Failing Brakes on 87 Cherokee- Brake Booster?
 

When i'm driving, sometimes there will be brake pressure and somtimes
there won't. If i apply pressure for a few seconds, the pedal loses
presure and goes to the floor. I have to pump the brakes to get the car
to stop. I tried bleeding the brakes and got through the back to wheels
fine, but when i tried to bleed the front right brake, air bubbles kept
coming out. After refilling the resivoir for the 3rd time (it never got
completly empty), i got the idea that it might be somethign more
complicated. I was able to bleed the front left with no problems but
the same thing kept happening when i tried to drive it. I checked all
the lines and can't find any leaks, but i have an oil leak so i might
be missing something thinking its just oil and not brake fluid. There
is some black fluid underneath where the brake booster connects to the
master cylinder but i don't konw if its coming out of there or is oil .
I can also hear some air come out of the brake booster inside the car
but i dont' know if that is normal. I don't know too much about brakes
and i don't want to take apart the whole system before i know what to
look for. Any ideas?

Re: Failing Brakes on 87 Cherokee- Brake Booster?
 

On 29 Jan 2006 16:57:45 -0800, "tyytyy22" <ssejk5@yahoo.com> wrote:

>When i'm driving, sometimes there will be brake pressure and somtimes
>there won't. If i apply pressure for a few seconds, the pedal loses
>presure and goes to the floor. I have to pump the brakes to get the car
>to stop. I tried bleeding the brakes and got through the back to wheels
>fine, but when i tried to bleed the front right brake, air bubbles kept
>coming out. After refilling the resivoir for the 3rd time (it never got
>completly empty), i got the idea that it might be somethign more
>complicated. I was able to bleed the front left with no problems but
>the same thing kept happening when i tried to drive it. I checked all
>the lines and can't find any leaks, but i have an oil leak so i might
>be missing something thinking its just oil and not brake fluid. There
>is some black fluid underneath where the brake booster connects to the
>master cylinder but i don't konw if its coming out of there or is oil .
>I can also hear some air come out of the brake booster inside the car
>but i dont' know if that is normal. I don't know too much about brakes
>and i don't want to take apart the whole system before i know what to
>look for. Any ideas?

It sounds like you need a master cylinder. About 20 or 25 bucks at a
parts house and a simple replacement you can do yourself. A new one
will come with all connectors and hoses necessary to bleed the unit
before you connect your brake lines to it. If you get a rebuilt one
(no reason not to), you will need to also get a bleeder kit for it.
You MAY (but probably don't) also have a problem with your right front
wheel cylinder.

Dan

Re: Failing Brakes on 87 Cherokee- Brake Booster?
 

On 29 Jan 2006 16:57:45 -0800, "tyytyy22" <ssejk5@yahoo.com> wrote:

>When i'm driving, sometimes there will be brake pressure and somtimes
>there won't. If i apply pressure for a few seconds, the pedal loses
>presure and goes to the floor. I have to pump the brakes to get the car
>to stop. I tried bleeding the brakes and got through the back to wheels
>fine, but when i tried to bleed the front right brake, air bubbles kept
>coming out. After refilling the resivoir for the 3rd time (it never got
>completly empty), i got the idea that it might be somethign more
>complicated. I was able to bleed the front left with no problems but
>the same thing kept happening when i tried to drive it. I checked all
>the lines and can't find any leaks, but i have an oil leak so i might
>be missing something thinking its just oil and not brake fluid. There
>is some black fluid underneath where the brake booster connects to the
>master cylinder but i don't konw if its coming out of there or is oil .
>I can also hear some air come out of the brake booster inside the car
>but i dont' know if that is normal. I don't know too much about brakes
>and i don't want to take apart the whole system before i know what to
>look for. Any ideas?

It sounds like you need a master cylinder. About 20 or 25 bucks at a
parts house and a simple replacement you can do yourself. A new one
will come with all connectors and hoses necessary to bleed the unit
before you connect your brake lines to it. If you get a rebuilt one
(no reason not to), you will need to also get a bleeder kit for it.
You MAY (but probably don't) also have a problem with your right front
wheel cylinder.

Dan

Re: Failing Brakes on 87 Cherokee- Brake Booster?
 

On 29 Jan 2006 16:57:45 -0800, "tyytyy22" <ssejk5@yahoo.com> wrote:

>When i'm driving, sometimes there will be brake pressure and somtimes
>there won't. If i apply pressure for a few seconds, the pedal loses
>presure and goes to the floor. I have to pump the brakes to get the car
>to stop. I tried bleeding the brakes and got through the back to wheels
>fine, but when i tried to bleed the front right brake, air bubbles kept
>coming out. After refilling the resivoir for the 3rd time (it never got
>completly empty), i got the idea that it might be somethign more
>complicated. I was able to bleed the front left with no problems but
>the same thing kept happening when i tried to drive it. I checked all
>the lines and can't find any leaks, but i have an oil leak so i might
>be missing something thinking its just oil and not brake fluid. There
>is some black fluid underneath where the brake booster connects to the
>master cylinder but i don't konw if its coming out of there or is oil .
>I can also hear some air come out of the brake booster inside the car
>but i dont' know if that is normal. I don't know too much about brakes
>and i don't want to take apart the whole system before i know what to
>look for. Any ideas?

