Brake Pedal going all the way to the floor

netsatwork · Mar 3rd, 2004, 09:15 AM

Earlier this week I had a problem with my brake pedal not raising back up fully to engage the brake light switch. I had to manually pull the pedal back up with my foot. After a hard braking yesterday the pedal suddenly starting work normal again.
Last night on the way home the brake pedal started getting REAL soft. I can now push the pedal all the way to the floor. The car still stops, but it does not feel safe. The brake fluid level is staying the same (and is near max). I'm figuring it's the master cylinder or the brake booster. Any thoughts?

**chimmike** · Mar 3rd, 2004, 10:18 AM

sounds like you've got some air in there maybe.....or you could be right. Every time that has happened to me it's because there's air in the system. Try bleeding the brakes and see how that goes.

KA24Tech · Mar 3rd, 2004, 11:38 AM

Most likely the Master Cylinder piston seals are leaking internally which is why the fluid level stays the same. You could either rebuild the Master Cylinder or replace it. A bad Power Booster would cause the pedal to be hard typically.
I hope this helps.

Troy

livelyjay · May 18th, 2004, 07:06 PM

Bringing back an old thread, I am kind of having similar problems with my brake pedal. It can go all the way to floor initially, but if I pump the pedal I get more and more pressure and finally it feels like it should. Along with this the brake pedal shudders/pulsates when I am pumping and finally get the pressure. Is this a bad master cylinder issue? I have a N13 Pulsar, in case that helps.

netsatwork · May 18th, 2004, 10:30 PM

Here's an update on my issue if I didn't post it:
The reason I was having so much trouble with the brakes was not the master cylinder, it was actually the brake booster. The output rod on the master cylinder end snapped off due to a stupid mistake when I changed my fuel filter: I did not fully secure the master cylinder to the brake booster when I removed the clip for the filter (check diagrams on those three parts if you're not sure what I mean). The brake booster's pressure eventually cocked the master cylinder to one side and hit the edge of the master cylinder, thus snapping it. Sorry for the long description, but the moral of the story is to be sure the two nuts holding the master cylinder to the booster are tight.

Anyhow, on your problem, I doubt the brake booster is messed up, from what I learned from mechanics and such, it's uncommon for the booster to have problems. The master cylinder was a pretty easy switch and wasn't all that expensive either. There's really not much to our brakes: booster pushes master cylinder valves which pushes fluid through the lines. Check www.howstuffworks.com for a cool diagram. One thing to remember when changing the master cylinder is to have a flare nut wrench when unscrewing and re-tightening the brake lines. The sets are sold at auto parts places for about $20. Maybe you already knew this, but I didn't the first time I changed my brake lines. I also don't have ABS, so that reduces the complexity of the brake system.

Overall, I'd say go for the master cylinder if you have already tried bleeding the brakes. Bleeding them will be necessary on the master cylinder change anyway, and it's easy with a friend pushing the pedal. Please email me at netsatwork@yahoo.com if you want more info or pictures. Thanks.