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Technical Information (MGB 4)

Composite Leaf Spring Overview

Last Modified - 01/28/03

INCLUDES TECHNICAL ARTICLES MGB4 (1) MGB4 (2) MGB4 (3) MGB4 (4) MGB4 (5) MGB4 (6) MGB4 (7) & MGB4 (8)

For over 10 years British Automotive has been developing and marketing composite springs for the MGA and MGB models. During this period we have seen design changes, which have resulted in the improvement of this product.

Thanks to customer feedback over these years, we now only market the 135# series composite spring sets.

Improvement in the composite springs has been in the changes made to the front spring eye mounting design. The following is a recap of these design changes:

1…….MGB OEM silent block bushings

2…….Split polyurethane bushings (without Delrin thrust washers)

3…….Split Delrin bushings (without Delrin thrust washers)

4…….Split Delrin bushings (with Delrin thrust washers and optional polyurethane insert kit)

5…….Split Delrin bushings with polyurethane insert kit.(current design).


Designs 1 or 2 can not be modified to design 5 specifications.

Design 3 can be modified to design 5 specifications as follows:

NOTE: springs must be removed from the vehicle.

! DO NOT ATTEMPT TO REMOVE THE SPLIT DELRIN BUSHINGS FROM THE EYE BRACKET! The following operation must be undertaken with bushings intact within the spring.

Machine down each Delrin bushing face approximately .0625". Install polyurethane insert kit.


Design 4 can be modified to design 5 specifications as follows:

Remove Delrin thrust washers and simply install polyurethane insert kit.
British Automotive will provide customers who have designs 3 & 4 with the polyurethane insert kit, along with appropriate lubricant, at no charge. However, shipping and handling charges will apply.

For additional information select from one of the following categories:

MGB4(1)...An Introduction to Composite Springs

MGB4(2)...MGB Vehicle Weights

MGB4(3)...MGB Vehicle Lean Problems

MGB4(4)...MGB Anticipated Ride Heights

MGB4(5)...Marketing Update

MGB4(6)...General Installation Instructions

MGB4(7)...Rear Ride Height Adjustable Shackle Pin Kit

MGB4(8)...Rear Telescopic Shock Absorber Choices