Brakes
Problem Solvers
MG Troubleshooting Guide
First published in "Abingdon Classics", November, 1981
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Brakes Problem Solvers |
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| Excessive brake
pedal travel |
1. Brakes need adjusting or replacement.
2. Air in system. 3. Faulty master cylinder. 4. Leaking or contaminated fluid. |
1. Adjust or renew brake shoes.
2. Bleed hydraulic system. 3. Fit new master cylinder. 4. Bleed hydraulic system. |
| Brake fade | 1. Incorrect pad or lining material.
2. Old or contaminated fluid. 3. Excessive use of brakes or car overloaded. |
1. Fit new pads or shoes.
2. Renew brake fluid. 3. Check vehicle load. |
| Spongy brake pedal | 1. Air in hydraulic system.
2. Shoes badly lined or distorted. 3. Faulty hydraulic cylinder. |
1. Bleed system.
2. Fit new pads or shoes. 3. Check hydraulic circuit. |
| Brake pedal too hard | 1. Seized wheel cylinder or caliper piston
2. Glazed fiction material |
1. Replace seized component.
2. Fit new shoes/pads |
| Brake pedal requires
pumping or loss of pedal |
1. Brakes wrongly adjusted
2. Air in hydraulic system 3. Fluid leak from component or brake pipe 4. Loss of fluid from master cylinder |
1. Adjust brakes.
2. Bleed system. 3. Check hydraulic circuit and replace parts as necessary. 4. Check hydraulic circuit and replace parts as necessary. |
| Brakes grab when
applied |
1. Contaminated friction material
2. Wrong linings fitted 3. Scored drums or discs |
1. Replace (don't clean) pads or shoes.
2. Replace (don't clean) pads or shoes. 3. Fit new drum or disc. |
| Brake squeal | 1. Worn retaining pins (disc)
2. Faulty damping shims or shoe retaining clips 3. Dust in drum 4. Loose back plate or caliper |
1. Fit new pins.
2. Fit new shims or clips. 3. Remove dust from drums and shoe. 4. Tighten caliper or back plate. |
| Brake shudder | 1. No clearance at master cylinder operating rod
2. Shoe tension springs either broken or weak 3. Wheel cylinder or caliper piston seizing 4. Faulty self adjusting mechanism 5. Seized hand brake mechanism |
1. Adjust rod if possible.
2. Replace tension springs 3. Fit new caliper or cylinder. 4. Check mechanism. 5. Check hand brake operation. |
| Brake pull to one side only | 1. Contaminated friction material on one side
(grease, oil or brake fluid) 2. Loose back plate 3. Seized cylinder 4. Faulty suspension or steering |
1. Replace shoes/pads all around.
2. Tighten back plate. 3. Replace seized cylinder. 4. Check suspension and steering. |
| Hand brake ineffective | 1. Worn rear shoes or pads
2. Brakes require adjusting 3. Faulty hand brake linkage 4. Cable or rod requires adjustment |
1. Fit new pads/shoes.
2. Adjust brakes 3. Check linkage and operating mechanism. 4. Adjust cable or rod. |
| Servo (where fitted)
late in operation |
1. Blocked filter
2. Bad vacuum sealing or restricted air inlet |
1. Clean or replace filter.
2. Tighten vacuum hose connections and check hoses |
| Loss of servo action
when braking heavily |
1. Air leak in servo-vacuum low | 1. Either overhaul servo or replace |
| Loss of fluid
(servo only) |
1. Seal failure
2. Scored servo bores 3. Damaged or corroded fluid pipes |
1. Replace or overhaul servo.
2. Replace or overhaul servo. 3. Inspect and fit new pipes. |
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Engine Problem Solvers |
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| Lack of compression | 1. Faulty valve seat, excessive wear in stem or guide.
