JAGUAR ENTHUSIAST MAGAZINE
How safe are your frames?
Graham and Fiona Heritage look into the implication of
replacing the front frames on their E-type Series 1
When we purchased a S1 2+2 E-Type last spring we were
aware of cracks in the front frames, which would
ultimately require replacement. Conscious of the costs
involved time was spent researching the subject and a
lot was learned. By nature frames are safety critical
items and all E-type owners should be aware of the
problems that can develop and the satisfactory remedies.
How it all came about
Fiona and I have been interested in classic cars for
many years. Fiona always regretted selling her last
sports car, a Triumph Spitfire whilst I had a soft spot
for the E-type but due to the price tag had never
seriously considered buying one. That was until, last
spring when my brother in law announced he was looking
to sell his S1 2+2. The car had been Californian import
11 years ago when much bodywork had been carried out by
a London garage.
Since then considerable time and money had been spent
keeping the mechanical aspects up to scratch. With young
twins, free time was not going to be plentiful so we
wanted something usable we could drive to the shows but
could be treated as a rolling restoration when time
permitted. The E-type seemed to fit the bill and being a
2+2, once the twins grew legs and were out of their car
seats they could come too. After lots of research we
made a trip to the Isle of Wight to take a closer look.
As newcomers to E-types and having done a lot of
reading we arrived with a long checklist and spent most
of the following morning inspecting our tentative
purchase. The main problem appeared to be that the front
engine frames were in poor shape. On an E-Type the
frames are a complex tubular structure, which
effectively forms the entire front third of the car. As
such they are a safety critical item as they not only
take the weight of the engine and bonnet but also hold
the mountings for the steering and front suspension. It
therefore pays to ensure the frames are in good shape.
With the car on ramps inspection showed that the
lower main tube on the right hand frame had fractured
and a crack had appeared in the lower diagonal tube on
the same side. Amazingly the car had just passed an MOT
indicating just how little such documents can be relied
upon as an indication of vehicle condition. The break in
the lower tube had evidently been there for some time as
the broken ends of the tube appeared to be somewhat
flared, no doubt due to buffeting as the road shocks
caused the frames to flex. It is frightening to think
what would have happened had the car continued to be
driven in this state with the driver unaware of the
Eight substantial mounting points on the rear top and
bottom of the frames secure the structure rigidly to the
front bulkhead where stresses are distributed throughout
the structure of the tub and the sills. The frame set,
comprises four parts, two engine side frames or "A"
frames, upon which is mounted the engine and front
suspension, a square "picture frame" ties the two "A"
frames together at the front and provides mounting
points for steering rack, horns, fan motor and radiator
header tank, (S1).
Onto this bolts the bonnet support frame, which as
the name suggests carries the pivot points for the
massive bonnet and front wing assembly. If anyone has
tried to lift an E-type bonnet you will appreciate just
how heavy this item is and what a job this frame has to
Picture: The E-type frame
set viewed from the front of the car showing the
A-frames, the picture frame and the bonnet support
Whilst all parts of the frame set play a major part
in the safety and integrity of the E-type structure it
is the "A"-frames that cause the main concern. For
lightness and rigidity Jaguar manufactured these frames
from special Manganese Molybdenum tubing known as
Reynolds 531, the design being taken from the then
current state of the art racing technology of the
1950ís. This material has a far superior strength to
weight ratio over conventional steel tubing enabling a
very strong yet lightweight structure to be produced,
and is the same substance as used in the manufactureof
lightweight racing cycle frames.
However, the concept was not without its drawbacks
and the limitations resulted in a design life measurable
in years rather than tens of years. Considering for a
moment that even the youngest E-type is now 30+ years
old it goes without saying that thereare a great many
cars out there with original frames well beyond their
design life and as owners of such vehicles we should be
aware of the problems that can arise so that potentially
dangerous failure can be prevented.
Due to the special properties of 531 the labyrinth of
lugs and tubes were bronze welded, (or brazed), together
rather than welded. Whilst, at first this may sound
strange for such a vital structure, the high strength
properties of 531 are destroyed if the material is
heated to above about 950C. Brazing is of course,
performed at a lower temperature and thus the
metallurgical structure of the material remains
substantially unchanged. The downside of the process is
that lower joint cohesion is achieved than with
traditional welding and this often leads to joint
failure. This is particularly common in the components
which are under extreme tension, such as the diagonal
round tube upper joint, which often fails after severe
Brazing also causes one of the commonest failure
modes of the frame structure, namely a localized brittle
fracture, most prevalent around joints of maximum stress
and particularly common in the front suspension/engine
mount assembly. Other sources of trouble are fatigue
caused by prolonged road use, internal corrosion
reducing the wall thickness of the tubing and sudden
impact damage caused by kerbing or minor crash damage.
