*I replaced the master cylinder on a 2002 Camry because the pedal was
fading. Now the front brakes lock after using them a few times. The
only they will release is to open a fluid line. I replaced the front
calipers and pads and still the same problem. Got any ideas? I'm now on
the 3rd master. 2 remans and 1 new.*

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rjcar
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E Meyer - 26 Jul 2007 19:22 GMT
Air bubble? Are you sure you bled everything according to the book when
installing the new MC? If it has ABS, there could be some interaction with
the ABS unit going on as well.
On 7/26/07 12:38 PM, in article rjcar.2uca4s@no-mx.nodomain.com, "rjcar"
> *I replaced the master cylinder on a 2002 Camry because the pedal was
> fading. Now the front brakes lock after using them a few times. The
> only they will release is to open a fluid line. I replaced the front
> calipers and pads and still the same problem. Got any ideas? I'm now on
> the 3rd master. 2 remans and 1 new.*
rjcar - 26 Jul 2007 21:40 GMT
*Good suggestion. I went through the process again just to make sure but
still have the problem. It doesn't have ABS nor TC. I don't see why it
should be so much trouble but it's really blowing my mind. Any more
suggestions?*

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rjcar
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E Meyer - 27 Jul 2007 02:09 GMT
On 7/26/07 3:40 PM, in article rjcar.2ucigs@no-mx.nodomain.com, "rjcar"
> *Good suggestion. I went through the process again just to make sure but
> still have the problem. It doesn't have ABS nor TC. I don't see why it
> should be so much trouble but it's really blowing my mind. Any more
> suggestions?*
As the other poster suggested, verify that its the correct MC for the car.
rjcar - 27 Jul 2007 04:23 GMT
*I never thought of that. This is the 3rd one, surely they didn't mess
up that badly at my parts place. Is that the proportioning valve you're
referring to. That sounds interesting. How would you check it?:banghead:
:banghead: *

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rjcar
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Steve - 27 Jul 2007 16:09 GMT
> *I never thought of that. This is the 3rd one, surely they didn't mess
> up that badly at my parts place. Is that the proportioning valve you're
> referring to. That sounds interesting. How would you check it?:banghead:
> :banghead: *
Prop valve is another thing to check, and actually most cars since the
70s combine the proportioning valve and the system isolation safety
valve (the one that keeps half the system pressurized if the other half
springs a leak, yet allows enough fluid to move between the halves to
balance the system pressure under normal operatioin) into a single
"combo valve."
I'm kinda guessing on general principles, I don't know anything about
the design of that particular braking system. No habla Toyota. Test
procedures for any of the system components like the combo valve
*should* be in the factory service manual.
Rodan - 27 Jul 2007 03:57 GMT
"rjcar" wrote: (2002 Camry)
I replaced the master cylinder because the pedal was
fading. Now the front brakes lock after using them
a few times. The only way they will release is to open
a fluid line. It doesn't have ABS nor TC. I replaced
the front calipers and pads and still the same problem.
I'm on the 3rd master;2 remans and 1 new. Any ideas?
____________________________________________
Possible things to check:
1.) Caliper hoses collapsed, acting as check valve preventing fluid from returning to MC.
2.) Brake pedal binds, does not return fully to release brake application.
3.) Brake pedal pushrod into vacuum booster too long or misadjusted prevents full release.
4.) Vacuum booster valve failing to fully release.
5.) Front & Rear brake lines interchanged at MC.
6.) Binding cylinders in calipers - probably not this because calipers worked before.
7.) Plastic dust caps not removed from new MC ports.
8.) Wrong MC.
9.) Return hole into MC reservoir plugged.
That's all I can think of now.
Good luck.
Rodan.
Steve - 26 Jul 2007 21:30 GMT
> *I replaced the master cylinder on a 2002 Camry because the pedal was
> fading. Now the front brakes lock after using them a few times. The
> only they will release is to open a fluid line. I replaced the front
> calipers and pads and still the same problem. Got any ideas? I'm now on
> the 3rd master. 2 remans and 1 new.*
That sounds like what happens when you put a drum brake master cylinder
on a disk brake car, because the residual pressure valve for drum brakes
acts as a check valve.
But unless you got "creative," I don't think that can happen on a master
cylinder for a car that was never built with drum brakes....
Have you checked the function of the safety isolation valve?
sdlomi2 - 28 Jul 2007 02:09 GMT
> *I replaced the master cylinder on a 2002 Camry because the pedal was
> fading. Now the front brakes lock after using them a few times. The
> only they will release is to open a fluid line. I replaced the front
> calipers and pads and still the same problem. Got any ideas? I'm now on
> the 3rd master. 2 remans and 1 new.*
On some cars, calipers can be swapped--are you sure your left one is on
left side and right on right side (assuming yours can be interchanged)?
Also, ensure flex lines on front are not "twisted" like when inadvertently
installing calipers with an "included twist". HTH, s