Sports Car and Lotus Owner, Vol. , No. April 1959
The Eleven (Series One and Two) by Mike Costin
Lotus Eleven is produced in three forms, Le Mans, Club and Sports, all
with basically similar chassis. The Sports version is fitted with a Ford
Ten engine and gearbox, the other models with Coventry Climax FWA or FWB
power units. The standard gearbox in these latter cases is a Lotus
modified BMC “A” series unit fitted with close ratio gears for
racing purposes. The final drive unit is also BMC ‘A” series,
thereby allowing changes of gear ratio between 3.7 and 5.3 to 1.
to the chassis, the Eleven first appeared in 1956 with a tubular steel
space frame chassis having independent swing axle front suspension and
de Dion rear suspension.
firstly with general maintenance of the chassis itself, starting from
the front, the body hinges are rubber moulded bobbins fitted to the
front chassis cross tube. These should be well greased at all times in
order to ensure correct functioning. Should they become mutilated or
broken they can he replaced by un-riveting the outer portion of the
undertray in this area and reriveting it after replacing the bobbin.
body-fastening hook has a cam arrangement to ensure that the body is
held rigidly in position, and the rollers on which this runs, which are
situated immediately behind and above the rubber grommets, should also
be kept lubricated.
front suspension on this car was a development of the Mark Nine
suspension except for the addition of Girling disc brakes. The half beam
axles are modified Ford Popular components hut the radius arms are from
an earlier type Ford, the “Y’, model, and are rather lighter.
to watch on the radius arm and axle beam assembly are:
(a) cracking from
the bolt through the rubber bush in the axle beam where it passes
through the channel across the front of the chassis,
(b) cracks in the
diagonal down tube where it meets the rear pick up of the radius arm,
of the bolt passing through the radius arm and beam. (Note: It is most
important that this bolt be absolutely dead tight at all times.)
suspension units used on the Series One Eleven were of Girling
manufacture in the first instance, but Armstrong counterparts are
bottom pick-up for the front suspension unit gave trouble in the early
days, when it was made up from a piece of 1/2in steel bar; the latter
type, which was made from a machined bar of 5/8in diameter, proved quite
satisfactory. The anchorage for the top of the front suspension unit
also gave trouble, particularly on the left hand side, and this was
(a) thickening up
the plate through which the peg top of the suspension unit protruded,
(b) raising the
gauge of the top chassis member.
adjustment of the front suspension which is required for alteration of
ride level should be obtainable at the top or bottom suspension pick-up
by either adding or subtracting rubbers and although the amount of
adjustment available is quite small, possibly in the region of plus and
minus 1/4 in, this actually gives something
front stub axles are modified Ford F93A, and the hubs are of a
proprietary brand modified to suit the Lotus requirements. The hubs
should need no maintenance whatsoever excepting possibly the renewal
of the Timken taper roller races and the inboard grease seal. A point to
note here is that there should also be an outer seal, which is in the
form of a light steel pressed cap, and this should be a press fit into
the outer race housing. I point this out because on the majority of
Elevens which I have seen recently this outer seal is missing.
steering gear of the Series One Eleven is of the rack arid pinion type,
and this again is a modified version of the BMC
rack and pinion. This unit should need very little maintenance apart
from stripping and re-assembling yearly and adjustment of the end pads
by the addition or removal of shims
The steering arms used on the Eleven Series One were of Lotus manufacture, and did present some trouble in the first instances in that the two bosses on which the arms are mounted, which are brazed into the steering arm itself, used to come loose and allow play in the steering. This was evident upon inspection and was easily detected by cracks on the braze at the points where the stubs enter the arm. The rack and pinion is actuated by a tubular steering column which has two universal joints. During overhaul these should be washed in petrol and checked for play, and replaced if necessary.
rear gearbox mounting and the undertray from the engine bulkhead to the
seat back are all highly stressed parts of the chassis and should
receive some maintenance attention. It is quite likely in older cars
that all the rivets holding the undertray on to the chassis itself have
become loose, and this can be repaired either by re-riveting between the
existing rivets or better still by drilling out all the old rivets,
drilling each hole oversize and re-riveting using oversized rivets.
de Dion assembly used on these cars was most satisfactory generally
speaking, but there are one or two points which should be watched.
