1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Passenger front rotor/wheel hot. Stuck caliper?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Thepriusthatcould, Sep 9, 2024.

  1. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    2004 Toyota Prius. I noticed after a 5 mile drive the front passenger tire and rotor was hot. Almost enough to burn. I could feel the heat radiating from the tire. Driver's side tire felt cool to the touch.

    Recently, after not driving for the car for a week and after rain, the car seemed "stuck" and required a little gas to get moving while on flat ground.

    The car can't really move while in drive with no gas applied on flat ground. I think it's because of the right front tire.

    No noises, did front wheel bearings a year ago. Front pads and rotors 3 years ago. Calipers are at least 7 years old but probably original.

    Jacked the car up on the front. Could rotate the driver's side tire but not the passenger while in neutral.

    Should I just replace the calipers? I am getting a tool to compress the pistons and will check to see if the slide pins can move. I am thinking I should test to see if the caliper pistons can be pushed inward.

    Thank you
     
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You just use a pair of channel locks to squeeze the caliper down If you can't squeeze the caliper down with slip joint pliers simply call channel locks in America you have a problem I can almost squeeze the pistons down in my front calipers with my bare thumbs . No kidding. And slide pins or the caliper bar should pull across with your pinky or middle finger without applying your whole body weight behind it to move the slide pins back and forth If not pop that mess off clean them with carb spray and a little bit of crocus cloth commonly called sandpaper for metal spray it off again wipe it regrease it with the proper brake grease You can get into a whole another hullabaloo about that too but it really doesn't matter You don't grease the brake pads in the rotors. Brakes of this type are similar on Corolla Camry matrix etc not a real big difference in calipers and pistons and rotors very similar All that stuff should be very inexpensive to deal with and it sounds like most of it will be just greasing slides or replacing pins and in this day and age you would just replace the caliper it's probably cheaper If you're way out in the country or in the Australian bush you can pop the caliper out clean the mess up again with your metal sandpaper buy some new rubbers It's like a piston ring made out of rubber for the piston in the brakes lube that up with brake fluid and push it all back together Not really much to it but these days are remand caliper locally is only about 20 bucks That's without the bracket and all. But yes all of that should pretty much move by hand You should need any hydraulics and what have you to make this stuff move when you push your piston in after you sand the boar clean up the piston and add a new rubber and some brake fluid as lubricant you should be able to push that right back into its hole with your fingers. Then you should be able to rotate your wheel around and around and backwards and all that with just one hand on the tire wax on wax off.
     
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,906
    16,213
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Sounds like you sure enough have a stuck caliper.

    You can buy a caliper rebuild kit from the dealer (includes all the rubber and miscellaneous bits for both calipers, plus a little packet of the correct grease).

    If you're sure the caliper you've got is original, you'll probably end up with a better caliper if you rebuild that one than if you throw on a cheap reman. (Then you'll get your core charge back when you turn in your original caliper, which will end up getting excessively sandblasted, rebuilt with cheesy parts, and appearing on a store shelf somewhere as a cheap reman.)

    More on that subject here. Includes how to check that the caliper piston properly returns when you're not braking. This is worth checking on a store-bought reman caliper before even installing it ... one I bought did not, right out of the box.

    Also describes how to search for a caliper from Toyota's reman parts program. Those are good, but they're not always available.
     
  4. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,668
    1,715
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    There are 4 reasons why a single (disc) brake is dragging.
    1) the brake pads are seized in the caliper bracket.
    2) the piston is seized in the caliper.
    3) the slide pins are seized in the caliper bracket.
    4) the caliper can't release because brake fluid is trapped (usually a faulty brake hose).

    I begin by lifting and supporting the car. Then remove the wheel, and open the bleeder screw to see if relieving any pressure releases the brake. If so then replace both front brake hoses.

    If not then disassemble things until you find the problem.

    Seized pads are the "easiest" fix. Seized pins sometimes require replacement brackets.

    A seized piston usually means the caliper should be replaced. It can take lots to extract the piston (which will be damaged), then the bore is also likely damaged (corroded).

    I might put a kit in a ($$) caliper that has a bad dust boot - IF the piston looks good. Anything else gets replaced.

