Okay, WTF!...I just put in my new BMC that I got from Mazda Malloy.....yeah soo when I bleed the BMC in the car with the car turned on it ummm spurts out liitle micro scopic bubbles and then after a little driving the pedal was total mush again...shoudl I just bench bleed the BMC or what? I am using new speed bleeders by the way.....

 

If you have a new Master Cylinder and you are still having problems, then either you aren't bleeding the MC properly, you have contaminants in your brake system, or probably one or more of a few other problems.

While the brake peddle may feel "mushy", is the car actually stopping when the brakes are applied?

 

some what stopping car not really though.

 

if bubbles are still coming out, then you still need to bleed. Try bleeding your full braking system.

 

How did you bleed the MC you got from Malloy?

 

I bled it by placing it on the car and using the pedal to pump it since I dont have a bench vice grip to hold it. I also did it once with the car on and once with it off. I think part of the problem might actually be the right frnt caliper becasue when I bleed that one, it feels the mushiest of all of them.....

 

You did this with it connected to brake system? If so, that's your problem. You'll never get the air out of there that way.

The MC from Malloy should have come with some tubes to run the lines back into the reservoir. With the MC out of the car and not attached to the brake system, you run those tubes into the reservoir with it full of fluid. Use your hand to push in the piston. Do this slowly for about 5 minutes or so (until you don't see any bubbles from the tubes.

Then remove the tubes and connect the MC back up to the car and the braking system. At that point, do your normal brake bleeding.

 

There is a rebuild kit for the calipers right? If so how much is it?

 

http://www.mazdatrix.com/getprice.as...m=49-2400-FB05

But that's not going to solve this problem.

 

why wouldnt it solve the prob? it is possible for the calipers to let air in right?

 

You have three problems:

1. You did not bench bleed the brake master cylinder. You MUST bench bleed if you want to solve this problem. Basically, you just feed the bmc output right back into the bmc reservoir ("bench bleed" is a bit of a misnomer since it is easiest to do with the bmc installed in the car). Read up if you need more info and do it. You won't make any progress until you go back and bench bleed the bmc.

2. Since you didn't bench bleed it, you probably have lots of air in the system. The solution to that is to bleed, bleed, bleed. Make sure you have lots of brake fluid.

3. Speedbleeders don't work well when there is lots of air in the system. I suggest switching back to regular bleeders until you have all the air out of the system.

I recommend getting a pressure bleeder to speed things up and make this a one-man operation: http://motiveproducts.com/. Note: when using the powerbleeder, BE SURE to pressure test your connection to the master cylinder before adding fluid. I like the powerbleeder so much I threw away my speedbleeders.

-Max

 

Maxcooper, do you mean you want me to take the BMC off the car and bleed it by hand? Or just keep the car turned off and bleed the bmc the way I have been? by just routing the fluid right back in to the container from the two female cennection points parallel to the container?

 

I would recommend taking the MC off to bench bleed it. That way you can watch it and make sure the tubes stay at the bottom of the reservoir (and that you are really getting the air out).

 

I had friend press the pedal whiel I watched and held the tubes though.....!!!!

 

It was not clear before, but now it sounds like you did bench bleed it. In other words, you pumped the bmc with the output lines squirting the brake fluid directly into the brake fluid reservoir, before connecting the bmc to the rest of the system. Is that right?

If you did indeed bench bleed it, before connecting the hydraulic lines, I suspect it is just that you have too much air in one of your calipers for the Speedbleeders to deal with. If you have big air pockets, the speedbleeders don't work well because the air just compresses instead of blowing out through the bleeder. Switch back to the regular bleeders (and bleeding method -- call a friend over) to get rid of the air. Then switch back to the speedbleeders.

-Max

 

Yes I did bench blle dit alright I'm sorry if that wasn't clear. I guess I will just have to try and switch back indeed. **** I wonder where my stock ones are.......

 

You could probably get away with having one bleeder of each size. If you can't find them, you can buy them at any auto parts store. I think they are 8mm x 1.0 thread pitch (threads per mm) and 7mm x 1.0 thread pitch -- you could verify the sizes at the speedbleeder site. Bleed with the stock one, switch back to the speedbleeder, move on. Then go back and re-bleed each caliper with the speedbleeders to finish.

-Max

 

I would also recommend a Power Bleeder: http://www.motiveproducts.com/

Makes the job a "one person" job and can easily push air out of the system.

 

How much pressure should you use for the brake system?

 

I think I shoudl clarrify the air issue. When I finish bleeding the pedal feels nice and firm liek it should, after driving around a little though its spungy as crap again. Any suggestions?

 

I'll have to look (it's in the instructions), but IIRC between 10-15 PSI.

 

Sounds like you still have air in the system. Take it to a brake shop with a power bleeder. It won't cost much, or take very long to get it done.

 

That is weird. I am not sure what's going on there. It seems like you would have to have a pretty big hole somewhere to let a bunch of air into the system, though. And you would see it leaking somewhere when you press the pedal.

I am not sure if this would matter, but have you tested the power brake check valve when the engine gets hot? I've heard of a few of those failing, and perhaps yours is only going leaking when it gets hot or something like that.

-Max

 

there are absolutely nooo leaks anywhere at any temp i have made sure of tis many times over.

 

I agree with Adam. Before trying to rebuild the calipers or messing with anything else, take it to a brake shop (like Midas) and have them flush and bleed the brakes. It shouldn't cost a whole lot. If that fixes the problem, then purchase yourself a Power Bleeder so you don't have to worry about it again.