Brake locked up, unlocked, now none are not working?

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193
Location
Maine
Just towed a 2008 Scion xB. The LR wheel apparently locked up but is now free. That wheel is brown and so is the bumper behind it, I'd assume the caliper seized and it was driven until the pads burned off. Issue now is that caliper is opened, that brake/caliper is still somewhat working but making some angry noises. Also the brake reservoir is full and clean, and it's not leaking fluid anywhere. When the engine is off, the brake pedal does NOT firm up after pressing it a bunch of times-it gets stiffer but still easily goes to the floor. You do have to pump the brakes to slow down so I haven't driven it over 15mph. So...I'm not sure if the caliper seized or what. And if the brake booster was bad wouldn't it be leaking? Just trying to figure out where to start. Wondering also if the ABS module is dead. No idea how to figure this one out.
 
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13,406
Location
North Carolina
What was the original reason for towing? Was it brake related?

I'm going to say the caliper is obviously toast as it got that hot, either from the parking brake set , or just being seized. I think the brake fluid boiled enough that there is probably gas in the caliper with the liquid. and thats compressing giving you a soft pedal.

If it were mine, Id replace the rear caliper, pads, the bearings on that side, and brake line. Bleed everything, starting with the line furthest away from the master.

If air got in the lines due to the overheated caliper losing its seals, you may even need a shop to cycle the abs pump while bleeding , with a scan tool.

If you let the pedal go al the way to the floor, the master cylinder may be bad now as well.
 

Rochev

Thread starter
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193
Location
Maine
that makes sense, thank you. I'll pick up the parts and bleed it afterward and see how it goes.
 
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5,194
Location
Pittsburgh,PA U.S.A.
I have a neighbor who had an old Taurus and some mechanic put the wrong type of brake fluid in it. That contaminated the entire system and ruined everything. The cost to repair was more than what the car was worth. My point is that if you are going to put money into it, it might be smart to start with a total drain and fill and flush of the old fluid. You do not know who worked on it in the past. And flushing out all the old is a good idea when it is old, but it is even wiser to do that before throwing parts into it, just incase the old fluid is bad enough to cause problems with the new parts.
 
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down in the park
Just towed a 2008 Scion xB. The LR wheel apparently locked up but is now free. That wheel is brown and so is the bumper behind it, I'd assume the caliper seized and it was driven until the pads burned off. Issue now is that caliper is opened, that brake/caliper is still somewhat working but making some angry noises. Also the brake reservoir is full and clean, and it's not leaking fluid anywhere. When the engine is off, the brake pedal does NOT firm up after pressing it a bunch of times-it gets stiffer but still easily goes to the floor. You do have to pump the brakes to slow down so I haven't driven it over 15mph. So...I'm not sure if the caliper seized or what. And if the brake booster was bad wouldn't it be leaking? Just trying to figure out where to start. Wondering also if the ABS module is dead. No idea how to figure this one out.


Fluid that has boiled, will never give a firm pedal again.
 
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36,601
Location
ME
If this is a project car and you have the time, you can get the dealer "techstream" software from ebay, with appropriate USB-OBD cable, for $15. Need an old 32-bit laptop (win xp to win 7) for it to work. This'll let you do ABS stuff and much more.

I would crack that LR bleeder and just STOMP on the pedal, but with a 2x4 under it so it doesn't bottom out. When you boiled the fluid you could have sent god-knows-what up the line. Rubber hose could be bad too, they're cheap enough, change it.
 
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Rochev

Thread starter
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193
Location
Maine
So the caliper was seized. I'm in the middle of replacing it but apparently Toyota requires a special piston tool that not only pushes it, but spins it too. So I'll have to order that before i can do anything else.
 
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13,406
Location
North Carolina
So the caliper was seized. I'm in the middle of replacing it but apparently Toyota requires a special piston tool that not only pushes it, but spins it too. So I'll have to order that before i can do anything else.
If it's the rear caliper, it's the parking brake function.
Need a rear caliper tool kit like this.

 
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Rochev

Thread starter
Messages
193
Location
Maine
Brakes and caliper replaced. The brake doesnt really firm up even when the engine is off, so I'm not sure if I can even bleed them. Again nonleaking fluid and looks good.
 
Messages
13,406
Location
North Carolina
Brakes and caliper replaced. The brake doesnt really firm up even when the engine is off, so I'm not sure if I can even bleed them. Again nonleaking fluid and looks good.
Air in system most likely. Master cylinder could be bad if the pedal was pressed to the floor. And it could be both, air in system and bad master. You may need to have the ABS system cycled to bleed it.

EDIT: If you can get some master cylinder plugs locally, you can try that and see if the brake pedal is solid. probably M10x1.
 
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360
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YYC
Anytime you replace a caliper you have to bleed the system, no exceptions. With a new caliper bleeding will be much less stressful than with a rusty old one
 

Rochev

Thread starter
Messages
193
Location
Maine
I ended up bringing it to a shop. Turns out the front calipers were seized but they were able to take them apart and clean+lube them up and do a flush. Cars going great now!
 
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18,343
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NH
The calipers were seized, or the brakes frozen? Usually calipers get swapped, I mean one can run a hone through 'em and put in new seals, but it seems rarely anyone does, at least not for late model stuff.
 

Rochev

Thread starter
Messages
193
Location
Maine
He said he took them apart, cleaned up the rust and re-lubed them. I believe the car sat since December of 2019 since the sticker and registration ran out January of 2020. Brakes are working well now.
 
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