Brakes - no pedal

[joslinm]

Let my brother borrow my 98 S-10 and before he even got home with it he called and said the brake light was on. I figured it was the emergency pedal was down a little. Said there were no leaks. Got it back today and the fluid level is way down. Filled, but the low pedal is still there. Can find no leaks. Also the ck engine light is on. May not be related. Didn't get a chance to ck code.
Any ideas?

[carrfixr]

Pull 4 wheels if no leaks calipers,wheel cylinders lines etc. move the 2 nuts holding the master cylinder to booster. It could have leaked into the booster from the master. Pedal could be low if air got into the system. Find cause of leak repair and bleed entire system..

[joslinm]

Originally Posted by carrfixr

Pull 4 wheels if no leaks calipers,wheel cylinders lines etc. move the 2 nuts holding the master cylinder to booster. It could have leaked into the booster from the master. Pedal could be low if air got into the system. Find cause of leak repair and bleed entire system..

If I end up removing the 2 nuts, what am I to do then. Pull apart?
No clue what it is supposed to look like if (when) I do it.

[carrfixr]

Remove the nuts and pull the master foward some leaving the lines attached to see if fluid is leaking out the back.. It should be dry. You need to find the cause of your leak

[joslinm]

Originally Posted by carrfixr

Remove the nuts and pull the master foward some leaving the lines attached to see if fluid is leaking out the back.. It should be dry. You need to find the cause of your leak

thanks. My next weekend job.

[joslinm]

Originally Posted by carrfixr

Pull 4 wheels if no leaks calipers,wheel cylinders lines etc. move the 2 nuts holding the master cylinder to booster. It could have leaked into the booster from the master. Pedal could be low if air got into the system. Find cause of leak repair and bleed entire system..

If there is fluid leaking out the back of the master cylinder, that would need to be replaced?
What about the booster?
Thanks for your time, Mike

[carrfixr]

You should be fine with just the master. You'll need to bench bleed the master then bleed all four wheels

[joslinm]

Originally Posted by carrfixr

Remove the nuts and pull the master foward some leaving the lines attached to see if fluid is leaking out the back.. It should be dry. You need to find the cause of your leak

Pulled the master away from booster and it's dry.
Would the brake line come on because of low fluid?
Maybe just bleed the brakes again and see if the peddle comes back?
Also have rust all over near there. I have no idea when it happened and have never seen it wet in the area. Any idea what could have caused it?
http://invite.homestead.com/engine_rust.jpg

[carrfixr]

that rust all over the place looks like its from the cooling system. maybe it overheated once and sprayed all over. i bet if you lift your radiator cap youll see a rusty system needing a flush... assuming you checked all the hydraulics and dont see any leaks bleed the system good and go from there

[joslinm]

Originally Posted by carrfixr

that rust all over the place looks like its from the cooling system. maybe it overheated once and sprayed all over. i bet if you lift your radiator cap youll see a rusty system needing a flush... assuming you checked all the hydraulics and dont see any leaks bleed the system good and go from there

the cooling syastem has been serviced recently and I think the rust was there then. So I think I'm ok there.
While bleeding the brakes, I did find a leak in one of the lines.

Another issue unrelated I think. I have 2 codes PO420 and PO420 p/b
Cat was replaced 3 yrs ago and only 4K on it since then. Any ideas?

[carrfixr]

Po 420 is cat effiency Make sure you have no exhaust leaks in front of the cat converter. Most probable cause is bad cat...

Glad you found your brake problem

[j cAT]

Originally Posted by joslinm

the cooling syastem has been serviced recently and I think the rust was there then. So I think I'm ok there.
While bleeding the brakes, I did find a leak in one of the lines.

Another issue unrelated I think. I have 2 codes PO420 and PO420 p/b
Cat was replaced 3 yrs ago and only 4K on it since then. Any ideas?

with your new york rust belt location the brake line failure is quite common. low pedal and fluid loss its the lines or the rear brake cylinders. never seen that master cylinder leak intro the booster ever.

cat 420 code replace the O2 sensor or if possible swap sensors tosee if the sensor is bad. I would replace both sensors if 10yrs old and over 100,ooomi.

it only takes a small leak for pedal to the floor and poor brakes. in hot weather the fluid evaporates.

high hard pedal would be the brake booster.

the master cylinder does fail some times this is because of contaminated fluid . using cross contaminated containers is all that is needed to create this failure.

[carrfixr]

very interesting never saw a master leak out the back into a booster..
you should have saw the taurus i had in the shop the other day it was so bad smoking out the exhaust just like a head gasket white smoke but had an oil smell to it and it lingered longer.. that was probably the worst one i ever saw most others i have seen go low without any other leaks seeps by the seals into the booster and sometimes a small stain is visible down the outside of the booster..
another thought brake fluid resists evaporation and is not to common..

[joslinm]

Originally Posted by j cAT

cat 420 code replace the O2 sensor or if possible swap sensors tosee if the sensor is bad. I would replace both sensors if 10yrs old and over 100,ooomi.

replaced the downside O2 sensor in the spring. Was a different code for that and none since till now.
Sensors are different. (plugs)

[j cAT]

Originally Posted by carrfixr

very interesting never saw a master leak out the back into a booster..
you should have saw the taurus i had in the shop the other day it was so bad smoking out the exhaust just like a head gasket white smoke but had an oil smell to it and it lingered longer.. that was probably the worst one i ever saw most others i have seen go low without any other leaks seeps by the seals into the booster and sometimes a small stain is visible down the outside of the booster..
another thought brake fluid resists evaporation and is not to common..

any seal will have the chance of leaking. the brake fluid being contaminated is the usual cause. getting into the booster will surely cause the engine to intake this to the combustion chamber.

ya brake fluid and the brake booster diaphram is not a very good thing when they get together.

like I said I never seen this before ,,,, but it is possible.

brake lines in the rust belt is more often the cause for the pedal to floor issue with all of us up here , with these GM defective brake lines androad de icing chemicals.

brake fluid does evaporate. small leaks will not be easy to find. low spongy pedal is with small leaks. stains on the lines/caliper/brake cyl need close inspection with a good light and frequent brake pedal cycling.

the other cause which is also common but not as bad as the lines would be the Abs VALVES LEAKING.

many replace with a scrap yard unit. some had success with getting the ABS to activate which can get these valve to sealt correctly. here on the forum 2 have had to do this and they lucked out.