Pedal hits the floor after sitting at a light

In the mornings when I drive to work my pedal is fine. The temp is about 60F and things are good. (For 20 mile commute)

On my way home the temp is 70-90f and after driving for about 15 minutes my pedal creeps to the floor and the car starts to move. It will touch if I dont pump it.

I have rear brake drums and have not touched the brakes in over a year.

No leaks or fluid loss from reservior.

Is it Master Cylinder time? Or just bleed the brakes time?

Do the Master Cylinders fail on these 3 Gen's often? Original Honda one is on there and 81,000Miles.

Thanks :)

i would bleed the breaks first and if it still does it then its prolly the master

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Originally Posted by EXI

In the mornings when I drive to work my pedal is fine. The temp is about 60F and things are good. (For 20 mile commute)

On my way home the temp is 70-90f and after driving for about 15 minutes my pedal creeps to the floor and the car starts to move. It will touch if I dont pump it.

I have rear brake drums and have not touched the brakes in over a year.

No leaks or fluid loss from reservior.

Is it Master Cylinder time? Or just bleed the brakes time?

Do the Master Cylinders fail on these 3 Gen's often? Original Honda one is on there and 81,000Miles.

Thanks :)

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if there are no leaks and the fluid level stays the same, then it's most likely an internal leak in the master

I'm going out on a limb here and state that it's definitely the M/C. I am on my fourth. They go out exactly as you are describing about every 100,000 miles like clockwork. I am beginning to wonder if following Honda's recommendation of changing out the brake fluid every 30,000 miles is really a good idea after all.

In your case, it's more age than mileage the has deteriorated the rubber piston rings in the M/C. I got a lifetime warranted unit from O'Reilly's. The aftermarket ones seem to last as long as the OEM's do, at least for me. My first one was replaced by the dealer at around 96,000 miles while still covered by extended warranty.

Yes, I have had this car THAT long.

Damn, i notice mine goes down a bit too, but it never hits the floor. I guess i'll have a M/C job to do within the year? heh. Or i could be imagening it, it was that small a diffrence. Maybe its cause im not used to Automatic.

if the pedal slowly sinks to the floor, you need to replace the master cyl, ASAP!! a sllight drop on starting is normal, due to the booster

Mmm... Yah figured as much. In my case the car has sat most of its life as i bought it off an 80 year old man so I guess I will be doing the MC.

Thanks!

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Originally Posted by EXI

Mmm... Yah figured as much. In my case the car has sat most of its life as i bought it off an 80 year old man so I guess I will be doing the MC.

Thanks!

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it's not a bad job, but for the sake of your sanity, get a set of decent metric flare wrenches first, they will make it much easier to remove the lines without damage. soak them a day ahead of time with pb blaster. don't forget to bench bleed the master first, and you will probably need to swap the reservoir, if you do, the screen in the bottom of the reservoir comes out, pop it out and clean it and the reservoir with brake cleaner

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Originally Posted by lostforawhile

it's not a bad job, but for the sake of your sanity, get a set of decent metric flare wrenches first, they will make it much easier to remove the lines without damage. soak them a day ahead of time with pb blaster. don't forget to bench bleed the master first, and you will probably need to swap the reservoir, if you do, the screen in the bottom of the reservoir comes out, pop it out and clean it and the reservoir with brake cleaner

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yup and also use a small dab of thread lock on the fittings when u put it back together. i had a problem in the past when i failed to do so. And if u dont have someone to help bleed the brakes u can get a do it ur self hand powered vac pump made for this. i use it all the time on side jobs when working on brakes or hydraulic clutches.

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Originally Posted by 3gmodifier

yup and also use a small dab of thread lock on the fittings when u put it back together. i had a problem in the past when i failed to do so. And if u dont have someone to help bleed the brakes u can get a do it ur self hand powered vac pump made for this. i use it all the time on side jobs when working on brakes or hydraulic clutches.

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when I say bench bleed, the new master will come with plastic fittings that screw into the ports, you clamp the master down after installing the reservoir, much easier to do it that way, and less messy, you run tubes from those fittings into the reservoir, and you have to fully depress the cyl with something that fits into the push rod hole on the master. you have to do it off of the car, because the push rod in the booster won't push it far enough,to remove all the air. after you do this, the master goes in the car. if you don't have help, get some speed bleeder bleed screws, they have built in check valves, you just run a tube into a container from them, then re tighten after you are done.

