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MOTRS

MGB GT V8

1973-1976 / Coupe / United Kingdom

All MGB GT V8 problems All workshop issues
Common Electrical

Lucas Alternator and Charging Failures

Symptoms

Dim lights, slow cranking, dead battery, charging light on the dashboard.

Cause

The Lucas alternator's brushes wear, the voltage regulator fails, and the bearings give out. On early cars with generators, the commutator wears and the brushes make poor contact.

Fix

  1. 1 Rebuild or replace the alternator. A modern replacement alternator ($100--200) is a practical upgrade. Ensure all earth connections are clean and tight -
  2. 2 poor earths cause more electrical problems on MGBs than component failures
Cost mentioned in fix
$100

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Other known issues

Common Electrical

Earth (Ground) Connection Corrosion

Intermittent electrical failures, dim lights on one side, instruments reading incorrectly, indicators flashing at wrong speed.
Common Electrical

Ignition Component Failure

Sudden engine death, misfiring, no-start condition.
Minor Body and Structure

Sill Corrosion (Inner and Outer)

The outer sill skin bubbles, softens, and eventually perforates. In advanced cases, the outer sill crumbles when prodded. The inner sill -- the structural member -- rots from inside the box section and loses its load-bearing capacity.
Critical Body and Structure

Floor Pan Corrosion

Soft or perforated floor pans, particularly in the footwells and under the seats. Wet carpet is a telltale sign. In severe cases, you can see the road through the floor.
Minor Body and Structure

A-Post Corrosion

Rust at the base of the windscreen pillars where they meet the scuttle panel. This area can be invisible until advanced.
Minor Body and Structure

Door Skin Corrosion

Rust along the bottom edge of each door, working upward from the inside.
View all 18 MGB GT V8 problems