I just changed the brake fluid for the first time in my 2005 Accord EX 4cyl (Using Honda fluid). Since I would be doing the job alone, I bought speedbleeders ahead of time. All the bleeder screws replaced real easy except the right front. The oem bleeder screw had evidence of corrosion at the seat and I had problems getting the new one tight enough to not leak.

I followed the bleed order in the Honda Service manual LF - RF - RR - LR. Everything went smooth and I was very diligent keeping the reservoir full. When I went to test drive it though, the pedal would basically bottom out. It did stop the car just fine but I could not force the ABS to kick in which tells me there wasn't enough power behind it. Thinking the RF bleeder might be leaking, I put it back in the garage and checked all four screws for leaks. Everything was dry.

I opened the cap on the reservoir and reseated it just for the heck of it. I took it back out around the neighborhood and it seems to have fixed itself. Would the cap not sealing cause this to happen? I am at a loss.

BTW, there were no issues with my brakes prior to bleeding.

 

I tried a set of speed bleeders and was not impressed. Poor quality material (too soft) and threads did not fit well. This has been a few years ago, and they may have improved. However they are not necessary. Only positive thing I got from the experience was a nice piece of surgical rubber tubing for bleeding.

A hand-operated vacuum pump allows single handed brake bleeding w/o special bleeders. I recently changed fluid on several of my vehicles w/o problems.

good luck

 

Pushing the brake pedal to the floor, and consequently the now rusted master cylinder shaft farther than it's been, while bleeding, can often be the death of your master cylinder. If your pedal sinks while sitting at a stop sign, and there are no leaks, you've killed the master cylinder. Vacuum is also the method I choose. The cap has nothing to do with it. It just keeps the fluid in, and dirt out.

 

Regardless of the speedbleeders, which worked quite well, I followed the Honda service manual bleed procedure exactly. The only difference being I didn't have to close the screw between pumps. You're saying the official Honda bleed procedure can ruin a master cylinder? Yikes! Any idea why it seems to have "fixed" itself or why the ABS light didn't come on? Thanks

 

Any recommendation on a vacuum pump that won't break the bank?

 

Harbor Freight, ebay, amazon?

I looked quickly and harbor freight had one for $26 (item 69328).

I've used "newton" to bleed brakes more than once, takes time but works well for me.

 

MityVac is one brand of a vacuum pump; make sure you get the kit that has the brake suction bottle. Motive is a brand of pressure bleeder (I've got one).

I've used the pedal method for probably 25 years before hearing the story about corrosion on the shaft & bore. That story sounds plausible, but maybe it's for cars that haven't had the brakes bled for many years. Still, I do it differently now.

Has it "fixed itself" like you say? Or maybe wait for the problem to come back?

Air remaining in the lines behaves like this: Pedal goes down way too far, but pumping the pedal will bring it right back up. Until next time. Solution is to bleed the brakes some more. I've often gotten clear fluid for awhile before the last bubble comes out.

A bad master cylinder behaves like this: Pedal is nice & solid, but holding it with moderate pressure (like a really long red light) the pedal will sink to the floor slowly & smoothly. Seems to happen more when the weather is hot.

 

First of all, if like you say, the brakes have "fixed themselves" I wouldn't worry about the master cylinder, unless the pedal starts sinking to the floor at stops, and you find no leaks.

I know that's the procedure in the service manual, but I am sceptical as to whether or not the techs at the dealerships actually do it that way (mainly because it would require two techs, if not using speed bleeders). IMO, you can use the pedal pumping method, but I would advise you not to push the brake pedal down any farther than it goes during normal braking. Point being that you don't want the master cylinder shaft going farther through the seals, than it does during normal braking. Brake fluid absorbs moisture, and this moisture, over time will cause the master cylinder shaft to rust. The seals will keep the shaft clear of rust, on the portion that goes through the seals during normal braking. During this method of bleeding, IF the brake pedal is pushed farther down than normal, it will push the shaft through the seals, over mostly unused/rusted portion of the shaft, and that rust could tear the seals. The older the brake fluid is, the more rust could have built up.

I also found this bulletin, for Honda techs explaining how to bleed brakes, and it definitely says vacuum bleeding. Using a small vacuum pump, you still may have to push the brake pedal, just a little, just to get the fluid flowing. But with vacuum on the system, there is no chance that letting up on the brake pedal during bleeding, will let air into the system. This bulletin also has a different sequence for bleeding, but IMO the sequence has minimal effect, if any.

 

Today I did some tests from the service manual that check the booster and master cylinder. One was hooking a tape measure from the brake pedal to a mark on the steering wheel, holding the brake just hard enough to keep the car from moving in drive, and hold it for 3 minutes. If the brake pedal moves more than 3/8" the MC is bad. It passed all the tests with flying colors. Tomorrow I go back to work so will get a few more miles on it.

Maybe there was some crud that let one of the seals leak by for a while and it passed through? Anyway, thanks for the suggestions and education on neglected MC's. I'll just wait and see what if anything happens.

 

I bought a Harbor Freight hand vacuum pump and was quite pleased w/ quality and parts.

good luck