Question about 1985 Jeep CJ7

1 Answer

Front brakes calipers locking up ,new calipers ,new lines , new mc, whats left?

Brakes kept locking up replaced calipers and lines and master cylinder but still driverside locks up until I bleed

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  • freedom ford
    freedom ford Mar 23, 2014

    non abs was completely bled

  • freedom ford
    freedom ford Mar 23, 2014

    not shure what else could cause just on caliper to build pressure

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  • Jeep Master
  • 20,706 Answers

Only one side.
until i bleed, what does that mean.? (we all know how to bleed all 5 ways) but why do you say that.
oddly unbleed brakes never lock, due to AIR in the system.
so only bled brakes lock, or work prefect.

this is hydralics 101.
if any caliper locks, it must Be blockage
so does it stay locked for at least 5min>? unsaid DURATION
if yes, this is childs play.
you have 1 person try to turn tire, its locked, and you take your
spanner to THAT line at the MC and CRACK it open
does it unlock, yes, mc bad, no then the flex hose is bad inside.
dang that was easy huh?
if the mc, locks that TOO is easy
the piston is inside is not retracting 100%
all brakes must back flow, or LOCK.
the piston has a port there.
so the person that put the MC on car did not read the FSM
that clearly stated how to adjust the push rod gap from
brake pedal to MC rear piston.
for sure.
see this drawing.
if the piston dont retract then it can not back flow and will LOCK.

http://static.howstuffworks.com/gif/master-brake3.jpg




Posted on Mar 24, 2014

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Posted on Jan 02, 2017

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  • 141 Answers

SOURCE: front brakes locking up

Sounds like the front brake hoses went bad on you. Fluid goes into the calipers and builds up pressure, and applies the brakes, because the fluid can't come back out of the calipers. Usually when hoses go, they tear on the inside, creating a one way valve type of flap. I hope that this helped. Best wishes to ya.
Bryon

Posted on Jan 26, 2009

  • 1779 Answers

SOURCE: I just put new calipers

Did u bleed the master cylinder before u installed it? If not, you'll have to also bleed the rear brakes. starting w/ the bleeder the farthest away, to next greatest distance,etc til u get to the closest bleeder.
If u did bleed the master cyl. before installation, I'm wondering if u did the following:
have someone pump the brakes (3 times, don't mash the pedal to the floor, just gentle push no more than half way down 3 times, while holding pedal half way down 3rd pump, open bleeder, when fluid or air slows coming out, close bleeder, and repeat, until only clean fluid flows. And of course, don't let the fluid get too low in the master cyl, or you will **** in air and have to start all over. Let me know how you do. countrycurt0

Posted on Sep 28, 2008

JMMARRERO59
  • 77 Answers

SOURCE: troubled brakes

TAKE IT TO THE DEALER, SINCE VEHICLE HAS ABS SYSTEM . THE BRAKES MAY NEED TO BE BLEED WITH DRB/SCANNER. OR YOU MAY HAVE LINES CLOGGED.

Posted on Dec 30, 2008

  • 434 Answers

SOURCE: all four brakes lock-up

could be the master cylinder or proportioning valve

Posted on Jun 24, 2009

  • 4340 Answers

SOURCE: front passenger brake locked up causing the

What happens is the caliper pistons seize. you could rebuild them, but much better to buy new or rebuilt ones.
Replace the flexible hoses at the same time, sometimes they deteriorate on the INSIDE and cause similar issue.

If you have pullsation, after all of this, I would expect that your rotors have suffered heat damage. They would need to be turned or replaced. DO not put up with pullsation.

ALSO, you do "wheel sets" do not replace JUST one side. The safety rule is always do the same to BOTH sides, when you do brakes.

Posted on Mar 22, 2010

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this is cause by the MC, the master cylinder, no ABS in 92
not replacing relic calipers in pairs is dumb, sorry risking life and limb using old 20 year old calipers is not bright. a fact, not opinion.
are both caliper locking, at ONCE?
that is the key question .
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2: the MC piston is not retraced,

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