Bolt size for removing rear drum

The Repair Manual (more info; see the topic Brake: Brake: Rear Drum Brake: Overhaul) doesn’t mention a need to thread bolts into the rear brake drum sub-assembly when removing it. It does offer a hint, however: “If the rear brake drum sub−assy cannot be removed, push the rear brake automatic adjust lever through the backing plate service hole using a screwdriver. Turn and contract the adjuster using another screwdriver.”

 

Think it's like fender bolt 10 mm head but long like 3 Inch or so.i use the ones with my steer wheel puller.

 

M8x1.25. 25 mm threaded length or more should do. The threaded holes tend to be quite rusty in my experience: take your time, screw them in, then back out and blow out the loosened dust, repeat. Alternative sides. Hammer taps as you go may help.

 

The M8x1.25 bolts help if the drum is sticking to the hub because of rust. The screwdrivers-on-the-adjuster procedure mentioned by Elektroingenieur helps if the drum is difficult to remove because the brake shoes are against it. Sometimes both kinds of help may be needed.

 

Usually the bolts ruin the threads in the drum even turning them in slowly well lubed a lot of times they just bow and splat. The best thing I found for a drum is the big mofo hammer and a last resort is a light blast of heat around the center hole even when I lived in New England these two methods generally produced a drum on the floor very quickly drums I usually replace not something worth playing with as cheap as they are now cost-wise might as well especially if you're doing the brake job and you're only got $50 in shoes and parts no labor charges you might as well just drop on two shoes another 150 K or so in the mileage department.

 

So far (knocking on wood) I have never stripped out the threads on a drum or rotor where I used the bolts for removal.

I have, however, been known to cuss at a car where somebody put on aftermarket drums or rotors that didn't have the threaded holes.

 

It would have to be something REALLY bad with the rear brakes (such as lots of air in the hydraulics or a fluid leak) before any warning lights come on. You may want to read whatever codes are present before ordering parts and tearing into things.

You would need a "compatible" scantool that can communicate with all the ecu's on a Prius. Or use a short length of wire to jumper the two correct pins of the OBD connector under the dash and count which lights flash how many times. Search for "flash codes" for more details. (the 2 digit flash codes can be "translated" into normal 5 digit codes and researched in the service manual).

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Seems to me with all those lights you're looking for bad hubs which have the counter for the ABS wheel running inside the hub with a sensor sitting there in the hub to monitor that wheel and/or the break actuator is going funky kind of two separate systems that run the brake lights as in the codes so you could be touching on two separate systems for no reason Good to have codes to kind of help guide you to the systems whether you're looking at electronics or hydraulics

 

The one thing you know for sure when you have all those lights is that there are trouble codes telling you what they're on about, and without them you're guessing what to do.

If you don't have a scan tool to read those trouble codes, you can use the short wire jumper between the Tc and CG terminals at the diagnostic connector, count the blinks of the warning lights, and report those here.

 

Pro tip...the exact size bolt you need is actually there in the rear well. I can't remember if its on the left or right side, but you can pull it out, use it, and then put it back in...

 

Rear well? What well are you talking about? Wheel well? The spare well under the hatchback floor? Only thing I recall back there is the giant eyelet screw that goes into the front bumper hole for towing.

 

I believe it's a 6 mm one of your fender bolts will thread in but it's not long enough The metric bolts from my steering wheel puller kit fit directly I believe they're 6 mm 1.25 but I'm not positive of that but I know that one of your front fender bolts will unscrew out of your front fender with the hood up and thread right in You just need longer they have them tractor supply and home Depot if you're smart you'll get the socket head cap screws extra long the ones that take the stop sign or Allen wrench as they are hardened bolts and if you screw them in carefully and evenly it'll pull your drum right off. But a little spray penetrating oil around the hub centric locator and a good size hammer generally releases these very well unless you're in a serious rust belt. Even then the big hammer the penetrating oil usually make short work and may scare some people but it makes generally short work of it I had to use the bolts in Massachusetts twice because of some rust around the hub centric locator or the hole around the drum

 

M8x1.25 was already given upthread.

 

My Prius goody box:

 

Wow. My goody box is nothing like that organized.