MG Trouble Shooting Guide

First published in "Abingdon Classics" November, 1981

Brakes | Engine | Steering | Fuel | Electrical | Clutch | Cooling


Excessive brake pedal travel Brakes need adjusting or replacement.
Air in system.
Faulty master cylinde.
Leaking or contaminated fluid.
Adjust or renew brake shoes.
Bleed hydraulic system.
Fit new master cylinder.
Bleed hydraulic system.
Brake fade Incorrect pad or lining material.
Old or contaminated fluid.
Excessive use of brakes or car overloaded.
Fit new pads or shoes.
Renew brake fluid.
Check vehicle load.
Spongy brake pedal Air in hydraulic system.
Shoes badly lined or distorted.
Faulty hydraulic cylinder.
Bleed system.
Fit new pads or shoes.
Check hydraulic circuit.
Brake pedal too hard Seized wheel cylinder or caliper piston
Glazed fiction material
Replace seized component.
Fit new shoes/pads.
Brake pedal requires pumping or loss of pedal Brakes wrongly adjusted
Air in hydraulic system
Fluid leak from component or brake pipe

Loss of fluid from master cylinder

Adjust brakes.
Bleed system.
Check hydraulic circuit and replace parts as necessary.
Check hydraulic circuit and replace parts as necessary.
Brakes grab when applied Contaminated friction material

Wrong linings fitted

Scored drums or discs
Replace (don't clean) pads or shoes.
Replace (don't clean) pads or shoes.
Fit new drum or disc.
Brake squeal Worn retaining pins (disc)
Faulty damping shims or shoe retaining clips
Dust in drum
Loose backplate or caliper
Fit new pins.
Fit new shims or clips.
Remove dust from drums and shoe.
Tighten caliper or backplate.
Brake shudder No clearance at master cylinder operating rod
Shoe tension springs either broken or week
Wheel cylinder or caliper piston seizing
Faulty self-adjusting mechanism
Seized handbrake mechanism
Adjust rod if possible.

Replace tension springs
Fit new caliper or cylinder.
Check mechanism.
Check handbrake operation.
Brake pull to one side only Contaminated friction material on one side (grease, oil or brake fluid)
Loose backplate
Seized cylinder
Faulty suspension or steering
Replace shoes/pads all around.

Tighten backplate.
Replace seized cylinder.
Check suspension and steering.
Handbrake ineffective Worn rear shoes or pads
Brakes require adjusting
Faulty handbrake linkage

Cable or rod requires adjustment
Fit new pads/shoes.
Adjust brakes
Check linkage and operating mechanism.
Adjust cable or rod.
Servo (where fitted) late in operation blocked filter
Bad vacuum sealing or restricted air inlet

Clean or replace filter.
Tighten vacuum hose connections and check hoses
Loss of servo action when braking heavily Air leak in servo-vacuum low Either overhaul servo or replace
Loss of fluid (servo only) Seal failure
Scored servo bores
Damaged or corroded fluid pipes
Replace or overhaul servo.
Replace or overhaul servo.
Inspect and fit new pipes.

Index | Engine | Steering | Fuel | Electrical | Clutch | Cooling


Lack of compression Faulty valve seat, excessive wear in
stem or guide.

Faulty head gasket.
Worn pistons, rings and bores.

Recut seat and valve, fit new guide and valve.
Fit new gasket or reface head.
Either fit new rings, or if badly worn, fit new pistions and rings, and have block rebored.
Piston slap As #3 above. As #3 above.
Smoke from exhaust
Lack of power
As above.
Blocked crankcase breather.
As above.
Check breathing apparatus.
Noisy tappet (with correct clearance) Wear in rocker pad face and/or rocker sleeve and shaft (OHV).
Worn cam follower (OHC).
Reface pad surface, replace rockers or shaft (OHV).
Fit new followers (OHC).
Big-end knock Wear between big-end shell and crankcase. Wrong torque on bolts. Depending on wear, fit new shells, regrind crankshaft and check torque
Mains rumble Wear between main bearing shells and crankshaft. As Above
Cam follower tap Camshaft worn or follower dished. Examine and replace followers or camshaft. Or Both
Knocking when clutch depressed. Movement at crank pulley Excessive crankshaft end-float.
Wear between crank and thrust washer.
Fit new thrust washers and recheck clearance.
Clattering from front of engine Excessive or slack timing chain, worn chain tensioner. Fit new chain and tensioner. Adjust chain were necessary.
Small-end or gudgion pin knock Excessive wear between gudgeon pin and con-rod. Fit new bush or con-rod.
Lack of oil pressure Excessive wear in crankshaft journals.
Faulty oil pump.
Blocked oil pick-up strainer.
Faulty pressure-relief valve.
Blocked oil filter.
Lack of oil
Overhaul engine.
Fit new pump.
Clean pick-up.
Fit new relief valve.
Fit new filter.
Install fresh oil.
Oil leaks Sump gaskets or packings.
Front and rear crankshaft oil seal.
Rocker or camshaft gasket.
Oil filter.
Fit new gaskets.
Fit new seals.
Fit new gasket.
Check filter seal.
Lack of power (engine in good condition) Faulty ignition timing.
Faulty sparking plugs, points or condenser.
Wrong valve clearance.
Tune engine.

