wheel cylinders stock vs s-10 manual

[pontiacgp]

I hear what you are saying, but you the force on rear pads is not increased, keep in mind the pressure is applied to edge of pad so you never gain surface contact with a larger bore cylinder, so you never get a increase in pressure. Unlike disk brake were your clamping force is contributed over a larger portion of the pad and rotor. But thats just a bunch of pascals laws and stuff, I know from my little experiment that there was a noticeable difference in pedal feel between the two and the stocker were much better, maybe someone else had better experiece with them. so maybe we have to agree to disagree, but you can check out this article to see what i was talking about.

http://science.howstuffworks.com/hydraulic1.htm

your wrong about there not being an increase in rear braking with the s 10 non power brake wheel cylinders...on a Grand National they can hold the rear wheels from braking loose up to 4 pounds of boost with the stock wheel cylinders...with the s 10 cylinders the rear brakes can hold the wheels from braking loose up to 8 pounds of boost....I know a speed shop where they specialize in Grand Nationals....theories are nice to read about but the real world is the best platform to test.....

another way to increase rear braking is to use two primary shoes on each side

You are very right about the real world, which is why I changed back to the stock cylinders. Keep in mind GN's have a different braking set-up from my monte carlo so maybe they had pressure to spare. All i know is that my stock cylinders stop much better than the s-10, So according to my car I am right.

Grand Nationals do not have a different braking system than any other G body including your car....the GN has a different system to obtain boost for the brakes since a turbo car has an issue with vacuum. If your pedal felt differently it was most likely cause by your rear brake adjustment. Do you have any measurement to show what improvement you obtained by going back to stock cylinders?

and as far as physics goes....are you are aware of this principle?

"A basic principle of fluid physics is that the larger a caliper or wheel cylinder piston, the more force will be applied. Force = P x A, where P is the hydraulic pressure in pounds per square inch and A is area of the piston in square inches."

 

[monte olrac]

I am very aware of the princible, I know more force will be applied but you will lose movement because of the larger area, Again i can say how much movement was lost from 1/8 inch difference. As far as my little experiment went I adjusted the brakes properly with both sets of wheel clyinders, that was from just draging the drum to beating the drum on and off. I'm sure someone has had great experience with them, i didn't mind them before I changed out all my components. So it maybe just my car, I can't say we can go back and forth on this for days to come throwing up theories, laws and princibles. So on that note i would have to say if you want to upgrade your brakes with a larger s-10 wheel cylinder I would do your own comparison to see if you notice a difference or lack there of. all in all for a rear brake upgrade get some damn disk brakes if you really want some noticable braking performance.

 

[pontiacgp]

go back and forth?.....it's an upgrade that many people have done and you are the first one I have ever heard that claims this upgrade is actually detrimental to braking performance...I guess those out in the non power brake s 10's should be changing the wheel cylinders to the smaller diameter piston... and as for braking performance I can lock all 4 of em up at 100 mph... 8)

 

[monte olrac]

go back and forth?.....it's an upgrade that many people have done and you are the first one I have ever heard that claims this upgrade is actually detrimental to braking performance...I guess those out in the non power brake s 10's should be changing the wheel cylinders to the smaller diameter piston... and as for braking performance I can lock all 4 of em up at 100 mph... 8)

well im happy that you can lock them up @ 100mph , I only went to about 95 when i locked mine up with out stepping as far down on the pedal, both will stop your car, BUT the stockers feel much more responsive with less pedal movement in my car. maybe i should go that extra 5 mph to see if i missed some gains, or put out some cones and measure. I'm sure you going to tell me that my foot has damaged nervers or something or that the better pedal feel is a figment of my imagination.

So basically for anyone else thats reading this, I would sugguest that before you slap some s-10 wheel cylinders on you may want to do your own test to see which ones you like better, that goes for s-10 guys that feel the same way.

 

[Bonnewagon]

Let me jump in here and state that you both are right. The larger wheel cylinders will translate to more force on the brake shoes. But it won't FEEL right. Why? Because the stock master cylinder is now trying to fill two bigger wheel cylinders and that translates to more pedal travel and less pedal effort. It doesn't FEEL like the brakes are doing their job. To get the added braking force AND maintain decent pedal travel and feel, then you must increase the master cylinder bore a like amount as the wheel cylinders. I do this on my G-body by using an F-body master cylinder which has a little bigger bore, maybe a couple of 16ths, with stock wheel cylinders, to get way less pedal travel at the expense of a little more effort.

 

[monte olrac]

Let me jump in here and state that you both are right. The larger wheel cylinders will translate to more force on the brake shoes. But it won't FEEL right. Why? Because the stock master cylinder is now trying to fill two bigger wheel cylinders and that translates to more pedal travel and less pedal effort. It doesn't FEEL like the brakes are doing their job. To get the added braking force AND maintain decent pedal travel and feel, then you must increase the master cylinder bore a like amount as the wheel cylinders. I do this on my G-body by using an F-body master cylinder which has a little bigger bore, maybe a couple of 16ths, with stock wheel cylinders, to get way less pedal travel at the expense of a little more effort.

so does the f-body master bolt right up? if so i would definatly upgrade my master

 

[Bonnewagon]

Yes. I used a second gen Firebird master, 1980 I think, the cast iron one. It had a 1" bore and the stocker had a 7/8" bore. On that one the front and rear brake feeds are reversed, so I just bent the lines over to match up. You'll notice the brake lines coiled up under the master, so lots of slack. If your lines are old and brittle, they may break so expect that. A little checking on Rockauto will show big bore master cylinders for our cars. Look up the stocker for your car and see what the bore is. Then compare other models and see what the bore is. I had an iron F-body one spare, but there are aluminum ones that will look stock, and reduce pedal travel. And then again you may have the biggest bore available allready.

 

[pontiacgp]

Bonne..the guys with the Grand National didn't do any upgrades other than the wheel cylinders to their brakes and like I posted they were able to hold the back wheel from spinning at a significantly higher boost with the s 10 cylinders and the GN's use the same master and lines of other G bodies. I can also lock up my back end much quicker than I could before the upgrade and I have also noticed that the front pads last longer with the increased rear braking. I agree if the caliper piston side is increased that the cavity behind the piston becomes marginally larger thus requiring a larger diameter piston in the master but I have seen 12" braked with duel pistons and the brakes worked fine with no upgrade to the master. In our circle track car we have drum brakes in the rear (have to maintain OEM set up) and we adjust the brake bias by reducing or increasing the flow to the rear brakes. I can also say the pistons in the rear cylinders are larger than the stock G body and we use a Chrysler non power brake master cylinder that has pistons no bigger than a master cylinder in a G body. There is alot of force coming out of the master and the master in a stock G body are basically oversized to begin with....

 

[Bonnewagon]

That's why I said he may have the biggest bore allready. It depends on what the factory put in. My Malibu wagon had terrible brakes. Lots of pedal travel and little effort, allmost to the firewall. Probably OK for a woman driving to the grocery store with a 3.8 V-6, but when I put a 70' GTO 400 in the brakes were scary to say the least. I used the Firebird master to reduce the pedal travel and get some decent pedal effort. I had a stiff clutch so it matched up pretty nicely.

 

[RUSTY OL BU]

I am also thinking of doing this uprgrade. But after reading this i am torn anyone else like to chime in that has done this.