Brake pedal sinks to floor?

psychofr_666

New Member
Hey everyone I just installed a Wilwood 6 piston front and 1 piston rear with parking brake kit and a new master cylinder in the car and i cant get the brake to hold its firmness... ive bleed the brakes 3 times bench bled the clutch and when i step on the brake pedal it goes to the floor and it sounds like you can hear air and spirting fluids... there is no leaks on any of the new brake lines all the bleeder valves are tightly closed and i have no idea what could be causing the problem... any suggestings would be great
 

98ej8

I LOVE MY GIRLFRIEND
Registered VIP
5+ Year Member
could it be that your master cylinder isnt large enough?
 


Platinumcloud

New Member
if it sounds like fluid is squirting then you still have air in the lines....you say that you have installed new lines...if they dont maintain "flow" your going to have air in them and its a mother $&%*#@ to get out... keep going till you get that pedal to get firm and go some more...breaks arnt something you want to mess with. also now that i think about it it may be the master cylinder...i know on some of the older chevys you had to prime them before you put them in. just an idea
 

psychofr_666

New Member
so i potentially just have to keep bleeding it more? like the last time i did it air came out of only the front calipers and that was after installing the new master cylinder... basically what happens is when i push the pedal it is more firm then it was with my stock braking system but the pedal sinks to the floor still... and if i pump it 3 or 4 times it gets stiffer and holds some pressure until i release it and try again... also with my old braking system i had a line leak and ran the master dry... thats mainly why i replaced the master but could that have caused a problem with excessive air in the system?
 


psychofr_666

New Member
The resevior hasnt lost any fluid so i dont think theyre is a leak anywhere all the new brake lines have thread sealant on the fittings and have no fluid build up around them
 

2NRSTV

Team Exile/ADO Garage
Registered VIP
On the end of the pistons in the brake master cylinder are rubber cups. When you press on the brakes the cups keep the seal (and pressure) for the pistons inside the master.
If you are loosing pressure but not leaking into the brake booster (by the way, check your booster and check valve for signs of brake fluid) but not missing any brake fluid, it could be a secondary piston (the piston meant for your rear brakes) that is leaking past and going back into the reservoir.

And, since you have ABS and you changed both the Master Cylinder and the Calipers, you may need to have the ABS Modulator bled too. Ask a local brakes shop if you would need it bled.
 


Top