Hello I'm currently running Ansen style swing pedals in my 32...A 60-62 Chevy Truck combo master cylinder and from what I come up the pedal ratio is 6-1 ( Pedal is 12" long from the hinge point to the middle of the pad...The push rod hole is 2" below the hinge ) It has 10" Fairlane rear drums and the front is a Lincoln style brake kit from Boling Bros to include what I believe to be early F100 wheel cylinders...The problem is the pedal feel is rock hard and the car doesn't stop well...Another problem is the length of the pedal makes the car difficult to drive as there is no place to rest my left foot because the clutch pedal is in the way...Has anyone shortened the pedal arms and will this create more issues for pedal ratio?...Thank You
Sounds like maybe you need smaller bore in master cylinder or bigger bore in wheel cylinders. Yes, shorter pedal arms require more effort if it changes ratio.
The clutch is also very hard due to using 80's Camaro slave with 1" bore..I didn't choose that..The person that started building the car had used the Camaro T5 and bellhousing
the tandem master cyl from my 61 chevy has 1 1/8 bores just some info if that helps the smart hydraulicists
According to Rock Auto 60/62 Chevy C 10 clutch slave cylinders were either 1 inch or 1-1/16 inch. https://www.rockauto.com/en/catalog...ransmission-manual,clutch+slave+cylinder,2044 Front wheel cylinders had/have a 1.125 bore and rears have a 1 inch bore. That said, brake pedal feel is quite often subjective and quite dependent on what the brakes in your normal daily driver feel like. Stopping for drum brakes can be affected a bit by the material in the actual lining. Stopping ability can also be subjective if you compare it to your 4 wheel disk performance model daily driver and some of the younger guys on here may actually be driving 4 wheel drum brakes for the first time in their lives when they buy or build an old hot rod and have no experience with drum brakes where us old farts that grew up with drum brakes and often rather suspect ones when we were young and broke don't have an issue with them. I did as many as 20 brake jobs a week for several years when I worked for Firestone almost all on drum brake cars and some of the harder long life shoes didn't have a good feel nor did they stop all that well until they were well broke in. The best feel as far as what customers liked was the dirt cheap lining that was barely good for 10,000 miles and that was stretching it if they did all in town driving. You could stick those shoes on cars that people just drove around town and they loved them. Put the spendy 40,000 miles shoes on and they complained about noise, hard feel and everything else.
I certanly appreciate the information...I currently have 2 other manual drum brake vehicles and have had several over the years and the pedal effort is this 32 is what I would consider on the extreme side...I have a 72 M151A2 military jeep that stops like the old lady's Jaguar compared to this car.. Thanks!
Rock Auto is wrong and Anthony Myrick is rite! Maybe there's a diff. in power verses non? I have the same master and re sleeved both sides from 1 1/8" to 1" it may help your situation if interested PM me it's for sale!
when I swapped in a hydroboost my 61 gm truck, I used a master cyl for the same year truck to work the slave cyl for the clutch. That non-tandem MS has a 1 1/8 inch bore. It is pushing a stock slave that has a 1 inch bore. Clutch pedal feels great. The truck was originally equipped with a frame mounted booster. the info I looked up on bore sizes at my local parts store listed a 1 1/8 inch bore for both the clutch and brake side for my truck. on a side note, I have wondered how those tandem master cylinders would work only pushing the brakes. One side for the front and one side for the rear.
^^^^^^^^^^ I did what you suggested, used the brake side for front brakes, "clutch" side for rears. Disc's up front, 9" shoes on rears. Used a balance bar push rods on a 7:1 ratio. Started with the stock bore 1 1/8" and pedal was real hard and no stopping power. Re sleeved to 1" and better but not safe. OP is drum/drum, may make a diff. Dunno!
The main issue with side-by-side master cylinders is higher pedal force vs. a dual tandem master cylinder.
You may want to check/replace the rubber flexible line's have had the same extremely hard brake on several cars and replacing the hose even if they look good on the out side always fixed the problem
Explain "side-by-side master cylinders" Is that 2 brake M/C's with a balance bar [pedal box] or some other terminology
The distinction should be made that there are individual dual side by side master cylinders and integral dual side by side master cylinders , although the only example of the latter I can think of is the early chev truck master cylinder .
First thing I would do is pressure test each wheel. You might need to change linings or have them worn in a little so they grab.. Also, the anchor pins at the front brakes might need adjusted. They make a big difference in brake performance.. Once you get a manual system dialed in, there's nothing like it... Secondly, you could always go hydro boost. I have one on my 2001 Chevy 3500 truck, wow do they work!!
There is no distinction between individual side by side masters and the Chevy truck integral master, other than fluid reservoirs. Any additional brake master cylinder will increase pedal force.
I was simply referring to their outward appearance since moist folks on this forum weren't around when the Chevy cylinders were popular & wouldn't know what they were looking at .I was not referring to operational function .
The front brake is a kit that incorporates 11x2 shoes on a single star wheel adjuster that I purchased as a kit. (I believe these incorporate late 60-70s F100 shoes and hydraulics?) The rears are stock 8” ford axle drums. The brake hoses are new also. I noticed yesterday that in pushing the brake pedal the master cylinder will only travel about a 5/16 to 3/8 of an inch . The brake adjustment may be slightly on the tight side. But not enough to generate heat issues. I’ve adjusted drum brakes for years like this to achieve good pedal. But have never experienced this type of problem
Here is some info that I found on line a number of years ago regarding master cylinder bore sizes, and it's effect on pressure output. Pedal ratio 6:1, bore size 1 1/8", pounds input 75 (leg pushing effort) PSI output 453. Pedal ratio 6:1, bore size 1", pounds input 75, PSI output 573. Pedal ratio 6:1, bore size 7/8, pounds input 75, PSI output 748. Be aware decreasing the master cylinder bore size will add pressure to you system, it will also decrease volume. This means if you don't have enough volume to fill your wheel cylinders, your brakes won't function as expected.
OP, You could have more than one problem BUT for sure you have a classic problem of a to big of bore size...……………………………..
With the pedal disconnected from the master, does it easily move full travel, with no binding? With the pedal push rod connected and adjusted to the master, can you fully bottom out the master with one of the bleeders open? Just checking for any pedal or internal master issues, but a 1" master bore is all you need for your drum brakes.
I haven't seen it mentioned , do you have a return springs on the pedals & are you sure the masters are retracting completely plus a bit of air gap ?
Just going through the same thing Too much pedal pressure required to stop car. I rebuilt the brake pedal itself changed angle & length in order to make it more comfortable to drive & stop without thinking about ( leverage issues) and now I have to stand on the brakes.I made a lot of extra work for myself...Gene in Mn
The Jalopy Journal
