Is it normal to have to tear down the entire base just to swap a Bosch dryer drum bearing?

You don't need to muscle the drum past the compressor lines, and whatever you do, don't try to drop or pry that bottom tray out. On these Bosch heat pump chassis, the sealed refrigeration loop stays completley intact. The **rear drum bearing** bracket can be unbolted from the backside once you pull off the rear cover plate and electrical covers. You remove the center bolt holding the drum spindle, release the bearing block from the rear bulkhead, and you can swap it right there without disturbing the sealed system underneath. If you do end up needing the drum completely out, it slides out through the front once the front fascia and door bulkhead are removed, not down into the mechanical bay. definately swap the idler pulley, support rollers, and belt while you've got it opened up. If the drum bearing was grinding metal-on-metal, the uneven drag was putting wierd sideways tension on the belt and likely flat-spotting the support wheels anyway. Spending an extra hundred bucks or so on a full roller and belt kit is cheap insurance on a Series 8 or 9. It’s a chore to get inside the casing, so doing all the wearable drive parts in one go saves you from having to do another teardown six months from now when a front roller seizes.

And since you already have access, take a shop vac and a soft brush to the entire bottom bay. Lint loves to creep around the blower wheel housing and the front edge of the evaporator fins in these units, choking airflow and dragging out cycle times. Clearing all that felted dust out while you’re swapping parts will get your dry times back to factory spec and make the job well worth the sweat.

Wait, does your model have that self-cleaning condenser feature too?!

I literally just made an account here becasue I bought a used Series 8 last weekend—I'm so obsessed with how ridiculously quiet it is and how little power it draws compared to my old vented monster! But seeing all this talk about lint packing around the bottom bay makes me wonder... does that automatic flush cycle acutally keep the coils clean over the years, or is cracking the side panels open just totally unavoidable eventually?

Make sure you acutally inspect the drum spindle stub with calipers once you unseat the old bearing housing, becuase running the unit to the point of a severe metal-on-metal grind almost always leaves galling or eccentric wear on the steel shaft itself. If that spindle is grooved or out-of-round by even a fraction of a millimeter, your replacement sintered bearing will fail prematurely within twenty loads regardless of how cleanly you seated it. Also, watch out for the delicate spring-loaded carbon brush assembly riding against that rear axle; it provides the ground reference for the conductivity-based moisture sensing circuit, and those tiny graphite blocks snap instantly under lateral deflection if you pull the rear bracket carelessly.

Before you commit to pulling that rear housing off, have you completley ruled out the front drum glides and felt seal?

When those teflon pads wear down to nothing, the drum drops just enugh for the front metal rim to scrape right against the bulkhead frame. It makes a horrendous metal-on-metal screech that sounds identical to a dead rear bearing.

Also, have you checked the front blower wheel housing for a stray coin or bra wire wedged in there? Might be worth double-checking the front lip before ordering parts for the rear.