MG T-Type TC/TD/TF, Known Issues and Common Problems
Overview
The MG T-Type series (TC, TD, TF, 1945-1955) is mechanically simple, robustly built, and well-understood after seventy-plus years of enthusiast ownership. The XPAG engine is a fundamentally sound design, the chassis is straightforward, and the body construction, while unusual by modern standards, is well-documented and fully repairable.
That said, these are cars from the immediate postwar era. They were built to 1940s standards with 1940s materials, and the passage of seven decades creates specific problems that every owner will encounter. The good news: every problem listed here has been solved many times over, parts are readily available, and the MG Car Club community has technical knowledge that rivals any marque club in the world.
Engine, XPAG/XPEG (1,250cc/1,466cc Inline-4)
Oil Leaks, Everywhere
What happens: Oil weeps from every gasket surface, rocker cover, timing cover, sump, rear main seal, and anywhere two castings meet. The area beneath a parked T-Type will have oil spots. Some engines leak enough to require topping up between services.
Why it happens: The XPAG predates modern gasket technology. Original seals were cork, felt, and rope, materials that harden, shrink, and lose their sealing ability with age. The crankshaft rear main seal is a scroll-type design that relies on oil being flung centrifugally back into the sump, rather than a modern lip seal. It will always weep.
How to fix it: Replace all cork and felt gaskets with modern equivalents. Use a quality sealant (Hylomar or similar) on mating surfaces. The rear main seal can be improved with a modern conversion kit, but some weeping is considered normal. Cost: $100-$300 for a full gasket set. The rear main seal conversion: $150-$250.
Severity: Normal for the type. Manage it rather than trying to eliminate it entirely. Keep the oil topped up and carry a litre in the boot.
Low Oil Pressure (Worn Bearings)
What happens: Oil pressure drops below 40 psi at cruising speed when warm, or below 15 psi at idle. A knocking sound from the bottom end, particularly under load, confirms the diagnosis.
Why it happens: The XPAG uses a three-bearing crankshaft (two main bearings plus a centre main). With mileage, the white-metal bearings wear, increasing clearances and reducing oil pressure. The three-bearing design is inherently more prone to crankshaft flex than a five-bearing crank, which accelerates bearing wear.
How to fix it: Bottom-end rebuild, regrind the crankshaft and fit new bearings. If the crank is beyond regrinding limits, exchange crankshafts are available. A quality XPAG rebuild costs $3,000-$5,000. This is a well-understood job that any British car specialist or experienced home mechanic can handle.
Severity: Urgent if oil pressure is consistently below safe limits. Continued running with low oil pressure will score the crankshaft journals and potentially seize the engine.
Dynamo (Generator) Failure
What happens: The charge warning light stays on above idle, the battery goes flat, and electrical accessories dim. In some cases, the dynamo seizes and the drive belt snaps or glazes.
Why it happens: The dynamo’s internal brushes wear, the commutator surface deteriorates, and the field coil windings can short. Dynamos have lower output than modern alternators and only begin charging at higher RPM, they’re marginal for cars with upgraded lighting or accessories.
How to fix it: Rebuild the dynamo with new brushes and a cleaned commutator. A competent auto electrician can do this for $200-$400. Alternatively, fit a modern alternator in a dynamo-style housing, these bolt straight on and provide significantly better charging performance. Cost: $400-$600 for the conversion kit. Popular suppliers include Dynalite and Powerlite.
Severity: Needs attention. A non-charging dynamo means you’re running on battery alone. The battery will go flat within 30-60 minutes of driving with lights on.
Overheating
What happens: Coolant temperature climbs above normal, particularly in slow traffic or on hot days. Steam from the overflow. In severe cases, the engine boils over.
Why it happens: The XPAG cooling system was designed for English weather, mild temperatures and damp air. Australian summers overwhelm the original radiator’s capacity. Blocked radiator core tubes, a worn water pump, collapsed hoses, and incorrect ignition timing all contribute. The original thermo-siphon cooling on very early engines (pre-TC) relied on natural convection rather than a pump, which is hopelessly inadequate.
How to fix it: Flush and test the radiator. If the core is blocked, have it re-cored or fit a new core with improved tube density. Check the water pump for leaks and impeller wear. Fit a thermostat if one isn’t present (some owners remove them, which actually makes overheating worse by allowing coolant to flow too quickly through the radiator). An electric fan behind the radiator is a popular and effective upgrade for Australian conditions. Cost: $200-$500 depending on what’s needed.
Severity: Urgent. Sustained overheating warps the cylinder head and blows the head gasket.
