swap/upgrades to front calipers

[scoob8000]

So I bought the 2500 calipers since mine needed replacement anyway. Now I'm second guessing myself before I put them on.

I realize there will be slightly more pedal travel, but would later doing the NBS MC swap correct this?

 

[TylerZ281500]

whty would there be more pedal travel?

 

[scoob8000]

whty would there be more pedal travel?

Just going on what I've been reading.

same size piston in the master pushes XX amount of fluid. Since the pistons in the 2500 calipers are a good deal bigger, it's going to take more fluid to move them the same distance as the smaller 1500 ones.

In theory, you'll have to use more of the stroke of the master cylinder to stop the same.

But from my understanding the NBS master which is a pretty simple bolt on, increases the MC piston by .2"

 

[TylerZ281500]

negatory ghost rider, your fluid is bled the same caliper has dimensionally the same stroke just a larger bore in the caliper. ive been told that the nbs and 1 ton brakes contradict one another, i have hydroboost and an nbs im waiting to install if i keep ifs, nbs bolts right up, line connectors may have to be changed i cant remember.

moving more fluid doesnt mean more pedal same pedal more fluid for bigger brakes equals same braking distance, hopefully better stopping power.

 

[Sparg93]

So I bought the 2500 calipers since mine needed replacement anyway. Now I'm second guessing myself before I put them on.

I realize there will be slightly more pedal travel, but would later doing the NBS MC swap correct this?

I can't speak to the NBS MC, but I would not put the 2500 calipers on a 1/2t brake system...braking distance will go through the crapper. I did this and you can see by the measured stopping distances it is a bad mod.

If you plan on swapping the MC, Booster (vacuum or hydro), PS pump, etc....swap the whole system vs mix and match and do it at the same time. You never know when you a panic stop will require every bit of stopping distance you can gather.

 

[TylerZ281500]

nothin bads gonna happen with the bigger calipers theres no extra pedal distance its a bigger bore thats about it. if you have to much pedal keep bleeding then cause thats your issue. i went with 1 tons and 6 lug 3/4 ton rotors on me, no more pedal travel than stock that everyones complaingin about and i can lock them up if need be

 

[Nakk]

Just going on what I've been reading.

same size piston in the master pushes XX amount of fluid. Since the pistons in the 2500 calipers are a good deal bigger, it's going to take more fluid to move them the same distance as the smaller 1500 ones.

In theory, you'll have to use more of the stroke of the master cylinder to stop the same.

But from my understanding the NBS master which is a pretty simple bolt on, increases the MC piston by .2"

Absolutely, it's only common sense. Bigger bore equals more fluid capacity equals more pedal travel. The larger bore will also deliver greater brake pressure for the same pressure at the pedal. So, assuming you have enough travel available you end up with greater brake pad pressure. But, is that a good thing? Good brakes is about far more than just "locking them up". Best braking is acheived with around 10% wheel skid. In other words, you're doing 50 mph and the wheels are rotating at 45 mph. That's what ABS is trying to acheive in a perfect world. Your front brakes should skid just prior to the rears. That keeps you stable and achieves best possible braking. Improve the fronts too much and they'll skid too long before the rears. As Sparg93 points out, that will increase your braking distance.

Putting in an NBS master will make things even worse. The NBS master is designed for four wheel disc. Using it with disc/drum setups may improve feel, but at the cost of increased braking distance.

Brakes act as a system. Improving one part of the system without understanding what you are doing will only decrease performance. I'm not saying brakes can't be improved; they can. But you have to change the whole system. The easiest way to do this is to match all brake components to a factory system. The ABS, master cylinder, combination valve, boost, front and rear brake components all have to match. Upgrading to JB6 brakes if you have JB5 brakes is pretty easy. Just the rear brakes and combination valve need to be changed. If that isn't enough, adding hydroboost to JB6 brakes should be more than enough for any half ton out there.

Whatever you do, either match a factory brake system completely or leave it stock. Unless you have the expertise to design and balance a custom brake system.

 

[TylerZ281500]

if you say so

 

[scoob8000]

Well got it all buttoned up last night. Going to the 3/4 ton calipers was a major mistake.

Soon as we started bleeding it I realized this. The master is just too small to move the volume needed for the bigger pistons.

With everything bled down and firm as I could get it, the pedal goes to the floor with ease. The truck stops okay, but there is zero fluid reserve for emergency stops.

Weather permitting this weekend, I'm going to see what I can do at the parts store to get the right calipers. At this point I'm thinking anything short of that or swapping master and booster is the only option.

Sparg93/Nakk,

I'm as sceptical with the NBS master cylinder. Wouldn't the porportiong valve/combi valve handle the residual pressure to the rears? Or do our trucks not have an external one, I don't have the truck with me and don't recall seeing it.

 

[ccreddell]

Id just put the 3/4T M/C on it.