Brake Booster Problem

[WZ JUNK]

I have a problem with a master cylinder/power brake unit.  The pedal has too much travel before the braking starts.  I do not have adjustment of the foot pedal linkage, as it is a direct connection to the booster.  

I think that the pedal assembly is causing the booster to deflect back more than it was intended to move and this is opening up some free play between the booster and the plunger in the brake unit. My friend wants me to add a spacer between the booster and the plunger or piston of the master cylinder.  

What do you think is wrong?   How do you think I should fix it?  Should I just limit the amount of return travel the pedal has and relocated the brake light switch?

[model a vette]

Why don't you have an adjustment between the pedal linkage and the booster? There should always be an adjustable rod going into the back of the booster. If you don't have that you should make it rather than changing other stuff.

[GPster]

Is the master cylinder and the booster a matched set? What your friend wants you to do might work if the master cylinder is not going clear to its "at rest". That might be a problem if they are not a matched set. But if they are you would be adding more monkey motion into the system. I would suppose that the pedal assembley and the booster/master cylinder are not a set. If the radius of the pedal swing is a lot longer than a stock ratio or the radius of the actuation point to the booster is shorter than the amount of foot travel is going to be different than a stocker. Also on some pedal set-ups there is enough weight and gravity in the system to keep the booster from being able to see it's "at rest". Years ago one of NSRA's best new products was a spring to back the pedal off the master cylinder.  Of course if you have already explained the obvious or included pictures of what I'm trying to explain, I've done it again. GPster

[WZ JUNK]

The complete under floor unit was purchased as a matched set(pedal,booster, and master cylinder).  It was built with a direct connection from the pedal to the rod that comes out of the booster with no adjustment at that point.  This morning I added a thick rubber stop on the pedal to limit the return of the pedal and it helped a lot but it still has a little to much travel before the brakes engage.  The brakes work good, there is just more pedal travel than I would like.

[37 Express]

The complete under floor unit was purchased as a matched set(pedal,booster, and master cylinder).  It was built with a direct connection from the pedal to the rod that comes out of the booster with no adjustment at that point.  This morning I added a thick rubber stop on the pedal to limit the return of the pedal and it helped a lot but it still has a little to much travel before the brakes engage.  The brakes work good, there is just more pedal travel than I would like.

 John, Dan brought up a point that you may have already considered.  Has the brakes been adjusted.  If there is alot of travel for the shoes before they contact the drums you will have too much pedal travel.  If that is correct, I suggest that you cut the rod going from booster to the pedal, thread each end and put in a long threaded nut in, this will allow you some adjustment, this is what we did on the '39 to have adjustment for the pedal.