Timing Chain Stretch
What happens: A rattling noise from the front of the engine, particularly on startup or at idle. The engine may feel down on power and the timing may wander.
Why it happens: The single-row timing chain stretches with mileage. The original tensioner is a simple spring-loaded slipper that can only compensate for so much wear. Eventually the chain becomes loose enough to slap against the timing cover or jump a tooth.
How to fix it: Replace the timing chain and tensioner. This requires removing the timing cover (front of the engine). Fit a duplex (double-row) chain conversion if available, it’s stronger and lasts longer. Cost: $200-$400 for parts.
Severity: Needs attention. A jumped timing chain will bend valves in the worst case, or simply make the engine run poorly.
Wooden Body Frame
Rot in the Ash Frame
What happens: Doors don’t shut properly or are misaligned. Body panels flex when pushed. Gaps between panels are uneven. The body feels “soft” when jacked up. In severe cases, the body visibly sags or the scuttle area cracks.
Why it happens: The T-Type body is steel panels attached to an ash (hardwood) frame. Water ingress, through leaking hoods, poor seals, or simply decades of exposure, causes the ash to rot. Once rot starts, it spreads through the frame members, weakening the entire structure. The areas most vulnerable are the door posts, the scuttle frame, the rear tub frame, and anywhere that water can sit.
How to fix it: Localised rot can be cut out and new ash sections spliced in. Extensive rot requires a complete reframe, the body comes off the chassis, all old frame members are removed, and a new frame is built from seasoned ash. Complete frame kits are available from SC Parts, British Frame & Engine, and other specialists. Cost: $5,000-$10,000 for a frame kit, plus $5,000-$15,000 in labour for a professional reframe.
Severity: Critical if structural members are affected. The body frame is the car’s skeleton, without it, the panels have nothing to attach to and the body loses its shape entirely.
Body Flex
What happens: The body creaks and flexes over bumps. Doors pop open over rough roads. Scuttle shake (the windscreen frame vibrates relative to the body) is noticeable.
Why it happens: Even a sound wooden frame allows more flex than a modern unibody. A frame with any degree of rot amplifies this dramatically. The T-Type body was never rigid by modern standards, it was designed for gentle English B-roads, not Australian conditions.
How to fix it: Ensure the frame is sound and all panel-to-frame fixings are tight. Check that the body is properly bolted to the chassis at all mounting points. Some owners add discreet reinforcement brackets at stress points. Scuttle shake can be reduced by tightening the windscreen frame mountings and ensuring the frame-to-body connection is solid.
Severity: Minor if the frame is sound. Critical if the flex indicates rot, investigate immediately.
Chassis and Suspension
Kingpin Wear (TC)
What happens: Front-end shimmy at speed, wandering steering, clunking over bumps, and uneven front tyre wear.
Why it happens: The TC uses a beam front axle with kingpins connecting the stub axles to the axle beam. The kingpin bushes wear with mileage and lack of greasing. The TC has multiple grease points that require regular attention, miss them and the wear accelerates dramatically.
How to fix it: Ream out the kingpin bushes and fit oversize kingpins, or replace the bushes entirely. Kingpin rebuild kits are readily available. Cost: $200-$400 per side. Regular greasing (every 1,000 miles or at each service) prevents premature wear.
Severity: Needs attention. Worn kingpins compromise steering accuracy and front-end stability.
Leaf Spring Fatigue
What happens: The car sits lower than normal, particularly at the rear. Ride quality is harsh. The chassis bottoms out over bumps. Handling feels wallowy and imprecise.
Why it happens: The half-elliptic leaf springs lose their camber with age and fatigue. Seventy years of use flattens the spring leaves. Broken leaves are also common, check by inspecting the spring pack from underneath.
How to fix it: Re-temper and re-camber the springs, or replace with new spring packs. New spring sets are available from specialists. Cost: $300-$600 per pair for new springs. Re-tempering existing springs: $200-$400 per pair.
Severity: Needs attention. Flat springs affect handling, ride quality, and ground clearance.
Front Suspension Wear (TD/TF)
What happens: Clunking from the front end, vague steering, uneven tyre wear. The car may pull to one side under braking.
Why it happens: The TD and TF use independent front suspension with coil springs, wishbones, and lever-arm shock absorbers. The wishbone bushes wear, the trunnions (lower pivot points) wear, and the lever-arm dampers lose their effectiveness.
How to fix it: Replace wishbone bushes, trunnions, and any worn ball joints. Rebuild or replace lever-arm dampers (specialists like Armstrong or Frontline Developments offer rebuilt units). Trunnion kits: $100-$200 per side. Damper rebuild: $200-$400 per pair.
Severity: Needs attention. Worn front suspension components are both a handling and safety issue.
