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MG MGB Technical - Lowering a rubber bumper car to chrome bumper spec.
A friend and I were discussing the differences between the suspension of a rubber bumper MGB and a chrome bumper MGB. We couldn't agree on what the differences are. To lower the front, all you need to swap is the crossmember. (Can it be that easy?) To lower the back, you need (from front to back): chrome bumper suspension mounts, chrome bumper springs and chrome bumper shackles. We agree that there are kits with lowered springs for both front and back, but the question is what is needed to swap from original spec rubber to original spec chrome. This must be an old conundrum and we were sure the BB would have the answers Mike |
Mike |
Changing the crossmember is a chore as the suspension has to be taken apart. If you need a front end rebuild this would be the time. At the very least I'd replace the rubbers. The rear is correct new mountings and the chrome bumper suspension has a 6 leaf instead of a 7 leaf spring. In my 73 I used the 7 leaf anyway as I have heard these last longer. If you have a later RB MG you also have a rear roll bar and I am not sure if this would help or hurt the handeling with the lower suspension. There are some threads on this in the MGB technical section. |
J Arthurs |
Mike, For a full story on what is needed etc look at this site. http://www.aote99.dsl.pipex.com/mgb_chrome/index.htm |
Cecil Kimber |
Hi Mike Front Swap RB cross member for CB cross member - but- Steering box on a RB car is different to that on a CB car. New steering box mounts need to be made, and the pinion shaft on the steering box needs to be shortened and resplined, or, extend the existing mounts on the CB cross member, and raise them at the same time. This can be done using packing pieces approx 12mm square. Rear Remove rear anti roll bar and discard. Either remove front spring hangers and replace with CB ones, or shorten spring hangers and redrill. If modifying existing, you will need to heat up and flatten out the support flares on either side of the hangers. Remove bump stop rubber and mounting boss. Dont damage mounting boss Remove plate under bump stop mounting boss. Weld bump stop mounting boss in CB postion on chassis frame. Remove shackle mount and supporting brackets from rear chassis frame. Dont damage shackle tube. Drill holes through chassis frame in CB position. Weld shackle tube back in new holes. You will need to obtain CB parts for a number of suspension items( rear shock adsorber links, rear check straps, front cross member bolts, all springs, (although on a well used car the springs may have already settled to CB dimensions). Check Moss catalogue for these. They list both CB parts and RB parts where there is a change. I carried out all this work on the rear while car was upside down on a rotisserie. I do not think that it would be feasable to carry out the work to the accuracy required from underneath the car. You will need a mig welder plus a certain amount of ingenuity when drilling the holes. Cheers Ian F |
Ian Fraser |
Mike Moss sells one and a half inch lower springs for the front. They also sell one inch lower springs for the rear as well as one inch lowering blocks. Total install time is less than four hours. Total cost is less than $300. The car sits level and aligned perfectly. With the addition a poly bushings and new shocks, the car handles great and rides OK. Matt |
matt |
I have just set out converting my 78 gt. I have had it for 22 years and decided to go chrome and lower as well. I bought all the bits from MGOC. The car is painted now. I fitted the slatterd grill and bumper and wow! what a difference. I cant believe I have gone so long with those heavy ugly bumpers. I would not hesitate to c/over . It is easy!. Like Cecil said ( he told me to contact the web site with all details)Good luck!!! |
Ray Clarlk |
This thread was discussed between 25/06/2002 and 28/06/2002
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