Particles in the brake fluid

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Boots97

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I can agree with the others, the NBS master isn’t the best idea if it’s the 1.34” bore. That’s the one I’m currently running and the pedal travel is amazing but the panic stops can be scary. I’m about to swap to the smaller 1.25” bore that some NBS trucks used which should help. I’m not using quick take up calipers so I can’t speak on how that will work. I have also tested braided lines vs stock and it’s not a massive change but there is some improvement under heavy braking, the pedal just has a bit less give to it. Could have also been from brakes being properly bled after the swap as well.
I understand. I didn't know how much bore size mattered until I got onto this forum. I'll check my bore size later. There's another guy on this thread who has an NBS Master Cylinder, 2500/3500 Wheel Cylinders, and 2500/3500 Calipers with 1500 pads. I'd like to do that mod someday but I want to hold out and wait till my pads and rotors are shot. I wanted to mention that to @Caman96 but forgot to type that out in my reply.
 

Boots97

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@Caman96 @Alteca Here's the link to the thread I found a while back.


@boy&hisdogs and @1998_K1500_Sub did the NBS Master Cylinder, Stainless brake lines, 2500/3500 Wheel Cylinders and 2500/3500 Calipers. This is what I want to do sometime in the future. Right now I'll try the NBS MC and see how it goes. At best, it improves braking, and at worst, I just wasted a few hours messing with parts that weren't originally meant for this truck.
 

Caman96

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@Boots97 the only thing I would say is replace all your parts with spec’d parts, maybe SS hoses and do an ABS bleed. If I wanted to improve on that, consider a 14b 9.5 rear end with 11” duo serv JB6 brakes.
 

Schurkey

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Are all 11" brakes duo servo?
Slightly bigger than 11 1/8.

Should be Duo-Servo.

I know that I have a 10 bolt rear end rn and I have 11" brakes.
Not impossible, but unusual for a 1500 pickup.

The Duo-Servo brakes have the adjuster at the bottom, directly between the shoes. The crappy 254mm (10") leading-trailing drums have the adjuster just under the wheel cylinder, near the top.
 

Caman96

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Slightly bigger than 11 1/8.

Should be Duo-Servo.


Not impossible, but unusual for a 1500 pickup.

The Duo-Servo brakes have the adjuster at the bottom, directly between the shoes. The crappy 254mm (10") leading-trailing drums have the adjuster just under the wheel cylinder, near the top.
If he has 11 5/32 drums, then I don’t understand why not a repaired JB6 system isn’t adequate?
 

Schurkey

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If he has 11 5/32 drums, then I don’t understand why not a repaired JB6 system isn’t adequate?
ABSOLUTELY.

That's what my '88 K1500 has now. Stops great, good pedal travel, appropriate vacuum assist.

There is NO need for magic master cylinders kludging up the works. Properly bleeding the ABS can do wonders.
 

Erik the Awful

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This would be a great time to upgrade to braided stainless brake lines instead of the factory rubber lines. It'll eliminate some slop from your brake pedal feel.
Meh. Properly bleeding your brakes will do more for pedal feel than stainless braided lines. I run rubber hoses on my street cars and save the braided stuff for actual race cars. If you do go with braided lines, you absolutely have to secure the brake lines so they can't possibly rub on your tires.

Because I have a GMT800 MC sitting in my garage, I'll swap it out sometime in the near future and test it out for myself. Once again, I completely understand where you and @Schurkey are coming from and I only have myself to blame if it doesn't end well. If the swap fails, I'll just buy a new GMT400 MC.
The problem is that the GMT800 master cylinder feels great right up until you have to make an emergency stop, and can't.

Skip to 5:30 to understand a little more of what you'd be facing trying to use the wrong master cylinder.

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Caman96

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I run rubber hoses on my street cars and save the braided stuff for actual race cars. If you do go with braided lines, you absolutely have to secure the brake lines so they can't possibly rub on your tires.
The ones @df2x4 posted are fixed exactly same as OEM.
 

Pinger

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Meh. Properly bleeding your brakes will do more for pedal feel than stainless braided lines. I run rubber hoses on my street cars and save the braided stuff for actual race cars. If you do go with braided lines, you absolutely have to secure the brake lines so they can't possibly rub on your tires.


The problem is that the GMT800 master cylinder feels great right up until you have to make an emergency stop, and can't.

Skip to 5:30 to understand a little more of what you'd be facing trying to use the wrong master cylinder.

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Fantastic insight into just how brutal a F1 car is. Buried his head in his knees at 40% of braking!

OP: I've been where you are. Replaced the MC and not one bit better. Your MC might be goosed - which is why I've shied from saying no need to replace - but a new MC didn't improve mine. Bleeding is what made the difference.
We've been conditioned to believe a 'solid' brake pedal is essential. My view has changed. It doesn't bother me in an automatic if the pedal is a touch soft. Being able to stop is what matters. On a manual trans car, braking with the right foot and heel/toeing on downshifts, then a solid pedal has worth but that isn't our trucks. I'm with the guys advising that you don't lose your hydraulic advantage for the notion of a firmer pedal. If you're going to replace the MC replace it with what was first fitted and devote your energies to proper and thorough bleeding is my advice.
 
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