HELP!!. No brakes after engine swap.

Chetly

New Member
Aug 6, 2003
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Before i changed my motor i had normal brakes. After i now have rock hard brakes that are impossible to stop the car. My cam has a lobe separation of around 110*. My new carb and intake dont half the provisions for half the vacume lines. Should i just plug these open lines. Carb has mech. secondaries and manual choke. What can i do to stop my car, the E brake is getting old.
 
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Vacuum leaks will make your power brakes useless, the booster must have 14 inches of vacuum to provide assist for the brakes.

Fix all the leaks by capping all the unused open vacuum lines. Then check the brakes & repost. The vacuum line for the brakes comes off the vacuum tree up by the windshield wiper motor. Make sure you have good vacuum there. Vacuum gauges are available at Autozone for about $18, you may want to get one.
 
Daggar said:
You might also consider going to a boosterless brake master cylinder.

then he would have the same problem. non power brakes and they suck. never are you supposed to leave vacuum lines unplugged. you also don't need an aftermarket vacuum canister. if you have driven some of fords older trucks and cars you might notice something that looks exactly like coffee cans with a nippled and a vacuum hose going to it. that is a vacuum canister and it is a cheap item at any junkyard.
 
dastang2 said:
then he would have the same problem. non power brakes and they suck.

That's not exactly true. Non boosted master cylinders use larger pistons to increase the mechanical advantage and make pedal feel lighter. Though they are not as easy to depress as a vacuum assisted unit they are no where near as hard to operate as a vac assist that doesn't have any.
 
i used to have a 71 f100 swb with non power brakes and it sucked big time, esp. if somebody pulled in front of you, how does just a little bit of vacuum help make the brake pedal feel about 40 pounds lighter.
 
dastang2 said:
i used to have a 71 f100 swb with non power brakes and it sucked big time, esp. if somebody pulled in front of you, how does just a little bit of vacuum help make the brake pedal feel about 40 pounds lighter.

It's simple. The booster is a large diaphram with lots of surface area... and lets say you have 14 psi of vacuum over a suface area of 10 inches connected to a linear actuator (the one that pushed in on the master cylinder plunger) that's 140 lbs of pressure that is assisting you (when the brake pedal is pressed and opens the valve to the booster) in operating that actuator.

EDIT: the numbers I used are just for example.
 
Hey Chetly,

Just check all your vacuum lines going into your intake. A few years ago I swapped an Explorer GT-40 intake onto my old T-bird and when I was done I had the EXACT SAME problem as you. I simply had the vacuum lines hooked up in the wrong spot. Fixed it instantly.

Don't go buy a new super-booster before you check your vacuum line placement from the intake to the tree! Good luck, let us know what happens! :nice: