The MG T-Series is a body-on-frame car: a strong steel ladder chassis carries a traditional coachbuilt body of an ash timber frame clad in hand-formed steel panels. This composite construction is beautiful but vulnerable — the enemy is rot, not rust — so keeping the body dry is the single most important thing an owner can do.
How the body is built
Every T-Type follows the same principle. Underneath is a separate all-welded steel ladder chassis — two box-section side rails tied together by crossmembers — which carries all the mechanical loads: engine, gearbox, axles, suspension and steering. Bolted down onto that chassis, and quite independent of it, sits the body itself: a traditional coachbuilt tub.
The body is a composite. Its skeleton is a frame of ash — a tough, slightly springy hardwood long favoured by British coachbuilders — stiffened in places by steel sub-framework and closed in with plywood panelling. Over that skeleton, hand-formed steel body panels are worked to shape and tacked to the timber with small nails and screws. Because the panels are shaped by hand, no two T-Types are dimensionally identical.
The main elements
- A pair of large main wood side rails runs down each side of the tub, from scuttle to rear body. The running boards bolt to these rails, and much of the tub's shape depends on them.
- The scuttle and bulkhead close the front of the cockpit and carry the windscreen fittings and instruments.
- The doors are ash-framed with steel skins, hung on wooden hinge posts and closing against wooden latch posts.
- The floors are timber and plywood.
- The wings (fenders) and their valances bolt on separately, with a rubber or piping beading sandwiched between wing and body.
- The bonnet is side-opening in two louvred halves, hinged along the centre.
- The windscreen folds flat forward onto the scuttle.
- The fuel tank is a slab-sided pressing bolted to the rear of the body, with an external spare wheel on early cars.
The important structural point is this: although the chassis carries the mechanical loads, the ash frame gives the body its shape, supports the steel panels and holds the doors. A rotten frame will not, by itself, make the car unsafe to drive — but it ruins panel fit and door alignment and progressively lets the body lose its integrity, even though it is not the chassis. For deeper detail on the timber itself see the Ash Frame article, and for the chassis it sits on see the buying guide's What to Check.
The history of the build
MG began life rebodying Morris cars in the traditional coachbuilt manner — a steel chassis under a hand-built wooden-framed body — and when the T-Series was designed in the mid-1930s the company simply carried that method forward. From the TA of 1936 to the last TF 1500 in 1955 the recipe barely changed: hand-formed panels tacked to a seasoned ash frame, bolted to a welded steel chassis, hand-fitted at Abingdon within the Nuffield/Morris organisation.
By the standards of the 1950s this was already old-fashioned. Mainstream manufacturers were moving to pressed-steel monocoques, and when the MGA replaced the TF in 1955 it did so with an entirely modern welded unit body. That is why the T-Series feels so distinct today — you are looking at a pre-war coachbuilt car that stayed in production for two decades — and it is also why they demand a specific kind of care.
Variant-by-variant body guide
Every T-Type shares the composite construction described above. The differences lie in width, styling, wheels and detail.
TA (1936–1939)
The first T. A classic coachbuilt body with flowing, separate wings, full-length running boards, a slab rear fuel tank with an external rear-mounted spare, a fold-flat windscreen and cutaway doors. Nineteen-inch wire wheels.
TB (1939)
Essentially the TA body — pre-TC narrower width — but with the new XPAG engine underneath. Only 379 were built before Abingdon turned to war work, which makes original TBs the rarest of the range.
TC (1945–1949)
The post-war TC used a body roughly four inches wider across the cockpit than the TA/TB, but otherwise kept the classic upright pre-war style: 19-inch wire wheels, slab rear tank, rear-mounted spare, fold-flat screen and side-opening louvred bonnet. All TCs were right-hand drive.
TD (1949–1953)
A major step. The TD used a new, wider ash-framed body on a shortened Y-type-derived chassis with independent front suspension. Pressed-steel bolt-on disc wheels replaced the wire wheels of the earlier cars, and chromed bumpers and overriders appeared front and rear for the first time. Left-hand drive was offered from the factory, which drove enormous US export volumes. The competition-oriented TD MkII arrived later in production.
TF and TF 1500 (1953–1955)
A restyle of the TD. The radiator grille was faired-in and sloped back, the headlamps faired into the wings, and the bonnet line lowered; the tail slopes down to a sloping fuel tank. It is a more streamlined-looking car, still ash-framed underneath. The TF began as the 1,250 cc TF 1250; from late 1954 the larger 1,466 cc XPEG engine turned it into the TF 1500.
