MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Need your ideas on suspension

I have rebuilt most of the suspension on my 1968 mgb roadster. Prior to the rebuild, the ride was very bouncy, the car would bottom out sometimes, and appeared to sit low. Since the rebuild, the ride has improved greatly - much more plush, no bottoming out, and appears to sit a higher. However, the car does not appear to sit level. I confirmed this by placing a level on the chrome trim strip. The car gets higher towards the rear. When I replaced the front coil springs, the new springs were about 3/4" - 1" higher when set next to the old springs. The new rear leaf springs were approximately 3-4" longer than the old springs. Will the rear settle any? The new springs have been on for about 1 year now. The rebound strap is not stretched tight. The hanger at the rear the spring attaches to is perpendicular to the ground, if not pointing a little back towards the bumper. The measurement from the hub center to bottom of the trim strip is 13.5" in the front and 15" in the rear. Any ideas on what can be done? I assume the car is meant to sit level.... Thanks.
Jack Caulder

Jack, My 68 GT measures very close to 14" on all corners. My springs are not new. It seems your front may be too low for new springs. Did you replace the inner A frame bushes? If not some new V8 bushes will help a little. Rear springs sitting high seem to be a problem and there seems to be no easy solution. The archives have lots of information on this problem. I remember in one case new springs were returned and the owner replaced them with one inch lowering springs and that solved his problem. Did you have the full weight of the car on the rear springs when the frong spring eye bolts were tightened? If not you may want to loosen them and retighten them with full weight on the car. That may help a little but probably not enough.
Good luck, Clifton
Clifton Gordon

I did replace the bushings with urethane bushings all around. I do not think I had the full weight of the car on the springs when the front of the rear spring eye bolts were tightened. Although, I'm not sure I understand how this would change anything as the rear hangers are perpendicular to the ground. The strange thing is the height of the front springs matched the spec. given in the Haynes manual. Would worn out front shock absorbers have any effect on the ride height? I cna't imagine they would...
Jack Caulder

“and 15" in the rear. Any ideas on what can be done? I assume the car is meant to sit level”

Many years ago I crashed my 74 ˝ MGB and inadvertently replaced the front RB springs with CB springs. The front sat at 14” while the back sat at almost 16”.
To fix it I simply got the rear springs re-arched.
Now it was only this off season (winter) that I have had them re-ached and the front end has not been re-installed so I can’t attest to the car sitting lower. But I can’t wee why it wouldn’t.
FWIW

Bruce
Bruce

Jack, Worn out shocks will not affect ride height. If the urethane bushings do not have a metal sleeve it probably wouldn't make any difference to have the springs loaded when tightening the eye bolts. The standard bushing for the front of the rear spring has a steel sleeve through the center. When the bolt is tightened the sleeve is clamped in position and the rubber bushing flexes without moving the center sleeve. If tightened without a normal load on the springs the bushing would try to push the front of the rear spring up because the added load would apply doward tension on the bushing. The added tension will keep the spring from settling at its desired ride height. I don't think it would change the height one inch, maybe 1/4" or less as a guess.

If your front springs measured the correct height you may either have the wrong springs or the new springs are of poor quality. Did you by chance measure the ride heights prior to rebuilding the suspension? If you did and the car is lower than with the old springs, the springs are wrong or too weak.

Clifton
Clifton Gordon

Jack, 'BB 1/6/2003 Replacing Rear Springs'
may be of interest, the measurements of a 73b were nominated as front 14.5" and rear 15" from the centre of wheel to chrome strip.
FWIW
Gordon
GORDON

There have been a huge number of complaints of new rear springs even OE making the rear too high, sometimes to the extent that you can't get the rear shackles or rebound straps engaged without a couple of burly mates sitting in the boot/trunk. Originally mainly from the USA, these complaints are now arising in the UK, where I have had two sets of OE springs in the past that gave the 'correct' ride height and no problems installing. Unless you have somehow installed them incorrectly the springs are simply to the wrong spec, being too hard or too arched. I have a theory about this - originally MG only allowed a maximum of 150lbs per occupant, how many of you weigh that or less these days? I reckon some spring manufacturers have tried to compensate for this to give a level stance when occupied rather than unoccupied which is how most of us measure them, and some of them have gone too far. With correct OE springs, and the Navigator and I just about meeting the original allowance, my occupied ride-height is too low and I get a lot of grounding. Last year I fabricated some extended shackles to increase the ride-height by about 1" and we haven't grounded since.

I have never seen any official ride-height figures, but I have compiled a list of owners measurements at http://www.mgb-stuff.org.uk/wn_suspensionframe.htm and click on 'Ride Height' if you are interested. I believe it should be possible to derive the original ride-height hub to trim strip measurements as a figure for overall height was given. Probably best done on a GT without sunroof, the roadster hood and frame may make for too much variation between cars.
Paul Hunt

This thread was discussed between 12/01/2004 and 13/01/2004

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.