[1971BB427]

I agree. Check the location of the operating rod on the brake pedal attachment. Make ure if there are two holes that it's closest to the pivot point. Also check your vacuum connection, and your vacuum with a gauge to ensure you've got no leaks and a good connnection.

[david-b]

Originally Posted by 1971BB427

I agree. Check the location of the operating rod on the brake pedal attachment. Make ure if there are two holes that it's closest to the pivot point. Also check your vacuum connection, and your vacuum with a gauge to ensure you've got no leaks and a good connnection.

Vacuum is 100% fine. Line is brand new coming off a new carb spacer and new PVC (the brake booster equivalent, not sure what the official name is) on the booster.

The booster came with a longer piston option, but seemed a little too long for the booster/cylinder setup. Thinking it over, it seems that the piston would already be putting a load on the master, which may make for quicker stopping. Or is that wrong?

I have a spare vac canister not in the car because with the larger cam, I was told I was going to need it. Never had too much of a problem with the stocker booster and vac unless the idle dropped really low. I've since changed out the torque converter and have had no issues with that.

I've got the brake pedal raised up some, because the rod going to the pedal was a little long. Have the 2 holes lined up and sitting on the pedal, and the shaft that the pedal sits on itself (connecting it to beneath the dash) is actually pushing the rod in to as you step on the brake. Thought that worked out well when installing.

I do appreciate the help and responses. Really hope I can get this back to normal before this coming weekend. Thanks everyone.

[david-b]

Just got a follow up to this. I've adjusted the position of the pedal numerous times, tried playing with the master, and even tried adding a little extension on the push rods going into the master. I've got it pretty good, but it still requires a lot of force for the car to really stop. I can't get the rod in any further into the booster off the pedal, and the pushrod is right up on the plate in the master without the brakes dragging. I still can't slam on the brakes without using both feet.

Last option I have to try is to hook up the extra vac canister. Question is, does the canister and the booster hold more vac than the motor makes? For example, if motor is putting out -10, the booster/canister won't be over -10?

And secondly, does it take time for the masters to "break-in"? Is it going to get "softer" with some miles? Only put about 4 miles on it so far, so still really new.

Thanks.

[1971BB427]

No, masters should be great right from the start, and not change as they age. If you only have 10" of vacuum that might be part of the issue. That's pretty minimal to run vacuum brake boosters.

[cobalt327]

Originally Posted by david-b

Question is, does the canister and the booster hold more vac than the motor makes? For example, if motor is putting out -10, the booster/canister won't be over -10?

If the vacuum canister you have is a reservoir (not a vacuum pump), it will hold whatever vacuum the engine makes. This can be somewhat more than what you generally see during steady state driving or idling, but not by a whole lot. For instance, if you were to decelerate while downshifting, the engine will make more vacuum than it will steady state. But that really cannot be depended on because you won't always have that "extra" vacuum available, like when driving in traffic, etc.

[PatM]

Also, you should have a check valve in the booster vacuum line.
PatM

[cobalt327]

You can also check the booster by pumping the brake pedal a few times w/the engine off, then while holding moderate pressure on the brake pedal, start the engine. The pedal should drop some.

[david-b]

Wanted to give the update here.

After reading all this and doing more research, it seemed to me the booster was bad. I drove it around and was always needing way too much pressure in order to get it to stop. Even after talking with other rodders at shows, they said the smaller booster will be more difficult, but shouldn't be as bad as mine was.

Got in touch with the company I got the booster from and they said to send it back for an exchange. Finally got the new one and installed last night and it works great. Drove up the driveway and nearly went through the window. Stops on a dime! Takes very little pressure and the pedal feels like it should.

Thanks to everyone for their help and suggestions.

[LARRY BOYD]

Call Bud Riser at Tuff Stuff 800-331 6562. He can furnish you with a direct bolt on setup,chrome or plain.He is a good friend and has helped me out more than once over the years.Use my name if you like.