Howdy im new on here and hello from the uk. I need help with the brakes on my 95 accord 2.2 es coupe. Disks all round and abs model. Its come up on a couple of forums but there doesnt seem to be a definitive explanation.

I got the car recently with mushy brakes and an abs fault that I traced to a bad sensor so I changed that and bled the abs and that cured the abs fault.

Next I bled the brakes with no joy but I did see a crack in one of the lines so I replaced that and the rear disks and pads then bled the system again. Brakes work really well but still mushy. I then did a pressure test and got a really firm pedal then when I turn on the engine the pedal drops to near the floor. so I drove it up the road and back and the brakes are sharp but when I stopped I could push the pedal right to the stop.

I then took the calipers off the hangers and cleaned and regreased the sliders so they move free and easy but still no good.

I tried putting light pressure on with the engine off and no movement then heavy pressure with the engine off with no movement. then I tried light pressure with the engine on and no movement.

I can build up good pressure with the engine off but as soon as I turn the engine on the pedal drops to near the floor then after a couple of light pumps I can push it to the floor. I cant figure it out and any help would be great thanks

 

I suspect the brake booster. It's the only component within that whole system which responds to changes in engine vacuum. (as indicated by your getting a firm pedal with the engine off).

Does the pedal go hard immediately after you turn the engine off, or do you have to make several brake applications b4 it stiffens?

P

 

Yeah it gets harder straight away at about half travel then after a couple of pumps the pedal is right at the top and rock solid. could you suggest a test and thanks for the reply

 

There are basically two subsections to the primary brake system
The hydraulic, which encompasses everything from the master cylinder to the wheel cylinders and everything in between (including the ABS).
The pneumatic, which encompasses the brake booster and the related vacuum feed hoses which power it.

For safety purposes, the booster and it's supply system store enough vacuum to allow safe application of the brakes should the engine stall / quit at speed. In order to properly check the hydraulic portion, you've got to take the booster out of the equation.
You can do that by pressing and releasing the brake pedal 5 or 6 times until the pedal becomes hard.

Let the car set for a few minutes.
Sit down and press down on the pedal just once.
You should have a hard pedal right off, without any additional pumping.

If you do not, then you can be assured that you either have air still remaining in the hydraulics or one of the flex hoses may have developed a burst reinforcement ply (very rare).
If you do, then you can assume that no air is present in the hydraulic system and can start turning a jaundiced eye at the booster.

P

 

Is the pedal steadily dropping to the floor? A weak master cylinder may not be obvious without the advantage of the vacuum booster. What I am saying is with the car off, even though you are pushing like a ****, you are not pushing as hard as when the car is running and you are using the vacuum assist from the booster cylinder. If the pedal is steadily dropping to the floor, I'd suspect the brake master cylinder. A vacuum booster works or it does not. Sounds like it's working pretty well to me.