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Rebuilt Vacuum Booster But pedal Still Hard 84 3.2

1984 Carrera Targa 3.2. I replaced the vacuum booster with a rebuilt one and new check valve. I did test the check valve before install, but not the booster. I replaced the master cyclinder with a new one. Old booster showed some signs of fluid leakag, so I assumed it was bad. Flushed and bled with the pressure pot from the maste cylinder backward. Old fluid was maybe 4 to 5 years old, which is the flush interval I use in my cars, bikes, etc.

When i start, the pedal does not go down a bit such as on my other cars indicating booster is working. Also, pedal does not feel like it is getting any boost assistance. I hooked an electric ac vacuum pump up to the booster and pulled 30 inches, but still no drop in the pedal. WTF. I really don’t know where to go from here.

Car’s brake pedal is really hard and fictions fine. However, with no vacuum assist it requires a Herculean effort to lock the brakes. Not good since my son and wife occasionally drive her. Any device would be greaty apprecrated.

Seems to me there is a rubber line coming off the back of the throttle body that likes to leak. Is your idle unusually high? Just for fun see if the engine still idles with the ICV unplugged. You likely have a vacuum leak somewhere in the booster line. Do you feel vacuum in the line at the booster when removing line from booster?

Quote:

Originally Posted by Amber Gramps (Post 14663890)

Vacuum to booster is indeed low from the engine. I have a small leak somewhere that I’ve been trying to track down for months. However, car idles and runs fine. Therefore, I hooked the booster up directly to my portable air condoning evaluator pump which pulls about 30 inches of vacuum. I was hoping that this setup would help troubleshoot the booster. I guess I’ll have to remove the new booster and bench check it. I’m just avoiding this since it is several hours of work including the reinstall and bleeding.

You should be able to just pop the vacuum line off the booster and listen for the " whoosh" no ?

Also shouldn't it have a check valve ??

Quote:

Originally Posted by Fr8trplt (Post 14666717)

OK, so you've got a guy that's telling you that your problem is in the line somewhere......you, yourself think its in the line....so you monkey rig some A/C tool to the booster in hopes of approximating the correct boost? I don't get that at all. What if your A/C vac popped your new diaphragm? It's too early in the morning for me to be rational so I'll just shut up now. :surr: Go find the leak in your line.

all right , who dropped the ball !!!! fess up , whose job was it to get Doug his coffee this morning ?

:)