I just recently had a issue with my brake pedal feeling spongy and sinking a little so i replaced the master cylinder and had to bleed the system a few times (finally found the right order) and everything was working great, just like when i bought the car, and now i've got the brake light coming on and only goes off when i apply the brakes a little harder than you normally would. As soon as i let off and push on the gas the light comes on. I've already checked the connections on the cap sensor and the floater and they all seem fine, and they are brand new (came with the new master cylinder). One thing that i have noticed and i don't know if this has anything to do with the light staying on but i noticed this morning that i hear a creaking noise everytime i release the brake pedal, is that normal? It's not really loud but loud enough for me to hear it while sitting up right. If you could shed some light on this, please, let me know.

 

well that light should only be on if there is low fluid. I would swap caps with teh old master cyl and see if that stops it. also double check that the fluid is up to the full mark

 

i can't swap it, i already returned it to the autoparts for the core and the fluid is almost as high as i can put it without it spilling out when the cap goes on. what about that creaking, do you thing the two are tied to each other?

 

I just got my new MC on the ups and notice the MAX fill line is way up the neck almost to the cap. The OE level was about the top of the main res.
Check for that level mark and see whats up

After bleeding- you did the 2- 45mph abs stops test to ensure NO air is trapped anywhere in the system?

 

My brakes started creaking/groaning right after the Tein install- go figure
time for a regrease of the calipers, and stop using a degreasing wash on the wheels~
that and a new MC to get rid of that recurring air in line prob... that caused brake shake... should fix me up.
Funny how all those parts interact

 

Note to those replacing Master Cylinder.
Much like when you replace calipers- its a good idea to get some brake fluid inside the unit before installation.
The internal shaft o-ring seal needs lube or it can be torn or moved out of place, and you are back to square 1
Use a small oil squirt can with brake fluid, shoot into the line fittings openings and add some fluid to the res. Move the shaft in and out gently= shes a virgin boys- play nice~
That should help by pre-bleeding the sysytem and protect parts.

When bleeding old school with a helper- put a small block of 2x4 under the brake pedal- limiting its travel to 3/4 of the distance to floor.
This protects the new seals as they explore the operating range- or more correctly- the Normal operating range- you dont push the pedal to the floor in normal situations- so its not really made to travel that far- so dont do it!
Bleeding order for TL/CL
LF = driver front then clockwise around the car
LF RF RR LR