It is not unreasonable to assume that over 30 years of
use most cars will have experienced one or more of the
Before assembly, key components within the frames
such as the uprights and mounting lugs were heat treated
to achieve greater strength. Once assembled the finished
frame-set was regarded as a homogeneous structure.
Sadly, the restrictions of the above processes mean that
it is virtually impossible to perform a satisfactory
repair on E-Type frames without compromising the overall
integrity of the structure and make any form of welding
a total no-no. This is a fact that is brought to our
attention in the Jaguar service manual (Pg. N25), which
reads as follows:
"It is most important, when accidental damage has
been sustained at the front frame, that the
appropriate sub-frame assembly should be replaced.
No attempt should be made to weld or braze
replacement tubes into these assemblies nor should
any heat in any form be applied in an effort to
Picture: Brittle fracture
of one of the sub-frame brazed joints on Graham's car.
Note how the crack has also spread to the tube itself.
Once aware of this potential pitfall we began to
notice evidence of such repairs at car shows and can
remember being horrified at the number of vehicles being
offered for sale at substantial price tags showing signs
of welding in this area. So if youíre looking for an
E-type you would do well to take a good look at the
front frames for evidence of welding.
Failure Modes and things to
Whilst Iím not trying to instill paranoia into E-type
owners itís as well to be aware of the likely failure
modes so that the early signs of failure can be spotted
before they become a safety issue. Certainly restorers
should pay more than a passing glance to the state of
the frameset before deciding whether to replace or reuse
the original items. In the rest of this article I hope
to provide some assistance to owners in identifying
specific areas to examine.
As I mentioned above our S1 2+2 had total failure of
one of the lower tubes and cracks around three sides of
the adjacent diagonal tube. It appears that this is a
common place of failure as not only are road shocks most
severe in this area but, being the lower tube, there is
a greater risk of physical damage and ingress of water
causing internal corrosion. As the main tube had failed
totally and we had to get the car home from the Isle of
Wight we did in fact Mig-weld the frame together on the
basis that this would be stronger than a broken frame.
However, the journey home was driven very gingerly
avoiding potholes and with regularly stopping to check
all was still OK. I have to say, however, that this is a
far from satisfactory solution and I wouldnít rely on
this as anything more than a last resort temporary fix.
Safely back home some phoning around revealed that a
replacement set of side-frames was going to cost us
about £1200 or £1600 if the bonnet support and picture
frames were included. Not being one to part with hard
earned cash readily we figured that somewhere out there
amongst the JEC members there must be someone with a
redundant set of new frames or very good used items so a
wanted ad was duly placed in the next issue of Jaguar
We were grateful to receive a number of calls from
members amongst which were several warnings to tread
carefully and be sure of what we were buying. We learned
a great deal from these discussions such as that the
frames tend to corrode from the inside which in itself
is not much of a surprise until you learn that the wall
thickness of the tubes is only 20s.w.g., (about 1mm), so
it does not take much rust to severely weaken the
assembly. Interestingly, the toughness of the Reynolds
531 material makes it very difficult to assess the
extent of corrosion by normal techniques of prodding
with a screwdriver or similar metal implement.
Alarmingly, even a badly corroded tube will still seem
resilient from the outside!
Picture: 'Get you home'
welding to the lower tubes. Here the frame is shown
inverted for clarity.
One simple test, which can be made if the frames are
off the vehicle, is to tip each frame to a steep angle
and to listen. A sound resembling that of sand running
down the tubes is a clear indication of internal
deterioration. Whilst this clearly isnít an option for
running cars, restorers should perform this test and
conduct a thorough inspection of the brazed joints
before deciding whether to refit or replace an original
Others spoke of extreme trouble in getting new frames
to fit their car finding mountings up to half an inch
out of line. Inevitably some of this must be due to the
tolerances to which these cars were manufactured in the
60ís but nevertheless it appeared that it was not going
to be an easy ride. We also learned that the supply of
original Reynolds tubing had dried up and that some
manufacturers were using alternative materials of
varying suitability, whilst others were not always
applying the correct heat treatment. Considering the
fact that the frames effectively provide the front
crumple zone in the event of an accident such actions
can clearly affect the way in which an impact is
absorbed and could themselves lead to latent penalties
for the unwary purchaser. We were keen to get things
right but it was difficult to know which way to turn.
It was at this point that Fiona received a call from
Uryk Dmyterko at ETF. Uryk explained that ETF, (E-Type
Fabs), had been set up following personal experiences
and frustrations in restoring E-types and achieving a
satisfactory fit. There was clearly a great deal of
knowledge within ETF and from an engineering background
myself I was more than a little impressed with the setup
and attention to detail. e.g. all ETF frames are
manufactured as matched pairs and guaranteed to fit the
original bulkhead mounting points. Each pair is jigged
to ensure the front suspension when fitted is set at mid
tolerance and each individual frame is discretely
numbered, dated and supplied with traceable certificate
Due to the varying availability of correct materials
we learned that ETF had commissioned their own supply of
tubing, which was being manufactured to an exact replica
of the original Reynolds 531 both in size and tensile
strength. Things were starting to look brighter
particularly as the asking price was 30% cheaper than
some of the sources I had tried.
