[Spanki]

I upgraded my brakes with SS lines, Dot4 fluid and powerslot rotors with Hawk HPS Street brake pads FRONT AND REAR, and I bled the brakes with special pressurized equipment. First few days the brakes were GREAT! At a 100MPH I would hit the brakes and they would lock up no problems! I loved it, brakes were nice and sharp. However now they are all mushy and I can hardy lock them up, which tells me there is not as much bite as before. The brake fluid is not boiled, and the pads are still good. Someone told me that it could be my master cylinder, any opinions on this?

 

[Turtlespd]

I would think it was a failing brake booster.

 

[supracar]

Has the fluid level gone down since you filled it? Sounds like theres a small leak and air somehow got in the lines.

 

[WoBbZ]

Im thinking along the lines of Supracar

 

[Spanki]

I would think it was a failing brake booster.

How can I check for sure?

 

[red94tt]

I would think it was a failing brake booster.

That wouldn't be it. If the brake booster went bad, the pedal would be very firm and hard to press, not mushy like he described.

The first thing I would do is check the fluid level and try bleeding the brakes again and then start looking at other things like the master cylinder if that doesn't solve the problem.