Body summary
| Variant | Years | Body notes / width | Wheels | Bumpers | Grille & styling |
|---|---|---|---|---|---|
| TA | 1936–1939 | Original narrow coachbuilt body | 19-in wire | None | Upright vertical grille |
| TB | 1939 | TA-width body, new XPAG engine | 19-in wire | None | Upright vertical grille |
| TC | 1945–1949 | ~4 in wider than TA/TB; RHD only | 19-in wire | None | Upright vertical grille |
| TD | 1949–1953 | New, wider body on shortened Y-type chassis; LHD available | 15-in pressed-steel disc | Chromed, front & rear | Upright vertical grille |
| TF / TF 1500 | 1953–1955 | Restyled TD: faired lamps, sloping tail & tank | 15-in pressed-steel disc | Chromed, front & rear | Sloping faired-in grille |
Known weaknesses and where they occur
On these cars, rot is a bigger problem than rust. The steel panels are tacked to an ash frame, and once water gets in between them, the wood softens and the steel corrodes at the joints from behind. The cars are not waterproof by modern standards — hoods, side screens and door seals were only ever intended to keep the worst of the weather off — so water gets in easily and takes its time getting back out.
Inspection hotspots
- The bottoms of the doors and the wooden door hinge and latch posts they hang from.
- The base of the cowl / scuttle.
- The rear of the body behind the fuel tank, where water runs down and sits.
- Along the lower skirt / valance and sills.
- The running-board mounting points and the main wood side rails, visible from underneath.
- The timber and plywood floors.
- The tack rails, where the outer panels are nailed and screwed to the frame.
- The wing beading, which traps water between the wing and the body.
Warning signs from outside
- Doors that have dropped, won't shut cleanly, or need lifting to latch — usually the first sign of frame trouble.
- Loose or rippling panels that move under a firm hand.
- Uneven, wide, or clearly-adjusted panel gaps.
- Cracked paint running along the joints between panels and wood — a sign the composite structure is moving.
Steel corrosion is still worth checking — panel joints, the inside faces of the wings, the fuel tank pressing, the valances and anywhere the panel meets damp timber — but on a T-Type it is almost always secondary to the timber underneath.
Maintenance and care
Look after the body in this order of priority.
- Keep it dry — above all else. Garage the car whenever possible, use a breathable cover (never trap moisture with plastic sheeting), and control humidity in storage. A T-Series left out in the weather is a T-Series slowly rotting. Long-term storage is worth doing properly.
- Weatherproofing. Maintain the hood, side screens/curtains and any seals so water does not get in through them. Fit the tonneau or hood when the car is parked, and keep a hood cover on top of a raised hood.
- Drainage. Keep any water paths and drain points clear so rain cannot pool in the body and soak the frame. Blocked drains are a slow-motion disaster.
- Regular inspection. Periodically probe the accessible timber — the main side rails and door-post bottoms from underneath — with a blunt tool. Look for softness or that dead, spongy feel that means the wood has gone. Act early; rot spreads faster than it appears.
- Paint and panel care. Wash the car and dry it thoroughly. Wax to protect. Address stone chips promptly — bare steel over damp wood will rust from behind. Understand that some paint cracking along panel-to-wood joints is normal on a composite body that flexes.
- Chrome and brightwork. Clean and protect the radiator shell, the bumpers (TD/TF), the lamps and the screen frame to prevent pitting. Chrome respects attention and punishes neglect.
- Underside. Protect it sympathetically. Be cautious with modern cavity waxes near bare timber, and keep the running-board area, valances and beading clear of trapped mud and leaves.
- Doors and fit. Treat a dropping door or worsening panel gaps as a signal to investigate the frame — not simply to lengthen a hinge slot or over-tighten a striker plate. Cosmetic adjustment on a car with a rotting hinge post hides the problem while it gets worse.
Restoration and repair notes
At a reference level rather than a how-to: repairing a coachbuilt tub takes real artistry, and it is not a beginner's job.
Most of the ash frame is hidden beneath the steel panels, so any serious assessment means removing panels or interior trim to see what is actually there. Rotten sections are cut out and replaced with correctly-seasoned ash — steam-formed where the shape requires it — and carefully spliced and pinned back into a frame that must end up dimensionally symmetric. A tub that has been repaired out of true will refuse to accept its doors, wings and bonnet properly, and no amount of subsequent adjustment will disguise that.
Two specific buyer warnings. First, be sceptical of partially-assembled project tubs offered for sale; the hard work of getting the frame straight is exactly the part the previous owner will have run out of patience for. Second, be sceptical of long, glass-smooth panels that ripple only when you tap them — thick filler over past bodges is common on T-Types and hides both rusted steel and rotten wood beneath.
Good frame and panel work is expensive, but it protects both the car's value and its originality. This is one of the areas where the cheapest option almost always becomes the most expensive one.
FAQ
What is the MG T-Series body made of?
A composite of an ash timber frame with hand-formed steel body panels tacked to it, bolted to a separate all-welded steel ladder chassis. The wings, valances and bonnet bolt on separately.
Do MG T-Types have a wooden frame?
Yes. Every T-Type from the TA of 1936 through the TF 1500 of 1955 uses an ash-wood body-frame skeleton beneath the steel panels. The wooden frame gives the body its shape and holds the doors; the chassis it sits on is steel.
Where do MG T-Series bodies rot?
At the bottoms of the doors and the wooden hinge and latch posts, the base of the scuttle, behind the fuel tank, along the lower valance and sills, at the running-board mounts and main side rails, in the floors, at the tack rails and under the wing beading.
