I have been reading on the forum and I have seen a bunch of posts about this subject, but never got a really good answer. I understand we all have different symptoms with our cars. This post to me makes the most sense. See link: https://www.hondaaccordforum.com/for...-brakes-39700/

But I still do not have a good answer. My 1996 Honda Accord has 270,000 miles on it without ABS and disc brakes in front and drums in the rear and the brake pedal has always been soft. I am driving and I stop at a stop light and the pedal goes soft about 65%-70% way down, but with a little force the pedal goes all the way down the to floor. So it is not that soft, but with a little pressure from my leg it goes all the way to the floor. A while back I had the front driver's side brake line break and had to replace it. We bled just that side and everything was back to normal with no issues. I did the tests in that post that JimBlake stated and I pumped the brake pedal and the pedal neither firmed up or became soft. I just feel this issue has been plaguing me for a while so I am trying to figure this out and I understand that different issues occur for different situations / cars, but I do not want to replace my master cylinder if I do not have too. I just want to know what things I should look for and why do these pedals become so soft. Could the Brake Booster be a cause? What does the Brake Booster do? I am a newbie with brakes on these cars, but want to learn. Thank you in advance.

 

I've noticed with older cars once in awhile you need to gravity bleed them to get ALL the air out of the system. Usually this is on cars older than a '96 though but I have done it on cars that were 10 years old which helped.

 

Usually when you bleed brakes you do the entire system. Air can get sucked into other parts of the system so it's best to do the entire. Another possible problem is you have a line getting ready to fail. It may be one of the steel lines or on of the rubber ones. Last possibility is the master cylinder starting to fail. That would be why you can push the peddle to the floor. Fluid will leak past the seals inside the cylinder allowing the peddle to go to the floor. If its the master it will only get worse until you have no brakes at all.

 

I concur with LS-300... sounds like a master cylinder...

To test for an internal bypassing M/C do the following
In Park, or Neutral with parking brake on press the brake pedal with moderate pressure. Hold that pressure for a second or two, then release almost all of the pressure, but don't let the pedal return to the top, only release the bulk of the pressure.
Apply moderate pressure again....
Repeat a bunch more times.

If the pedal drops as you reapply the pressure, and keeps dropping further and further towards the floor, then it's a bad master cylinder provided there are no external leaks pumping the fluid out. A working M/C will always bottom out at the same place

 

So I went ahead and replaced the Master Cylinder with a Brand New Dorman Replacement and bled the breaks and I am still having the soft pedal issues. I mean it is a little better, but the pedal still stills feels a little soft and when I step on the pedal at high speed and purposely trying to lock the wheels up it still feels soft even when locking up the wheels purposely to make sure the brakes are working like expected since my accord is a non-ABS car. How can you tell if the brake booster is failing? What does it do? I am just at a loss that the pedal is not much tighter since I replace all those components and bled the brakes. Any information would be great. Thank you in advance.

 

If you installed a new master cylinder, bench bled before instillation, and you still have a soft peddle after bleeding the entire system. I would be checking the lines and hoses. If they are getting ready to go out they can expand and take out some of the pressure. First I would look at the rubber hoses then the steel lines running front to rear. The booster is only an assistant to breaking as it makes the peddle easier to push.

 

I concur with the above, a booster failure generally leads to a hard pedal.

Another thing to check is the caliper slide pins. If the pins are seized, it can present as a low pedal. It should be easy to check. Pull off the wheels and remove the caliper making sure all are free moving and well greased with anti-seize.

 

And while inspecting the front might as well check the rear drums.......just me but if the rear drum brakes are not adjusted properly, it can give you a "soft" pedal feel.

 

I have a 95 disc front & rear and had the same problem here are some things i did to have a better pedal feel.
-new not reman master cyl
-bleed ms and wheel cyl
-all pads in good condition
* most important adjust brake pedal to manu specs
My wife had a 96 and brakes were completely different for the better.