Brakes
Cable Brake Adjustment (TC)
What happens: Brakes are weak, pull to one side, or require excessive pedal effort. One wheel may lock while others barely slow.
Why it happens: The TC’s mechanical (cable-operated) brakes require regular adjustment to maintain even braking across all four wheels. The cables stretch, the adjusters seize, and the brake drum clearances change as shoes wear. Any variation in adjustment between wheels causes uneven braking.
How to fix it: Adjust all four brake cables to equalise braking effort. Free seized adjusters with penetrating oil. Replace worn cables. Ensure brake shoes are in good condition and drums are not scored. This is a regular maintenance task, not a fix-once-and-forget item. Cost: minimal for adjustment; $200-$400 for new cables if needed.
Severity: Critical for safety. Uneven or weak brakes on a car without modern safety aids are dangerous.
Wheel Cylinder Leaks (TD/TF)
What happens: Spongy brake pedal, reduced braking power, visible fluid leak at a wheel.
Why it happens: The hydraulic wheel cylinders’ internal seals deteriorate with age. Brake fluid absorbs moisture over time, which corrodes the cylinder bore and damages the seals. Original brass cylinders may be pitted internally.
How to fix it: Rebuild or replace wheel cylinders. Stainless steel sleeved cylinders are available as an upgrade, they resist corrosion and last far longer. Flush and replace brake fluid every two years. Cost: $50-$100 per cylinder for rebuild kits; $100-$200 per cylinder for stainless-sleeved replacements.
Severity: Critical for safety. Brake fluid leaks lead to brake failure.
Electrical
Wiring Degradation
What happens: Intermittent electrical faults, lights flickering, gauges reading erratically, indicators not working, starter not engaging reliably.
Why it happens: Original wiring insulation (cotton-covered rubber or PVC) becomes brittle and cracks after 70 years. Exposed wiring shorts against bodywork. Connections corrode. Earth points lose conductivity.
How to fix it: Replace the entire wiring loom with a new reproduction harness. Complete harnesses are available from Autosparks, British Wiring, and MGCC suppliers. The T-Type wiring is simple enough that installation is a weekend job. Cost: $300-$500 for a complete harness.
Severity: Needs attention. Electrical shorts can cause fires, this is not a trivial concern in a car with a wooden frame.
Fuel Gauge Inaccuracy
What happens: The fuel gauge reads erratically, reads full when the tank is half empty, or doesn’t register at all.
Why it happens: The tank sender unit’s float mechanism or resistance wire fails. The Smiths gauge itself can also lose accuracy. Earthing problems between the tank sender and the gauge cause intermittent readings.
How to fix it: Clean and check the earth connection at the sender unit first. If the gauge still misbehaves, test the sender resistance with a multimeter and replace if out of spec. Rebuilt sender units are available. Cost: $80-$150 for a replacement sender.
Severity: Minor annoyance. Carry a dipstick or learn to judge fuel level by mileage.
Cooling
Water Pump Leaks
What happens: Coolant dripping from the water pump housing. Low coolant level. Overheating.
Why it happens: The water pump seal and bearings wear with age. The original water pump design uses a carbon face seal that deteriorates.
How to fix it: Rebuild or replace the water pump. Rebuild kits are available and the job is straightforward. Cost: $100-$200 for a rebuild kit; $200-$400 for a new pump.
Severity: Urgent. Loss of coolant circulation leads to overheating and engine damage.
Preventive Maintenance
To keep a T-Type reliable, follow this schedule:
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Grease the chassis every 1,000 miles or at each service. T-Types have numerous grease points, front suspension, kingpins (TC), trunnions (TD/TF), steering linkage, and propshaft. Carry a grease gun and use it regularly.
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Check oil level before every drive. These engines consume and leak oil, running low will destroy the bearings.
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Adjust brakes (TC) or check brake fluid (TD/TF) at every service. Brakes are your primary safety system.
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Check the wooden frame annually. Look for water ingress, staining, soft spots, and any panel misalignment. Catching rot early saves thousands.
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Service the dynamo annually. Check brush length, clean the commutator, and ensure the voltage regulator is functioning correctly.
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Inspect the hood and sidescreens for leaks. Water getting into the body is the number one cause of frame rot.
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Check coolant level and condition regularly. Use a quality corrosion inhibitor, the XPAG has mixed metals (iron block, aluminium head) that are prone to galvanic corrosion if coolant protection is inadequate.
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Change engine oil every 3,000 miles using 20W-50 mineral oil. The XPAG was designed for mineral oil and thrives on it. Short oil change intervals are cheap insurance against bearing wear.
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