The Front End Shimmy
BMW SERVICE SPECIALIST A did a diagnostic inspection for me and found about $1500 worth of work to do on the front brakes and suspension, transmission mounts, shift linkage, flex disk and a few other items. After having all of the suggested work done, including an alignment done by THE LOCAL BMW DEALER, the front end shimmy was still pretty disturbing when braking any where near 55 mph, which just happens to be where most really critical braking occurs.
Research on my part revealed that the wheels had been installed with the wider rear set on the right hand side of the car and the front ones on the left, so tires had to be re-mounted and the front end was supposedly re-aligned. The shimmy, especially under braking, still persisted.
On a trip to Oregon the condition got so bad that the car became practically undrivable, so it was taken to A PORTLAND AREA BMW DEALER who replaced the front brake rotors and master cylinder, explaining that the master cyl. was not fully releasing the calipers, dragging the pads, which in turn cooked and warped the rotors. The brake related shimmy was at last cured! (another $900 tab) however- there still persists a little oscillatory kickback in the steering while cruising at 50-55.
Because I was not particularly confident of the either shop's appraisal of the overall condition of this vehicle, I took it to BMW SPECIALTY SHOP B to have a full diagnostic run again to see if they might be able to spot what was causing the front end problems, and if there might be any other preventable problems.
In taking out the spark plugs to run the compression tests, the plug in the #1 cylinder broke. Attempts at removal of the debris proved to be beyond the scope of what can be done through the spark plug hole, so they had to pull the head - this leads into another story entirely.
They also pointed out that the alloy rims have taken some hits and are not exactly round and true, and that because of the compliance in the suspension bushings, it is probable that- in time, this will imprint the brake rotor and send me into the braking shimmy again. Incidentally, this fact was either totally overlooked, or not mentioned by either the first shop, the alignment shop, the tire shop that re-mounted the tires, or the dealership that serviced the brakes.
So I ordered a full set of new snow tires on new steel rims, which came balanced, and had them put on the car by BMW SPECIALTY SHOP B for $74. They also dis-mounted the tires from the allow rims, so I could take them to get straightened.
But even with the brand-new rims, there is still a little shimmy when cruising at about 55 mph . . .
From here you can go: