Technical Information (MGB 4D)

MGB and MGA Front Eye Mount Repair Kits

Last Modified - 9/20/04

British Automotive has introduced two different replacement front eye-mounting kits for both the MGA and MGB composite spring application. These two kits are designated minor and major

It was necessary to introduce these repair kits to satisfy owners who have experienced unusual composite spring front bushing wear characteristics with MGA DESIGN 2 and MGB DESIGNS 3, 4 or 5 as outlined further on in this article.

It would appear that the rear shackle eye design is satisfactory, therefore, no upgrades are being considered at this time.

In regard to the above, we have looked into the cause(s) of these conditions, and concluded that lateral movement of the rear axle assembly is the primary cause for both of these problems. This movement is further exaggerated through aggressive driver techniques.

Of a secondary nature, during the composite spring installation process, we have always indicated the importance of deburring and smoothing the inner surfaces of the front spring mounting abutments. I am not too sure exactly how many installers bother to take notice of this point.

I would like to point out that we have always, as outlined in the appropriate technical article(s), recommended the installation of a panhard rod assembly (MGB tube axles only) to compliment the installation of composite springs. When installed, this component virtually eliminates the lateral rear axle movement as outlined above.

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MGA AND MGB REPAIR KIT (MINOR)

P0002715

The above kit, part number MINOR/KITA or MINOR/KITB is applicable to the designs below:

MGA Design 2.

MGB Designs 3. 4. & 5

The kit contains the following:

2 - .565" OD x .447" ID x 2" (MGA) Insert tubes.

OR Part Number BUSH/TUBE

2 - ,565" OD x .447" ID x 2.125" (MGB) Insert tubes

4 - Replacement polyurethane insert bushings. " " U-61120-RD

2 - Prothane Teflon lube tubes. " " TEF/LUBE

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MGA & MGB INSTALLATION INSTRUCTIONS (MINOR)

NOTE: To carry out this operation, it is not necessary to remove the entire composite spring assembly from the vehicle. However, if the split shouldered Delrin bushings have not been further secured within their respective front eyes, or if the Delrin bushings need to be replaced, we highly recommend their removal. Further information follows in this article.

To allow for full rear axle defection, in all probability, it will be necessary to remove the rear section of the exhaust system.

Upon assembly be sure to liberally coat all bushings, tubes and hardware with the supplied lubricant. This includes the rear spring shackle as well.

During installation, do not overtighten hardware. Final tightening should be carried out with vehicle on the ground, ramps or such.

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1. Jack up vehicle and place axle stands slightly forward of the front spring mounting abutment.

2. Lower vehicle down until the axle is supported by the axle check straps.

3. Remove road wheels.

4. Remove rear section of exhaust.

5. Raise rear axle and remove axle check straps.

6. Lower rear axle to allow for full axle deflection.

7. Working with one side only, reposition jack to one side of the axle tube, and support.

8. Remove both the shackle pin assembly and front spring eye hardware.

9. Lower jack until front spring eye is clear of mounting abutment.

10. Remove old polyurethane bushings and tube. Install new bushings and tube.

11. Re-install both the shackle pin assembly and front spring eye hardware.

12. Position jack to the other side of the axle tube, and continue with same.

Reverse operations 1 thru 12.

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MGA FRONT SPRING EYE DESIGNS

Over the years there has been only two MGA composite front spring eye design changes. These are as follows:

DESIGN 1. Split .0625" shouldered Delrin bushings with OEM silent block bushing

inserted within.

NOTE: This type of bushing must be secured with 2- 1/4" SAE x 7/16" Allen

drive set screws. Use either drill bit #3 (.213") or 7/32" (.2187").

DESIGN 2. Split .0625" shouldered Delrin bushings with polyurethane insert bushings

(Current design)

NOTE: Delrin bushings must be secured within the front eye with the addition

of 1/4" SAE x 5/16" Allen drive set screws, or 3/16" x 5/16" split roll pins.

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MGA REPAIR KIT (MAJOR)

P0002725

NOTE: The above kit, part number MAJOR/KITA, is applicable to both DESIGN 1 & DESIGN 2.

This kit contains the following:

4 - .0625" split shouldered Delrin support bushings.

4 - 1/4" SAE x 5/16" Allen drive set screws.

4 - 3/16" x 5/16" Split roll pins.

4 - Replacement polyurethane insert bushings.

4 - .007" Brass shim stock.

2 - .565" OD x .447" ID x 2" Insert tubes.

8- 3/8" SAE grade 8 nyloc nuts.

2 - Prothane Teflon lube tubes.

MGA INSTALLATION INSTRUCTIONS (MAJOR)

The following instructions should be read in conjunction with the appropriate section of the MGA workshop manual covering rear road spring replacement.

With the composite spring removed from the vehicle carry out the following:

1 - Remove any securing hardware as indicated in DESIGN 1 or DESIGN 2 above.

2 - Remove either DESIGN 1 OEM silent block bushing, or DESIGN 2 insert tubes and

polyurethane insert bushings, from the spring eye.

3 - Along with a small hammer, use a putty knife between the shoulder of the split Delrin

bushing and spring eye. Tap around the periphery of the Delrin bushings to force

them out of the spring eye.

4 - If fitted, remove existing brass shim stock .007" from within the spring eye.

5 - Using coarse sandpaper thoroughly cleanup any epoxy within the spring eye. The

inner surface must be smooth before installing new bushings.

6 - Trial fit new bushings within the spring eye.

7 - If required, wrap .007" brass shim stock around Delrin bushings. Insert bushings

into spring eye with the gap facing the spring blade. Be careful not to distort brass

shim stock. Use of a soft jawed bench vise would be ideal to press the Delrin

bushings into position.

