brakes seizing?

hi folks...
this one's got me miffed totally..
wife drives car today and calls me at work to tell me car is done...lol
I get home and drive the car and all seems fine until I almost get home..that's when I find out what she was talking about. I find that the brakes seem to be seizing after maybe 20 times stopping. Eventually preventing the car from moving in drive or reverse.
I have just spent the last 3 hours removing and greasing and checking for movement of front calipers and piston removal and cleaning. whilst on jack stands all seemed well and stopping and releasing was good.
I take it for a road test and same thing happens....the car is along the road unable to go any further...I'm waiting for whatever the problem is to relax again so as I can get the car home.
What I did notice when I reset the caliper pistons was that they refused to go back unless I opened the relief valve and then they flew back with ease...that tells me that the calipers are fine.
front wheels wouldn't move at first when I jacked the car earlier.

So my question is this...
Does the brake master cylinder have some sort of valve in it that could be screwed...or does anyone think the ABS is screwing up...no lights on dash except a little hotter than usual coz it's revving up high to get it to move.
all ideas welcome...

thanks folks

hey astro,sounds like to much pressure.metering/proportioning valve i'd try cranking open the bleeders to see what happens.would'nt think abs is involved but dont no alot on newer systems.''what are you driving please''!!

sorry
2001 malibu.
cracking the bleeders allows the pistons to go back.
pressure builds up again and won't release...
I'm going back along the road to try and get the car home now...
back in a few mins I hope..hope it has relaxed enough to allow driving.
thanks for reply by the way.

sorry for double post...
somehow my browser won't let me edit.

In addition to above symptoms...The pedal seems to be lower than usual...may be imagination...but seems like much less travel on the brake pedal than usual.
don't know if this will help anyone diagnose.

perhaps master cylinder is partially seized and not allowing return fluid?
clutching at straws but am a very logical thinker.
this has to be either the master cylinder or the abs. from my knowledge of the system.
however my understanding of the abs is that the solenoids are open until needed...meaning that if a problem was present it wouldn't inhibit braking and allow the master cylinder to do the job...
still looking for some clever folk's input...
thanks

just adding i've seen where the rubber hose collasped not allowing fluid in/out
is the car at home now
how many miles on car??

yes car is at home now
both front wheels from what i can tell.
boss at work has suggested proportioning valve....makes sense.
don't know where it is though.
just got home from work and going out to look at this now.
I'm assuming my car has one of them.
I could see the abs motor but didn't look for no prop valve.
will post back today's findings in about an hour.

thanks again for input..
both hoses are fine from what i can tell right now.
2001 malibu...93000 miles.
almost no trouble from car since bought new in 2001.
so no history of screwy car.

EDIT:
my findings today are...
no proportioning valve anywhere.
brake lines come from master cylinder and go to the abs hub/module.
from there they go to each wheel.
2 in and 4 out.
now I'm sure this does the proportioning .
sadly it seems to be a dealer part with 2 options...1 is $800+ (ouch) the other is $900+ (just bend me over now please).
It's looking like I have to go get another job just to foot this bill.
even with doing the repair myself it's gonna hurt.
I'd hate to think of the labor charge on something like that.
maybe I can pick up a used part somewhere.
this sucks.
Now I do HATE my loved chevy.

i had the exact same problem!!!! It was locking up on while driving. It turned out to be the hydraulic control module. or the ABS control module either one of those can be casuing the problem. The master cylinder cannot make the brakes lock up. It has to do with the traction control also....since the traction control is combined with the abs system youd have to replace one of those 2 modules. When my car would lock up it would come to a complete stop and it would start up with a high rpm and the hot or cold arrow would go above normal.

You would be able to tell which side by how hot the brakes are. The side that is sticking will be way hotter. I suspect that it is one side or another. If this is the case it is likely that it is as simple a collapsed frake hose. They will look perfectly fine on the outside but its what you can't see that may be broken!

How does the seal look on the resavoir? Is it bloated?

i had the exact same problem!!!! It was locking up on while driving. It turned out to be the hydraulic control module. or the ABS control module either one of those can be casuing the problem. The master cylinder cannot make the brakes lock up. It has to do with the traction control also....since the traction control is combined with the abs system youd have to replace one of those 2 modules. When my car would lock up it would come to a complete stop and it would start up with a high rpm and the hot or cold arrow would go above normal.

thanks for the input....
I meant to update this thread when I fixed the car.
Turns out that after ordering an ABS unit..(which I got for $75 on ebay with lifetime warranty) and replacing the master cylinder....that the brake booster was shot...yeah..new one on me too.
I spoke with a mechanic before tearing down the system who told me a neat trick to tell if the abs was holding the pressure....
when the wheels were locked...crack the pipe at the master cylinder...if fluid spurts with pressure...then it's making it'sway back there and therefore the abs cannot be at fault....he'd never heard of one actually failing on my car year and model. This would tell me that the master cylinder was at fault.
I go home and voila I crack the pipe and fluid spurts...I'm thinking...oh yeah...easy meat this one is.
But after replacing the master cylinder I have the same problem and just manage to get the car home again, and I have a brainwave.
After starting the car a couple of times I could hear the brakes pressurising before I even touched them....I'm thinking...sounds like my booster is kicking a bit hard there.....I remove the vacuum hose and put to firewall to as not to stall the motor...I put the car in N and I can push it....I'm thinking dang...This might just be it. I put the vac hose back and instantly the brakes pressurise.
After a few cuss words and the tedious task of figuring out how this removes and replaces...I have a functional car again.

I now call this thread

RESOLVED

I can honestly say i would have never of thought that would be it. Just shows how a little detective work can go a long way!

Nice job finding the fix Astro!!!

I can honestly say i would have never of thought that would be it. Just shows how a little detective work can go a long way!

Nice job finding the fix Astro!!!

thank you sir...
me neither...but when the master cylinder test was the same result 2nd time around after replacement...I was a little upset about the advice I got...but the guy was right also...The pressure would not be there if the abs was at fault.
The only other logical factor had to be what was driving the master cylinder...hence me testing the booster.
Although it has now cost me $75+ shipping for abs unit + $79+ tax for master cylinder and $83 + tax for power booster I think I come out cheaper than using a mechanic to diagnose the issue and I honestly think they would have replaced the master cylinder and told me both were shot when they found out that it didn't fix it and had to do the booster.
but that's just my opinion. My wife's been had like that before more than once before I met her.
Now I have 2 new parts on the car and good peace of mind about the wife driving it again.
I still have the abs unit...I'm gonna hold onto it just in case it should go out one day. After all I have a lifetime warranty on it and if I ship it back I'll only end up with like $30 of my $90 total...what's the point eh?