I replaced the back drum brakes on my PX150e last night. All in all the job took about an hour and a half, and certainly went much faster than the front brakes did a couple of weeks ago.

The right tools for the job
I’d had a failed attempt at getting the back hub open a couple of weeks ago. The nut was held on with the strength of a thousand Gorillas and wouldn’t come loose with my torque wrench, even with my girlfriend sitting on the bike and lending some additional, erm, weight and me hitting the end of the torque wrench with a hammer.

As with all things mechanical, this was a situation of not having the right tools for the job. A trip to the recently opened AutoZone in Gowanus, Brooklyn gave me an opportunity to pick up a two-foot long breaker bar. I bought one with a 1/2″ fitting for sockets, but you can just as easily use a steel tube from somewhere like Home Depot and slip it over the end of your existing torque wrench. The bar cost me $25 but hey I would have paid at least that in labor costs for a local scooter shop to do the brakes for me and now I have another tool sitting around to feel like a real dude.

To get at the back hub you need to remove the spare tire from under the cowl to give you more clearance. You also want to loosen the nut before you remove the rim and tire from the bike so you can gain the extra stability of having the bike grounded when you tug at the nut. Once I had the hub nut cover removed, and the split pin and castle nut removed, I placed my left foot on the rear brake pedal while pulling up on the breaker bar and 24mm socket on the 1/2” shaft. Man you have to admire the power of physics. With the extra leverage the bar gave me the nut came loose in one relatively painless move. A far cry from my cursing on the previous failed attempt.

Spring is on its way
Another tip I wished I’d known when working on the front brakes? It’s damn easier to pull the old brake shoes out by removing the spring first. Most folks I’ve spoken to suggest that you should wiggle the old shoes off still attached by spring and they would eventually collapse. I was able to do this on the front hub but only after some serious leverage with a claw hammer, and chipping the back-plate of the front hub in the first place.

This time, I pulled the retaining spring that holds the two shoes together off first, and after that the shoes fell limp and were easily removed by hand. I did this with a series of tugs on a pair of needle-nose pliers. I do recommend a good pair of goggles however; yanking at a high-tension spring that’s been in place a few years is a rush and had me on my guard.

Inside the hub
The back drum was at least braking somewhat last season, which is more than I can say for the front brakes. With the hub off I could see that the brake shoes themselves still had a fair amount of material left on them, the brake actuator cam was nice and square and the inside of the drum was fairly clean and not glazed with braking material. These are all of the things you’re looking for in a set of drum brakes, but given I had the hub off and a spare set of shoes sitting by; there was no harm in swapping them out. Hopefully it will at least address the squealing I’ve been getting out of the back drum on occasion. I also used this opportunity to wipe out the interior of the hub to clear the brake dust. Of course, I did this using a dust mask, and in lieu of brake cleaner used mineral spirits to wipe away the dust without leaving residue.

I’d loosened the back brake cable to allow me to change the shoes, but frankly it probably wasn’t necessary. Once the new shoes, retaining clips and new spring were back on, the hub was quickly closed back up.

Ready for the snow to end
I’m hoping to fire the PX back up again in a week or so after I get back from a trip and this infernal snow has cleared. With two new sets of brakes ready for the season I should be in good stopping shape. I’ll make a point of going cautiously on them at first though until they “bed in” and also keep an eye on making sure the hub nuts are tight with no wheel wobble during the first week or two of riding.

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