Brake Petal Travel on Drum Brakes

[rhtopdown]

Drum brakes, single master cylinder, just not wanting to stop. No slack in petal tight when you start to stop its hard and only travels about 2in but have to put weight on it to top. Any ideas

[Lou's Comet]

Drum brakes, single master cylinder, just not wanting to stop. No slack in petal tight when you start to stop its hard and only travels about 2in but have to put weight on it to top. Any ideas

I am assuming you have manual brakes??

Seen in your other post that everything is new. Does that include the master cyl?

Some random ideas.....
First thing I would do is pull all the wheels and drums and make sure all the shoes are in the correct location. Primary shoes (the ones with smaller lining) are located on the front of the backing plate, toward the front of car. Secondary shoes(the ones with longer lining) are on the rear.

I would also check and see if the pads on the backing plates are good. There are three pads for each shoe to ride on built into the backing plates. I have seen grooves worn into the pads that were severe enough for the shoes to hang up on and screw with the brakes.

Is the correct brake pedal in car? The manual brake pedal has the pivot pin located higher than the power brake pedal, this gives you more leverage. So if you have manual brakes with a power brake pedal that would make it harder.

If you have power brakes, the booster could be bad, vacuum going to the booster could be screwed up.

You could have bad rubber hoses as Lavern said in the other post. Assuming they are not new, but usually when the hoses go bad the brake hang up/don't release.

Are the brakes adjusted up good? Probably not your problem if pedal is only moving 2 inch, but while your at it make sure they are adjusted correctly.

Hope it helps
Lou

[comethead]

Lou is the man!!
Along with all the stuff Lou mentioned be sure your master cylinder bore is matched to your wheel cylinders. I believe the stock bore size was 15/16”. The bigger the bore the more foot power needed. Manual brakes had a smaller bore to help with foot pressure. Power brake systems used a larger bore (1” and bigger) to push more fluid but require more foot pressure...unnoticed because of the booster assist.
Sorry to yap on but just be sure your replacement parts have matched bores.

Joe

[rhtopdown]

I think I am going to try new dual master cylinder has to be better than single. Which dual master cylinder should I get? thanks

[Lou's Comet]

I think I am going to try new dual master cylinder has to be better than single. Which dual master cylinder should I get? thanks

The only thing better about a dual bowl master cylinder is for safety. If you blow a line to the rear brakes you will still have front brakes and vica versa. Where with a single bowl you blow a brake line you lose all brakes. And changing to a dual bowl for safety isn't a bad idea. But may not solve your problem.

A dual bowl master with the same bore as a single bowl will pretty much work the same. Only way I see a performance improvement in your brakes by replacing your master with a new dual bowl, is if the master cyl you have is bad, or has wrong bore size. If your master cyl is good and correct bore size you prob won't see a improvement.

As far as which one to get you need to do as Joe said and match the bores. There are formulas on the net for this. Or find out what the bores are of your wheel cylinders are and find a master cyl for a ford product 1967ish or newer that has 4 wheel drum brakes with the same size bore wheel cylinders and go with that master.

If you just want to take a chance/guess I would guess/look for a dual master cyl for like a 67 Mustang with manual drum brake, with a 15/16 or 7/8 bore as Joe mentioned above. A dual master for drums will have same size bowls. Where disc/drum setup the master will have a bigger and smaller bowls.

A bad master usually means soft/spongy pedal, or pedal going to floor. For your master to be causing your problem it would prob be with the bore size. You could pull the master cyl push rod from the brake pedal, remove it from the firewall, and measure the bore size to see where your at.

Has the car always had this problem? Or did this begin after some work was done? And does it have manual brakes or power with a power booster?

I would try to find out the cause before throwing parts at it.

Lou

[Lou's Comet]

Lou is the man!!
Along with all the stuff Lou mentioned be sure your master cylinder bore is matched to your wheel cylinders. I believe the stock bore size was 15/16”. The bigger the bore the more foot power needed. Manual brakes had a smaller bore to help with foot pressure. Power brake systems used a larger bore (1” and bigger) to push more fluid but require more foot pressure...unnoticed because of the booster assist.
Sorry to yap on but just be sure your replacement parts have matched bores.

Joe

Thanks Joe, Just trying to help. And your right with the bore sizes. Wrong size bore makes for some sucka$$ brakes

Lou