It sounds like you need a master cylinder. About 20 or 25 bucks at a
parts house and a simple replacement you can do yourself. A new one
will come with all connectors and hoses necessary to bleed the unit
before you connect your brake lines to it. If you get a rebuilt one
(no reason not to), you will need to also get a bleeder kit for it.
You MAY (but probably don't) also have a problem with your right front
wheel cylinder.

Dan

Re: Failing Brakes on 87 Cherokee- Brake Booster?
 

When the pressure drops out below a pushed down pedal, you either have a
leak or a dead master cylinder. If you have a leak that drops the pedal
to the floor, you will run the master dry of fluid 'very' fast, there
will be no wondering about a leak.

The bleeding is another issue. You likely have the type of combination
valve that has a pin in the end that needs to be held from moving to get
all the air out. The combination or proportioning valve is below the
brake master where all the lines meet and should have a rubber cap on
one end. Under this cap is the pin that needs holding.

Or, the master is just plain dead so it won't push any volume of fluid
out to the front wheels so the air just hangs around.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tyytyy22 wrote:
>
> When i'm driving, sometimes there will be brake pressure and somtimes
> there won't. If i apply pressure for a few seconds, the pedal loses
> presure and goes to the floor. I have to pump the brakes to get the car
> to stop. I tried bleeding the brakes and got through the back to wheels
> fine, but when i tried to bleed the front right brake, air bubbles kept
> coming out. After refilling the resivoir for the 3rd time (it never got
> completly empty), i got the idea that it might be somethign more
> complicated. I was able to bleed the front left with no problems but
> the same thing kept happening when i tried to drive it. I checked all
> the lines and can't find any leaks, but i have an oil leak so i might
> be missing something thinking its just oil and not brake fluid. There
> is some black fluid underneath where the brake booster connects to the
> master cylinder but i don't konw if its coming out of there or is oil .
> I can also hear some air come out of the brake booster inside the car
> but i dont' know if that is normal. I don't know too much about brakes
> and i don't want to take apart the whole system before i know what to
> look for. Any ideas?

Re: Failing Brakes on 87 Cherokee- Brake Booster?
 

When the pressure drops out below a pushed down pedal, you either have a
leak or a dead master cylinder. If you have a leak that drops the pedal
to the floor, you will run the master dry of fluid 'very' fast, there
will be no wondering about a leak.

The bleeding is another issue. You likely have the type of combination
valve that has a pin in the end that needs to be held from moving to get
all the air out. The combination or proportioning valve is below the
brake master where all the lines meet and should have a rubber cap on
one end. Under this cap is the pin that needs holding.

Or, the master is just plain dead so it won't push any volume of fluid
out to the front wheels so the air just hangs around.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tyytyy22 wrote:
>
> When i'm driving, sometimes there will be brake pressure and somtimes
> there won't. If i apply pressure for a few seconds, the pedal loses
> presure and goes to the floor. I have to pump the brakes to get the car
> to stop. I tried bleeding the brakes and got through the back to wheels
> fine, but when i tried to bleed the front right brake, air bubbles kept
> coming out. After refilling the resivoir for the 3rd time (it never got
> completly empty), i got the idea that it might be somethign more
> complicated. I was able to bleed the front left with no problems but
> the same thing kept happening when i tried to drive it. I checked all
> the lines and can't find any leaks, but i have an oil leak so i might
> be missing something thinking its just oil and not brake fluid. There
> is some black fluid underneath where the brake booster connects to the
> master cylinder but i don't konw if its coming out of there or is oil .
> I can also hear some air come out of the brake booster inside the car
> but i dont' know if that is normal. I don't know too much about brakes
> and i don't want to take apart the whole system before i know what to
> look for. Any ideas?

Re: Failing Brakes on 87 Cherokee- Brake Booster?
 

When the pressure drops out below a pushed down pedal, you either have a
leak or a dead master cylinder. If you have a leak that drops the pedal
to the floor, you will run the master dry of fluid 'very' fast, there
will be no wondering about a leak.

The bleeding is another issue. You likely have the type of combination
valve that has a pin in the end that needs to be held from moving to get
all the air out. The combination or proportioning valve is below the
brake master where all the lines meet and should have a rubber cap on
one end. Under this cap is the pin that needs holding.

Or, the master is just plain dead so it won't push any volume of fluid
out to the front wheels so the air just hangs around.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tyytyy22 wrote:
>
> When i'm driving, sometimes there will be brake pressure and somtimes
> there won't. If i apply pressure for a few seconds, the pedal loses
> presure and goes to the floor. I have to pump the brakes to get the car
> to stop. I tried bleeding the brakes and got through the back to wheels
> fine, but when i tried to bleed the front right brake, air bubbles kept
> coming out. After refilling the resivoir for the 3rd time (it never got
> completly empty), i got the idea that it might be somethign more
> complicated. I was able to bleed the front left with no problems but
> the same thing kept happening when i tried to drive it. I checked all
> the lines and can't find any leaks, but i have an oil leak so i might
> be missing something thinking its just oil and not brake fluid. There
> is some black fluid underneath where the brake booster connects to the
> master cylinder but i don't konw if its coming out of there or is oil .
> I can also hear some air come out of the brake booster inside the car
> but i dont' know if that is normal. I don't know too much about brakes
> and i don't want to take apart the whole system before i know what to
> look for. Any ideas?