Contemplating adding a small power brake booster to my "no power brake" 4 wheel drum roadster. master cylinder is located under floorboard and has room for a small booster...any ideas about the best way of going about this and possibly best choices of boosters....also, any pros/cons on this.
Do not know what models you have had over there but the small Japanese cars used to have small boosters.
A lot of the brake threads on here say that the small diameter boosters like 7" don't seem to have any effect at all.
That's a fact. I've used 'em on a 55 and my 40 chev. coupe with booster under floor. IF you have to use one because of space, then go only with the dual diaphragm type, not single. Otherwise, an 8" dual is the solution, ugly but will stop the beast.
There are single and dual diaphragm versions available, going to a dual diaphragm version made an appreciable difference on my '58
If you are just trying to reduce the pedal effort a little couldn’t you change the M/C diameter or pedal ratio? Sent from my iPad using The H.A.M.B. mobile app
You don’t say whether you have a single or dual MC. bchctybob is giving you the easiest solution and the diameter change maybe the easier of the 2. If your cylinder is back a ways from the pedal arm an additional hole might be your answer. If your MC has a 1” cylinder diameter a change to 7/8” is good.
So you go smaller bore for more pressure (less effort)? Its pretty stiff as is, though I have no issues with it but a little worried when my daughter or granddaughters want to drive it. so looking for less effort.
The smaller bore reduces effort but increases pedal travel, so there is a trade-off. But if your pedal is high and hard, that would be the easiest solution.
Well I have plenty of pedal travel so this may be the solution. I checked master cylinders online and find all dual MCs say disc/drum.....my current setup is drum/drum with dual MC.....do they make a dual MC for drum/drum combo. Or, could my current arrangement be the problem.
Ok. Just measured my MC and it is 1” bore. Should i try 15/16” or 7/8” bore Sent from my iPhone using H.A.M.B.
Thanks for pointing me in the right direction Steve. Been reading up on the subject. First time trying to use a dual chamber MC. Always used single chambers with no issues BUT always the big raincloud over your head with that route....thanks again Sent from my iPhone using H.A.M.B.
Ron, Call Wilwood and ask tech guy they were extremely helpful when I did my brakes. They offer 2 different size/style MC’s and I use a 7/8” bore with no power. It is a disc brake front but I’m sure the can as it you I learned a lot from them before buying anything. You can also check into a late 60’s MC for a Mustang with all drum brakes. They had gone to the dual reservoir by then. There is always the option of drilling another hole in the pedal if you have the room below the pivot. Good luck..
Most “kits” use a corvette type MC. They are kinda big. here’s a typical “kit” aftermarket MC next to a 1968 Pontiac drum/drum master cylinder I’ve built several braking systems for hot rods using the geo metro booster with great results. Some have the metro master cylinder as well. You need to understand what’s important and how to make some brackets to make it work. But it fits a lot of small places. There’s also a system similar to the Old T birds. There’s a small tiny single bail MC attached to the brake pedal. The line goes to a remote booster and works a dual bail master of your choosing. It has some obvious drawbacks but also some obvious pluses to complicated confined builds. Hunting the link for you - I found one on amazon !! Haven’t played with it yet https://www.jalopyjournal.com/forum/threads/remote-booster-and-master-cylinder-id.1193709/
My car is drum all around...can you use a MC for disc/drum or does it need to be drum/drum also, will a master cylinder for a brake booster work ok without the booster
Greatly depends on the application your getting parts from. Sometimes yes and sometimes no. For example, 1985 Chevy trucks use the same master for booster or no booster. Im 100% sure. Not all do though also 100% sure. Many times the designation for disk/drum is simply the addition or omission of an internal residual pressure valve, but not always.
And sometimes it's just the depth of the socket for the actuating rod that makes for a different part number. Does your current system have the M/C below the floor? Does it have two residual check valves?
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