On my 98 F-150 I just did a complete rear brake job. New pads, new drums, all new hardware. No problems up to that point...original shoes finally wore out. Fronts have been done many times. I noticed a light shudder when I got done. If you hit the brakes hard...no shudder. I thought it may "go away", but 1000 miles later is getting worse. I know it is rear end....if I use the parking brake to slow down I get that shudder. Anyway.... I pull both wheels today and drums. The primary shoes on both sides have horizontal ridges in them for about half of the shoe...all about 1/4" apart. I sanded them out, sanded the drums, sprayed all down with brake cleaner, put back together. Went for a ride, all is fixed. Does anyone know what may have caused that? I did notice when I put the 2nd new drum on ( the first time) it was really oily. I sprayed that down good to clean it. But I never sprayed down the other drum from the start. I just wonder if a light coating of oil that I failed to remove the first time could have caused this. I did notice when I sprayed the shoes down before I sanded those ridges, that a LOT of black liquid flowed off them.

Thanks....Jeff

 

The drums were probably coated with oil or something to keep them from getting rusty during shipment/storage.

When ever I do a brake job, I always spray the drums/rotors down with brake cleaner before installing them. That way if they are coated, or if you get any grease on them while handling them, it is removed when you assemble everything.