How much Vacuum for a PB Booster?

[prayers1 153]

I'm trying to gather information for my Winter project, changing Manual front Drums to Disc. I'd like to have Power Brakes, but due to my Vacuum at idle 11Hg and cam size (512 lift, 280 dur, Center line 106 & Lobe sep. 110 in a 289) I don't know if it's possible.

 

I don't want to use a Vauum canister. Also sometime in the future and who knows when, I have a 351C 4V I want to put in.

 

So, should I go Manual or PB Master Cylinder.

If I go manual, it will be a 1974 Maverick Master Cylinder.

 

What do you think?

[det0326 179]

I'm trying to gather information for my Winter project, changing Manual front Drums to Disc. I'd like to have Power Brakes, but due to my Vacuum at idle 11Hg and cam size (512 lift, 280 dur, Center line 106 & Lobe sep. 110 in a 289) I don't know if it's possible.

 

I don't want to use a Vauum canister. Also sometime in the future and who knows when, I have a 351C 4V I want to put in.

 

So, should I go Manual or PB Master Cylinder.

If I go manual, it will be a 1974 Maverick Master Cylinder.

 

What do you think?

 

I personally don't know the answer to your question, but I read somewhere that the manual disc work great, may have been on this site. I am interested in doing the same to mine and would like to know also.

Are you using after market front disc or from a donor car.

Dave

[prayers1 153]

I have a complete set of 1970 front disc.

[chillininnh 21]

I LOVE the feel of my manual disc brakes. Not having the booster in the engine compartment is also very sweet. My setup is factory front manual disc with the maverick master. My car was a power setup and I'm having ZERO regrets.

[prayers1 153]

Thanks Chillininnh for the positive confirmation!

 

What year Maverick MC did you use, any problems hooking it up, could I use my Manual MC rod with the Maverick or do I need a rod form the Maverick MC?

[LiLMike 42]

I was looking into this about 7 years ago. I came across a hydraulic brake booster that ran off of the power steering pump. It eliminates the vacuum problem. At that time they were very pricey. Something like $800! They may have some cheaper conversion kits now. You might want to research that avenue.

[prayers1 153]

Thanks LiLMike, but I have Manual Steering.

[chillininnh 21]

The Maverick master was a 74. Spring for the adjustable length rod and eliminate any trouble with using the wrong length rod. I sourced the stuff for the swap from Dan Chock @ Chockostang. He is an expert with vintage Ford braking systems. The toughest part was swapping the pedal, something you won't have to worry about. Give him a call, he's a good guy.

Edited December 15, 2013 by chillininnh

[prayers1 153]

Yes, Dan is a great guy. He rebuilt my Manual Dist Valve a while back.

During this brake rebuild, I'm gonna ship him my Steering box to rebuild as well.

[Max Power 74]

I ran a car that had 10" of vacuum at idle in gear and you learn to pop the car into neutral coming up to intersections, or downshifting to get the vacuum up.

[Monzy 10]

I've got 10" of vacuum which isn't enough for the power brakes. Ran it all summer this way and its not really the safest because the booster doesn't work well at all and in return the pedal will be soft at first then turn extremely firm before you've even made a complete stop. Only way to keep the booster alive is to down shift or put in neutral and rev the motor while braking which is not ideal because your using the wrong foot to brake with. lol Side stepping the brake and gas is not easy with the factory pedals setup the way they are. Switching to the manual brake 74 Maverick master next spring.

[stangme428 33]

I've got 10" of vacuum which isn't enough for the power brakes. Ran it all summer this way and its not really the safest because the booster doesn't work well at all and in return the pedal will be soft at first then turn extremely firm before you've even made a complete stop. Only way to keep the booster alive is to down shift or put in neutral and rev the motor while braking which is not ideal because your using the wrong foot to brake with. lol Side stepping the brake and gas is not easy with the factory pedals setup the way they are. Switching to the manual brake 74 Maverick master next spring.

 

hmmm i have 10" of vacuum with stock brake booster and master... no problem with brake feel.. but... i have aftermarket disc brakes all 4 corners... nothing near stock..

[Monzy 10]

Stangme428, next time you get the girl out try pumping the brakes a few times at speed and then make a stop... 60mph brake test would be good. 10" is real low for any engine with power booster brakes. You don't have a vacuum booster for the brakes do you? As you say, your brake setup is far from stock so I have no idea how your setup would work. Your using the tilton 3/4 master cylinder also? The stock was 1", maybe this helps vacuum brakes? Either way I'm curious to know if your brakes hold vacuum for multiple stabs of the brake pedal in a short period.

[prayers1 153]

I went with the Manual 1974 Maverick MC. I contacted Dan at Chockostang, he told me that I wouldn't need to change out my present Manual brake Proportionate Valve, that all I need is to attach a separate PV to the rear brake line coming out of the manual PV. The entire kit plus shipping cost $134.90. I don't know if you need the separate rear one, that's if you have a PB Port Valve. Best to call Dan, real easy to talk to, great personality, he won't steer you wrong and his prices are the best out there, 217 882 2083.

 

Here's the part list:

Master Cylinder 1974 Maverick (36-440) With Push Rod/Clip MC push rod w/ clip. $45.00

Hard brake line kit to hook up 69 Manual Dist block to 74 Maverick MC. $20.00

Rear Port Valve (In line Proportioning Valve) $55.00

Small hard line from Rear Port Valve to 1969 Manual Dist block.In Line Kit

(2) Adapters from front hard brake line to rubber disc brake hose. If you need, get at NAPA -Different sizes.

 

Hope this helps whoever wants to make the switch.

Edited December 30, 2013 by prayers1

[Monzy 10]

I'll be re-using my power brake proportioning valve. Didn't know there were different valves because it doesn't care about power or manual brakes? Right...? I've got a Hurst line lock to go in with this also. Its going to be fun getting all this in a tight engine bay.

[prayers1 153]

I believe there is a difference between manual and power brake PV's

I'm sure you'll have enough room w/o a booster.