Help needed asap..

Tim_72zg

Forum User
Hi everyone,
I have a 72 240z , stock brake booster and MC. I recently had the booster rebuilt.

I’ve bled my brakes now 3 times all around.
My brake pedal is fine and stiff once the car is off, but when turned on, the pedal is soft and touchy for about 2 inches then gets rock hard.

Any idea how I can solve this ?
Thanks
 

toopy

Club Member
Reaction disc issue aside, if the threaded adjustable end of the pushrod that goes into the back of the MC was moved for the rebuild, then the adjustment could be way off, the difference of just 1mm adjustment either way can be significantly amplified with regards pedal feel/travel.
 

Tim_72zg

Forum User
Reaction disc issue aside, if the threaded adjustable end of the pushrod that goes into the back of the MC was moved for the rebuild, then the adjustment could be way off, the difference of just 1mm adjustment either way can be significantly amplified with regards pedal feel/travel.

correct me if I’m wrong but if the rod adjustment was off , with the car turned off / no vaccum the brake pedal would be spongy/soft to a point ? But That’s not the case , pedal is stiff , only when vaccum is applied to the booster the pedal is soft/touchy for a few inches then goes rock solid . I’ve spoken to a few people who believe it is the reaction disc. It’s coming off today and taken to check.
 

toopy

Club Member
correct me if I’m wrong but if the rod adjustment was off , with the car turned off / no vaccum the brake pedal would be spongy/soft to a point ?

I believe the pedal would still be firm, you may get slightly easier initial movement but i don't think it would feel soft or spongy at all with no vacuum.
 

Tim_72zg

Forum User
I believe the pedal would still be firm, you may get slightly easier initial movement but i don't think it would feel soft or spongy at all with no vacuum.
Ok thanks , I’ll be removing it today to check for the reaction disc
 
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