'76 280Z Question on dist/manifold vacuum, dist timing, fuel pressure, brake booster

[cozye]

Are you using tubing connected to the end of the bleeder screws so that you can see the air bubbles? The bleed screws only need to be loosened 1/4 to 1/2 of a turn. Make sure your helper is not pumping the pedal when you have the bleed screw open. You should be pumping the pedal 5 times or so, holding the pedal down, crack the bleed screw, tighten the bleed screw, then the helper can let off the pedal. No letting off the pedal or pumping when the screw is open.

Did you take the MC off the brake lines ? If you did, you need to bleed all the way around. Air was introduced. No way around it, don't care what the FSM says about it.

I'll just share what I do, and what works for me and maybe you can try it.

I use a mighty vac to pull brake fluid through the lines first before bleeding. This primes them well so that you can then pump and bleed manually. If you have too much air in the lines, you will never be able to bleed them manually unless you "bench" bleed the system or use a vacuum pump. What I do is take the mighty vac, pump up a good amount of vacuum, and starting with the MC I'll suck brake fluid through both bleed screws, then tighten down. On the MC I'll have a helper hold the pedal to the floor once when I do this to open the system up. Then I will go to each wheel cylinder and do the same thing. I make two passes to the whole car. Then I have a helper manually bleed them with me by pumping then cracking the bleed screw with a hose attached going into a small cup. I make two more passes around the car with the manual method. I have the helper pump the pedal 5 times. I don't poor the brake fluid directly back in, I always use fresh fluid from the bottle. The fluid that's being pumped out is full of tiny bubbles that take a while to settle out. This method always works for me, 100% of the time and usually takes about 20-30 minutes.

[cozye]

oh, and I wouldn't worry about the groan noise when pumping the brakes without vacuum on the booster. This is normal.

[cozye]

another tip if you are worried about sucking air in around the bleed screw (which shouldn't be happening if you aren't pumping with it open), is you can put teflon tape around the bleed screw threads. This is common, but it really doesn't buy you anything and will wear out after cracking the screw 2 or 3 times.

[Jennys280Z]

oh, and I wouldn't worry about the groan noise when pumping the brakes without vacuum on the booster. This is normal.

Cool! I was sorta thinking that might be the case.

[Jennys280Z]

Are you using tubing connected to the end of the bleeder screws so that you can see the air bubbles? The bleed screws only need to be loosened 1/4 to 1/2 of a turn. Make sure your helper is not pumping the pedal when you have the bleed screw open. You should be pumping the pedal 5 times or so, holding the pedal down, crack the bleed screw, tighten the bleed screw, then the helper can let off the pedal. No letting off the pedal or pumping when the screw is open.

Did you take the MC off the brake lines ? If you did, you need to bleed all the way around. Air was introduced. No way around it, don't care what the FSM says about it.

I'll just share what I do, and what works for me and maybe you can try it.

I use a mighty vac to pull brake fluid through the lines first before bleeding. This primes them well so that you can then pump and bleed manually. If you have too much air in the lines, you will never be able to bleed them manually unless you "bench" bleed the system or use a vacuum pump. What I do is take the mighty vac, pump up a good amount of vacuum, and starting with the MC I'll suck brake fluid through both bleed screws, then tighten down. On the MC I'll have a helper hold the pedal to the floor once when I do this to open the system up. Then I will go to each wheel cylinder and do the same thing. I make two passes to the whole car. Then I have a helper manually bleed them with me by pumping then cracking the bleed screw with a hose attached going into a small cup. I make two more passes around the car with the manual method. I have the helper pump the pedal 5 times. I don't poor the brake fluid directly back in, I always use fresh fluid from the bottle. The fluid that's being pumped out is full of tiny bubbles that take a while to settle out. This method always works for me, 100% of the time and usually takes about 20-30 minutes.

