Hard brake pedal, poor braking

JamesGarfield
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Joined: August 22nd, 2011, 4:13 am

September 8th, 2018, 10:18 pm #1

Car is a 94 Metro hatchback, 3cyl 5speed.

Lately the brake pedal has become hard and stiff to press down, and takes much more pedal force to stop.

I'm in the middle of working on another car right now, and haven't made any investigations yet on this brake issue. Just thought I'd toss this out and see if someone could suggest what the problem might be.
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pdqrunner
Elite Member
Joined: April 27th, 2009, 3:13 pm

September 8th, 2018, 10:36 pm #2

Check the vacuum line off the brake booster they tend to break down. I believe it is a std. vacuum line with no check valve.
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MR1 Kingsbury
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Joined: January 6th, 2012, 12:01 am

September 8th, 2018, 10:50 pm #3

I had to remove mine to clean it out well... they can get a carbon block in them...
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geogonfa
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Joined: April 7th, 2010, 2:03 am

September 9th, 2018, 2:45 am #4

Usually the large vacuum line at the back of the intake manifold clogs full of carbon and restricts flow as it plugs up ...
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JellyBeanDriver
Elite Member
Joined: May 6th, 2009, 4:44 am

September 9th, 2018, 3:09 am #5

Exactly what others have said. The rubber hose that attaches to the manifold for the brake booster disintegrates over time and swells up and closes off the hose. Replace that section with something with a thick wall from your local parts store and you'll be fixed.
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Woodie
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Joined: February 13th, 2009, 12:29 pm

September 9th, 2018, 11:28 am #6

And there's a check valve somewhere. Some cars had them in the middle of the rubber hose, others where the hose connects to the booster can.
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Roley
Advanced Member
Joined: June 18th, 2012, 1:37 am

September 9th, 2018, 1:48 pm #7

If the caliper is bound up and not floating on the guide pins it will act like that. The pads would not contact the rotor flush. The longer it is stuck the worse it gets.
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JamesGarfield
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Joined: August 22nd, 2011, 4:13 am

September 14th, 2018, 3:51 pm #8

Hi guys, thanks for your replies, and please pardon the time it's taken to get back here.  

Got done with the car I was working on ahead of this one.  It's another Geo, a Tracker.  Changed the oil pan gasket, and that job took longer than expected.  Got the pan off easy enough, but getting the pan out of the chassis was a bear.  You'd think that wouldn't be a problem on a vehicle with that much ground clearance.  Had to drop one end of the tie rod to get the pan out.  

But that's done, and I digress, now back to this Metro with the hard brake pedal and poor braking.  This is my wife's car of 24 years,  and to show what kind of a dummy I can be, all this time I never knew it had power boosted brakes-- just assumed they were standard brakes (DOHH!).  This car has been very reliable all these years, you see, and only just lately have some major issues come up.  The steering rack, for instance, developed a loose INNER ball joint.  Replaced that, along with overhauling all the front end bushings.  So she rolls and steers nicely now.

Then I wanted to look at the IAC.  You might have seen my posts here about that.  The IAC had never worked right on this car.  Had to compromise on the idle speed setting-- it would either bog and shake with the A.C. on, or idle too fast with it off, you know the story.  So I removed the IAC motor to examine it, and that was another mother of a task.  Those 3 little bolts must have been put in there by Hercules, to where I had to remove the whole throttle body to get good access to them.  Everything went back together ok, but I might have damaged a vacuum hose somewhere in that process, because the idle is kinda rough now, and the exhaust smells funny like too rich maybe.  You might have seen my posts asking about the TPS calibration procedure.  And I know there's a vacuum hose diagram I can check, that'll be next.  I just can't catch a break.

Oh yeah, BRAKES, back to the brakes (see how easy i get rambling).  I massaged the rubber vacuum hoses between the manifold and the booster, looking for any splits or cracks, none found.  Then I pulled the hose off the booster.  With the engine running, my calibrated thumb shows good  vacuum in the booster hose.  Plus, the engine idle revs up with the hose open, and settles back down with thumb closing the hose.   This would indicate that manifold vacuum is reaching the booster, yes?  I guess the next step is to take Roley's advice and check for a stuck caliper.

Well, thanks for reading this far.  Hope all of you in the storm's path are staying safe.
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wizard93
Elite Member
Joined: September 28th, 2010, 12:40 am

September 14th, 2018, 4:49 pm #9

My 1994 Metro had hard brakes with almost no braking when I first bought it.  After replacing the hoses and fixing a stuck caliper slider pin, I gave it a good bleeding and the brake pedal was back to normal.
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