Squishy brakes... need advice...

[uflnuceng]

Ok... I just did a m30 and 5-lug swap so I had a lot of equipment off of my car recently. It was basically just a shell and as I prepared the parts to go I just let the brake fluid drip out the rear. Now my brake and my clutch are soggy as shit. This makes me believe that I have air trapped in my Master Cylinder. I ordered a new slave cylinder because I think my current one is fucked. When I open the bleeder valve on it nothing comes out... at all. When I hit full extension I am able to release the clutch and activate the brake pedal, but I shouldn't have to push that far. Things are slightly improved when the engine is running with the vacuum assist. The fluid resevior seems to be really thirsty as well since I have to top it up every couple of minutes.

I have checked for fluid leaks in the bell housing, at the calipers, at all the line joints, in the vacuum booster hose and with the amount of fluid I am putting in there (about 0.5L so far) there would be a bloody mess in the bell housing or under the car if there were a leak.

I don't think my MC is screwed because it was fine before I did this. Brake and clutch pedal feeling is improving as I flush the brake fluid, however its nowhere near what I would consider streetable or trackable. Need some advice.

I have a BavAuto Power Bleeder. Is there a certain PSI I should be running on the bleeder? I have been using about 5-7 PSI. Should I bleed the fluid a couple more times, pressing on the brake pedal in between each caliper? Turn the car on a couple times to get the vacuum boost to suck fluid up into the MC? Is there any risk that the MC is toast? Let me know...

Thanks
Jared

[nando]

I go up to 15psi with my power bleeder. don't go too high or you'll pop the gromments on the resivior and have a big mess to deal with.

[uflnuceng]

That's what I did... just bled the brakes for about 2 hrs... seems to have resolved the problem in both pedals. I also stepped on the clutch and brake pedals... man was she thirsty.

[Brew]

Did you bench bleed the master cylinder?

[uflnuceng]

bench bleed? probably not. can you describe it to me and why i would do that?

[Brew]

Well, I'm guessing that you pulled the MC off when you did the swap... Whenever you drain the master cylinder of fluid, you should bench bleed it, which literally means to bleed the MC off of the car by hand. Without doing that, it is almost impossible to get all the air out of it.

[Sean]

Well, I'm guessing that you pulled the MC off when you did the swap... Whenever you drain the master cylinder of fluid, you should bench bleed it, which literally means to bleed the MC off of the car by hand. Without doing that, it is almost impossible to get all the air out of it.

I removed my brake fluid reservoir so I could clean it out and stuff. Will I need to bench bleed my master cylinder if I did that? The pedal has not been stepped on since I put my car on jackstands a week ago. I've disconnected all calipers, and have let it sit all week. I'll be finishing up in the next few days. My plan was just to bleed everything and get all the bubbles out. But, will I need to bench bleed the brake master cylinder if I removed the reservoir?

[Brew]

You probably should. Its easy enough to pop it off and bleed it, you might as well.

[Sean]

You probably should. Its easy enough to pop it off and bleed it, you might as well.

Is this in the bentley?

If not, what's the best way to go about doing it? Do you just take it off and remove all the air by compressing it?

[Brew]

You probably should. Its easy enough to pop it off and bleed it, you might as well.

Is this in the bentley?

If not, what's the best way to go about doing it? Do you just take it off and remove all the air by compressing it?

I'm not sure if its in the Bentley, but its fairly easy to do.

You'll find a bunch of write-ups if you google it.

Basically, you put the master cylinder in a vice, mount the resevoir, connect two lengths of hose from the two outlets on the MC to the full resevoir, and then pump the rod until there is no longer air in it.

[Sean]

You probably should. Its easy enough to pop it off and bleed it, you might as well.

Is this in the bentley?

If not, what's the best way to go about doing it? Do you just take it off and remove all the air by compressing it?

I'm not sure if its in the Bentley, but its fairly easy to do.

You'll find a bunch of write-ups if you google it.

Basically, you put the master cylinder in a vice, mount the resevoir, connect two lengths of hose from the two outlets on the MC to the full resevoir, and then pump the rod until there is no longer air in it.

Ohh, so you're essentially running the same fluid thru there until there are no more bubbles.

So, what happens when you're all done and you want to put the MC back in. When you remove those hoses, will fluid leak out on ya?

[Brew]

You probably should. Its easy enough to pop it off and bleed it, you might as well.

Is this in the bentley?

If not, what's the best way to go about doing it? Do you just take it off and remove all the air by compressing it?

I'm not sure if its in the Bentley, but its fairly easy to do.

You'll find a bunch of write-ups if you google it.

Basically, you put the master cylinder in a vice, mount the resevoir, connect two lengths of hose from the two outlets on the MC to the full resevoir, and then pump the rod until there is no longer air in it.

Ohh, so you're essentially running the same fluid thru there until there are no more bubbles.

So, what happens when you're all done and you want to put the MC back in. When you remove those hoses, will fluid leak out on ya?

Yeah, you've got it. It might get a bit messy, but you can plug the holes in the MC with your fingers as you attach the brake lines. As long as you don't completely drain the resevoir, you're good.

[Sean]

You probably should. Its easy enough to pop it off and bleed it, you might as well.

Is this in the bentley?

If not, what's the best way to go about doing it? Do you just take it off and remove all the air by compressing it?

I'm not sure if its in the Bentley, but its fairly easy to do.

You'll find a bunch of write-ups if you google it.

Basically, you put the master cylinder in a vice, mount the resevoir, connect two lengths of hose from the two outlets on the MC to the full resevoir, and then pump the rod until there is no longer air in it.

Ohh, so you're essentially running the same fluid thru there until there are no more bubbles.

So, what happens when you're all done and you want to put the MC back in. When you remove those hoses, will fluid leak out on ya?

Yeah, you've got it. It might get a bit messy, but you can plug the holes in the MC with your fingers as you attach the brake lines. As long as you don't completely drain the resevoir, you're good.

Good deal! I'll definately be doing this. Thanks for the useful information! :D

[Sean]

My brakes are soft too, after finishing my install, but I started my own thread so I wouldn't high-jack his.