brake problem, what gives? UPDATED 2

[zmech]

z

[Firehawk]

I would not recommend using a clamp on the rubber lines. If you want to block off a line, plug it. You can even plug it at the master. If you are not losing fluid and the pedal is soft, its the master.

[Az4u2c]

Firehawk wrote: I would not recommend using a clamp on the rubber lines. If you want to block off a line, plug it. You can even plug it at the master. If you are not losing fluid and the pedal is soft, its the master.

Yeah i don't plan to clamp lines. Here's what i've found: when you romove the master from the booster (with brake lines still attached) and stick a screwdriver in it the piston is firm. You can only push the screwdriver like 1/8 in at most. That doesn't seam spongy to me, so I can't help but suspect the booster. I'll swap booster's with my parts car when I get a change. If i still have nothing, I'll get yet another master from Nissan this time and call VB to give them a royal "screw you". I don't know what's in a booster to cause this, but I figure i'll try it since i have another one handy.

I have a hard time believing VB sent me two consecutive DOA masters. Especially since it passes the screwdriver test (granted i know that screwdriver doesn't apply near as much force as the booster would).

[khyronzx]

NO YOU TARD :lol: , if the booster goes out the brakes will be harder to press not spongy

[Chris86NA2T]

khyronzx wrote: NO YOU TARD, if the booster goes out the brakes will be harder to press not spongy

a bad brake booster does not necessarily mean that you loose power assist

[Az4u2c]

Chris86NA2T wrote:
a bad brake booster does not necessarily mean that you loose power assist

exactly what i was thinking. I guess I'll find out whenever i get around to swapping them out. Finals are coming up here before too long.... :roll:

[Firehawk]

Don't go by your screw driver test as it will not provide even fraction of the force the brakes need. The brake booster uses vacuum to help apply force when you apply pressure. If the booster was bad, just makes you press the pedal harder to apply the same brake pressure.

I have had three consecutive bad masters that were all supposed to be remaned. I wonder if they just cleaned up and repackaged old cores.

And khyronzx, lose the attitude. This is not z31.com.

[khyronzx]

sorry, see edited post, had about the same problem a few months back, just went to the parts store and got a new m/c, not remanned, problem solved.

[khyronzx]

sorry, see edited post, had about the same problem a few months back, just went to the parts store and got a new m/c, not remanned, problem solved. here is kinda a easy test have someone pump the brakes, while you listen to the master cylinder, if it is as bad as it sounds, you'll problably be able to hear the brake fluid rushing past the seals.

[Guest]

mine are starting to come along quite well. I bled the you know what outof them and now they pretty good!

[khyronzx]

You could have air sneaking in through the threads of the bleeders if they're old and rusty, pull them all the way out put some teflon tape on them and try bleeding them again

[Az4u2c]

khyronzx wrote: You could have air sneaking in through the threads of the bleeders if they're old and rusty, pull them all the way out put some teflon tape on them and try bleeding them again

Bleeding has been eliminated as a problem. After bleeding a gallon of fluid through them I had them professionally forced bled. Bleeders, calipers, and pads all appear to be brand new, nothing corroded, worn, or shitty looking.

I called VB, they do no sell manufactured masters, this is the 2nd NEW one I've had on there. I told them I'd fuck with it some more before having them send me another one.

[Timo944]

Did you ever resolve this? I have been wondering if vacuum level to the booster could be too high.

[Timo944]

FWIW I had similar issues. Tried a lot of things but eventually changed the M/C. I had a spare that looked new and it did the trick. The old M/C was a Tokico but it did not say NISSAN on the side. The new one is a Nabco. bench bleed - for a long time to get every little bubble out, installed and flushed the system with new fluid.