240z turbo no brakes

[J240ZTurbo]

Guys I need your help again, I got new wildwood brakes all around, new 15/16 master cylinder, all was working fine until my brake booster wen't bad last week, so today i installed a new 8.5 brake booster, and i had no good reaction from this, I adjusted the rod lenght and even, re-bleeded my entire brake system, and still my brakes are no safe for me to say lets hit the road, any ideas what could be wrong, maybe the new rebuilt booster I got is damaged from factory?

scratching my head on this one.

thanks,

J.

Edited August 26, 2011 by J240ZTurbo

[TimZ]

Two things come to mind:

 

1. 
    
   
2. Read this post and see if it applies to you:
   http://forums.hybridz.org/index.php/topic/69706-reaction-disk-pictures-and-walkthrough/page__p__658366__hl__%2Breaction+%2Bdisc__fromsearch__1#entry658366
    
   
3. Did you bleed the system at the master cylinder first, or did you just bleed at the four corners? There should be two bleeder screws right on the master cylinder - bleed it there first, then do the calipers, in order starting at the farthest from the MC (left rear, due to the line routing).
   

Edited August 26, 2011 by TimZ

[jhm]

Seemingly silly question, but did you remember to re-install the one-way check valve in the original (correct) orientation after installing your new brake booster? If you accidentally left it in the "backwards" (reversed) position that we discussed to test your system, the new booster won't do you any good.

 

It's easy to test the check valve. Hold it to your lips and blow through it. It should be easy to blow through in one direction (the direction you want your intake valve sucking on and putting vacuum on the system), and impossible to blow through in the other direction.

 

Hope this helps.

Edited August 26, 2011 by jhm

[J240ZTurbo]

jhm, I did check the valve and I get "no" flow thru either side???

Edited August 26, 2011 by J240ZTurbo

[jhm]

Are you sure?? In some cases, you have to blow pretty hard to "uncheck" the valve (i.e. it can stick slightly in the closed position).

 

If it truly is not allowing air passage in either direction, it needs to be replaced. A stuck check valve will prevent your brake booster from functioning properly. MSA, ZCarSource, BlackDragon, and ZSpecialties all carry a good selection of these kinds of stock mechanical bits:

 

http://www.zcarsource.com/content/p/9/pid/50122/catid/7482_7504/Master_Vac_Check_Valve_70_78_used

[rossman]

my brakes are no safe for me to say lets hit the road

 

You need to explain what you mean by this statement. Is the brake petal still "hard" as you described in the other thread? Or, do the brakes go to the floor or spongy when you push the petal? Do they immediately lock-up?

 

A thorough description of the issue would help us help you.

[J240ZTurbo]

Hi Ross, with the old booster the pedal was hard, now with this new rebuilt booster, there is lots of dead space before it has little brakes and goes to the floor, does not lock up at all.

Edited August 26, 2011 by J240ZTurbo

[jhm]

Good point, Rossman....now we have a little more clarity on the situation. I was (incorrectly) assuming that he was having the same problem as previously.

 

+1 on recheck bleeding your system, per TimZ's suggestion.

 

Double-check the adjustment on where your new brake booster connects to the brake pedal (via adjustable clevis pin). As a good starting point, pedal travel should be adjusted via instructions in the FSM. You may simply have too much pedal travel, and may be able to fix with a simple adjustment.

Edited August 26, 2011 by jhm