Brakes | Index | Steering | Fuel | Electrical | Clutch | Cooling


Steering feels stiff               
Low tire pressures
Incorrect wheel alignment
Stiff track rod ends
Steering box/rack needs adjustment 
Correct tire pressures.
Correct wheel alignment.
Check and replace if necessary.
Adjust if necessary. 
Steering wheel shakes Wheels and tires need balancing
Tire pressures incorrect

Incorrect wheel aligment
Wheel hub nut loose

Wheel bearings damaged
Front suspension distorted
Steering box/rack needs adjustment
Shock absorbers faulty
Balance as necessary.

Correct alignment.

Adjust wheel bearings.

Replace wheel bearings.
Check, repair or replace.

Adjust as necessary.

Replace as nessary.
Steering pulls to one side Uneven tire pressure
Wheel alignment incorrect
Wheel bearings worn or damaged
Brakes improperly adjusted
Shock absorbers faulty
Suspension distorted

Steering box/rack worn

Replace and adjust.
Adjust brakes.

Check and rectify.

Check and rectifly.

Adjust and replace.
Wheel tramp Over-inflated tires
Unbalanced tire and wheel

Defective shock absorber

Defective tire
Correct pressure.
Check and balance if necessary. Check and rectify.
Repair or replace.
Abnormal tire wear Incorrect tire pressure
Incorrect wheel alignment
Excessive wheel bearing play
Improper driving

Check pressures.
Check wheel alignment.

Adjust wheel bearings.

Avoid sharp turning at high speeds, rapid starting and braking, etc.
Tire noises Improper tire inflation
Incorrect wheel alignment
Correct tire pressures.
Correct wheel alignment.

Brakes | Engine | Index | Fuel | Electrical | Clutch | Cooling

Flooding Improper seating or damaged float needle valve or seat
Incorrect float level
Fuel pump has excessive pressure
Check and replace parts as necessary.
Adjust float level.

Check fuel pump.
Excessive fuel consumption Engine out of tune
Float level too high
Loose plug or jet
Defective gasket
Fuel leaks at pipes or connections Choke valve operates improperly Obstructed air bleed
Tune engine.
Adjust float lever.
Tighten plug or jet.
Replace gaskets.
Trace leak and rectify.
Check choke valve.
Check and clear.
Stalling Main jet obstructed
Incorrect throttle opening
Slow-running adjustment incorrect Slow-running fuel jet blocked
Incorrect float level
Clean main jet.
Adjust throttle.
Adjust slow-running.
Clean jet.
Adjust float leverl.
Poor acceleration
Defective accelerator pump (if fitted) Float level too low
Incorrect throttle opening
Defective accelerator linkage
Blocked pump jet
Overhaul pump.
Adjust float lever.
Adjust throttle.
Adjust accelerator linkage.
Clean pump jet.
Spitting Lean mixture
Dirty Carburetor
Clogged fuel pipes
Manifold draws secondary air
Clean and adjust carburetor.
Clean carburetor.
Clean and replace pipes.
Tighten or replace gasket.
Insufficient fuel supply No fuel in tank!
Clogged fuel pipe
Dirty fuel
Air in fuel system
Defective fuel pump
Clogged fuel filter
Get Gas!
Dismantle and clean carb
Clean fuel pipe - fuel tank.
Check connections, tighten.
Repair or replace fuel pump.
Clean or replace filter.
Loss of fuel delivery No fuel in tank!
Pump faulty (electric)
Slotted body screws loose Diaphragm cracked
Loose fuel pipe connections
Defective valves

Cracked fuel pipes
Get Gas!
Replace pump.
Tighten body screws.
Overhaul fuel pump.
Tighten fuel pipe connections. Replace valves.
Replace fuel pipes.
Noisy pump Loose pump mounting
Worn or defective rocker arm (if manual)
Broken rocker arm spring (if manual)
Tighten mounting bolts.
Replace rocker arm. Replace spring.