See then I'm just not an experienced bleeder. Among other things, I was turning the wrench too far when loosening the valve. I do remember as I was bleeding, when I only loosened the wrench a little, I would see the tip of the tube twitch a little bit as it was submerged in fluid and zero bubbles came out. I was sending pure fluid into that jar and the fluid level in the jar has risen considerably.

After bleeding each side of the master cylinder twice, I went into the car and felt the brake pedal and it was still spongy.

But, after bleeding many more times (was only pumping the pedal three times between bleeds) I checked the pedal and it's maybe tighter than ever. Doesn't this assure me that the brakes are successfully bled? How else can you notice air in your lines if not with a loose pedal?

If you think my brakes will only be 90% of what they could be if I don't bleed my wheel cylinders or something....then I'll bleeping do it.

And yep, one of my earliest questions about the brake booster was whether I could take it off without removing the MC from the brake lines. I didn't get anyone saying I could, and none of the manuals suggest that I can, so I just went with it being something I had to do. I didn't want to do it. Brake fittings are one of my most hated of all gizmos.

Edited January 12, 2011 by Jennys280Z

[cozye]

See then I'm just not an experienced bleeder. Among other things, I was turning the wrench too far when loosening the valve. I do remember as I was bleeding, when I only loosened the wrench a little, I would see the tip of the tube twitch a little bit as it was submerged in fluid and zero bubbles came out. I was sending pure fluid into that jar and the fluid level in the jar has risen considerably.

After bleeding each side of the master cylinder twice, I went into the car and felt the brake pedal and it was still spongy.

But, after bleeding many more times (was only pumping the pedal three times between bleeds) I checked the pedal and it's maybe tighter than ever. Doesn't this assure me that the brakes are successfully bled? How else can you notice air in your lines if not with a loose pedal?

If you think my brakes will only be 90% of what they could be if I don't bleed my wheel cylinders or something....then I'll bleeping do it.

And yep, one of my earliest questions about the brake booster was whether I could take it off without removing the MC from the brake lines. I didn't get anyone saying I could, and none of the manuals suggest that I can, so I just went with it being something I had to do. I didn't want to do it. Brake fittings are one of my most hated of all gizmos.

Based on this info, I'd make two passes bleeding from each wheel cylinder, you definitely put air in the lines if you took the MC off. It won't take long, you can do it with the car on the ground. After that, just take it for a drive and see how it feels.

[cozye]

Also, if you want to bleed the easy way, you can replace your bleed screws with these

http://www.speedbleeder.com/

1/4 turn, and you can pump freely with the bleed screw open. You would be able to bleed with one person and not worry about sucking air in the lines. I use them and have used them on my motorcycles as well. They work very well.

[Jennys280Z]

Also, if you want to bleed the easy way, you can replace your bleed screws with these

http://www.speedbleeder.com/

1/4 turn, and you can pump freely with the bleed screw open. You would be able to bleed with one person and not worry about sucking air in the lines. I use them and have used them on my motorcycles as well. They work very well.

OMG those look exactly like the ones I have on my MC now.

[Jennys280Z]

Based on this info, I'd make two passes bleeding from each wheel cylinder, you definitely put air in the lines if you took the MC off. It won't take long, you can do it with the car on the ground. After that, just take it for a drive and see how it feels.

Okay But I want to take my car for a test drive first. Mainly because, I have a new booster I am aching to test it fully before sending Geek the core back.

[cozye]

OMG those look exactly like the ones I have on my MC now.

Yeah, you can't tell from the outside. The speed bleeders have an internal ball check valve. I know some bleeder screws on new stuff look the same.

[cozye]

Okay But I want to take my car for a test drive first. Mainly because, I have a new booster I am aching to test it fully before sending Geek the core back.

Sure. Just make sure the pedal is firm. If it's spongy at all, it's got air in it.

[Jennys280Z]

Sure. Just make sure the pedal is firm. If it's spongy at all, it's got air in it.

Will my pedal get any spongier with my motor on, do you think?