• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Power to Manual brakes?
I found a previous thread on switching from power to manual brakes but there was no resolution to the question. Has anyone made the change? What was involved?

If I stick with power brakes and have low vacuum what will happen?

(03-14-2018, 02:53 PM)CalgaryChris Wrote: I found a previous thread on switching from power to manual brakes but there was no resolution to the question. Has anyone made the change? What was involved?

If I stick with power brakes and have low vacuum what will happen?


I think you still have brakes, just not the effectiveness of the booster.
I chimed in because a buddy of mine has a 73 Torino with a transplanted 429. it has a large cam resulting in only about 10"hg vacuum and the same issue. His solution was to add a vacuum pump to aid the engine vacuum. This seems to work quite well. Unfortunately, I can't get further details until he returns from Florida next month.

This company is featured in the latest Mustang Monthly News Bit section. Vacuum Boosters for your hot rods.


mustang7173 Thankyouyellow

"Courage is being scared to death but saddling up anyway" -- John Wayne
first why are u thinking of getting rid of p/b. and do u have disc front's. the m/c hopefully will bolt to firewall and just remove the power booster. u will end up with reduced braking power for sure. but if u do have disc i don't feel it's a major effect but u will notice it. if u have drums all around u will notice a big difference. and i'd recommend a complete rebuild on all 4. wheel cyl to pads to springs. when i got my stand it had manual drums and i did a complete overhaul. m/c to wheel cyl to shoes to springs and it made a major difference. so i left it manual.
Calgary Chris, I agree with Bill, why are you considering changing to manual brakes? It will be a lot more work than you think. It's not just pulling the booster off and bolting the M/C back on. On a manual brake car, the M/C mounts 2" higher and the pedal push-rod pin location is also 2" higher. I know this because I went the opposite way, from manual drums to power front discs. Believe me it's a lot of work. An electronic vacuum booster would be the best way IF you will not consider a more streetable cam, as that's your real issue. Believe me, with all the "couldn't care less about you" idiots driving our streets these days, you want all the braking power you can get.......... ask me how I know!!
The booster that is shown is quite expensive and looks to be a bit more complicated than the one my friend has, which tells me there are options. Do some research and post what you find.
[+] 1 user Likes Stanglover's post
You can also go with hydraulically or electrically assisted power brakes, to eliminate the need for vacuum and large boosters:



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
I grew up driving with no PS or PB and have never really understood the fascination with PDB. The big benefit is if you are doing repeated hard braking or driving in lots of wet conditions. If your drum brakes will slide all four tires then DB will not really add much.
I just sold the PDB off a 72 vert to a guy that just had to have them, lol.
The master cylinder on manual brakes is 1" in diameter where the PDB cylinder is 15/16" diameter so that gives you more braking power without the boost.
I have been driving my car with the PDB booster not working. Pulling off to send for new diaphragm and seals tonight.
Even if you are running autocross I doubt that PDB would make a difference. If you have to brake you are going into corner too fast usually. Yes if you are running laps on a track over and over the drum brakes will fade faster than disc.
You will probably loose about a mile to the gallon going to PDB since they drag all the time. If you had anti lock brakes then PDB would be fantastic but you do not.
The drum brakes are self adjusting and not as bad as the old ones. You can get drum brakes adjusted to where you can do panic stop and let go of steering wheel and stop straight if you adjust correctly. Cutting the shoes to the arc of the drum is also a big step in improving drum brakes. That gives you full surface area contact instead of just in the middle of the arch.
My first car with PDB was my 73 Mach 1 that I bought new.

When a man is in the woods and talks and no women are there is he still wrong??
Low engine vacuum is my concern. Currently sitting between 7-9. I have disk brakes front and rear. My 67 has manual brakes and I don’t mind them at all. I will be doing some autocross but some means maybe 3-4 times a year. I will likely try it as is with the old booster and see what it feels like. 
Thanks for the replies
stang u are correct.. i totally forgot about the difference in location of m/c with p/b to manual
Share Thread:  

Possibly Related Threads...
Thread Author Replies Views Last Post
  More braking power needed Higgins56 29 530 2 hours ago
Last Post: tony-muscle
  Saginaw 800 Power steering Box rebuild Stanglover 50 2,230 05-16-2019, 12:34 PM
Last Post: uk1973
  Front brakes not locking up tony-muscle 17 414 05-09-2019, 02:50 PM
Last Post: Don C
  do your brakes lock up nailpounder 6 283 05-08-2019, 09:33 PM
Last Post: Spike Morelli
  Front power brakes factory or not Nige 2 158 05-04-2019, 08:04 AM
Last Post: Carolina_Mountain_Mustangs
  Fitting issues with Wilwood brakes and Magnums Mike1972Mustang 15 2,737 04-23-2019, 12:49 PM
Last Post: mavgoustis
  Power steering pump problem Pegleg 6 259 04-11-2019, 02:03 PM
Last Post: Stanglover
  Saginaw Power steering Box Pegleg 14 370 04-11-2019, 12:44 PM
Last Post: Bentworker

Users browsing this thread: 1 Guest(s)