Ok so now my brake paddle is sinking. Whenever it does it though, it comes back up after about half a second. The brakes are brand new and the lines have been bled. My dad suggested either master cylinder or brake booster. Anyone have any experiance w/ this? Thanks.

 

What I would do:

1) Check brake fluid level in reservoir under hood.
2) Pull off front rims, look for any obvious leaks near calipers
3) Pull off rear rims and brake drums, look for leaks again

How recently did you get the brake work done? Its easy to not completely bleed the system, so if its just a mushy pedal (ie, fluid level is fine, no obvious leaks anywhere), I would think you've still got air in your lines.

 

Check the easy stuff first. Level, and re-bleed the brakes.

If it still doesn't work, then its most likely the master cyl.

 

If it goes down and then comes back up the brake booster or the master cylinder would also be my first guess. Any leaks or air in the lines would not cause that to happen.

 

The fluid is fine and hasn't gone down, so I assume there's no leaks.

Yea my dad's leaning towards the brake booster, since it sinks, then goes back up. Do you know if the booster can be taken apart and repaired, or should I just look into a new one?

Thanks.

 

ugh, brake booster all bad!! get ready for alot of this followed by some of this :cry: along with a whole lot of this so you may want to do alot of this ahead of time. i replaced a brake booster on an accord one time and it was by far the biggest PITA i have ever undertaken on a vehicle. i got a rebuild from a parts store that didn't work. i was told by several people that brake boosters are one of those parts that you have to get from the dealer more often than not. the rebuids just don't cooperate granted truck-type vehicles may be completely different

i'm with SLC Punk, i'd bleed the brakes again first before you start taking things apart - its simple and doesn't require a whole lot of time

 

You can do a quick test on the booster by using a vacuum hand pump. Apply vacuum, if press holds then it's fine. Make sure to check the vac hoses going to the booster too.

 

If you pump the brakes with the engine on, then hold steady pressure and the peddle sinks to the floor, it is the master cyl.

I agree with the other guys, do the cheap stuff first (re-bleed).