Electric vacuum pumps

[Ahoey]

Has anyone used an electric vacuum pump to power their power brake booster. If so what what kind and how many inches of vacuum does it require? The cam I’m running doesn’t provide enough vacuum

 

[Dana67Dart]

Has anyone used an electric vacuum pump to power their power brake booster. If so what what kind and how many inches of vacuum does it require? The cam I’m running doesn’t provide enough vacuum

you could get a vacuum reservoir from the wrecking yard and plumb it in?

15in is all you would need

 

[Bewy]

A vacuum reservoir does NOT increase vacuum, it merely stores it. So with a VR, if you have crappy brakes, they will be crappy for longer....

 

[Ahoey]

you could get a vacuum reservoir from the wrecking yard and plumb it in?

15in is all you would need

Have a vacuum canister, doesn’t seem to do the job. On the highway when you’re not using the brakes much it’s semi ok but can’t keep up in town.

 

[Ahoey]

Have a vacuum canister, doesn’t seem to do the job. On the highway when you’re not using the brakes much it’s semi ok but can’t keep up in town.

Thanks for the input

 

[Dana67Dart]

A vacuum reservoir does NOT increase vacuum, it merely stores it. So with a VR, if you have crappy brakes, they will be crappy for longer

Correct, but any engine will generate high enough vacume on closed throttle deceleration from 2-3k rpm. The reservoir stores it till it's needed. The booster has (or should have) a check valve in the hose fitting. If it works properly you typically have 1 assisted brake press after the engine is shut off.

This had been my experiences

 

[Dana67Dart]

Have you checked that your booster is holding vacume?

 

[Ahoey]

Seems. To be nut have to investigate further.

 

[Ahoey]

Correct, but any engine will generate high enough vacume on closed throttle deceleration from 2-3k rpm. The reservoir stores it till it's needed. The booster has (or should have) a check valve in the hose fitting. If it works properly you typically have 1 assisted brake press after the engine is shut off.

This had been my experiences

That’s Exactly what it does but driving around town it can’t keep up with the demand

 

[Dana67Dart]

Time to pump you up!

Or ditch the power brakes and go manual.

 

[RedFish]

Many aftermarket cams don't generate enough vacuum to support a power brake booster. A late member, Tony Fields, tried the electric pump route. He wasn't happy with it although I forget why. Anyway, it was pointed out that with the right small bore master and adjustable proportion valve set up right, you have plenty of stop without a booster.

 

[Ahoey]

Time to pump you up!

View attachment 1716437691


Or ditch the power brakes and go manual.

Thinking about it need to do research on slave cylinders

 

[Ahoey]

Thinking about it need to do research on slave cylinders

Will the power brake slave cylinders work with a manual master cylinder

 

[missing linc]

Your calipers and wheel cylinders are the same regardless of whether the car has power or manual brakes. The vaccuum booster only multiplies the pressure your foot applies to the pedal. Get the correct master cylinder for manual brakes, and pushrod, once properly set up you will never miss the booster. Added bonus, more room to access the plugs on the driver's side!

 

[Dana67Dart]

In theory, yeah but......
I have tried several different combinations of master cylinders in my Charger and nothing feels as right as the booster and a 15/16" master cylinder

Look at the FSM and see whay was used for front disk manual brake cars and copy that.

My bet is you are so used to the modern car pedal feel that you can't equate the normal manual brake feel

 

[Ahoey]

Look at the FSM and see whay was used for front disk manual brake cars and copy that.

My bet is you are so used to the modern car pedal feel that you can't equate the normal manual brake feel

Did some research the stock manual master works on all the slave cylinders including disc brakes, just needs a little more effort but not as much as a power unit with out vacuum. Available from rock auto. So a decision has to be made.

 

[Howard1784]

73 Duster, .600 lift cam etc, rebuilt brake booster and LEED vacuum motor. WORLD OF DIFFERENCE. Brakes on point and stops on a dime

 

[Dana67Dart]

just needs a little more effort but not as much as a power unit with out vacuum

I haven't done the math but the linkage ratios for manual vs power might be different.

There's the see saw on the engine side of the firewall if it's not 1 to 1 that will make a difference, if the cl of the pedal to the pushrod is different than on manual that will make a difference.

 

[Ahoey]

I haven't done the math but the linkage ratios for manual vs power might be different.

There's the see saw on the engine side of the firewall if it's not 1 to 1 that will make a difference, if the cl of the pedal to the pushrod is different than on manual that will make a difference.

Thanks guys got a lot to chew on. Will post my findings and results.

 

[Bewy]

Another possibility: a booster that is larger in diam.....or.....a dual diaphragm booster that is large in diam. May not be perfect, but may be good enough.