Firstly the chassis at the rear of the A bracket pick-up on the rear of
the prop shaft tunnel should be inspected very closely for cracks. Later
chassis have a modification here whereby an angle bracket was inserted
joining the right hand vertical member of the rear prop shaft frame on
to the seat back tube, which went between the sides of the prop shaft.
This would be a worthwhile modification on any chassis which is not
already so modified.
de Dion outer drive castings should be stripped and re-assembled and the
bearings and grease seals checked for condition.
Hardy Spicer unions used on the articulated drive shafts were of 1100
series, and these should be carefully checked for any signs of wear and
replaced if necessary.
of the rubber bushes on the radius rod ends should be checked, but these
should have an almost indefinite life and should be discarded if they become
perished or swollen due to excessive oil or petrol soakage.
differential housing casting is of Lotus design, and was developed
specifically for the Eleven. The drive shaft bearing housings should have
provision for a sealing “0” ring, and anyone having a very early
casting in which this “0” ring groove is not machined would profit by
incorporating this modification, as it certainly helps to keep the
brakes free from oil. The differential assembly itself is held into the
casting by eight 3/16in bolts. Should any of the threads in the magnesium
housing be damaged then they can be retained by the use of an Armstrong
Girling disc brakes used on the Eleven should be maintained as recommended
in the February 1958 issue of SPORTS CAR AND LOTUS OWNER.
Owners of Series One Elevens fitted with discs of chromium plated
steel should be careful only to use pad material Ferodo DSI or Mintex
equivalent. Conversely, cars with cast iron discs should use Ferodo DS3 or
twin master cylinders fitted to these cars are the remote tank centre
valve type and should be of 3/4in diameter; some early ears were fitted
with 5/8in diameter master cylinders. The clutch pedal and linkage is
assembled in one and fitted in the car through the hole in the side of the
driver’s foot box. It is essential for correct operation that the
assembly should be fitted loosely, and then the bolt through the
Metalastik-type bush should be tightened up only when the pedal is pulled
backwards to the full extent of its rearwards travel. The reason for this
is that the only means of returning the pedal to the normal position is by
the spring action of the pivot bush, which is of a special double bonded
variety. This special treatment also applies to the brake pedal on Series
One cars, although a spring push-off is fitted to the brake pedal of
Series Two Elevens.
The throttle linkage also should receive some attention, in particular to the ball joints on the carburetter link, as these have a tendency to come undone when the wear becomes excessive.
In early cars the gearbox oil used to leak from the gearlever attachment plate, and this was cured by soldering a short piece of tube on to the top of the plate and then fitting the normal A.30 rubber moulding over this tube and fastening it into position with a Jubilee clip.
hand brake on the Series One Eleven is quite effective generally speaking,
and maintenance should be confined to greasing the cable, adjusting
it—if necessary—at the differential end and replacing the hand brake
Series Two Eleven differed from the Series One in many respects. Firstly
the front suspension was replaced by an entirely new wishbone-type layout.
The chassis was re-designed to accommodate this new suspension and at the
same time the rear suspension was also modified, although it bore a very
great relationship to the previous year’s de Dion set up.
front suspension on the Series Two Eleven is completely Lotus in design
and utilises only the very minimum of proprietary items. These are the
king posts, the stub axle, the hub and the king post bottom bearings. This
suspension has proved to be most successful and has remained unaltered
even to the latest Formula One car, where it is still precisely the same
as on the Eleven but turned back to front. Maintenance on this suspension
is confined merely to checking for wear at the stub axle bearings, the top
king post ball joint, the bottom king post bearings and the rubber
bearings on the bottom wishbone.
Eleven Series Two de Dion was introduced (a) to widen the base on which
the bearings worked and (b) to bring it into line with the 1957
Lotus standard, in order that the cars could be fitted with either
spoke wheels or the cast magnesium type. The de Dion is principally the
same as for the Series One, but instead of the aluminium grease seals for
the outer drive shaft bearings a special seal is now used, which is made
of pressed steel approximately 12 thou thick, and this is designed to
run on the outside edge of the bearing outer tracks and polish its own
line; once it has polished this line it forms a very good grease seal.
the Series Two Eleven the Hardy Spicer joints were increased in size to
1300 Series, this again to bring the car into line with the firm’s 1957
spare wheel mountings on early Elevens were made of 1/2in tube, but these
were later replaced by mountings of 5/8in tube.