2. Faulty head gasket. 3. Worn pistons, rings and bores. |
1. Recut seat and valve, fit new guide and valve.
2. Fit new gasket or reface head. 3. Either fit new rings, or if badly worn, fit new pistons and rings, and have block rebored. |
| Piston slap | 1. As #3 above. | 1. As #3 above. |
| Smoke from exhaust
Lack of power |
1. As above.
2. Blocked crankcase breather. |
1. As above.
2. Check breathing apparatus. |
| Noisy tappet
(with correct clearance) |
1. Wear in rocker pad face and/or
rocker sleeve and shaft (OHV). 2. Worn cam follower (OHC). |
1. Re-face pad surface, replace rockers
or shaft (OHV). 2. Fit new followers (OHC). |
| Big-end knock | 1. Wear between big-end shell and
crankcase. Wrong torque on bolts. |
1. Depending on wear, fit new shells,
regrind crankshaft and check torque |
| Mains rumble | 1. Wear between main bearing shells and crankshaft. | 1. As Above |
| Cam follower tap | 1. Camshaft worn or follower dished. | 1. Examine and replace followers or
camshaft, or both |
| Knocking when clutch depressed. Movement at crank pulley | 1. Excessive crankshaft end-float.
2. Wear between crank and thrust washer. |
1. Fit new thrust washers and recheck clearance. |
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Clattering from front of engine |
1. Excessive or slack timing chain, worn chain tensioner. | 1. Fit new chain and tensioner. Adjust
chain where necessary. |
| Small-end or gudgeon
pin knock |
1. Excessive wear between gudgeon
pin and con-rod. |
1. Fit new bush or con-rod. |
| Lack of oil pressure | 1. Excessive wear in crankshaft journals.
2. Faulty oil pump. 3. Blocked oil pick-up strainer. 4. Faulty pressure-relief valve. 5. Blocked oil filter. 6. Lack of oil |
1. Overhaul engine.
2. Fit new pump. 3. Clean pick-up. 4. Fit new relief valve. 5. Fit new filter. 6. Install fresh oil. |
| Oil leaks | 1. Sump gaskets or packings.
2. Front and rear crankshaft oil seal. 3. Rocker or camshaft gasket. 4. Oil filter. |
1. Fit new gaskets.
2. Fit new seals. 3. Fit new gasket. 4. Check filter seal. |
| Lack of power (engine in
good condition) |
1. Faulty ignition timing. Faulty sparking plugs, points or condenser.
Wrong valve clearance. |
1. Tune engine. |
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Steering Problem Solvers |
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| Steering feels stiff | 1. Low tire pressures
2. Incorrect wheel alignment 3. Stiff track rod ends 4. Steering box/rack needs adjustment |
1. Correct tire pressures.
2. Correct wheel alignment. 3. Check and replace if necessary. 4. Adjust if necessary. |
| Steering wheel
shakes |
1. Wheels and tires need balancing
2. Tire pressures incorrect 3. Incorrect wheel alignment 4. Wheel hub nut loose 5. Wheel bearings damaged 6. Front suspension distorted 7. Steering box/rack needs adjustment 8. Shock absorbers faulty |
1. Correct.
2. Correct alignment. 3. Adjust wheel bearings. 4. Replace wheel bearings. 5. Check, repair or replace. 6. Adjust as necessary |
| Steering pulls to
one side |
1. Uneven tire pressure
2. Wheel alignment incorrect 3. Wheel bearings worn or damaged 4. Brakes improperly adjusted 5. Shock absorbers faulty 6. Suspension distorted 7. Steering box/rack worn |
1. Correct.
2. Correct. 3. Replace and adjust. 4. Adjust brakes. 5. Check and rectify. 6. Check and rectify. 7. Adjust and replace. |
| Wheel tramp | 1. Over inflated tires
2. Unbalanced tire and wheel 3. Defective shock absorber 4. Defective tire |
1. Correct pressure.
2. Check and balance if necessary. 3. Check and rectify. 4. Repair or replace. |
| Abnormal tire wear | 1. Incorrect tire pressure
2. Incorrect wheel alignment 3. Excessive wheel bearing play 4. Improper driving |
1. Check pressures.
2. Check wheel alignment. 3. Adjust wheel bearings. 4. Avoid sharp turning at high speeds, rapid starting and braking, etc. |
