When the driver side mount broke, engine torque made the block lift up, and pull open the accelerator linkage.
This caused an increase in pull on the throttle to the carb, causing increased revs and more torque twist to the engine, and with more upward movement causing more runaway acceleration in a vicious circle.
This runaway sequence would only stop when the engine hit the underside of the hood.
But that wasn't all, the twisting upward engine pulled the power brake booster vacuum hose loose, making it harder to stop the car, and if that wasn't bad enough... the twist also caused a problem with the automatic transmission, which would shift to the right, with a result of the car no longer having a park position and being able to start in reverse.
New motor mounts cost $50 a unit, and so GM fixed the issue with a $1.00 bracket and cable to hold the engine down if/when the motor mount broke.
Consider that the problem caused a 6.68 million car recall, then multiply the number of cars by the cost of the repair part, and you can see why Gm went for the cheap simple fix.
I learned all this from the May 2012 issue of MuscleCar Review, page 24
This caused an increase in pull on the throttle to the carb, causing increased revs and more torque twist to the engine, and with more upward movement causing more runaway acceleration in a vicious circle.
This runaway sequence would only stop when the engine hit the underside of the hood.
But that wasn't all, the twisting upward engine pulled the power brake booster vacuum hose loose, making it harder to stop the car, and if that wasn't bad enough... the twist also caused a problem with the automatic transmission, which would shift to the right, with a result of the car no longer having a park position and being able to start in reverse.
New motor mounts cost $50 a unit, and so GM fixed the issue with a $1.00 bracket and cable to hold the engine down if/when the motor mount broke.
Consider that the problem caused a 6.68 million car recall, then multiply the number of cars by the cost of the repair part, and you can see why Gm went for the cheap simple fix.
I learned all this from the May 2012 issue of MuscleCar Review, page 24
