. Page 75 details the camber and toe-in checking procedure – a step that many home garage enthusiasts skip because aftermarket manuals tell you it is not adjustable. It is adjustable. The factory procedure requires a specific gauge, but the manual explains how to interpret the readings. Silentbloc replacement for the support brackets is on page 77. Without this information, you will be guessing at rear suspension geometry, and the car will handle like a shopping cart.

Related resources for other models: Interact 4.0, 6.0 2003 Repair Manual – OEM Factory Specs is for a different brand, but the same principle applies – factory documentation beats aftermarket every time. For a broader context on automotive repair documentation, check the Automotive Industry Overview and the Automotive Industry Overview resource. But for your Citroen Twelve or Fifteen, this manual is the only source you should trust.

Does this manual cover the clutch assembly?

Yes, pages 23-24A cover clutch and toggle adjustment.

What tools are required for the gearbox overhaul?

The manual lists specific mandrels and spanners on page 32 for assembling the gearbox. You will also need an extractor for the coupling flange (page 27), a stop tool for tightening the layshaft front bearing lock nut (page 34), and a stand for dismantling (page 25). Without these, you risk damaging the gearbox casing or misaligning the synchromesh. The manual shows you exactly which tools to fabricate or source – it does not assume you own a full Snap-on set from 1956.

When you have a 1938–1950 Traction Avant on the lift, you need the same information the factory mechanics had. Access the Factory Manual now and get the correct timing wheel settings, torque sequences, and alignment procedures. Your engine and gearbox will thank you.