Re: Re-installing rear brake drums

Posted by ScottG On 2023/7/26 20:23:52

O_D

Funny you mention the axle shaft runout as I did check it but couldn't find any reference spec in the manual with which to compare my numbers.

At the end of the taper I measured .012" runout and near the thicker end I measured .0085" of runout. This is with new outer Timken bearings, races and seals-I have no idea the runout with the old bearings which were in service when my problem first arose.

Regarding my measurements...I am not machinist and am working with a Harbor Freight dial gauge and an old magnetic stand that I inherited from my grandpa (who was a machinist) so my results may not be the best.

Also, here's the short version of the backstory:

-Bought car and drove it regularly for a year or so. It was regularly maintained by the previous owner.
-On a weekend drive I noticed a grinding from the left rear drum at braking speeds of 25-30mph. Brake performance was not affected.
-At this point I had never had the rear brakes apart so I adjusted all four brakes and hand brake and nothing changed with the grinding.
-I replaced all hold-down hardware and return springs and nothing changed with the grinding.
-I replaced rear axle shaft bearings, races and seals and reset the end clearance to .0045" (using a dial gauge) with a shim stack of .024" on the right and .020" on the left. Again, no change with the grinding.
-I disconnected the hand brake completely to eliminate possible misadjustment. Still no change in the grinding.
-Today, one of the last shops around me that will turn drums looked at the drum and didn't find anything wrong. He turned it the absolute minimum just so I could definitely rule it out as the culprit. Of course, it rained this afternoon and, as a matter of prudence, I just won't test brakes in the rain. So here we are...