I found the problem with my brakes. The issue seems to be that the caliper casting contacts the inner pad. The issue existed with the pads that came on my dolly (not sure whether they were original or not) and with both sets I've applied. I considered grinding it down, but it would need to lose about 1/8 of an inch to clear. I tried another set of pads from a third manufacturer, but the fit is consistent. For now I sanded the casting smooth there, and applied a touch of brake grease. I'll keep an eye on it.
For those considering this job, here are some notes:
Disassembly:
Remove wheel.
Remove vault bearing cap -- just spin the hub and smack it with a rubber mallet until it comes off. The lip is about 1/4 inch deep so it takes roughly a minute of spinning and smacking.
Remove brake caliper. It's connected with a hard line, and if you can support it underneath or hang it out of the way, you can move it enough to get the the hub off. I did not need to disconnect the line.
To remove the brake caliper, you'll need to remove the clip on the outside pad, then remove two bolts that connect it to the frame. The lower one was tough for me to access -- a thin walled 9/16 socket works. I got in there with a 3/8 drive breaker bar which was enough to break them both loose, then backed them out with a 1/4 drive 9/16 ratchet.
Remove cotter pin
Remove castle type bearing nut retainer.
Remove bearing nut
Slide hub off.
The outer bearing will fall out as you do this. The inner bearing is held captive by the grease seal.
Remove the grease seal -- there may be a better way, but I just mangle them up with a flat chisel/punch and pull them out.
Clean up the hub -- I needed to sand the rotor and clean out where the seal seats.
There is an o-ring in the outer part of the hub that seals the vault bearing cap. Mine looked fine, but I replaced them anyway. Keep an eye on these if you're reusing them.
I did not remove the bearing cups from my hubs because they seemed fine and fit the new roller bearings perfectly.
Parts:
Here is what I used:
2x O-rings for the vault caps: UFP O-Ring for UFP Vault Hub/Rotor 1.980
https://smile.amazon.com/dp/B07MXRHS...roduct_details
1/4"-28 taper thread grease fitting (for filling hub):
https://smile.amazon.com/dp/B0059HK8...roduct_details
2x Timkin 473336 Seal:
https://smile.amazon.com/dp/B001544U...roduct_details
2x Timkin L44649/L44610 Tapered Roller Bearing Set:
https://smile.amazon.com/dp/B000X3EP...roduct_details
2x Timkin L68149/L68111 Tapered Roller Bearing Set:
https://smile.amazon.com/dp/B000IX99...roduct_details
Dynamic Friction 5000 series ceramic brake pads 1551-0925-00:
https://smile.amazon.com/dp/B07PG327...roduct_details
Permatex 81160 High-Temp RTV:
https://smile.amazon.com/dp/B00QTMVM...roduct_details
UFP Vault System Hybrid Lubricant (14 oz):
https://smile.amazon.com/dp/B07MXR5P...roduct_details
PVC 2" to 1.5" adapter.
Re-assembly:
Starting with everything wiped, scraped, and sanded clean.
Wipe some UFP hybrid oil/grease on the axle.
Work UFP hybrid oil/grease into the bearings.
(Note: the timkin bearing sets specified in the parts list are made in the USA -- nice, originals were chinese)
Set inner bearing into hub.
Clean hub again where the inner seal will seat, we want no oil here.
Coat outer edge of bearing seal with red RTV, seat it fully (bearing seat kit makes this easy, but you can do it a variety of ways -- youtube if you're new at this).
Clean any red RTV that leaked outside the seal, keep it off the rubber part specifically.
Slide the hub onto the axle.
Install inner bearing (should already be packed with grease from earlier).
Install washer.
Install bearing nut. Finger tight. Hub should spin easily now and have no movement in/out.
Install new UFP O-Ring in the outer hub O-ring groove, or verify that the original is still there.
Install castle type bearing nut retainer and cotter pin.
Screw grease fitting into end of axle.
Let it sit for a few hours so your RTV can cure. (or go work the other side)
Reset your brake piston (push back with C-clamp). It's a good idea to remove the brake fluid cap and put a pan under it in case it overflows.
Clean up brake pad contact points with sand paper and brake cleaner.
Lubricate pins and brake pad contact points with rubber-safe brake grease.
Assemble brake caliper with new pads. Wait on the wire clip.
Hang the caliper by the upper bolt. Now install the wire clip. It's kind of finicky-- reference the other side to see how it goes.
Install the lower caliper bolt. Then finish installing the upper caliper bolt. Tighten german spec (guuudentite).
Install UFB hybrid oil/grease into axle with grease gun. Stop when you see grease start to come out around the axle washer. Fill Vault Bearing cap with fresh grease.
Install the Vault Bearing Cap using 2" to 1.5" PVC adapter, block, and mallet. If you're not sure what this, look at the vault cap installation kits. You can get this at most hardware stores with a PVC selection.
Re-install wheel (75 ft-lbs on those lugs).
Enjoy a beer and then finish the other side.
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