MGB-GT Ride Height

[Crazyman60]

I‘ve recently rebuilt the front suspension on my ‘72 B GT and lowered it its wheels. I have not torqued the wishbone arms yet. It has not settled more than 15” on drivers side and 15 1/4 on the passenger side. I assume that when it’s driven it will help the height, but is there something that I may be overlooking?

 

[Tybalt]

Two things come to mind. First, have you rolled the car back and forth to settle out the camber from taking an unloaded suspension directly to the ground? Second is what are your reference points for that 15" and 15 1/4" that you mention.

 

[Crazyman60]

I measured from the center of the hub to just chrome molding. It is my understanding that that chrome bumper cars should have a ride height of 14 to 14 1/2 inches.
I did not tighten the wishbone pivot nuts until the car was sitting on its wheels. I bounced ( pushing), if you will, on the bumper up and down. I didn’t roll it back and forth. A member of the MGOC said that in his experience that the suspension would settle after putting some miles on the car.

In addition to torquing the wishbone pivot bolts, should I have also waited to torque the upper and lower trunnion bolts after lowering it to the ground.

Thanks to all.

 

[Tybalt]

Things can get a bit screwy on the 1972 cars when it comes to front springs. There was a recall to remove and replace the front springs due to the headlamp level (height) not meeting federal safety standard requirements. For US spec cars to raise the front of the car and meet the safety standard the BL answer was a different set of front springs. In the intervening years between now and then, I don't know if at some point, they decided to only supply one spring for the chrome bumper GHN series and another for the GHD series cars in the spares marketplace and if so, is it the originally fitted spring or the recall fitted spring? Perhaps someone out there in MG land rode it out to the bitter end at the dealership level can shed morelight on that. Adding insult to injury, I did not get a measurement of the recalled and the replacement springs for comparative purposes, so no further info on that from me.

Now to your questions so you have not rolled or driven the car since setting it on the ground, correct? Then you need to give it some back and forth rolling to settle out that excess positive camber or as the MGOC guy said, take it for a very short, around the block type, easy ride with everything just snug enough to keep it from leaving a trail of crumbs to find its way home. I would also do the same with the trunnion pivot bolts. The thing to keep in mind is that if it has anything to do with the suspension and its range of motion, the final torque application should be with the car on the ground with all the bushing in their nominally static and unbound condition. If you put the bushings in a preloaded bind before you start driving the car, the buxhing will be twisted to some degree which in turn shortens bushing service life.

 

[Crazyman60]

First of all, let me thank you for your advice. I failed to mention that I did take my car for a short run but not far. It still needs an alignment and the shop was only a little distance from the house. I was advised, per several members from the MGOC club to tighten everything including trunnion bolts except the the pivot bolts.

Since I torqued the trunnion bolts before I initially lowered the car, can loosening these bolts and tightening them now help rectify the situation?

I’ve thought about doing this but I wasn’t sure if would make any difference at this point. I has been rolling around in my head for several weeks.

I bought the springs from Moss Motors BHH 1077.

Thanks again,
Thomas

 

[Tybalt]

The BHH1077 springs would be a valid choice, but thanks to brain/memory fade, I just don't know if that is the "original" spring for a 1972 GHD series car or the "recall" spring, although I am leaning toward saying that it is the US spec "recall" spring initially used on the 1972 GHD cars.

I still think that loosening up those trunnion pivots at the top an bottom of the kingpin would be a good idea. Then roll it back and forth about 5 to 6 feet about half a dozen times and that should take that excess camber out of the front end. The reach under, turning wheels as requires in order to snug everything up, test drive and recheck. You really only have those two plus the two lower arm inner pivots that you have to worry about with respect to bound and pre-loaded bushings. Since the front dampers also serve as the upper arms, they take care of themselves thanks to those arms acting on the damper shafts, they can't pre-load and bind like the bushings can.

 

[DrEntropy]

I still think that loosening up those trunnion pivots at the top an bottom of the kingpin would be a good idea.

That couldn't hurt, but: as long as the inner lower A-arm bushings are not tightened, the lower trunion through-bolt can be torqued. The vertical travel on the kingpin would not (should not, if properly assembled) be restricted there. The upper bolt through the damper arm should be loose, though.

 

[Crazyman60]

I Think that the damper bolts being tightened and torqued before I lowered the car to the floor has been on mind quite a bit.
the damper arms are resting on the bump stops. I know that fitting the stub axle assembly to the damper was quite a feat and a very tight fit.