|
By dolan - 12 Years Ago
|
|
Have a 1956 Mercury Mont 2 dr hdtp.Have changed intake to a 9425B with a 57 distributor etc,new out of box Holley 390 CFM carb with elec choke;changed to electric wiper motor,vacuum measures 18+.Installed a new m/c& booster from Ir Dave,changed to two brake lines(front and back),replaced a couple bad hoses and some line,changed rod length longer/ shorter ,bled system,checked wheel cylinders and shoe action and everything is working but there is no stopping power above .10mph,like zip.Drum brakes all 4 wheels.The work has been done by a professional mechanic.Is the booster too small for a car this weight?Should I go back to the old Bendix T-V?Is there a later unit that is an easy replacement?Thanks,All help appreciated.
|
|
By 56_Fairlane - 12 Years Ago
|
I'm wondering if you're really getting vacuum at the higher engine speed. Was your reading at idle or at speed with a load?
Maybe the source for the vacuum is at fault?
Other things to check is the booster or a bad check valve on the booster.
|
|
By oldcarmark - 12 Years Ago
|
|
Those boosters are dual diaphragm(equivelant to a bigger single diaphragm type) which is more than sufficient for that vehicle.It is possible you have a defective booster.Is the brake pedal completely released when you take your foot off?There should be a little freeplay( not much but enough that booster is completely released) when you depress the pedal by hand with the engine off.In other words you should be able to tell when the pushrod comes in contact with the plunger inside the booster.If everything checks out I would suspect the booster is defective and you should contact the seller.I am guessing you bought this setup from Irish Dave in New Mexico?He's very good about replacing the unit if its defective.Give him a call.I have that setup on mine with Granada Disc brakes and it works great.My buddy with a 55 has one also with drum brakes.Very happy with his.Not sure if your setup is angle mounted to cleae exhaust manifolds but with mine I drilled a hole lower on the pedal so the pushrod is not on the angle but more inline with the booster.About 1/2-3/4 inchs lower on the pedal.
|
|