what is the difference between a manual one and a power one? can you put a manual onto a power canister?
@fastcar1953 Is right. Power master usually has a shallow pushrod hole, the manual usually has a deep pushrod hole.
A master cylinder is a master cylinder. The differences are in the design/construction not that one type is for a power booster and another one not. Pushrod difference? Nothing that can't be altered to work. In this craft, the concerns are more along the bore size, mentioned, and brake pedal pushrod ratio.
I hope you're right. Somebody gave me this new MC for my replica champ car. I am not using a booster. Does anybody know where I can buy the rubber dust bootie that fits on the end of the bore? It will be very useful on a dirt track.
You probably don't want to use a booster type MC with manual brakes. Think about what happens with the pushrod, when something goes wonky, and it falls out, or gets wedged into the wrong place.... Some later manual cylinders have the push rod retained in the piston, to prevent this type of problem.
I'm running a power/booster type master on my 51' with manual brakes front and back, have been for over 20 years. Absolutely no issues!
The real difference is in pedal ratio. Most GM cars built back when there were cars sold with manual or power brakes had pedals with two hole locations in the arm. You put the pushrod into the hole closest to the pivot point for manual master, and furthest away for power. When I converted my OT Chevy to power brakes I used the same master, and simply mounted the booster behind it, and moved the pushrod to the lower hole. Worked perfectly fine.
Vacuum booster MC’s are usually 1” or 1-1/8”; manual are 7/8” and can be as low as 3/4”. Manual work best with 6 or 7 to 1 ratio but are fine with 5 to 1. A vacuum booster system with a 7/8” MC and a 6 to 1 pedal ratio will be very sensitive especially in a light vehicle and may put you thru the windshield. If using drum rears on a non booster system and the rear end is from a booster system vehicle you should change the wheel cylinders to a smaller size to be compatible. Auto manufacturer engineers design systems for specific use. We are the ones that mix and match incompatible parts at times.
As mentioned, the pedal should be adjustable. Rod length could be an issue, but you can shorten it if it's too long; get a longer one if it's too short. Wilwood has a good selection of rods. However, power brakes usually use a mc/w a larger bore diameter. I have manual brakes on my 55 Tbird-discs up front/drums rear. 15/16th bore was recommended; OEM is 1-inch. By the way, I also have Wilwood's proportioning valve.
thanks for all the replies. as far as the rod length goes. if i can build a whole car i can surely make a new rod.
If you want to use the power master cylinder on a manual system, pull the piston out, and drill the the pushrod end of it deeper so there is no chance the pushrod can fall out. you can go a half inch or so with no problems.
The rod goes in about 2 inches. The piston has a stroke of 1.05". Thanks for the Dorman suggestion egads. I'll check out their offerings after I measure the OD groove..
I don’t know what you are working on but I bought an adjustable rod from Summit for a Mustang on the recommendation for the disc brake kit supplier. It made my installation easier. I also could have made my own.