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Master cylinder bore

rockdog57

Getto fab garage owner
Joined
May 21, 2020
Member Number
868
Messages
577
Loc
Lindon, Utah
What bore master cylinder are you guys running on rigs with 60 front stock calipers and 14 bolt with stock disc’s? I’m gonna run a wilwood pedal and no booster. On my current setup I’ve never had good brakes.
 
Current setup is disc and drum. On a Toyota truck pedal and stock Toyota booster. I put a one ton master cylinder on it. I can’t push hard enough to lock the brakes and drive through them with 5to1 in the atlas. I’m ditching the drums for disc on the 14. But going manual brakes on the buggy I’m building. I’ve already bought the wilwood pedal and know it is longer than my Toyota pedal, so more leverage. Just not sure what bore master to go with?
 
auto trans? try out a smaller diameter TQ converter :flipoff2:

i would say do the math and see what you come up with, and then probably grab a 7/8" bore :rasta: have you tried calling up wilwood and seeing what they suggest?

What is the piston diameter of your calipers?

What is the lever arm ratio of your pedal?

Toyota Pickup Brake Bible - 4x4 North

the last few posts in this thread are all general stuff, the first several are toyota specific.

if you can fit a booster, it will make life much easier. trying to hold back aggressive low range with an auto trans and manual brakes sounds....tiring
 
Iirc wilwood recommended 6.5 or 7:1 pedal ratio for manual brakes
 
You need to know your rotor diameters, caliper piston areas, and pad coefficients of friction if you want to make a proper decision on on master cylinder size. If your brakes are otherwise satisfactory, your best bet will probably be a higher stall converter as Provience suggested.

Busted Knuckle has a brake design calculator that can get you going in the right direction, although it has a lot of errors. I have a version of it on my work computer where I have corrected some of the errors, but I don't have it handy right now. Here is the Link.

Here is Matt Burkey's video on how to use it (there are errors here as well, but will get you going down the right path):

 
if you can fit a booster, it will make life much easier. trying to hold back aggressive low range with an auto trans and manual brakes sounds....tiring

I agree, physics are against you. You'll either end up requiring tons of leg strength, or lots of pedal travel, and Toyota's don't have the room for much travel. Personally I would go the other way and add hydroboost.
 
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I agree, physics are against you. You'll either end up requiring tons of leg strength, or lots of pedal travel, and Toyota's don't have the room for much travel. Personally I would go the other way and add hydroboost.

This isn’t going on a Toyota. That is the rig I was using for comparison. I’m building a new buggy. Hence my question. I know people are using manual brakes in some buggies. I was just asking those that have done it what they went with.
 
On mine I'm running dual 3/4" masters, 15.75" pedal length, Wilwood Dynalite calipers up front and Ford 8.8 calipers at the rear. The dual master assembly has a bias bar that I probably have dialed ~25% towards the front. Pedal feel is fantastic and I've never had any problems with it.

The Dana 60 calipers are probably a little larger so 7/8" is likely a good choice for the front. With manual brakes especially it becomes a tradeoff between pedal travel and pedal effort just in the master cylinder bore (do you want a longer-travel 'squishy' pedal or a shorter-travel pedal that you have to really stand on). Both have their advantages, the longer travel is easier to modulate but when you need to panic-stop it can feel a bit unnerving. Likewise the other feels solid but when you're sitting on a hill it can get tiring having to mash it the whole time.

BillaVista did a comprehensive bible on brake components and sizing:
http://billavista.com/tech/Articles/Brake_Bible/index.html

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Thanks vetteboy. That’s what I was looking for. I’ve already read billavistas article. I have his sight bookmarked. Lots of good info there. I just wanted others real world experience with this.
 
On mine I'm running dual 3/4" masters, 15.75" pedal length, Wilwood Dynalite calipers up front and Ford 8.8 calipers at the rear. The dual master assembly has a bias bar that I probably have dialed ~25% towards the front. Pedal feel is fantastic and I've never had any problems with it.

