Thought I had a wheel problem until.....

[djwarner]

It was weird, I would feel a shimmy in the front that would even show up at the steering wheel. Thought it got worse after I had a flat in the passenger front tire and it was removed patched and re-mounted. Checking showed the wheel was balanced correctly. Also, it seemed to get better after making a turn but returned soon after.

While driving with the shimmy, I pondered the condition when I remembered that the last time I had the rear end jacked up, turning the rear wheel showed an area where the brake was dragging. But after a few turns it seemed to free up. Thinking I might be feeling the brake dragging, I pulled the parking brake at 30 mph and released it. Sure enough the steering smoothed out until the next time I applied the brakes when the shimmy returned.

Apparently I had a shoe dragging. But repeated application of the parking brake did not adjust the clearance.

So I tore down the rear brakes and immediately found several problems. First, the drum refused to come off, bound to the hub. When I finally got it off, I found the previous owner replaced the shoes, but had never lubed the touch pads. Actuating the parking brake spread the brake shoes, but the adjusting mechanism was frozen. The parking brake shifted the piston forward, where it stuck. The next time the brake was actuated with the piston, the piston assembly shifted back re establishing the intermittent drag.

Examining the touch pads, I found fairly deep grooves matching the profile on the shoes. A thorough rebuild ensued, grinding the touch pads flat, lubing behind the piston assembly and exercising it back and forth til it moved easily. Found the self adjusting mechanism frozen, cleaned and lubed them. Installed new shoes and springs. Took care to reset the adjusting levers. Re-assembled, I could now clearly here the adjusting lever as it ratcheted.

Having never heard the ratcheting before, I didn't realize the adjusting mechanism was Inop.

With a proper brake job completed, my shimmy is gone. I would never have suspected a hanging rear brake shoe would cause a shimmy felt in the steering wheel but it did.

Edited December 9, 2015 by djwarner

[zKars]

That is such a cool thing to discover. There are so many inter-related actions and reactions to consider. Good sleuthing.