Brakeing Problems

[TommyG]

An old man with an old truck is having problems...Have 4 wheel drum power brakes on my truck, and is hard to stop. Have replaced the M/C,lines down to the Dist. block, and front shoes..If I stand on the breake pedal with both feet, it will stop in a reasonable distance, but not slide the wheels..with the motor not running, the pedal is high and hard..holding it there and starting the motor, the pedal goes down..shut back off, and the pedal pushes back up....Have no vacuum leaks...I am now at a loss....

Anyone else ever had this problem....?

TommyG

[jor]

It sounds as though your vacuum canister is not doing the job although its behavior at startup sounds right. Do you have a dedicated vacuum source to your canister? The reason I ask is that I had the same problem a few years ago. The vacuum source for the canister was shared with the PCV valve. As soon as I provided the canister with a dedicated vacuum source, the brakes performed normally.
jor

[TommyG]

Thanks for the quick response..!...PVC valve, and trans. vacuum modulator are both pulling from the same place..I have the 352CID engine, running a 2 BBL. carb...I see no other place to get vacuum from...Not a removeable plug any where in the intake manifold that I can see..how did you get around the problem..?

TommyG

[Heavenlyfire]

You have it hooked up to the right place it sounds. Have you checked the rear brakes out? There could be a leak or they could just be shot altogether. Just an idea. Other than that, I would say that they are not adjusted right.

[farmtruckman]

I am attempting to install a PB booster on my 67. I have the same problem with the 352 engine. The only fitting is the one that the auto trans uses for the kickdown. If I tee off of this, will I get enough vacuum to run the brakes also? My PVC valve goes elsewhere. On my manifold and the carb base have no other points to go off of. Any help, greatly appreciated.

[dcbullet]

I am attempting to install a PB booster on my 67. I have the same problem with the 352 engine. The only fitting is the one that the auto trans uses for the kickdown. If I tee off of this, will I get enough vacuum to run the brakes also? My PVC valve goes elsewhere. On my manifold and the carb base have no other points to go off of. Any help, greatly appreciated.

I think that you probably have the distribution block on the top of the picture below. If you get the distribution block on the bottom of the picture, it will give you the extra fitting needed to run your booster hose to. You put the two together, and you are good to go.

There are other fittings as well, but these is one option.

[Jake11]

Sounds like a bad booster. Does it hiss under the dash when you press
on the pedal? Could it have a leak on the booster? If it's working right
you should get it to stop with one foot pretty easy.

[TommyG]

Hi...No hissing under the dash...The master cylinder bowl is partitioned off into two different sizes...why..? If the lines were reveresed,would it have an effect on thr braking..?Do the two sections put out different pressures to the wheels?.I understand that the brakes Have 60% braking in the front and 40% in the rear...how is this controled..? Lots Of questions I know, But would like to understand a little better what is happening...

Thanks again...TommyG

[fordman]

i would think in theory that if the lines were reversed it could have a affect on the performance of the brakes. but that is just what i think.

[FORDification]

You might check the master cylinder, too. If someone installed a disc-brake master cylinder in there that will give you a hard pedal. I'm not entirely sure if this applies to our trucks but typically a disc-brake master cylinder has a larger bore than a manual version, and hooking it up to a drum/drum setup will definitely give you a harder pedal.

[Jake11]

If it's all drums, the front ones are larger than the back ones. So they
do more of the work. You done any work to the brakes at the wheels?
If the drums get glazed, they won't stop to good.

[TommyG]

New shoe, weheel cylinders, bearings and seals....Shoes adjusted to a slighjt drag,, and the drums have had any and all glaze aded out...Nothing has changed as far as the stopping goes...Thanks foer the come-back..TommyG