MAINTENANCE


for AC's post-war
2 Litre Saloon

Page 1
Axles, Brakes,
Steering, Springs

The AC 2 Litre is reliable just as long as it has been, and is, well maintained, and is run regularly. The biggest difference from modern car maintenance is that routine servicing is more frequent. Maintenance and sourcing spares is harder than more modern mass-produced classic cars, but it is by no means impossible. Many mechanical and electrical parts are shared with other makes of car, and so other marque specialists can be useful sources.

Manuals

Three versions of AC's "General Instructions" were issued: Series 1 to 3. The numbering refers to the booklets themselves, and not versions of the car. In fact, the manuals do not cover all the many detail variations, particularly the electrical system which went through a great many alterations. What follows here comes partly from the official manuals, but also from my own experiences and what I've picked up from knowledgeable owners.

Front Axle

King-pins need to be greased every 500 miles (800km). It is worth going to this amount of trouble, because unfortunately, this is not one of the better areas of the AC's design. The plain bushes wear out fast if any grit gets into them, and pumping grease into them helps to expel any grit (but make sure that no grease gets onto tyres or other rubber parts). Even so, I have found that wear becomes noticeable after a few thousand miles. This can affect the steering quite badly, but it is quite easy to correct the problem by fine-tuning the wheel alignment. The symptom of slight wear is that the car veers off left or right when the front wheels strike bumps. Adjusting the front wheel toe-in and testing the car on a bumpy road (a deserted road, for safety's sake!) will eliminate the trouble by trial and error. Even with slight - but noticeable - wear, the car should keep a perfectly straight line on bumpy roads without any corrections needed from the driver.

The nominal toe-in figure stated by AC, was 3/16 inch (4.76mm) measured at the wheel rim. Wheel camber should be 2.5 deg. King-pin inclination 7.5 deg. Castor angle 2.5 to 3 deg. The tapered wheel bearings should have just 0.003 in. (0.08mm) of end play.

If you change to tyres with a smaller rolling radius, then note that the steering offset will slightly increase and the castor trail will decrease. The original tyre sizes were 5.50 x 17 and 6.70 x 16, each giving the same rolling radius. Many ACs have been changed to sizes such as 6.00 x 16 which reduces the outside diameter.

Renewing the king-pin bushes is not easy to do at home. The bushes are split, and after fitting (the easy part!) they have to be accurately reamed.

Front Springs

Grease the shackles every 500 miles (800km). I used a graphite-grease for the sliding shackles. Originally, AC recommended periodic cleaning and oiling of springs every 5000 miles (8000km), but later stated that the springs were greased and wrapped when new and no periodic maintenance is needed. Front springs (by Woodhead) were originally of a type with 5 clips and a number of short damper leaves on top. This was superceded by another design (part no. 535C), with just 4 clips and no damper leaves. The early type of spring had a free camber of 3 7/8 in. and a laden camber of 7/8 in (measured to main leaf, not top leaf). The later spring was specified with free camber 3.5 in. and laden camber 0.5 in. In both cases, the reference line for camber measurement passes through the bush centre at the front end, and a point 1.5 in. from the rear end

Steering

Ball joints should be greased every 1000 miles (1600km). For the steering box, "Kamoil" was specified, but due to its non-availability, I used a heavy gear-oil of SAE 140. The steering box does have some scope for adjustment for wear. There is an adjustment screw, with lock-nut, on top of the steering box. With both front wheels raised from the ground, the screw should be tightened until there is just the slightest amount of drag felt, when turning the steering wheel.

Brakes

Front brakes on cars up to chassis EL1239 were Girling Hydrastatic (HSI). These are self adjusting and have just one cylinder per wheel. These cylinders are the same type as used on the early Landrover 80 inch (for their rear brakes) up to the early 1950s. The leading brake shoe wears out the fastest, and alarmingly quickly if the lining is held on with copper rivets. Curiously, the earliest handbook describes the front brakes as "Girling Hydraulic Non-Servo", with a single adjusting bolt for each brake. The Series 3 handbook states that the Hydrastatic system was fitted to cars from chassis L801 (prototype Saloon) onwards. From chassis EL1240 onwards, front brakes were Girling Hydraulic Leading Shoe (HLS). These are adjustable, and each shoe should be adjusted so that it is just free of the brake drum. If dealing with asbestos linings, precautions should be taken to prevent any chance of inhaling dust.

