Model A Vacuum for brakes

Im running the stock 4 banger and have disk brakes. The set up Im using utilizes a booster with a port for a vacuum. Ive read briefly that there was a vacuum for windshield wipers. where was this vacuum? would it work for a brake booster? any other places to tap in for a vacuum?

Cheers
Mike

 

you could probably drill and tap into the intake manifold

 

If you don't have enough manifold vacuum, GM used a suplimental vacuum pump in the '80's to augmant the vacuum for the power brakes. Hard to find. Also there are aftermarket 12V vacuum pumps on the market. Also some Ford, Volvos. Do an internet search for 12V vac. pumps. Also used on homemade electric cars to supply brake vacuum.

 

On my Model B four banger the port for the windshield wipers was on the rearmost area of the intake manifold. It is pointing towards the firewall. Let me know if you need me to take a pic of it for you.

 

With a 6 to 1 compresion motor your not going to make enough Vacc to run a booster. Just go to an electric pump and move on,, that is unless your still 6V. My question is, Why do you need power brakes on a Model A ?
The Wizzard

 

Good point. I've put the Flathead teds brake floater kit on my 32 banger and it stops way better now. Mechanical brakes arent that bad if set up properly.

 

A lot of folks think you automatically need power brakes with disc brakes, and we know that on a light hot rod that isn't necessarily true. I see that question on the T bucket forums all the time and I think it is because people have them on their daily drivers and just assume they need them on their hot rods too. In fact, power brakes can potentially give some bad brake characteristics, like locking up and skidding to a stop.

Don

 

And if you want a slick hookup point, swap in an early Model B intake (and carb, for a bit more power!), which has a BIG, I think 3/8 pipe, hookup designed to work a power clutch that almost reached production.

 

Very true. I'm running disc brakes with no power booster on my big ol Merc. Been trouble free for many years.

 

Hell on a heavy car you can get away with manual disc brakes. The '64 Avanti tipped the scales @ 4K and it had manual disc brakes with optional power brakes.

By the way you can buy that vac pump for the buicks at a parts store new and they are not a pricey unit. I don't remember what year b buick it was would have to go look at an old vac wiper thread but I think Bruce was who gave out the information.

Bruce are you still reading was it you who had the information on the buick vacumm pumps?

 

Many small engine early FWD GM cars had electric vac boosters because the things had to be run at full throttle to keep moving...look for cars with 2 big hoses instead of one on booster. They had a switch to turn the thing on when vac got low...some had an awkwardly mounted swith in a hole on booster, others had what seemed a neater version with switch plumbed into hose. I also saw a Cad V8, one of those '80's ones, with a tint little belt driven vac pump...

 

Bruce
Glad you are still reading, I couldn't remember what you had said before.

 

if you decide to go without the power booster, and you have the room, mechanical advantage can be increased by making the pedal longer.

 

I hate to see things done because everyone else does it, then you get to try and make it right. This is a case of better off without it.
The Wizzard

 

You are correct in assuming I thought I needed it. This is my first build so learning as I go. Im utilizing the stock brake pedal and everything sits flush under the floor so plenty of room for the booster. I have the 2 lbs and 10 lbs pressure valves suggested for the disk front and drum rear. Its already done with the exception of running lines. Call it blasphemy that I would put discs on the car but I like the way they look and to each there own right? maybe someday when I have more time for a build Ill do one of the amazing period builds I see here. I appreciate all the info here fellas. Is there any issue with me running the car as is with out hooking up the booster? (leave it for a later date?)

Cheers
Mike

 

Give it a run. You'll then know if yu need a booster. Run the brake lines from frame to MC aft a little too far then angle forward slightly to MC...then if you decide to add a booster you just push the MC back and slife the booster in.

 

I guess my questions would be if I can leave it as is? Since eveything is mounted and in place. would it hurt to simply run it the way it is with out hooking up the vacuum line?

 

I think you will get some extra pedal travel with booster inop, but then you will reach the right place and it will stop. This will be fine for a test run as long as you are not flummoxed by the funny pedal, but you will want to remove the booster if you decide to run without it as a permanent thing.

 

At the risk of being slightly O.T., how much manifold vacuum might you expect to see at idle or steady cruising speeds with a 4 banger or flathead V8? Does the static compression ratio really have an effect on manifold vacuum?

 

Ditto,...that power brakes aren't necessary with disc.... I've used a non boosted disc / drum setup on my 72 F100 since 1985,...Still works great.


4TTRUK

 

Your going to want to protect the booster from getting anything in it at the hose sight. Not sure what to tell you to do. A solid plug will make a hard pedal. A vented plug is pointless. A power booster master cyl does not have a deep bore for a pushrod.

 

Ditto on not needing the brake booster. I am finishing up an O/T '89 Mustang with 400 SBC and T-56. I needed room for the clutch linkage and the only way was to get rid of the booster and convert to manual brakes. I contacted one of the Mustang performance Gurus and bought the reccommended parts. It stops and handles great, pedal pressure is not a problem. The key here and on any other non stock issue is to match all of the parts so they work together.