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BRITISH AUTOMOTIVE |
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| Technical Information (MGB 4) Last Modified - 07/04/01 Installation Instructions for Composite Springs The aluminum blocks that are supplied with this kit are designed to bring the composite spring back to the original steel spring thickness and are fitted directly below the lower nylatron pad; these may or may not be required. Additional items that may be required, which are not supplied with this kit, include: U-bolts (regular or long), lowering blocks, spring locating plates, bump stop pedestals, and lower s/abs attachment plates. In addition, all bushings, spring seating pads and bolts must be liberally coated with the supplied lubricant prior to installation. Final tightening of suspension components should be done with the vehicle on the ground. 1. Jack up vehicle and support with axle stands placed under rear axle tubing. 2. Remove road wheels. 3. Disconnect axle check straps and s/abs from their lower attachment point. 4. Disconnect center and rear exhaust mounts. Support exhaust system with bungee cords or mechanics wire. 5. On 1977 models and onwards, disconnect rear sway bar mounting brackets. 6. Jack up vehicle again, this time support body with axle stands placed forward of the road spring front mount bracket. To prevent under vehicle body damage, place 2 blocks of wood between jack stand and vehicle body. 7. Working with one side only, remove axle U-bolts, bump stop pedestal, spring locating plates and lower s/abs attachment plate. 8. Raise rear axle tubing clear of road spring, proceed and remove rear shackle assembly, and lower the spring. 9. Remove front spring mount, bolt and nut. NOTE: Should this bolt be seized, the most effective way for its removal is to hacksaw through the bolt on both sides between the silent bloc bushing and mounting bracket. 10. Liberally coat the spring blade contact area of the nylatron pads and attach to the spring assembly. These may require some pressure to install and can be tapped into position if necessary. 11. Apply the small tube of prothane lubricant to the polyurethane front bushings and tube assemblies, this includes the bushing thrust face. Work the tubes within the polyurethane bushing assembly and work the polyurethane bushings within the split Delrin bushings. Assemble the tube into one half of the polyurethane bushing, insert into eye and then install remaining bushing. Apply main lubricant to bolt, install and tighten. 12. We now provide (4) polyurethane upper shackle pin bushes (95 Durometer scale) with your kit. These bushes have been substituted in place of their Delrin counterparts, thus making installation of the upper shackle assembly much easier. Please lubricate before assembly. NOTE: refer to 12A for Delrin bushing installation. 12A. To avoid "binding" between the Delrin bushings and the shackle end plates installation of these bushings requires careful assembly. Before proceeding further be sure that shackle pins and end plates are rust free and deburred. These bushing IDs are reamed to .502"-.503" ready to accept a new 1/2" OD shackle pin, this leaves .002"-.003" working clearance which will be later filled with lubricant. If your shackle pin OD is less than 1/2" consider 3 options: 1. Heavily packing the Delrin bushing assembly with the supplied lubricant. 2. Purchasing new shackle pin assemblies in the hope that the shackle pin OD is 1/2" 3. Purchasing British Automotive's "Adjustable Ride Height Shackle Pin Kit" Prior to final assembly we recommend a dry assembly run to establish that there is no binding present. It is now essential that you MARK the shackle plates (with pins) and the shackle end plates relative to their individual spring and also their relative upper or lower vertical locations. In all probability binding will exist. Since we find slight variations in shackle pin dimensions (both length and diameters). We suggest simply using a flat file and CAREFULLY filing the outer end of the offending bushings until you are satisfied that no binding exists. Do not OVERFILE the bushings as you will end up with lateral movement of the shackle assembly. Liberally lubricate bushings and shackle pins, then assemble and lightly tighten. 13. Install upper spring locating plate then lower rear axle tubing onto the spring assembly. 14. Install bump stop pedestal and axle U-bolts. 15. Install aluminum spacer block followed by lower spring locating plate and s/abs lower attachment plate. Fit new 3/8" SAE locknuts and torque to 10-15 ft.lb. Overtightening will only result in a bent attachment plate. NOTE: If you are converting to the recommended telescopic gas type s/abs set up, it will be necessary to switch the attachment plate with the opposite side, as well as the installation of an additional 1/2" spacer block (with locating ring). Carry out #16 before proceeding further. NOTE: Modified lower shock absorber attachment plates are shown in technical article "Telescopic Shock absorber Choices" MGB13. 16. Repeat operations 7 thru 15 for the opposite side. 17. Jack up vehicle and support with axle stands repositioned under rear axle tubing. 18. Refit center and rear exhaust mounts. 19. Reattach axle check strap and lower s/abs. NOTE: See "Telescopic Shock Absorber" article if converting to telescopic type. 20. On 1977 model and onwards it may be necessary to adjust the sway bar to be able to refit the rear mounting brackets. If this is required, proceed as follows: slacken both L/H and R/H front mounting bush jam nuts, remove locating bolts (it will be necessary to remove the battery for removal of this bolt on the passenger's side). Equally adjust both bushings until both front and rear mountings line up. Install and tighten bolts and nuts, including jam nuts, and reinstall battery. 21. Refit road wheels. 22. Jack up vehicle, remove axle stands, lower vehicle and tighten rear axle and suspension components. !CAUTION! Once you have financially recovered from your new investment, you may want to consider purchasing British Automotive's Panhard Rod assembly (Tube Axles only). See technical article MGB15 "Panhard Rod". See technical article MGB15, "Panhard Rod". For a superior rear suspension setup that does not require major fabrication, a complement of these 3 components, I.E. Composite Springs, Tube S/Absorbers and Panhard Rod assembly, is very hard to beat. For additional information select from one of the following categories: |
