lately, my brakes started to feel wierd. ive already bled them and that went fine. the problem thats occurring is that when im at a dead stop at a light, after about5-10 seconds, the pedal starts going all the way to the floor when im pressing it. to clear that up, ill be sitting at a light with my foot pressing the pedal to keep the car from moving, and after a few seconds, it will slowly just depress all the way to the floor like ive lost the vacuum in the system or something. i can pump the brakes a few times and it will be fine and the car stops fine when im moving. this happens only when im at a stop and the pedal is being pressed for more than a few seconds. maybe there is still an air pocket in the system, im not really sure, because the brakes feel fine when im driving and initially apply them. i know the bleeding procedure, starting with the furthest from the brake MC, which is the passenger rear, driver rear, pass. front, driver front, which is how i bled them after i first noticed this problem. any ideas or suggestion??

btw, this is a 4th gen DX accord, MT, non-abs.

 

the check valve are bad, your booster is most likely to be leaking.

to check, with the car turn off, pump the brake panel a good 8-10 time until it got rock hard, keep the panel down(steping with some force, but nothing too much), stick in the key crank the motor and start it. see if it will sink to the flood slowly.

 

replace the brake master cylinder asap use a honda or an ADLER

 

iam just for your information if the brake booster leaks vaccum it will make the brake pedal feel hard as a rock ...vacc leak at booster will not make brake pedal sink to floor

 

after pumping the brakes while the car is off and letting the pedal get rock hard; once i start the car, the with the pedal being pushed on, it drops all the way to the floor.

also, i checked hondaautomotiveparts.com to see how much a booseter would be, but couldnt tell what part it was on their diagrams. anyone know the part number of the booster?

 

yo scru it is not the booster do not waste your money...... replace the brake master cylinder , make sure you bench bleed it before installing it

 

what exactly do you mean by bench bleeding it? im taking that to mean partially bleed the fluid through the new MC before hooking up the lines to it?

 

ttt

 

MC/booster adjustment...
The piston rod sticks out the back of the MC. Measure carefully, you'll HOPE the old & new ones stick out exactly the same length. If they don't, there's an adjustment on the push-rod from the pedal. There's a $$special little measuring tool for this, it's not just a casual eyeball measurement. (Mine matched perfectly so I never had to figure out how to do this without the tool.)

Bench-bleeding...

Find some hoses to fit into the new MC where the car's brake lines are gonna go. Loop those hoses up so they squirt into the reservoir.

Fill the reservoir & pump the MC piston. As the fluid squirts into the reservoir, it'll flush air bubbles out from the MC.

Install the MC into the car; be prepared for a mess since there's fluid already in the MC.

Now bleed the brakes. If you don't bench-bleed the MC, it takes forever to work all the air out of the MC. (But it CAN be done.)

I would have thought the bleeding order is RR-LF - LR-RF. Without ABS you normally want to bleed each diagonal circuit starting with the rear. Try that if you can't find specific information for your model/year.

 

JimBlake has it correct, a few little details if I may, while bench bleeding and pushing the piston inside with your screwdriver or other long round tool, do not push the piston all the way in, my own personal procedure is to push it in about 75% and hold for several seconds and release slowly to the end of the travel and wait a few seconds. I have seen pistons get stuck from lack of lubrication on brand new rebuilds when they are jammed all the way in to rock bottom.

In the beggining of the procedure of bench bleeding (holding the master cylinder in a vise) there will be air in the looped hoses going back into the fluid, if you get a one man master cylinder bleeder kit from autozone or some place and if it has clear hoses you can watch the air bubbles, people who pump fast are drawing the air back and forth quickly and IMHO it wastes energy and your time sometimes making you bleed longer after everything is back on the car.

I also like the x pattern of bleeding starting with the furthest from the master cylinder, in todays cars the system is designed to keep one front and the opposite rear brake operational in the event of some serious problem. Remember brake fluid will eat your paint so use plenty of rags under there. Good luck.

Duane in Japan

 

a little thing you can do so you dont have to blled brakes if you dont want to is after you bench bleed cylinder, let a bit of fluid spill out from the holes, reinstall caps on holes, leave reservoir full of course this way it is ready to install as soon as you remove the old cylinder , after you remove the old cylinder , don't let too much time elapse before installing new one ..i have done dozen upon dozen this way and you dont have to bleed system, brake padal is hard and normal

 

thanks for the help everyone. put in a new MC, bench bled it, hooked one lie up at a time, and re bled it diaginally, starting from RR, LF, LR, RF. although, desert was right about not needing to re bleed it if i disconnected the old one quickly and connected the new one to the lines quickly. i tested the brakes both immediately after install and after rebleeding them, and there was almost if any no difference. HT comes through again.

 

Thanks to desert, duane, and JimBlake for the good info. Searching really does pay off.

It seems like these MC's go bad a lot. I've seen a few threads, and now I am finally a victim of a bad MC. Not for long.

to good info.


Junior

 

yah i think mine is going too. mines starts to sink to the floor if i push the brake for a while..

 

here's a follow up question, i just replaced the MC on my 1987 lxi and now after about a half of an hour or regular driving the pedal gets rock hard and the brakes are applying pressure without pushing the pedal is this the vac booster??? i fully bleed the whole system with new brake fluid and it still does this.

 

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Never seen this.

 

guessing u have rear brake drums on the back.

raise rear of car & spin wheels to see if there's only a slight drag. mebbe the rear springs w/in the drum are worn/rusty, causing the shoes to be in contact w/ the drum or parking brake is on too tight...

raise front end, put in neutral, & have someone step on brakes as u spin just to check if that's binding. mebbe remove/clean/relube front caliper sliding pins.

 

Yo, kinda out of date but i recently replaced my Power brake booster also and i am getting the same problem u are/were. My pedal will become rock hard and my brakes will stay engaged and car wont move without good force. If i get out and remove the vacuum line from the power brake booster the air rushes out and the car will move again. I replaced the brake booster vacume valve with another one but didnt help. Any clue?
John

 

I had the same problem with my 86 accord lxi.After putting new brakes on the car the brakes would stay on.I removed the brake callipers one at a time and flushed them out.I was ammazed at the amount of gunk in them.I used a large c clamp to push the cylinder back in to flush them.It is a pain to disconnect and reconnect every time to push the cylinder back out.Now the brakes work like new,no sticking at all.Also check the brake fluid resevore and clean if needed.
Mark