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MG MGB GT V8 Factory Originals Technical - Rear Ride Height

Guys, I must be doing something wrong...I'm having problems with the rear suspension of my '79 V8 project car. First, I'm using an MGB disc wheel rear end w/MGC 3.31 gears...everything in it is new all way out to the brake rotors..but, that's not the Doug Jackson composite springs appear to be...
...spprings up under car, the rear shackle points almost perpendicular to garage floor (straight down)...but, whenever the rear end is mated to the springs (chrome bumper rebound straps, GAZ tube shocks) & she's on the ground (everything just finger tight) & I slide up under her to attach my panhard bar & anti-tramp bars, the rear spring shackles point forward & the car rides 16-3/4" high center of hub to bottom of stainless side trim...pushing her around doesn't change things...I sat in the trunk (yep, all 250lbs of me) as friends pushed car around & they didn't rotate backwards...
...I can jack it up & take the rear end off the springs & reset the shackles towards the rear but when rear end weight is on they rotate forward keeping car's rear end too high...
...some integral measurements:
1. Springs, center of front eye to rear eye at normal arch: 43-1/2"
2. Spring mounting points:
Rear shackles 20-degree forward: 41-3/8"
Rear Shackles perpendicular to garage floor: 43"
Rear Shackles about 20-degrees rearward: 44-3/8"
..Now, I've put rear ends under lots of MG's but have never had this problem...what am I doing wrong?
Tony Barnhill

Huh. I don't get it. I put on some of the Doug Jackson springs with the adjustable shackle plates in back (chrome bumper car -- not exactly sure what the difference is to the later spring mounts) and they just bolted right up and the shackle plates pointed rearward on any setting. This notwithstanding my confirmed status as a hack mechanic ... if it were possible to screw up, surely I would've. Something must be out of order ... I'd just take a digital photo and email it to Doug -- he can probably walk you through this.

Is it possible the the anti-tramp bars are pulling the differential forward and that when weight is applied the only way the shackles can go is up instead of back?
George B.

That would be true but I took the photos for my web site & then disconnected them until after the car was on the ground....gonna go for try #3 tomorrow am
Tony Barnhill

Well, I've put the rear end in again.....anti-tramp bars are not under car, just their brackets....GAZ shocks & chrome rebound straps installed...original rear anti-roll bar installed....panhard bar finger tight
........&, rear spring shackles are pointing straight downward (perpendicular to garage floor)....they rotated there on their own, I couldn't pull them back any farther.....
.......but, the car's ride height is still 17" from center of hub to bottom of trim line....rolling forwards or backwards doesn't change anything....
....empty gas tank under engine or tranny/driveshaft in seats in car... never will have a rear bumper...trunk lid is on & I don't plan on carrying any spare except one of those little Saab donut spares.....

......So, I added 6 concrete blocks over the rear end in the trunk (22 pounds each: I figured roughly 8 pounds per gallon of gas times 12 gallons = 96 pounds + approximately 30 pounds weight for a battery) for a total of 132 pounds...added a spare tire & brought it down to 16-1/4"....however, doesn't appear to be moving the rear shackles off perpendicular but, instead, is flattening the spring....

....16-1/4" is still too chrome cars run about 14" & this one should get down to there (hech, my rubber cars run 15-1/4")

....any thoughts?
Tony Barnhill

You mention lack of spare. Which SAAB doughnut fits?

Will the shackles swing back without the spings installed or is there someting on the spring attachment hardware that is interfering? It's hard for me to imagine how a spring could flatten without one or both spring eyes moving away from the spring center.
George B.

George B....the shackles move easily & are still just finger tight...there is some movement to the rear but not much....
steve....I go down to my local foreign car salvage yard & get them out of saab sedans (900 & 90 to 1987)
Tony Barnhill

This thread was discussed between 02/08/2002 and 03/08/2002

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