The Dana 60 calipers are probably a little larger so 7/8" is likely a good choice for the front. With manual brakes especially it becomes a tradeoff between pedal travel and pedal effort just in the master cylinder bore (do you want a longer-travel 'squishy' pedal or a shorter-travel pedal that you have to really stand on). Both have their advantages, the longer travel is easier to modulate but when you need to panic-stop it can feel a bit unnerving. Likewise the other feels solid but when you're sitting on a hill it can get tiring having to mash it the whole time.

BillaVista did a comprehensive bible on brake components and sizing:
http://billavista.com/tech/Articles/Brake_Bible/index.html


What master cylinders are thosse?
 
What master cylinders are thosse?

The cylinders, pedal assemblies, brackets etc are all from CNC Brakes, which sucks because they closed up a year or two ago (family run for 34 years) due to retirement and decided not to sell the business. I always had a great experience working with them and their components were awesome.

Aside from sizing, I don't even know who would replace that stuff if I needed to. I suppose Wilwood or Jamar probably has equivalent stuff but likely not bolt-in, and I designed that whole bulkhead area of my buggy around those components. I'm not worried, their stuff has always lasted (and I suppose is still rebuildable, anyway), but it still sucks.
 
The cylinders, pedal assemblies, brackets etc are all from CNC Brakes, which sucks because they closed up a year or two ago (family run for 34 years) due to retirement and decided not to sell the business. I always had a great experience working with them and their components were awesome.

Aside from sizing, I don't even know who would replace that stuff if I needed to. I suppose Wilwood or Jamar probably has equivalent stuff but likely not bolt-in, and I designed that whole bulkhead area of my buggy around those components. I'm not worried, their stuff has always lasted (and I suppose is still rebuildable, anyway), but it still sucks.

my understanding is kartek bought all the backstock from CNC, I have wilwood masters on CNC pedals
 
When I had stock GM 60 calipers front and 3/4 ton calipers rear I had a 1" front/7/8" rear masters with the long CNC pedal. I switched to 3/4 ton calipers to the front as well and tried the 1" MC and it worked but ended up going to the 7/8 on it as well and worked better. Its a balance of pedal stroke and leg pressure required. I tried 3/4 masters originally since my pedal assembly came with them and took way too much pedal travel. I also had 2 psi residual valves to help takeup the first little pedal travel.
 
My current setup with a Wilwood reverse swing brake/clutch, 13/16 masters w/residual valves and 3/4 ton GM calipers ft and rear stops my buggy OK. It takes a good amount of effort to hold still on a hill but most manual brake do. IMHO running a longer pedal would help but I have the longest one Wilwood makes. The other option is assist right from the start which seems to be the way most are going now.

I'll be making my own longer pedal soon just help reduce effort on steep hills.
 
I like the idea of this pedal setup since you can get the pivot point higher based off a tube and effectively make a longer pedal than a bolt in hinge assembly that will be under the tube typically. I feel manual brakes is all about the pedal ratio.
https://goatbuilt.com/product-catego...ke-pedal-kits/

All the newish (last 5yr) off-road ortiented pedal assemblies that have come on the market in aren't much help for those of us running rigs that utilize a stock firewall and pedal assembly.

I wish someone would make a small lever that bolts to the engine bay side of the firewall (like the equalixer bar used for dual masters, but with one side pinned or like the right angle adapter used in Grumman step vans) with multiple pivot point adjustments so that we can turn our ~5:1 OEM assemblies into what's could be anywhere from a 7:1 to 30:1 with no tradeoff other than the extra length (that the master and booster (if applicable) will stick into the engine bay) and slop from doubling the number of pivot points (which won't really matter since gravity will mostly take up the slop).

I could make one myself and fully plan to when I get around to doing brakes on my trail rig but I'm only gonna build one for me. Somebody should be making something like that as a production piece though.
 
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