My '99 Accord LX (4dr, 4 cyl vtec, non ABS) just crossed the 200,000 mile mark about one month ago. At about that same time I noticed that my brake pedal was getting pretty spongy. I’ve repaired brakes myself all of my adult life so I didn’t hesitate to take this task on. The rear drums were also squeaky so I began there. I installed new wheel cylinders and metal lines along with new shoes and hardware. I then installed a new master cylinder and new calipers, pads and rotors. When I attempted to bleed the system, I got great pressure at the wheel cylinders but almost nothing came out of the bleeders at the calipers. I then returned the master cylinder for another one and I replaced the front brake hoses. To my surprise, I’m still getting very little brake fluid to flow out of the bleeders on the calipers. The brakes won’t pump up fully and if you start the ignition, the increased pressure from the booster sends the pedal to the floor. The only thing I haven’t replaced is the brake proportioning valve. All the lines appear free and un-kinked so this would appear to be the only answer despite the fact that I’ve never had this happen before. Are Hondas know for proportioning valves failing? Am I off base with my diagnosis? Help!!!
Try bleeding the master cylinder or of the car first. Make sure that it is completely free of air.
OK, I tried that. The master cylinder did have air in it. I reconnected it (being sure not to let any air back in) and then pumped the brakes. At first things looked good. The pedal came up and fluid did easily pass through the bleed valves at the calipers and wheel cylinders. Unfortunately, once the ignition was turned on, the pedal went to the floor. When I tried to bleed each wheel again, all the same sypmtoms came back. Again, I’m leaning towards the proportioning valve. It’s the only thing I haven’t done.
Check the flex lines at each wheel
Forget the proportioning valve. I believe you need to bench bleed the master cylinder. Heres why. The m/cyl when mounted on the booster is normally at an angle so when you bleed the m/cyl. on the car there will still be air in it. Take the m/cyl off and put one of the mounting tabs in a vise. It should now be horizontal. Fill the resorvoir. Take a screwdriver or some kind of shaft and press in the piston in the m/cyl. Before you let go put your fingers over the holes where the lines would be. Keep doing this and eventually the m/cyl will be shooting fluid out of the line holes and make a hugh mess. Brake fluid eats paint!!! Now when that is done with no air coming out, install the m/cyl on the booster and connect the lines. Now bleed where the lines go in and all other points that were disconnected. You might be able to purchase a m/cyl bleed kit. Plastic fittings that fit the holes with rubber tubes that push onto these fitting and loop back into the resv. easy to see if any bubbles come out and less mess. Hope this helps.
it sounds like the master cylinder is either not completely ‘bench bled’ as meaneyedcatz says, or… the adjusting rod which pushes from the pedal to the MC needs to be adjusted.
the rod which is connected to the brake pedal and pushes into the booster must be adjusted for each Master cylinder. even though it may be just a turn or two, it is enough to make the MC NOT be able to be bled to get the brakes working correctly.
secondly if the rod into the MC isn’t adjusted correctly you will NEVER get all the air out of the MC, and since you can’t get all the air out of the MC, you will never get the air out of the system. no matter how ‘clear’ you get the calipers to flow, if the air is still in the MC it will never firm up.
after all the m/cyl I have installed I have never adjusted that rod. Kinda like “wax on- wax off”. There is no need to.
What’s wrong with taking it to a shop that knows brakes. You’re so close to being able to drive it. Sounds like it’s been down for a week already. It sounds like you have no manual either. You are a victim of half-vast knowledge.
I’ve had to do it, once. He could have a defective Master Cylinder.
If he took it to a shop and had it repaired then we would not have this opportunity to be automotive know-it-alls. We would then have to listen to ours wifes.