| Tire noises | 1. Improper tire inflation
2. Incorrect wheel alignment |
1. Correct tire pressures.
2. Correct wheel alignment. |
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Fuel Problem Solvers |
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| Flooding | 1. Improper seating or damaged
float needle valve or seat 2. Incorrect float level 3. Fuel pump has excessive pressure |
1. Check and replace parts
as necessary. 2. Adjust float level. 3. Check fuel pump. |
| Excessive fuel
consumption |
1. Engine out of tune
2. Float level too high 3. Loose plug or jet 4. Defective gasket 5. Fuel leaks at pipes or connections 6. Choke valve operates improperly 7. Obstructed air bleed |
1. Tune engine.
2. Adjust float level. 3. Tighten plug or jet. 4. Replace gaskets. 5. Trace leak and rectify. 6. Check choke valve. 7. Check and clear. |
| Stalling | 1. Main jet obstructed
2. Incorrect throttle opening 3. Slow-running adjustment incorrect 4. Slow-running fuel jet blocked 5. Incorrect float level |
1. Clean main jet.
2. Adjust throttle. 3. Adjust slow-running. 4. Clean jet. 5. Adjust float level. |
| Poor acceleration | 1. Defective accelerator pump (if fitted)
2. Float level too low 3. Incorrect throttle opening 4. Defective accelerator linkage 5. Blocked pump jet |
1. Overhaul pump.
2. Adjust float lever. 3. Adjust throttle. 4. Adjust accelerator linkage. 5. Clean pump jet. |
| Spitting | 1. Lean mixture
2. Dirty Carburetor 3. Clogged fuel pipes 4. Manifold draws secondary air |
1. Clean and adjust carburetor.
2. Clean carburetor. 3. Clean and replace pipes. 4. Tighten or replace gasket. |
| Insufficient fuel
supply |
1. Clogged carburetor
2. Clogged fuel pipe 3. Dirty fuel 4. Air in fuel system 5. Defective fuel pump 6. Clogged fuel filter |
1. Dismantle and clean carburetor.
2. Clean fuel pipe. 3. Clean fuel tank. 4. Check connections and tighten. 5. Repair or replace fuel pump. 6. Clean or replace filter. |
| Loss of fuel delivery | 1. Pump faulty (electric)
2. Slotted body screws loose 3. Diaphragm cracked 4. Loose fuel pipe connections 5. Defective valves 6. Cracked fuel pipes |
1. Replace pump.
2. Tighten body screws. 3. Overhaul fuel pump. 4. Tighten fuel pipe connections. 5. Replace valves. 6. Replace fuel pipes. |
| Noisy pump | 1. Loose pump mounting
2. Worn or defective rocker arm (if manual) 3. Broken rocker arm spring (if manual) |
1. Tighten mounting bolts.
2. Replace rocker arm. 3. Replace spring. |
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Electrical Problem Solvers |