Metric Flare wrenches are a MUST. You will fight and cuss over the lines forever without them. Also, the longer you wait to replace your master cylinder, the higher your chance will be of ruining the brake booster. Brake fluid will get into it and ruin the boosters seals. Instead of a 30 dollar master cylinder, it will be a 30 dollar master + an 80 dollar booster.

Thanks for all the advice. Never done one before. Picked up a new unit today made by Beck Arnley not a reman.

It came with a new reservior but no bleeding tubes just plugs over the holes.

Should I go to my local wrecker and cut some brake lines out and make my own? Or should I just bench bleed till it pisses out the holes, put it on quickly then bleed the whole system?

I have also heard I could put it on and just crack open the lines at the booster to let the air out while someone pumps.

Quote:

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Originally Posted by EXI

Thanks for all the advice. Never done one before. Picked up a new unit today made by Beck Arnley not a reman.

It came with a new reservior but no bleeding tubes just plugs over the holes.

Should I go to my local wrecker and cut some brake lines out and make my own? Or should I just bench bleed till it pisses out the holes, put it on quickly then bleed the whole system?

I have also heard I could put it on and just crack open the lines at the booster to let the air out while someone pumps.

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cut some fittings off at the yard with a section of line, you have to do it off the car because the booster pushrod won't push the piston far enough to get out all the air. you need to submerge the lines in fluid or air will be sucked back into the master. the auto parts store may also have a kit with metric brake fittings in plastic just for this purpose

http://URL=http://img192.imageshack.us/

http://img192.imageshack.us/img192/2193/img0578y.jpg

Like this.

someone needs to sticky this thread as brake pedal goes to floor, good info here and a common problem

make sure to flush all the old fulid out, dirty fulid is what normally causes this to happen... reminds me the 4ths gens is black already lol only 50k miles on synthetic dot3 in about a year

Black means your piston cups are disintegrating. Stop adding sand to the reservoir.

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Originally Posted by Civic Accord Honda

make sure to flush all the old fulid out, dirty fulid is what normally causes this to happen... reminds me the 4ths gens is black already lol only 50k miles on synthetic dot3 in about a year

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did you flush and clean out your entire system before adding synthetic fluid? it's not worth the effort unless you are racing the car, DOT 3 or 4 is just fine for street use as long as you take care of your brakes

Thanks everyone for the advice.

This is what I learened here and valued when I made the swap:
- Metric 10mm flared wrench set an absoulte must!!!
- Remove the old seal between the MC and the booster. Sometimes people forget and it gives you a mushy pedal.
- Bench bleading a must
- Then crack the front line while someone pushes the pedal to get any air out of the line. Then repeat on the back line while pushing down.

All in all the whole process took under an hour as it is super easy to access on this car. Will bleed the entire system at a later date as the systems just had fresh fluid last year.

Essentially if you bench bleed this is a plug and play unit.

Quote:

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Originally Posted by EXI

Thanks everyone for the advice.

This is what I learened here and valued when I made the swap:
- Metric 10mm flared wrench set an absoulte must!!!
- Remove the old seal between the MC and the booster. Sometimes people forget and it gives you a mushy pedal.
- Bench bleading a must
- Then crack the front line while someone pushes the pedal to get any air out of the line. Then repeat on the back line while pushing down.

All in all the whole process took under an hour as it is super easy to access on this car. Will bleed the entire system at a later date as the systems just had fresh fluid last year.

Essentially if you bench bleed this is a plug and play unit.

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you still HAVE to bleed the rest of the brakes before you drive the car!! there is no plug and play, you opened the system, so there is a lot of air in there. you need to bleed diagonally, left front, right rear, right front, left rear

Just an interesting note. ALL brake fluid is "synthetic." Silicone brake fluid is the one for which you need a flushed out system. Fluids labeled synthetic (like the Valvoline stuff I have used for years) is really just a nice way to say DOT 4. I have changed out my brake fluid consistently every 30,000 miles since the car was new and it has never gone beyond light brown in color. My master cylinders still don't seem to last more than 100,000 miles. I guess it could be the heat here that kills the piston seals, or maybe DOT 4 is not as good to use in this system as DOT 3?

i changed my master on thursday diddnt do anything accept for bench bleed and it feels fine to me