Brake shoes wavy wear pattern

Several weeks ago I replaced my drivers side rear axle seal due to a leak. Since the gear oil has drenched the brake shoes, I had to get a new set which I put on both the passenger and drivers side.

Since then I’ve noticed that when braking I get this pulsing motion throughout the truck when braking but my brake pedal doesn’t shudder. I took the drums off again to inspect the drums and shoes and found this wavy pattern on the shoes on both the driver and passenger side.

I’ve never seen this before, so I’m. It sure what this is indicating… any input would be appreciated.

 

For some reason after market brake shoes seem to cause strange brake issues. Which brand did you purchase??

New hardware Kit??

Did you replace the drums or have them turned.

Many times they are so very hard to get clean after being soaked in gear oil.

 

I was intrigued, I've never seen this with almost a half century of wrenching. I did some searching, there is an old post on Reddit with a guy that had this in an old Datsun but of course, no real answers as to why. The pulsing effect is a cause of concern, something is up there. If I had to guess, drums not perfectly round? Mismatched shoes with the drums, like not seating against the drum evenly? Shoes not properly seated against the backing plate or moving during braking? Is the e-brake properly adjusted, with barely enough clearance for the drum to turn? Poor shoe composite?

The edge where the composite meets the shoe looks a little sus, if it were me I'd do a proper revamp with better shoes and either turn/replace the drums, they're not that expensive for good aftermarket drums.

 

So the brake shoe hardware and drums are both reused. I never had this issue before replacing the shoes and even the side that never got soaked with diff oil is having this problem. Pretty weird.

If I’m looking at replacing the entire braking system with new parts, I might just consider doing a disc brake conversion… I’m a lot more familiar with disc brakes.