How do I stop my MG T-Type's body rotting?
Keep it dry. Garage the car under a breathable cover, maintain the hood and side screens so water does not get in, keep drain paths clear, and inspect the timber periodically. Damp is the single greatest enemy of a T-Series body.
Is rust or rot the bigger problem on a T-Type?
Rot. The steel panels are tacked to an ash frame, and once water gets between them the wood softens and the steel corrodes at the joints. A rotten frame is far more expensive to put right than surface rust on a panel.
How can you tell if a T-Series frame is rotten?
Look for doors that have dropped or won't shut cleanly, uneven or widening panel gaps, loose or rippling panels, cracked paint along panel-to-wood joints, and softness when the accessible timber is gently probed from underneath.
Frequently asked questions
Why does my tuned XPAG misfire under load?
Misfire under load is almost always ignition on an XPAG, not carburation. Check the plug gaps and colour first — sooty plugs mean the mixture is rich or the ignition is weak; white or blistered electrodes mean it is lean. Then confirm the points gap and dwell, the rotor arm and condenser, and that the coil is producing a strong blue spark. On a Stage 1 or Stage 2 engine, also check the static timing has not crept too far advanced; a pinking engine often feels like a misfire and will eventually burn a hole in a piston. Finally, balance the SUs again — an unbalanced pair can leave one cylinder running lean enough to misfire at wide throttle.
Why does my XPAG hesitate when I open the throttle?
Hesitation on pick-up is the classic SU weak-mixture signal. The piston in the carburettor is lifting too fast for the fuel to follow, usually because the jet is set too lean, the needle is worn, or the dashpot oil is too thin. On a Stage 1 car with standard 1.25 in SUs, start by checking the damper oil level and weight — SAE 20 is correct — and that the piston rises smoothly without sticking. Then richen each jet by one flat, test again, and confirm with the lifting-pin method. On a Stage 2 car with 1.5 in SUs the same rule applies, but the needle profile is more critical; a worn or mismatched needle will hesitate whatever the jet setting.
Why is my tuned XPAG hard to start when hot?
Hot-starting problems on a tuned XPAG usually come down to fuel evaporation or flooding. A free-flow exhaust and a hot engine bay can boil the fuel in the float chamber and carburettor body, making the mixture over-rich. Check the float level first — it should be at the workshop-manual figure, not simply "looks about right". If the car starts cold but floods hot, try easing the throttle fully open while cranking to clear the cylinders, then start with no throttle. On Stage 2 engines with raised compression the starter also has to turn a higher-compression engine against a hot block; a good battery and clean earth straps matter more than on a standard car.
My Stage 1 XPAG pings on acceleration — what do I adjust?
Pinking means the combustion pressure peak is arriving too early. On a Stage 1 tune running on modern 95 RON petrol, retard the static timing by one or two degrees first and re-test on a warm day under load. If it still pings, check that someone has not already advanced the distributor beyond the Stage 1 figure, verify the compression ratio has not been raised by a previous skim, and make sure you are not running the engine below about 1,500 rpm in a high gear. Do not simply richen the mixture to mask pinking — it helps a little, but the real fix is timing or compression.
After fitting 1.5 in SUs my Stage 2 idle hunts — what is wrong?
An uneven idle after a Stage 2 carburettor swap is usually one of three things: the throttle spindles are worn and drawing air, the inlet manifold is not matched to the head ports and is causing reversion pulses, or the jets and needles are not centred and matched. Re-check the manifold face and gasket match, recentre both jets with the piston-drop test, and confirm both carburettors are drawing the same airflow at idle. Stage 2 engines with a fast-road cam also have less manifold vacuum at idle, so the idle speed may need to be set a little higher than standard — typically 800–900 rpm — to keep the SUs stable.
How do I know if my tune is running lean?
Lean running shows up as a flat spot under load, popping in the exhaust on the overrun, white or grey spark-plug insulators, and elevated exhaust-manifold colour after a run. On a rolling road the air/fuel ratio will read above 14.5:1 at cruise or above 13.0:1 at wide throttle. Fix it by richening the mixture a flat at a time on the SUs, checking for air leaks around the manifold and balance pipe, and confirming the fuel pump is delivering at least 1.5 psi at the carbs. Lean mixture is the fastest way to burn exhaust valves on a tuned XPAG, so do not ignore it.
Related reading
- The Ash Frame: The Most Expensive Thing Your T-Type Can Hide — the deep dive on the timber itself.
- What to Check on Any T-Type — chassis-vs-body inspection points for buyers.
- The Buying Guide — model-by-model buyer's advice.
- The Models — TA, TB, TC, TD, TF and TF 1500.
See also — coachbuilt T-Types
The standard T-Type body is not the whole story. A minority of cars — the Tickford drophead by Salmons of Newport Pagnell, the Art Deco Airline coupé, and the 1950s Arnolt-MG bodied by Bertone — carried coachbuilt bodies that share the ash-frame construction discussed above but with more elaborate joinery and trim. For history, production figures and buying guidance, see Coachbuilt T-Types.