The brake fluid level should be checked frequently, to be certain that any leakage can be spotted quickly if it occurs. The reservoir is located to the right of the engine next to the bulkhead.


The master-cylinder is located under the
aluminium bulkhead at chassis level.
When bleeding the brakes, one can do it single-handed because with the little panels removed from the back of each front wing, one can see the brakes at the same time as pressing the brake pedal. I found that brakes need a second bleed after the car has been driven, to expel every trace of air.

Rear brakes on cars up to chassis EL1806* were Girling Non-Servo (GNS), that is, mechanical. Rear drums were 12 in. x 1.656 in. up to chassis EL1239, and then 12 in. x 1.676 in from chassis EL1240. Note that the mechanical expander is mounted on the backplate in slotted holes. Its fixing nuts have double-coil spring washers under them, and are not fully tightened. This allows the expander housing to float slightly. The reason for this feature tends to be incorrectly explained in articles. The real reason is to equalise the forces applied to each shoe. On a fixed expander, the force applied to the leading shoe is reduced by the self-energising effect of the shoe. A floating expander thus increases the force on the leading shoe. It might be worth checking that the brake expander is still able to slide, and has not seized up.

From chassis EH1807* onwards, rear brakes were hydraulic, Girling Hydraulic Non-Servo Sliding Shoe (with handbrake mechanism), and drums changed to 12 in. x 1.75 in.

*AC manuals state that hydraulic rear brakes were fitted from chassis EH1806, but records show it to be from EH1807.

Every 5000 miles (8000km), lubricate the brake cable conduit greasing point with graphite grease. For adjusting the rear brake for wear, tighten the adjusters until some drag is felt on the drum, and then slacken by 2 clicks. The operating mechanism of rods and cables does not have any scope for adjustments during normal running.

Rear Springs

No maintenance required if they are packed with grease and wrapped, otherwise oil every 5000 miles (8000km). These are by Woodhead (part no. A336C) and have Silentbloc bushes. If having them overhauled, note that the free camber required is quoted incorrectly in AC's literature! With the flat damper leaf fitted (top leaf), the free camber should be 5.75 in. (measured to the top of the main leaf, not tp leaf). Camber when laden should be 7/8 in. Without flat damper leaf fitted, free camber increases to 6.25 inches, and this is the mis-leading figure quoted by the AC manuals.

Rear Axle

For cars with chassis number prefixed "EL" or "EH", an ENV axle is fitted (some earlier cars, "L" prefix, have also had an ENV axle installed): For ENV axles, oil should be changed every 5000 miles (8000km). This axle uses EP 90 oil, as used for hypoid type gearing - quantity, 3 pints (1.7 litres). The oil filler can be seen in the photo. There is a dip-stick attached to the cap, and the level should be checked 2500 miles (4000km) after an oil change. There are greasing points under the axle bearings, and grease should be applied every 5000 miles (8000km). The axle is of the semi-floating type with tapered roller bearings. Adjustments are only made when overhauling, and nothing beyond lubrication can be done during normal running. End float of the axle should be between 5 and 8 thou (0.13 to 0.20mm), checked with both wheels clear of the ground. Adjustment is by shims between the bearing housings and the brake back-plates. Some Jaguar XK120s were fitted with a similar ENV axle, (although a narrower track), so parts may be available from XK specialists if you are overhauling although not all the part numbers are the same.

For the earlier Moss rear axle (original equipment on cars with chassis prefix "L"), lubrication of the differential is the same as for the above mentioned ENV axle (except that AC's first owners' manual omits to state at what intervals the oil should be changed). This axle is of the fully floating type - or maybe 3/4 floating depending on your opinion! It is fitted with ball-race wheel bearings.



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Website started 29th December 2006