We just bought drums for a 94 Dana 80 from Napa in Redding, CA and they are Raybestos and made in China. They are identical to OEM, same fins, etc. We haven't had any touble with them.
Joe Mc: That bounce may have to do with your locker, not the brakes. When you brake, one of the clutches in the posi could be grabbing and you get a little jerk. We had this problem with a Dana 80 and we added one friction modifer and did some
figure 8's and it went away.
a while back when i did the rear brakes i got raybestos drums, they do have weights on them for balance. at the time i also did the chevy wheel cylinders, everything has worked beautifuly untill a few months ago. i was replacing the front brakes and after getting it all bled out i noticed the truck felt a little strange during braking. so since it had been a long time i adjusted the rear brakes, this lead to a bucking/chatter during braking. i pulled the drums off and found the adjusters were siezed. i removed them, tore them down, cleaned and lubed them, reinstalled and adjusted. since then i have had better brakes (the rears worked but not as well as they should have) but it was still chattering. it looks like its due to uneven wear left to right. i could feel the brakes adjust and it would brake smooth, then as the wore down it would start chattering, it would get worse as they wore, untill they adjusted again. this is from one of the adjusters siezing before the other did. i have not messed with the adjustment hoping that the brakes would balance out. so far it seems to have been working, the brakes have been getting smoother and more consistent.
im giving the background so that my solution has more credit. as i mentioned the brakes have slowly been getting better. a few days ago i installed a set of balance masters wheel balancers on all four corners. during the install i removed the rear drums for inspection. what i found was the left side was tighter and closer to the drum than the right. also the leading edge of the forward brake shoe was more worn down on the left vs the right.
now with the balancers the brakes have been chattering some but not as bad as it was. since i have installed the wheel balancers the chatter has been nearly eliminated. i do still get it from time to time but it is much less often and almost imperceptable. i also think that once the brakes wear evenly they will be completly smooth.
over all the truck drives much smoother, and the brakes feel amazing. not only are they smooth now, they also feel stronger. i have braided stainless lines which really helped pedal feel. the balancers though make the brakes feel like a brand new truck. i barely have to touch them and they start braking. they also feel amazing under hard braking. one problem with the big rear cylinders is the tendency to brake too hard and cause lock up on an empty truck. i have heard the tires skid several times, mostly at lower speeds but even with only moderately hard braking. it happened enough that i was able to feel when the tires would lock before they would lock. now i dont get that feeling, the brakes are strong and the braking feels very positive. under hard braking i no longer get that nose dive, it feels much more square and level. i am really happy with the effect the balancers made. i installed them to increase tire life but these side affects are great too.
my suggestion is get a set of drums that is of a quality manufacturer, adjust the brakes to make sure they are set correctly, if the problem does not go away, then get the balancers. i think though that your vibration problem would cured just by the balancers alone. the same company also has driveline balancers, which i have also, they where installed at the same time. i think they are helping a lot with driveline, axle, brake/wheel vibration as well.
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