Brakes | Engine | Steering | Index | Electrical | Clutch | Cooling


Starter doesn't turn (lights dim) Battery flat or worn
Bad connection in battery circuit
Charge or fit new battery.
Check all feed and earth connections.
starter doesn't turn (lights stay
Faulty ignition switch
Broken starter circuit
Check switch.
Check starter circuit.
Solenoid switch chatters Flat battery Charge or replace battery
Starter just spins Bendix gear sticking Remove starter and clean or replace Bendix gear.
Low or no charge rate Broken or slipping drive belt Poor connections on or faulty alternator. Fit new belt. Check and replace alternator.
No lights (or very dim) Flat or faulty battery, bad battery connections Check battery and connections.
Side and rear lights inoperative although stoplights and flashers
Fuse blown Fit correct value fuse
One lamp fails Blown bulb
Poor bulb contact
Bad earth connection
Broken feed
Fit new bulb.
Check connections.
Check connection.
Check feed.
Flasher warning bulb stays on or flashes twice as fast Faulty bulb or connection on front or rear of offending side Fit new bulb, make good connection.
Lights dim when idling or at low speed Loose drive belt
Flat battery
Faulty charging circuit
Tighten belt.
Check charge output and battery.
Check charge output and battery.
One dim light Blackened bulb
Bad earth
Tarnished reflector
Fit new bulb or sealed-beam.
Check earth connections.
Fit new bulb or sealed-beam.
Wipers do not work Blown fuse Poor connection Faulty switch Faulty motor Fit fuse. Check connections Check switch. remove and examine motor.
Motor operates slowly Excessive resistance in circuit or wiper drive worn brushes Check wiper circuit. Remove motor and check brushes.

Brakes | Engine | Steering | Fuel | Index | Clutch | Cooling

Clutch slips Clutch facing worn
Clutch facing contaminated
Warped clutch cover or pressure plate
Incorrect adjustment (if adjustable)
Replace clutch assembly.
Replace clutch assembly.
Replace clutch assembly.
Adjust clutch.
Clutch drags faulty clutch hydraulics (if hydraulic)

Faulty clutch adjustment (if adjustable)
Clutch disc warped
Clutch hub spines worn or rusty
Diaphragm worn or mal-adjusted
Overhaul or replace clutch hydraulics.
Adjust clutch.
Replace clutch disc.
Replace or lubricate clutch.
Replace pressure plate
Clutch chatter Faulty pressure plate
Faulty clutch disc
Loose or worn engine mounting
Replace pressure plate.
Replace clutch disc.
Replace mounting.
Clutch noise Insufficient grease on bearing sleeve
Clutch installed incorrectly
Check installation.
Clutch noise (pedal down) Faulty release bearing Replace bearing
Clutch noise (pedal on the way up) Damaged or worn pilot bearing Fit new bearing
Clutch grabs Contaminated clutch lining
Clutch worn or loose rivets
Clutch splines worn or rusted
Warped flywheel or pressure plate
Loose mountings on engine or power unit.
Replace clutch.
Replace clutch.
Clean or replace.
Repair or replace.
Tighten or replace.

Brakes | Engine | Steering | Fuel | Electrical | Index | Cooling


Overheating Inoperative thermostat
Radiator fin choked with mud, leaves, etc.
Incorrect ignition and valve timing
Dirty oil and sludge in engine
Inoperative water pump
Loose fan belts
Restricted radiator
Inaccurate temperature gauge
Impurity in water
Replace thermostat
Clean out air passage.

Tune engine.
Change engine oil and filter.
Replace (or check electrical).
Adjust tension.
Flush Radiator.
Replace temperature gauge.
Use soft, clean water.
Loss of coolant Leaking radiator hose(s)
Damaged radiator
Leak at heater connection or plug
Damaged cylinder head gasket

Cracked cylinder block

Cracked cylinder head

Loose cylinder head bolts
Bad heater control valve
Repair or replace radiator.
Repair or replace.
Replace gasket. Check engine oil and refill as necessary.
Replace cylinder block. Check engine oil in crankcase for mixing with water.
Replace cylinder head.
Tighten cylinder head bolts.
Replace and dry out distributer.
Inoperative thermostat
Inaccurate temperature gauge
Replace thermostat.
Replace temperature gauge.
Poor circulation
Restriction in system

Insufficient coolant
Inoperative water pump
Loose fan belt
Inoperative thermostat
Check hoses for crimping. Clear the system of rust and sludge.
Replace water pump.
Adjust fan belt.
Replace thermostat
Corrosion Excessive impurity in water Infrequent flushing and draining of system Use soft, clean water.
Flush thoroughly at least twice a year.

Brakes | Engine | Steering | Fuel | Electrical | Cooling | Index