Chev

iTrader: (2)

About a month ago, I had to replace my master cylinder in my 1993 honda civic because it was leaking brake fluid rapidly. After replacing it I bleed just the front 2 calipers to and everything was good, I had pedal again and no leaks. Well yesterday I was driving my car, and I go to press the brake and it went almost all the way down to the floor easily, but luckily it still stopped like normal. When I got home, I checked the Master Cylinder for fluid and it was still full, it hasn't lost any fluid or anything. I haven't done anything yet, mainly because I wanted to know what could of caused it to do something like that, and also if I did anything wrong when bleeding before. Is it possible something else failed? Thanks for any input.

Bert209

For peace of mind you should bleed all four starting with the one farthest from the MC and work your way forward, while down there check your brake lines/hoses for any wet or damp spots, once youve eliminated that issue then you can move on to the MC, double check everything. If equipped with ABS then bleed it also, theres not much to the braking system just spend some time to look it over, should go quick for you, good luck.

rfmerrill

Just something that comes to mind: When you replaced the MC, did you fill with a brand new just-opened bottle of brake fluid, or a bottle that had been opened a while ago?

civic402lx

New mc require bench bleed. Was it done?
You still have air in the system. Go back and bleed all four corners.

Chev

iTrader: (2)

I will go back through and do all 4 this time make sure everything looks good. It's a little hard to tell if it is wet near the lines from the back of the engine bay because a month ago when I took it to my mechanic to look over it, he left the oil fill cap off and it got oil everywhere in the engine bay, but I know brake fluid goes through paint, so I guess I can go through and see if the paint smears when I drag my finger through it, and it doesn't have abs, so one less thing I have to worry about!

I did use a bottle that I bought a couple months ago when the clutch master cylinder failed, that was back in August.

By bench bleed do you mean bleeding the MC itself before going into the car? If so then yes I did, buy I didn't do the four corners, so I know what I'm doing tomorrow.

I'm just confused why it took a month to do something like this, I'm assuming it's because the brake pads have wore down a bit and air was still in the system or something, but I thought it would of been noticeable that day when I was bleeding the brakes. Anyway, I will give you guys an update tomorrow after it's finished!

mk378

Engine running, press the brake pedal and hold it. If it slowly sinks to the floor, and you're not leaking brake fluid anywhere, the master cylinder is bad. Likely to happen with a chain store part.

Chev

iTrader: (2)

I will do that as soon as I get home, thanks for the advice!

rfmerrill

Was it open though or did you just open it?

Chev

iTrader: (2)

It was already open.
​​​​​​

Chev

iTrader: (2)

Ok, so quick update, today I was going to head out to bleed my brakes so I get in my car to move it into my garage, and my car has brake pedal again???? I went to drive it and it was back to normal, can anyone explain to me what can cause that, because the last thing I need is it to lose pedal while I'm driving it. I haven't done anything to it at all, it's just fixed???

assetfokonofua

i will advice you check your brake pads on all four tires

Chev

iTrader: (2)

Pads still have some meat on them, but I planned on changing them out next month.

Chev

iTrader: (2)

Quick update, we went to bleed the lines on Tuesday, but their was so much air in the line that we just thought we might as well get a brake bleeder, we got one on Wednesday from Harbor Freight and we were able to knock out the back right brake line in about 20 minutes, we did the front 2 and now we are at the back left and we are getting fluid but their is a lot of air bubbles, so we waited to finish it today since it was getting late, we went back to do it today and it's been doing the same thing for over an hour now, and it has been going at the same rate for about an hour now. Is it possible something is wrong with the line itself?

Chev

iTrader: (2)

So, I'm pretty sure whatever is causing my issue is with my back right brake line or something, when I got the issue, the back right brake line, had almost nothing in it, when using a brake bleeder kit, I was able to get fluid back there, however it looks like it still has a bunch of air in the lines and I've gone through 2 bottles of fluid now with no change. Does anyone know what could be causing this?
​​​​

civic402lx

You have a leak somewhere back there. Either at the bleeding screw or at the hardline. Air is entering the system, hence the bubbles. System is open somewhere.