A quick poke around under the bonnet revealed a
slight bend in the front of the bonnet support frame
caused presumably by a minor shunt in a previous life
and also evidence of jacking. There was also a fair
amount of surface pitting. The picture frame appeared at
first sight to be in reasonable condition but on closer
inspection the top cross member was badly battered on
the reverse side.
Picture: 'The Heritage's
2+2 chassis number was authentically reproduced to match
At first we couldnít understand how this had occurred
but having later removed the engine all was revealed.
The clearances between the XK engine and the picture
frame are in fact so small that the timing pointer bolts
have to be removed to provide the last few mm of
clearance if the engine is to be lifted out rather than
lowered. If great care is not exercised during the
lifting process the front of the sump can collide with
the rear of the picture frame and with an engine
weighing over 400Kg it became evident that this had
almost certainly been the cause of the damage.
After some consideration Fiona and I decided that
both items would be replaced. A phone call to ETF
revealed their "Full Monty" package containing all four
frames could be bought at an additional cost saving over
individual items. Things were certainly getting better.
My one concern at replacing the picture frame was the
fact that the chassis number is stamped on the top right
hand side and since the vehicle had been purchased with
all matching numbers this was clearly a reason to retain
the original part. Another phone call to ETF resulted in
an offer to reproduce our original chassis number on the
new frame. All we had to do was to supply a copy of the
V5 showing us as the rightful owner and provide sight of
the original frame in order to satisfy the DVLA. Once
again ETFís attention to detail impressed us as we were
requested to supply details of the type of numerals
found on our original frame.
Since the number contained a 4 it was possible that
this could have been stamped as a closed or an open 4
and also a 7 which could have had a straight or curved
side. ETF were intent on achieving perfection, a quality
so desirable but so seldom found in suppliers today.
The replacement process
The replacement frames were duly collected from the
ETF stand at Stoneleigh last March and on reaching home
the protective bubble wrap was removed revealing an
unmarked etch primed finish over truly beautiful
construction. I remember sitting with a beer that night
wondering how they managed to get it so perfect. By this
time the front of the E-type had been stripped and the
old frames removed.
Picture: The 'Full Monty'
package on display at Stoneleigh.
As is often the case with such projects what was what
was originally intended to be a rolling restoration
starting with the frame change has evolved into a
somewhat bigger project. It was not until the process of
dismantling did we spot a hairline crack in the lower
member of the picture frame. This was virtually
impossible to detect until the grime was cleaned off and
looks like it may well have stemmed from some minor
front-end accident damage, see picture below.
Although we had set out to replace the frames and get
the E-Type back on the road in time for the summer I
have to say that the opportunity of having the front end
totally stripped down provided too great a temptation to
replace corroded floors and toe panels and inevitably
many other parts so its going to be some months before
the frames are finally fitted for real.
However, keen to see how well things were going to
align, the replacement frames were gingerly offered up
to the bulkhead and as a trial loosely bolted in place.
All but one of the bolts aligned perfectly, the only
exception being one of the upper offside mounting plate
bolts, which was about 1mm off centre. On closer
examination however, this was found to be down to a
discrepancy in the positioning of the bulkhead hole
rather than an error in the new frame.
Someone told me that Jaguar technicians often fitted
stubborn bolts with a hammer, as tolerances were not so
well controlled as they are today! In fact the old frame
showed signs of the mounting being filed out to align
with the bulkhead. I was also most pleased to find the
mounting plates lay completely flat against the bulkhead
indicating that when fitting time came for real it
should be a straightforward nut and bolt job.
Anyone replacing frames should ensure that when
rebuilding the assembly that the correct bolts are used.
These should be high tensile bolts at least "R" rated
45-55TSI on the frame assembly itself with T rated 55-65
TSI used on the torsion bar keeper plates.
When frames are replaced, (whether new or original
items), it is vital to ensure that the following items
are re-adjusted in accordance with the specs in the
Jaguar service manual. Front suspension standing height,
(torsion bar setting), and front wheel camber, castor
angles and alignment.
Because of the inherent damage frames suffer through
internal corrosion I would also recommend that before
fitting frames be treated internally with a liberal
coating of a good quality cavity wax. It is worth
mentioning to other owners of 4.2 litre Series 1 cars
not to forget to refit the shim below the right hand
front engine mounting to ensure that the accelerator
linkage misses the engine frames under hard