car pulls to the left when accelrating right when lifting off the throttle?

[2000m]

while going above 45- 50 mph, and specially above 60 mph, the car kinda shifts over to the left when accelerating, and shifts right when lifting off the throttle. any ideas?

[Z3racer701]

Something's loose in the back end... Do you have toe adjustors? Jack up the back and try moving each wheel fore-aft when it's off the ground. The loose point will be easy to spot.

[Randy Forbes]

Roger that. This is still a fairly common symptom in old MGs and Healeys; the U-bolts holding the axle to the leaf-springs become looer as the rubber isolators deteriorate, and it creates rear wheel steering.

I find it hard to imagine that the suspension carrier (subframe) bushes could become so compliant to allow that much rear-steering, but I can't rule out the possibility either. Do you have aftermarket subframe bushes?

Any chance the differential is only being supported by the exhaust system...?

[mcoupemindy]

Roger that. This is still a fairly common symptom in old MGs and Healeys; the U-bolts holding the axle to the leaf-springs become looer as the rubber isolators deteriorate, and it creates rear wheel steering.

I find it hard to imagine that the suspension carrier (subframe) bushes could become so compliant to allow that much rear-steering, but I can't rule out the possibility either. Do you have aftermarket subframe bushes?

Any chance the differential is only being supported by the exhaust system...?

I heard if you rip out the spot welds and let the differential hang low, you get better cooling - is that true?

(p.s. I'm joking for those who fail at sarcasm.)

I would check subframe bushings and rear trailing arm bushings for excessive wear or play.

[wreckedrex]

Check your tire pressures, a delta in pressure between the rears it will cause the behavior you're describing. I've also experienced it after having new tires installed, the shop put a 205-50-15 on one side and a 195-50-15 on the other. Fairly small delta in OD but it was very pronounced going down the road. Took some starring at to figure out too

[2000m]

i had the kmac adjustable camber kit but went back to stock rubber trailing arm bushings after a trailing arm bolt broke about 2 weeks ago... i have a h&R springs and bilstein shocks all around and front and rear H&R sway bars... subframe bushings are also original ...... also i didnt mention a big thing, the night before i noticed the movement a tuck backed into my car and hit just the hood but pushed the car back a bit...i know i should have mentioned that initially in the first post.

[gmushial]

I heard if you rip out the spot welds and let the differential hang low, you get better cooling - is that true?

(p.s. I'm joking for those who fail at sarcasm.)

I would check subframe bushings and rear trailing arm bushings for excessive wear or play.

Would they give you that effect? If so, what would be the mechanism? (I'm trying to picture the physics of it - I can understand the trailing arms causing such... not the RSFBs.)

[mcoupemindy]

Would they give you that effect? If so, what would be the mechanism? (I'm trying to picture the physics of it - I can understand the trailing arms causing such... not the RSFBs.)

Yes, it could if you have one worn out one and one OK one. The whole subframe could twist and since all mounting points (except the upper shock mount) attach to the subframe, it surely could happen in an extreme situation. Even an 1/8" out of spec on toe or thrust angle with our antique rear suspension could cause a pulling feel.

[gmushial]

Yes, it could if you have one worn out one and one OK one. The whole subframe could twist and since all mounting points (except the upper shock mount) attach to the subframe, it surely could happen in an extreme situation. Even an 1/8" out of spec on toe or thrust angle with our antique rear suspension could cause a pulling feel.

Hadn't considered such - As always: many thanks.

[aga080]

A truck backed into you? That's a pretty important point. I would have the entire car looked over by a professional.

[mcoupemindy]

A truck backed into you? That's a pretty important point. I would have the entire car looked over by a professional.

Yep. I didn't read that either. I think something will be smacked out of spec.