MG Car Repair: Acceleration Problem

Question
While driving my '73 MGB when I accelerate the car pulls to the right and when I back off the gas it seems to go back to the left. Would this be caused by bad motor mounts?

Answer
Hi David,

No, motor mounts can't do that. There are two things that are the usual causs of that.

Jack the right rear of the car up and check the nuts that hold the axle to the spring. There are two "U" bolts that hold the axle to the spring plates. The nuts are on the bottom of the spring plats. Us a 9/16 socket and check those nuts. (Be careful if there are double nuts on each stud). If there are two nuts on the stud loosen the bottom one first and then tighten the upper one to secure the "U" bolt to the spring plate. After tightening all four "U" bolt studs, then run the extra nut up as a "Lock nut".  

Most just used "Nylock" nuts and not a second nut. On these type from the factory just tighten all four nuts.

If these nuts were not loose then you need to look at the right front spring mount on the car body to see if the mount has it's rubber broken out. To replace this you have to remove the spring and the bushing has to be pressed out of the spring and a new one pressed in. If you don't have a press you can do it in a large bench vice using short pieces of pipe or large sockets. If you don't have the equipment, you can just remove the spring and take it to a local machine shop with the new bushing. The bushings are available from any of the many MG parts companies like Engel Imports, Moss Motors and Victoria British. Just to name a few.

If the right one is bad, be sure to replace the left one too and at the same time replace the rear shackle bushings too. They are not expensive. The rear shackle bushings don't need to be pressed in. only the front ones have to be pressed in.

When you accelerate the rear axle tries to go forward and when somethng is loose on the right side the right side of the axle moves forward and that steers the rear of the car to the left which makes the car vear to the right. When you decelerate the axle tries to hold the car back and with the right side loose the right side of the axle moves to the rear which then moves the rear of the car to the the right thus steering the car to the left.

Let me know how you do with it.

Howard