BoogeymanXJ

cannot figure out why but randomly today my brake light came on when i was driving.

having previously had this issue with a car of mine i thought it might just be low on brake fluid indicating a leak somewhere in the system.

however when i went to check the fluid it was full up.

pedal does feel a little more spongey than usual but still stopping fine (if not better than usual oddly enough)

now today my coolant cap blew off (common renix problem i was unaware about until it failed) as as i was driving it i heard a loud whinning noise coming from the back of my jeep. now i havent heard the noise since i got the volvo cap replacement and refilled the system but thats about the time the brake light issue started.

is it possible that when my coolant bottle exploded in the engine bay that one of the sensors got liquid damage or is the fact that the pedal is also a little spongey an indicator of something more severe?

im sure this has been asked and answered before but i couldnt find anything similar when checking the forums because most of the time people said that their mc reservoir was bone dry or at least low on fluid.


As always, thanks for reading and i look forward to any insight on this issue

cruiser54

IIRC, there's a connector on the proportioning valve. Follow the metal lines from your master cylinder and you'l find it.

Sure your parkbrake lever isn't triggering the light?

BoogeymanXJ

yeah. i havent used my parking brake since i got it because it doesnt work

edit....also i noticed that my braking power is degrading now. i dont know whats going on but im probably gonna have to park it till i can figure it out

Kingfisher

I think you need a master cylinder

BoogeymanXJ

is there a way to test the mc? wouldnt it be losing fluid or something if the mc was bad?

Kingfisher

Not necessarily.
Sometimes fluid leaks past the piston internally.

If you release brake and hit again quickly does it get better?
If you apply pressure and hold it does the pedal gradually go down?

BoogeymanXJ

na i tried pumping the brakes to build up pressure because thats what i used to have to do to get good response in one of my old cars but it still stayed spongey.

when i depress the pedal it goes almost all the way to the floor before hitting resistance and applying the brakes. it even kind of vibrates or wiggles when you first go to depress it because theres so little resistance

cruiser54

I'm betting your master cylinder is ****ting the bed.

BoogeymanXJ

damnit....feel like thats a pita to replace. summer has been messing my jeep up hardcore and its barely started lol

i was still saving up to fix the steering system and get new tires but at this rate ill have to replace everything in the engine bay before i get to do it. guess thats what i get for buying a jeep with 275+ k on it

cruiser54

Easy as hell. Under $50 to do.

BoogeymanXJ

good to know thanks! do i have to bleed the system or anything?

EZEARL

As long as you don't introduce air in to the rest of the system you won't have to bleed anything but the m/c. You can bench bleed it before installing it or install it,fill it,and then bleed it at the connections.

This is may help:
http://www.soyouwanna.com/replace-ma...kee-31780.html

cruiser54

Yes. Bench bleed the master.

But, why not bleed the system afterwards just to get all new fluid into the system. Brake fluid breaks down with time and gets corrosive. Get that old **** outta there.

BoogeymanXJ

thanks for that it will be a great help!

thanks for the advice. never done breaks before so im probably going to try and find a friend that has or have to do alot of research first. too important of a thing for me to just wing it xD cant have my breaks go out when im drivin my kiddos around