My 68 has manual drum brakes on all fours. I'd like to put disc brakes on the front, however don't have the $$ at the present. Has anyone gone from a manual drum system to a powered drum system? I'd like to replace my master cylinder with a master cylinder/booster. What all is entailed in doing this swap? Thanks in advance!

I think all you need to do is buy a Power booster and a master cylinder. Maybe need to bend up some lines.Also need to get the boot for the rod that comes out of the master. I may have overlooked a few things but thats it basically.

you should just need to get a booster and the pushrod that goes to the pedal. i believe the power and non power drum brake masters are the same. there should be enough slack in the brake lines that you won't even need to disconnect them- just unbolt the master from the firewall and dlip it out of the way with the lines hooked up, bolt up the booster, and bolt the master to the booster. hook the pushrod to the lower hole in the pedal, hook up a vacuum line to the carb, and go for a test drive.

Interesting post....Sorry if my question is a newbie type one but....could you use the same power booster later on when you're ready to convert over to a front disk setup?

Or would one have to use a different PB with the disk brake setup? I'm guessing they're the same right?

Thanks,
Mark P.

ding-ding
we have a winner.
yes, same booster, disc or drum.
new booster may come with that rubber boot mentioned.
when you switch the rod to the lower hole in the pedal, you will probably have to relocate the brakelight switch. i think there is another bracket you can get for it ("power brake light switch bracket" or some such name)

you will have to remove the master cyl. because it has the pedal pushrod attached to it. you need to remove the rod, or buy a new master.

no new masters come with that rod anymore, so keep the old one. someone will want it someday. it is the same rod for manual disc brakes too.
the power booster comes with the pedal pushrod, and a master pushrod. it is best to buy them as a combo to make sure you get the right length master pushrod for your master cyl.

pick up a salvage yard master and booster from any GM car to use as a core, and save a few dollars.

pedal pushrod adjustment is "zero play plus slop". in other words, it should jiggle just a hair.

Not familiar with the pushrod and boot. Where can I look on ( or near) the master cylinder to educate myself.

Next question, how much will the booster powered system improve overall braking? Thanks again!!

I have done both conversion, so I know the good and the bad smile.gif Pushrod comes with the booster and master, don't reuse the old one. You may have to use the clevis pin and U shaped bracket. The rubber seal is also just for manuals, if you use the seal on a booster, it will not function properly.

Do not use a manual master cyl with a power booster. The brakes will be SO touchy, you just breath on them, they will lock up.

You have to use a power master with a power booster. It is the size of the piston. The power master is a larger bore.

You may have to get new lines. With the correct power master and booster with 4 drums stops the car very well! Almost as good as front discs but cheaper.

My plan was buying a master with booster kit from Ricks First Gen or someplace like that. I believe I can get one for around $270. My problem is getting it installed. I haven't really worked on brakes much and this would be a job that needs to be done correctly.

Just go to NAPA or other parts place. My booster was $75 and the master was around $35. Paint the booster with gold paint and the master with cast blast. You can see it here. This pic is a little old, it's been on the road for a year.
http://www.fototime.com/CDBFA2046658CFE/standard.jpg

the power drum master i pulled out of my Nova last year has a really tiny bore- 7/8" i think, and it worked pretty damn good- for a 4 wheel drum setup. it also had the deep hole in the back like manual masters have. i ditched the booster and front drum brakes for a manual C4 front setup with a 15/16" master, and the pedal feels about the same as with the drums- firm and responsive, but not touchy. from the bore size and what i've seen in the boneyard, i assumed the power drum master was the same as the manual drum master, but never tried it in a manual configuration.

the parts book i have shows the power and manual masters being the same...but it's been wrong on alot of stuff on these 1stgen Fbodies.
the new booster generally Will come with a rubber boot around it's pedal rod, to keep dirt out. any rubber boots or insulators from the manual setup should be removed if they will be in the way, or serve no purpose. but you dont want any air coming in thru the firewall.

to answer the question of whether it will improve braking preformance:
No, it cannot physically affect the braking performance.
it will only reduce the amount of pedal effort required to get the same braking performance.
this may seem like a subtle difference, but, it wont stop any better. it will just require less effort from your foot to get more pressure to the wheels.

the brakes at the wheels remain unchanged.
if you can't get the wheels to lock up with manual brakes, a booster is just a band-aid.

By ohcscott,

"pedal pushrod adjustment is "zero play plus slop". in other words, it should jiggle just a hair."

Yes, it's fun on your head under the dash of the sucker and then crawling back in and out taking the whole shebang off and on at least four or five times ta get that "schosh"..

Been there, done that when I had ta make a new M/C p/r for my pdqCBB setup..

pdq67

can't you just have the rod a bit short, and loosen the jamb-nut with the clevis connected to the pedal, and the booster or manual master bolted in place, then spin the rod until it lengthens enough to get the pedal to contact the brake light switch? bottom out the switch, then shorten a "scosch" and tighten nut?
or is it different than i remember (or don't remember)?
it's been 13 years since i swapped my '68 'bird's master, but that's what i've done on other car's since then.
i am going to have to do the 'bird again soon.

now, an adjustable rod between the master and the booster- those are the ones i remember taking on and of a half dozen times to get right. mostly on :shudder: ford escorts.