8 - If your original Delrin bushings were secured with 1/4"SAE x 5/16" Allen drive set

screws, you will need to re-drill through the brass shim stock (if fitted) and

completely through the Delrin bushings. #3 (.213") or 7/32" (.2187") drill bit.

Using 1/4" SAE (28 TPI) tap, tap all the way through the Delrin bushings.

9 - Apply loctite to the new set screws and install.

10 If your original Delrin bushings were secured with 3/16" x 5/16" split roll pins, simply

drill 3/16" through the brass shim stock (if fitted) and completely through the Delrin

bushings.

11 Drive in new roll pins until flush with outer spring eye surface.

12 Before installing new polyurethane bushings, tubes, and assembling rear shackle

assembly, apply supplied lubricant liberally.

NOTE: If your original Delrin bushings have not been further secured with additional

hardware, proceed as follows:

Measure 3/8" in from either side of the underside of the spring eye, that is the side facing the ground, center punch location and use 1/16" pilot drill followed by 3/16" drill. Remember to drill all the way through the Delrin bushings. Drive in supplied 3/16" x 5/16" split roll pins until flush with the outer spring eye surface.

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MGB REPAIR KIT (MAJOR)

P0002723

The above kit, part number MAJOR/KITB, contains the following:

4 - .0625" shouldered Delrin front eye support bushings

4 - Fiber spacer washers 7/8" ID x 1.3/16" OD x 031" thick.

4 - 3/16" x 5/16" Split roll pins.

4 - Replacement polyurethane insert bushings.

4 - .007" Brass shim stock.

2 - .565" OD x .447" ID x 2.1/8" Insert tubes.

8 - 3/8" SAE grade 8 nyloc nuts.

2 - Prothane Teflon lube tubes.

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MGB FRONT SPRING EYE DESIGNS

Over the years there have been various changes in the MGB front spring mounting design, these changes can be identified as follows:

DESIGN 1…… OEM silent block bushing.

DESIGN 2…… Split polyurethane bushings with 7/8" OD pin.

DESIGN 3…… Split .125" shouldered Delrin bushings with 7/8" OD pin.

DESIGN 4…… Split .0625" shouldered Delrin bushings with .0625" thrust washers and

7/8" OD pin.

DESIGN 5…… Split .0625" shouldered Delrin bushings with .031" fiber spacer washers

along with polyurethane insert kit. (Current design)

NOTE: We are unable to match a particular design with a designated composite spring identification number.

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MGB INSTALLATION INSTRUCTIONS (MAJOR)

The following instructions should be read in conjunction with the appropriate section of the MGB workshop manual covering rear road spring replacement.

With the composite spring removed from the vehicle carry out the following:

DESIGN 1 …. This OEM bushing was secured within the spring front eye with epoxy and, possibly with additional hardware.

NOTE: The replacement polyurethane bushing (Moss Motors 267-525) has a larger OD than the OEM bushing, therefore, this type of bushing can not be retrofitted.

1… If fitted, remove the 1/4" SAE x 5/16" Allen drive set screws.

2… Press out the old OEM silent block bushings.

3… Thoroughly clean out any remaining epoxy within the front eye. Check Delrin

bushings for interference fit. If they appear loose, wrap .007" brass shim stock

around bushings.

4… Insert bushings into spring eye with the gap facing the spring blade. Use a soft

jawed bench vise to press home the Delrin bushings. Be careful not to distort the

.007" shim stock as you proceed.

5… If the front eye was fitted with additional hardware as mentioned above, you will

need to drill completely through the shim stock and Delrin bushings. Use a #3

(.213") or 7/32" (.2187") drill bit, followed by a 1/4" SAE (28 TPI) tap.

6… Apply a small amount of locktite to the new setscrews, and install.

NOTE: The next instruction only applies if no additional hardware was used, on the spring eye, to secure the OEM bushing.

1….On the underside of the spring eye, mark and center punch 2 locations, 3/8" in from either edge of the spring eye.

2… Using 1/16" pilot drill bit, drill all the way through the spring eye, brass shim stock (if fitted) and Delrin bushing. Follow this up with a 3/16" drill bit.

3… Insert 3/16" stainless steel roll pins. Tap into the spring eye until level with the spring eye surface.

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DESIGN 2

1 …. Along with a small hammer, use a putty knife between the shoulder of the split

polyurethane bushing and the spring eye. Tap around the periphery of the

polyurethane bushings to force them out of the spring eye.

2 …. Using coarse sandpaper thoroughly cleanup any epoxy within the spring eye. The

inner surface must be smooth before installing new split Delrin bushings.

3 …. Trial fit new Delrin bushings within the spring eye.

4 …. If required, wrap the .007" brass shim stock around the Delrin bushings. Insert

bushings into spring eye with the gap facing the spring blade. Be careful not to

distort brass shim stock. Use of a soft jawed bench vise would be ideal to press the

Delrin bushings into position.

NOTE: The new Delrin bushings must be additionally secured within the spring eye with the use of 3/16" x 5/16" split roll pins

5 …. On the lower portion of the spring eye, mark and center punch 2 locations, 3/8" in

from either edge of the spring eye.

6 …. Using 1/16" pilot drill bit, drill all the way through the spring eye, brass shim stock

(if fitted) and Delrin Bushing Follow this up with a 3/16" drill bit.

7 …. Insert 3/16" stainless steel roll pins. Tap into the spring eye until level with the

spring eye surface.

8 …. Before installing new polyurethane bushings, tubes, and before assembling rear

shackle assembly, apply supplied lubricant liberally.

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DESIGN 3 4 & 5

NOTE: Please follow earlier instructions as found under the heading "MGA INSTALLATION INSTRUCTIONS (MAJOR)"

To thoroughly familiarize yourself with the technical information contained in this article, I recommend the text be read several times.