Front Brake Rotor Stuck?

Hi Mike,

I've attached three pages from the repair manual regarding front brake disassembly. It is not necessary to remove the hub nut.

If the rotor is rusted to the hub, then you might have to insert a couple of 6 mm bolts into the threaded holes to force the rotor off the hub.

 

I'm unsure why the rotor is stuck. There should be a couple of threaded holes near the hub that you can use eg like a jackscrew to pop the rotor off the hub

For reference, this is an exploded view of the hub assembly

http://i653.photobucket.com/albums/uu256/jayman_photo/Prius Stuff/Priusfronthubrotorassb.gif

This is how the caliper mounts to the assembly

http://i653.photobucket.com/albums/uu256/jayman_photo/Prius Stuff/Priuscalipermount.gif

This is an exploded view of the rotor and caliper

http://i653.photobucket.com/albums/uu256/jayman_photo/Prius Stuff/Priusfrontdiskbrake.gif

Note: you should be aware that you CANNOT BLEED the Prius brakes without the dealership scantool. It is IMPOSSIBLE to do just by opening bleed screws.

Please read the factory manual warning and procedure about bleeding Prius brakes

http://priuschat.com/forums/attachm...n-bleeding-prius-brake-bleeding-procedure.pdf

And please learn from another forum member, who with good intentions learned this the hard way

http://priuschat.com/forums/prius-t...em-rear-brakes-no-pressure-when-bleeding.html

 

I swear that Patrick follows me around PriusChat just to beat my posting, by mere moments!

 

Hi Mike,

How many miles on the odometer, and are you replacing the rotors due to rust, warping, or being thinner than minimum spec?

 

Hi Banks,

Hub nuts are torqued extremely tightly. I have used a 4 foot pipe on the breaker bar, and usually bend the breaker bar rod before some come free. I have not done this on a Prius. As Patrick says, you do not need to take it off. But, they are always tight. The specs are up around 110 foot pounds, and with road usage, they get tighter. Its better to do this type of stuff on a hot day, as that reduces the preload as the axle will be just a little longer.

The rotor being stuck on really tight by rust is common with all cars. I remember squirting WD-40 in the back of rotors. Letting it sit for a half hour, then taping around the outside of the rotor in a radial direction with a mechanics mallet, and finally more WD-40 and getting the rust joint to crack, and allow the rotor to come off. This is probably the main reason these lead-pellet filled mechanics mallets have such good sales. Besure to clean up all the WD-40 with brake-cleaning solvent. Do not want that to get flung off onto the rotor surface and new pads the first time you run down the road. If you are reusing the pads, put them in a plastic bag to avoid any incidental polution of the surface with oily stuff.


My experience is that VW rotors tend to fall off when you undo the single screw - they paint the hub portion of the rotor. But my Ford Tempo was similar to this. Its nice they provided the threaded holes in the rotor. Should make it allot easier. I would use Grade 8 bolts to avoid deforming the tip of the bolt, and then bunging up the internal thread in the rotor when you retract the bolts.

 

As far as rotors rusted on, I've had that happen with cars more than 6 years old. But just for 3-4 years old? Maybe

I do know that when I tried to remove the rear wheels on my then brand new FJ, a light coating of rust had already made them stick to the rear drum-in-hat mating surface. I can only imagine if they had stayed on 4 years .... sledgehammer time

 

Mine just fall off after the caliper is taken away. But I do try
to get in there every year and clean things out, fore and aft.
.
_H*

 

71K miles and the pads have to be replaced and the rotors are warped? This is not typical. Have you been riding the brakes on long downgrades instead of using "B", or made some severe panic stops?

 

I've never had a "pulsing" in any vehicle I personally have worked on. I'm pretty careful about properly torqueing lugnuts in the correct pattern

 

I'd recommend trying the bolts first, supplemented with a couple of moderate whacks on the inner face of the disk if needed (don't want to damage the hub). If you decide to use lubricant, please clean off the hub using brake parts cleaner after the disk has been removed so that you don't have lube spinning up on all of the new brake parts.

 

What else could cause that? An ABS fault?

 

Just driving in "B" harmed nothing except MPGs :_> Have fun!

 

Congratulations, glad to hear that the rotors came off. A small sledge hammer is an excellent tool to have available.

New front pads have 11 mm depth while the minimum allowable is 1 mm. What's the thickness of the old front pads from your car?