    Now I absolutely loath cheap reman calipers (say it with me kiddies... "A1 - Cardone" The devil himself). I've spent way too much of my life dicking around with bad parts. The only caliper I'd get for my cars now is Toyota from the dealer.

    When it's all apart, look at the pads and rotors. Maybe they're ok, maybe they overheated (and the pads are "cooked" or the rotor warped).

    Posted via the PriusChat mobile app.
     
  5. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    Thank you for the reply.

    On step 1, I release the brake bleeding valve with the wheel off to see if brake releases. Do I test this by pushing the caliper in or if the wheel spins? With the caliper still on the rotor?

    I am prepared to replace front calipers, pads, rotors, and hoses if necessary but it would be great if I could save money.

    I agree on the remanufactured parts. You save a few bucks but I wouldn't want to use it for anything safety related

     
  6. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    Thank you for the reply. I see Rock Auto offers new calipers for $70-$80 dollars a piece but I don't know if they are actually new or remanufactured. Remanufactured one's can be had for $30 but I don't think the risk is worth it.

    Thank you for the link!

    Rock Auto caliper choices:

    2006 TOYOTA PRIUS 1.5L L4 ELECTRIC/GAS Caliper | Shop Now at RockAuto

     
  7. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You just cracked the bleeder Don't do anything but crack the bleeder does fluid come out It won't squirt but do you see pressure relief fluid rising up out of that zerk fitting you just opened now close it Don't want to let any air in basically close it and see if you're now can jog your rotor and wheel studs back and forth You're probably in park so they're not going to move round and round but you can now turn the rotor back and forth a few degrees You can see it sliding through the pads where it wasn't a minute ago sometimes I use my pry bar in between the wheel studs if my hands not feeling up to the task now it's either moving or it's still stuck like it was before You tell me. If it just got loose look at your hoses they're rubber they look deteriorated crushed otherwise fubar replace them I've replaced the brake hose about four times in my 45 years working on cars believe it or not and that was in the '80s and '90s and usually the hose would have a bubble blister etc in the rubber outer portion of the hose at least You could see it didn't look like it should be there I'm not sure what the problem is with remanufacturing calipers I really don't Toyota units are very basic there's not a lot going on some of the newer ones even have composite Pistons which are real easy to work with unless they've overheated and melted or broken The repair kits from the dealer are relatively cheap or from any company that manufactures the rubbers you talking an outer boot and a rubber piston ring if you will wipe out and sand the bore with your flex hone of that size or just croaka's cloth on your finger not really going to be much science to this it'll turn silver and you'll wipe it out and so on fit the new rubber piston ring to the piston a little bit of brake fluid around the rubber you don't have to kill it You don't have to flood the bore to install the piston You want to put it up not dry but not soaking wet
     
  8. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,668
    1,715
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    Open the bleeder and some fluid should dribble out. If the problem is hydraulic, then the rotor should now move more freely.

    If not, then the problem is mechanical and keep going.

    Posted via the PriusChat mobile app.
     
  9. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    Okay, do I try to rotate the tire with the bleeder valve open or do I let some fluid out, close and try to rotate?

    Thank you for the tips.
     
    Tombukt2 likes this.
  10. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
     
  11. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You're cracking the zerk fitting with a 8 or 10 mm wrench You see some fluid run out you close that fitting right back up now you see if you can jog your rotor back and forth even if you have to put a pry bar in between the wheel studs just see if it'll jog up and down In other words of pads aren't locked to the rotor The rotor isn't rusted and so on If it is jogging up a little more may free it The point is is when you let the zerk fitting loose and then close it back up some fluid comes out and that should release the caliper enough to allow the pads to slide If it's really stuck you may have to hit it with an aluminum or rubber mallet You're not trying to beat it to death You're just trying to get the piston to come back a little bit as in away from the pads now it moves now if you go in the car and step on the brakes again and come out in that wheel is locked then you've got to releasing issue generally that's the caliper It's got so much crap and junk inside of the bore. Once you pop the piston out you'll see the rust in the corner and what have you.
     
  12. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,906
    16,213
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    There a 5th also, where the piston isn't seized, but simply doesn't return when you're done braking.

    Disc brake calipers are funny. The only thing that makes the piston return is the slight deformation of the rubber seal when the piston extends:

    [​IMG]

    When you release, the rubber springs back by a few tenths of a mm.

