2005 new rear brake pads the old brakes drums wont fit on now Help

Sorry I can't be of more specific help, but my understanding is that modern drum brakes are "self adjusting" so as to maintain good contact between the shoes and the drums over the wear life of the shoe. My assumption would be be that after replacing the shoes you may need to "reset" the self adjusting mechanism as it had pushed the shoes further out as the old ones wore down.

Hopefully someone who has actually done it will pipe up

Rob

 

if you have everything done correctly, they will fit unless the shoes are either incorrect or made wrong. recheck your work make sure the adjuster isn't installed backwards or something.

 

Are the new brake shoes sourced from Toyota or aftermarket?
What is the thickness of the new shoe lining? The spec is 4 mm when new.

Did you compare the work you did on one side of the car, with the undisturbed brake setup on the other side of the car, before calling the work on the first side good?

If you can't figure out why the drums won't fit over the new brake shoes then take some good, sharp, close-up photos of your work and post.

 

yep, a mechanic would not put brake pads in drum brakes.

 

Ok. Technically, drum type rotors require SHOES and Disc type (actually, SPOT DISC TYPE, Smarty) require PADS. It's not nice to tease a novice, dude.

That said, @60_mpg: You almost certainly do not have the shoes properly adjusted. As Mr. Wong said, we can't tell anything without some pictures, but it's almost a rite of passage for novices to screw up their first drum brake job. I did and so did most of the mechanics you'll meet on this site (I'm not a regular here but confident because EVERYBODY screws up drums the first time.)

I haven't done a drum job since the '90s, but all of the self adjusting types I've ever seen need to be manually reset when the drums are changed. Take everything out and LOOK HARD at the adjuster. You should be able to figure out if its retracted or not by playing with it.

It's not uncommon to have a little interference on new shoes but it shouldn't be anything you can't overcome by "screwing on" the drum. I've never seen (or even heard of) any shoes being so oversized that they can't clear the rotor. This includes aftermarket parts, which are usually fine, btw. Drum technology was perfected in the bloody '40s.

Maybe the inner rotor could be scored or chamfered, leaving a burr, but You'ed easily see anything big enough to create a jam, and, again, it wouldn't be both brakes.

Check it again, bro. I know you probably don't want to hear it, but it's probably operator error. You're not the first guy to be stumped by drums. Hang in...

 

Agree with above to first really, really carefully check that the adjuster has mbeen manually reacrewed to the "farthest retracted" position--on my old,cars I has to hold the little locking ratchet thing out of contact with the star wheel and the turn that star wheel,by hand to get it into the fully retracted position.
BUT if you are absolutely sure that everything is right and the brake drum will not fit around the shoes you have two choices:
1. Have the drum turen down on the inside by a machine shop. You MUST be sure it is safe , that you will have sufficient drum thickness left to have effective, non-fading brakes. In the old days, drums were design d to be thick and nough to do that and we could turn them down up to three times and have enough drum left. But I am totally unsure about whether the Gen 2 rear drums are designed that way. (Turned down, I meant to type--I cannot edit my posts now)
2. Have the brake shoes themselves ground down so that they fit. Again a machine shop is your best choice and they should grind off as little as possible for you to be able to cram the drums back over the shoes. Again in the old days the after market parts store would sell "1-oversize", "2-oversize" and so forth brake shoes that were designed to fit into the ground out drums. If you have accidentally gotten a pair of oversize shoes, that would explain your problem.
Good luck and hope this helps!

 

can you have the inside of the drums machined to enlargen them?

 

You could but that certainly would not be considered an acceptable solution to address the OP's problem. He has to figure out why there is interference and fix that problem rather than apply a band-aid solution.

The point of machining the drums would be to address uneven wear within the drum interior surface, and this is subject to the maximum diameter spec which should be engraved on the drums.

 

don't the drums get a bead of rust around the onboard edge over time?

 

I haven't noticed that. But I don't live in an area where salt is applied on winter roads.

 

o/p is from west va, i'm not familiar with the climate. i think somewhere is the snowiest place in the u.s.?

 

Ok. I was thinking about this last night.

You forgot to compress the slave cylinder.

didn't you? I bet you did.

Take a C clamp and SLOWLY compress the slave cylinder until the expansion boots are retracted into the housing.

Then try everything again

 

It's been a long time since I've done drum brake shoes, but I seem to remember that on some cars you may need to back off the tension on the handbrake cable to ensure that the shoes are fully retracted. Not sure if this applies to the Prius though.

 

man, I missed that one. Very Good Point.

Check it, though. Some handbrake systems are squirrelly (usually European types). The repair manual should say...

 

I typically had the bleed nipple cracked open briefly whilst I applied compression pressure to the slave cylinder so that it compressed easily and all the way without blowing the seals. Can you do that on modern cars in general and the Prius in particular ??

 

slave cylinder? this isn't a clutch job. no slave cylinder on drum brakes. its got wheel cylinders which should compress when you install the springs on the shoes. most likely the shoes aren't on straight or the e brake adjuster isn't installed correctly. I bet by now he's got it figured out.

 

probably out for a weekend drive.