I have a 94 civic ex with ABS. The brakes have always been very soft and today I replaced the pads and I bled the brake system until all of the old fluid was out. I bled them working from the farthest caliper from the Master cylinder to the closest.

After I was done the brakes worked great, drove it around for about 30mins and it worked great. I let the car sit for a few hours and went and drove it, about 15mins into driving it the brakes started going all the way to the floor in order to stop. I'm assuming the seals in the master cylinder are bad but just wanted to your guys opinion before I buy a master cylinder. I did check the fluid and it was still full as well.

 

Did you make sure you tightened all your bleeder screws? Odd for that to happened randomly. And why in the world would you bleed all your brake fluid lol.

 

I checked all the valves again to make sure they were tight. What do you mean why would I bleed all the fluid? The car has 185k on it and is the original fluid, it needed to be changed.

 

Anybody?

 

i have had this happen to me and it was my brake master cylinder. I dont wanna give you incorrect information but look into that and see if its that. Good luck with fixing your problem

 

Make sure you have no external leaks. To see if your master cyl is bad, with your car off pump up your brakes and hold the pedal down. If your pedal drops you have a leaky master. If it stays firm, your problem is elsewhere.

 

i'm assuming your talking about the test where he starts the engine with the brake pedal depressed

this test is to test for a properly working brake booster, every car brake pedal drops about an inch when applying pressure and starting the engine.

when you have no braking ability and dont see any leaks, you can narrow it down to two categories

-if the pedal is hard with the engine running, the brake booster is bad
-if the pedal holds little to no pressure with the engine running, the master cylinder is bad

 

master cylinder.
when they're border line ready to fail, sometimes just bleeding the system will send them over the edge.

 

most likely ur master cylinder is bad if u bleed the brakes properly as u stated

 

thats your vtec....

 

I had this problem 96 honda odyssey 40k miles dealer said abs bad 2800 to fix i removed abs system and replaced. Abs with 2 tees 3 unions and 3 lines can send pic if needed . Still had problem bledd brrakes had tight pedal started engine pedal went to floor 5 miles driving used emer brake to stop. Looking at this site learned it could be master cylinder. Replaced master cylinder bled brakes problem fixed.

 

Do this test. And when you do pump the pedal, do it fast reapeatedly until the pedal gets firm while its away from the floor. If the pedal drops, as mentioned in the earlier post, look for a leak somewhere. If there are no visible leaks, most likely the master cylinder has an internal leak. If the pedal doesn't get firm no matter how hard you pump it, there must be still air in the system. Search online for the proper bleeding procedure.

 

master sillender.

 

What he said. If you have no drips coming from anywhere around the car, while it's RUNNING, pump up the pedal and hold pressure on it. If the pedal sinks to the floor it is your master...

 

This was a two year old thread bump

 

Oh,I failed to even read the date on 1st post.