Vac booster pushrod length (1 Viewer)

[Strait Cruisin]

Any idea what it should be? Say protruding from the booster past the plane of the master?

The FSM is vague.

 

[DougAustinTx]

If I remember correctly (from about 5 years ago) , the nut on the end of the shaft is just even with the outside plane of the housing. In other words, the threaded end of the adjusting nut is flush with the housing when it is not activated. Of course the depth of the master cylinder plunger varies a little from maker to maker. I would say that the key to it is for the end of the booster plunger to just barely not be touching the master cylinder plunger when the pedal is not being depressed. I think I used some children's clay on the end of the shaft to set my clearance.

 

[1911]

The important thing is, there needs to be just the tiniest few thousandths of an inch clearance between the pushrod contacting the master cylinder piston. You do not want any pressure at all on the master cylinder piston when the brake pedal is at rest, but you don't want a big gap either. There is a simple tool that works well to tell you what the length/gap should be:

Amazon product ASIN B079QGXY55

 

[Strait Cruisin]

So, just shy of resting contact then. Thanks.

 

[1911]

So, just shy of resting contact then. Thanks.

Yes, exactly.