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Author Topic: Brakes to the floor  (Read 952 times)

Offline deucekazoo

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Brakes to the floor
« on: 07:55:04 AM / 25-Aug-16 »
So finally finished redoing the front suspension last night. I had a little ball joint problem, more with parts stores than the car. So I noticed I had some fluid missing out of the brake reservoir. It has been sitting and this happened before. When I drive it the fluid goes down a little but don't really have to refill it. I know its a closed system so it should not be going anywhere but its not leaking by any of the wheels or lines. So add some fluid and start the car. I pumped the brakes to have the pads close on the rotors because I had them off the car but did not take any of the brakes lines apart. So the brake pedal has nothing. I pump it a few times to feel a stiff pedal and nothing. I pump for a good minute and still nothing. Pedal goes to the floor. I shut the car off and the pedal gets a little stiffer but not as it should be.
So any ides from you guys. I think its probably the brake booster, and it might be or is leaking. That is where the fluid is going.
Am I sucking the fluid into the vacuum lines?
Anyone have this same issue?
Just trying to get ideas what to look at. The car did start fine but idled weird after it warmed up. Now to think of it, it sounded like it has a vacuum leak. So any info on this would be helpful. I will try to tackle this tonight when I get home.
Thanks,
John
« Last Edit: 07:56:18 AM / 25-Aug-16 by deucekazoo »

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Offline iceageg

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Re: Brakes to the floor
« Reply #1 on: 08:56:25 AM / 25-Aug-16 »
In our pathfinder the brake fluid doubles as the fluid for the hydraulic clutch.  I have a slow leak in the slave cylinder that causes my brake fluid level to slowly drop.  It is on my list to repair but it is such a slow seep that it is too easy to ignore.  I'm not sure if the S12 clutch is a similar system but it would be easy to check out.
I was afraid all the five gallon buckets of pain stacked four high were going to fall over

Offline deucekazoo

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Re: Brakes to the floor
« Reply #2 on: 09:24:49 AM / 25-Aug-16 »
On the S12 the clutch has its own reservoir. That is kind of weird that they doubled it up like that on the Pathfinder.

Offline iceageg

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Re: Brakes to the floor
« Reply #3 on: 09:57:10 AM / 25-Aug-16 »
I thought so too.
I was afraid all the five gallon buckets of pain stacked four high were going to fall over

Offline kelso840

Re: Brakes to the floor
« Reply #4 on: 11:00:33 AM / 25-Aug-16 »
My brakes were weak when I got my car and I just swapped the master cylinder out and did a bleed from the back right tire and everything woke up just fine.

Not sure if you need a new master, but it does stand to reason that if fluid is leaking out someplace, then air can (and will) be drawn back into the system. I'd suggest bleeding the system to get a baseline and see if you can get pressure to return temporarily. With the system pressurized and the car not moving you might be able to identify your leak.
Infrequently driving an s12.

Offline rednucleus

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Re: Brakes to the floor
« Reply #5 on: 05:44:04 PM / 25-Aug-16 »
I agree, bleed system 1st. I don't think fluid should be able to escape into the booster - no physical connection. Wonder if your master has failed.

Offline Cajun1guy

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Re: Brakes to the floor
« Reply #6 on: 06:28:14 AM / 26-Aug-16 »
Ian, don't let that slave cylinder leak. It ain't fun having the clutch go to the floor when you are out and about. And with yours sharing the brake fluid (?) that could leave you down to the E-brake. It's bad enough trying to drive to a safe place to park with no clutch!

Offline iceageg

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Re: Brakes to the floor
« Reply #7 on: 07:48:27 AM / 26-Aug-16 »
It's more of a seep than a leak, and it's on the list to replace.  In 4 years i have had to fill the reservoir half way.  Just part of the magic of owning older cars with no payment.  There is ALWAYS something to fix/replace.  The pathfinder needs new tires for this winter and a new centerlink to remove the slop in the steering next.  The slow seep just hasn't been enough to work it's way to the top of the list yet.  Being back in Denver though with the hangar available Ihave been making great progress on both the Pathfinder and my T/A though.  Finish this 182 that is taking all my time and I can start working on the cars again soon.  Its good to be back.
I was afraid all the five gallon buckets of pain stacked four high were going to fall over

Offline deucekazoo

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Re: Brakes to the floor
« Reply #8 on: 11:32:39 AM / 26-Aug-16 »
I fixed it.
First I checked the vacuum valve going to the booster, and it works how it is supposed to.
Then I bled the brakes following the directions. All were good except I had quite a bit of air on the front left. Now the brakes are stiff and work good.
So it still leaks bout but not sure where. The master cylinder might be seeping somewhere. Its just weird that that much fluid disappeared that quick when it was good for a few weeks just siting there.
So bled the brakes and they work how they should. I guess there was just the right amount of an air pocket in the right place to make the pedal go to the floor. I will just watch the reservoir level to make sure it is always filled up. 

Offline Cajun1guy

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Re: Brakes to the floor
« Reply #9 on: 01:07:27 PM / 26-Aug-16 »
See if it is leaking aft of the firewall into your carpet.
Ian, good to hear you are back in your hemisphere, looks like you got out in time...my slave unit seeped until one day the pedal got soft, then went to the floor. I opened the door and looked underneath to see a stream of fluid coming from the slave unit-not a good feeling!. Shut off engine, put in first, start and carefully speed shift until getting to a safe place to wait for a tow.

Offline deucekazoo

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Re: Brakes to the floor
« Reply #10 on: 12:29:53 PM / 30-Aug-16 »
I looked inside at the firewall by the brake rod and everything is dry in there and no signs of discoloration from a leak.