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| STARTER | ||
| Starter doesn't turn
(lights dim) |
1. Battery flat or worn
2. Bad connection in battery circuit |
1. Charge or fit new battery.
2. Check all feed and earth connections. |
| Starter doesn't turn
(lights stay bright) |
1. Faulty ignition switch
2. Broken starter circuit |
1. Check switch.
2. Check starter circuit. |
| Solenoid switch chatters | 1. Flat battery | 1. Charge or replace battery |
| Starter just spins | 1. Bendix gear sticking | 1. Remove starter and clean or
replace Bendix gear. |
| CHARGING CIRCUIT | ||
| Low or no charge rate | 1. Broken or slipping drive belt
2. Poor connections on or faulty alternator. |
1. Fit new belt.
2. Check and replace alternator. |
| LIGHTING CIRCUIT | ||
| No lights (or very dim) | 1. Flat or faulty battery,
bad battery connections |
1. Check battery and connections. |
| Side and rear lights inoperative
although stoplights and flashers work |
1. Fuse blown | 1. Fit correct value fuse |
| One lamp fails | 1. Blown bulb
2. Poor bulb contact 3. Bad earth connection 4. Broken feed |
1. Fit new bulb.
2. Check connections. 3. Check connection. 4. Check feed. |
| Flasher warning bulb stays on
or flashers twice as fast |
1. Faulty bulb or connection on
front or rear of offending side |
1. Fit new bulb, make good
connection. |
| Lights dim when idling or
at low speed |
1. Loose drive belt
2. Flat battery 3. Faulty charging circuit |
1. Tighten belt.
2. Check charge output and battery. 3. Check charge output and battery. |
| One dim light | 1. Blackened bulb
2. Bad earth 3. Tarnished reflector |
1. Fit new bulb or sealed beam.
2. Check earth connections. 3. Fit new bulb or sealed beam |
| WINDSCREEN WIPERS | ||
| Wipers do not work | 1. Blown fuse
2. Poor connection 3. Faulty switch 4. Faulty motor |
1. Fit fuse.
2. Check connections 3. Check switch. 4. Remove and examine motor. |
| Motor operates slowly | 1. Excessive resistance in circuit
or wiper drive 2. Worn brushes |
1. Check wiper circuit.
2. Remove motor and check brushes. |
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Clutch Problem Solvers |
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| Clutch slips | 1. Clutch facing worn
2. Clutch facing contaminated 3. Warped clutch cover or pressure plate 4. Incorrect adjustment (if adjustable) |
1. Replace clutch assembly.
2. Replace Clutch assembly. 3. Replace clutch assembly. |
| Clutch drags | 1. Faulty clutch hydraulics (if hydraulic)
2. Faulty clutch adjustment (if adjustable) 3. Clutch disc warped 4. Clutch hub spines worn or rusty 5. Diaphragm worn or mal-adjusted |
1. Overhaul or replace clutch
hydraulics. 2. Adjust clutch. 3. Replace clutch disc. 4. Replace or lubricate clutch. 5. Replace pressure plate |
| Clutch chatter | 1. Faulty pressure plate
2. Faulty clutch disc, loose or worn engine mounting |
1. Replace pressure plate.
2. Replace clutch disc. 3. Replace mounting |
| Clutch noise | 1. Insufficient grease on bearing sleeve
2. Clutch installed incorrectly |
1. Lubricate
2. Check installation. |
| Clutch noise
(pedal down) |
1. Faulty release bearing | 1. Replace bearing |
| Clutch noise
(pedal on the way up) |
1. Damaged or worn pilot bearing | 1. Fit new bearing |
| Clutch grabs | 1. Contaminated clutch lining
2. Clutch worn or loose rivets 3. Clutch splines worn or rusted 4. Warped flywheel or pressure plate 5. Loose mountings on engine or power unit. |
1. Replace clutch.
2. Replace clutch. 3. Clean or replace. 4. Repair or replace. 5. Tighten or replace. |
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Cooling Problem Solvers |
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| Overheating | 1. Inoperative thermostat
2. Radiator fin choked with mud, leaves, etc. 3. Incorrect ignition and valve timing 4. Dirty oil and sludge in engine 5. Inoperative water pump 6. Loose fan belts 7. Restricted radiator 8. Inaccurate temperature gauge 9. Impurity in water |
1. Replace thermostat
2. Clean out air passage. 3. Tune engine. 4. Change engine oil and filter. 5. Replace (or check electrical). 6. Adjust tension. 7. Flush Radiator 8. Replace temperature gauge. 9. Use safe, clean water. |
| Loss of coolant | 1. Leaking radiator hose(s)
2. Damaged radiator 3. Leak at heater connection or plug 4. Damaged cylinder head gasket 5. Cracked cylinder block 6. Cracked cylinder head 7. Loose cylinder head bolts |
1. Replace.
2. Repair or replace radiator. 3. Repair or replace. 4. Replace gasket. Check engine oil and refill as necessary. 5. Replace cylinder block. Check engine oil in crankcase for mixing with water. 6. Replace cylinder head. 7. Tighten cylinder head bolts. |
| Overcooling | 1. Inoperative thermostat
2. Inaccurate temperature gauge |
1. Replace thermostat.
2. Replace temperature gauge. |
| Poor circulation | 1. Restriction in system
2. Insufficient coolant 3. Inoperative water pump 4. Loose fan belt 5. Inoperative thermostat |
1. Check hoses for crimping.
Clear the system of rust and sludge. 2. Replenish. 3. Replace water pump. 4. Adjust fan belt. 5. Replace thermostat |
| Corrosion | 1. Excessive impurity in water
2. Infrequent flushing and draining of system |
1. Use soft, clean water.
2. Flush thoroughly at least twice a year. |
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