    That can stop happening if the rubber seal gets old and hard. (Which then, because of the heat of the dragging brake, gets cooked even harder.)

    But I've even seen an aftermarket reman caliper have zero return of the piston, fresh out of the box.

    That gave me a giant headache, because I'd bought the reman because the brake was dragging, then when the brake still dragged I went down a whole lot of other directions, thinking the fresh reman caliper couldn't be the problem.

    Now I'll always test a caliper's piston return on the bench before putting it on the car. Learned that lesson.

    [​IMG]

    Toyota has their own reman parts program, so you can sometimes buy a Toyota reman through a dealer. Search for the caliper's normal part number with -84 tacked on the end. There isn't always inventory available.

    I have not seen a Toyota reman caliper have the zero-return problem ... only a cheap aftermarket reman.

    The return of the piston depends on a bunch of small details like the type of rubber in the seal and even the texture on the piston and how much grip the seal has on it, and the reman vendors seem to substitute other materials sometimes and not get those details just right.
     
  13. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    Thank you for all do the information. I will be sure to avoid cheap reman calipers if I have to buy them. I probably do because I don't want to mess around with rebuilding a potentially 20 year old caliper driving around in Boston weather.
     
  14. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    Will first try to verify if it's mechanical or hydraulic. Will lift the 2 front tires up, crack open the bleeder valve to see if the tire can rotate. If so, replace the hose. If not, look at calipers, and other mechanical parts.

    I have the front of the car up and will hope to start the job this week.

    Thank you for the tips!
     
  15. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    There's not really much to a caliper it's just a hunk of iron with some holes in it and the piston that you're putting the rubber seal on is just a hunk of whatever material is used on the given vehicle some now or a form of resin if you will plastic very inexpensive to buy the piston and the seal You clean out the bore with what you call sandpaper today blow out the airways That's pretty much it don't machine a caliper and things like that It's generally not necessary and if you start using brake fluid that doesn't attract water You won't ever have rust in these things where they do rust The calipers on a couple of my cars that I run funny fluids as brake fluid have been in the systems for 25 years seriously purple silicone brake fluid I had to do a pad exchange the other day. And I just cracked open a caliper just for the hell of it to look inside of it normally the little corner of rust that's forming in the bore. Nothing nothing but pure purple fluid and not a trace of rust or any metal degradation at all and this is in an ironed caliper Corolla 1995 LE 7 AFE.
     
  16. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,906
    16,213
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Usually they'll only look like 20 years of Boston weather on the outside.
     
  17. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Usually when I crack open a caliper or a wheel cylinder using DOT 3 or 4 brake fluid there is a corner of rust or where the side of the bore meets the bottom there is a rust ring right there that's got to be where moisture is collecting in the system I would imagine that is what glycol does there's nothing bad it's not hurting a thing but it's there I imagine that is what's turning that brake fluid but very light tan color when it went in almost water clear but hey at all works so I guess it doesn't really matter but the purple stuff doesn't take on water at all and when I crack a system open that's been like that for well probably a decade or so You don't see anything purple fluid.
     
  18. Thepriusthatcould

    Thepriusthatcould Junior Member

    Joined:
    Sep 16, 2020
    25
    5
    0
    Location:
    Andover, MA
    Vehicle:
    2004 Prius
    Model:
    II
    20240927_155605.jpg 20240927_155605.jpg 20240927_155021.jpg 20240927_154919.jpg Got the wheel off, unbolted the 2 caliper bolts, and couldn't get the caliper off. Tried hitting with a hammer.

    I then tried cracking the bleeder valve and it sheered off. No brake fluid leaked out after starting the car.

    I'm thinking I can take off the rotor and caliper together since I'll be replacing them anyway. This possible?

    Should also replace the hoses too but the metal looks pretty gnarly and I don't want to mess with that.
     
  19. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Break caliper hydraulic bolt . Wedge a screwdriver a large one or a small pry bar in between the pad and the rotor and hammer it in with a hammer Don't worry about the damage you're replacing these pieces you'll beat it enough where the caliper will fall off the rotor you'll see a big rough spot on the rotor and so forth but you don't care about that you getting a new one then you should be able to tell if you're hose is good once you have that bolt off
     
  20. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,376
    1,792
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You're in the serious rust belt obviously so this is perfectly normal looking