GMT 400 Hydroboost swap

[Jesse_Wenting]

I decided today that I'm switching my 97 obs to hydroboost. I just started LS swapping it. Lq9, big cam, gen 4 rod, holley intake, Terminator Xmax with a built 4l80. Currently painting the firewall on my OBS as I didn't do this originally. I still have my 06 denali that was my donor. Im pulling the hydroboost off of it. I've removed the vacuum booster and pedal from the OBS. But, my pedal off the denali has all sorts of plugs and cables. What will I do with all those, specifically that cylinder with cable coming out of it? I can take pictures if needed.

The only wires going to the brake pedal on my truck (and every other 400 I've ever seen) are for the brake light switch

 

[Jesse_Wenting]

Wanted to check in a few weeks post conversion; something I noticed when I start my engine is the brake pedal doesn't sink a bit and return as pressure is built at the PS pump. Also while my brakes do work, when I apply the pedal it sinks an inch or 2 with no resistance, then becomes very stiff as the brakes begin to apply. Also the distance the brake pedal travels between the beginning of brake application to full lockup is only maybe 2 inches which feels way too "on/off" to me. Hoping someone can explain if this is all normal, as admittedly this is the first time I've ever experienced a hydraulic brake booster so it's all new to me still

 

[Supercharged111]

Sounds like the booster may be on its way out. I've driven trucks that did that before. Does it get better when the truck warms up?

 

[Jesse_Wenting]

Sounds like the booster may be on its way out. I've driven trucks that did that before. Does it get better when the truck warms up?

not really. I was wondering if it was the nitrogen cylinder was the culprit. I opened up and cleaned the booster prior to installing, and I did my conversion just before having an inspection where the mechanic said the brakes felt good My PS pump does sound like it's on its way out but I'll be replacing it soon since it's now a part of my brake system.

Just to be clear, what are the implications of a failed nitrogen cylinder? How difficult will braking be?

 

[Supercharged111]

I'm lost on the nitrogen bit?

 

[Jesse_Wenting]

I'm lost on the nitrogen bit?

The gold and blue cylinders on the hydroboost are nitrogen charged lol

 

[Supercharged111]

The gold and blue cylinders on the hydroboost are nitrogen charged lol

I thought they were accumulators

 

[Jesse_Wenting]

I thought they were accumulators

They're nitrogen charged accumulators lol. The Gold one is for disc/drum and supposedly has 350lbs of Nitrogen gas charge. Blue is for disc/disc and supposedly has 450lbs of Nitrogen gas charge

 

[99k3500]

I have a 99 k3500 454 with hydro boost already, is there just a simple master cylinder swap I can do to get better brakes or should I swap out for the nbs hydro boost

 

[Jesse_Wenting]

I have a 99 k3500 454 with hydro boost already, is there just a simple master cylinder swap I can do to get better brakes or should I swap out for the nbs hydro boost

Describe the feeling you get when braking. Is it spongy?