power steering pump whine issues

[kylenautique]

So I did some research, evidently the gmt400 quick take up master cylinder is designed to be used with rear drum and as such incorporates the function of a residual pressure valve into it. Have you considered using a Gmt800 master cylinder (from the rear disc ones, not the later rear drum ones)

THe pedal feel may improve and it may also help your situation. I guess I could see maybe a sticky piston is somehow contributing to your whine but I doubt it. But consider this suggestion as an offshoot of your whine issue and just based on my preliminary searching.

And did you mean single piston rear gmt800 rear calipers, not 400?
I didnt know the escalade or denali got two piston rears. Is this only in the half tons or does it apply to the 3/4 tons?
Cables worked directly with your parking brake pedal and routed nicely? Nice.

Do you by chance have a dial indicator?

I tried the NBS MC swap. It doesn't work with JB6 stock brakes. The pedal almost goes to the floor. With the Hydroboost, I'd have to see if the NBS hydroboost MC works, but honestly, the brake performance has been stellar with the stock hydroboost and master cylinder. I deleted the ABS anyways because the unit failed, so running an adjustable proportioning valve was the simple solution for the rear brakes.

 

[AuroraGirl]

I tried the NBS MC swap. It doesn't work with JB6 stock brakes. The pedal almost goes to the floor. With the Hydroboost, I'd have to see if the NBS hydroboost MC works, but honestly, the brake performance has been stellar with the stock hydroboost and master cylinder. I deleted the ABS anyways because the unit failed, so running an adjustable proportioning valve was the simple solution for the rear brakes

Do you know what pressure is running to the rear? It seems the rear anti lock managed the rear pressure so as not to cross into lockup but allow maximum braking it could handle

 

[Schurkey]

I deleted the ABS anyways because the unit failed, so running an adjustable proportioning valve was the simple solution for the rear brakes.

How 'bout the holdoff valve, and the safety switch?

 

[kylenautique]

Do you know what pressure is running to the rear? It seems the rear anti lock managed the rear pressure so as not to cross into lockup but allow maximum braking it could handle

The valve regulates the pressure to a max of 1200psi, and generally you want around 1000 for disc brakes. Drums around 5-600psi. There are others that allow for a higher pressure than 1200, but that pressure works great. It I really really slam on it at I can lock up the rear brakes. It feels perfectly safe the way its dialed.

 

[kylenautique]

How 'bout the holdoff valve, and the safety switch?

The main proportioning valve on the ABS unit failed. It was kinda scary. Something would get stuck in the valve, leaving me with a firm pedal and hardly any brakes. If I stopped the truck, restarted it, slammed on the brakes a ton, it would eventually start working. And because there are no new replacement parts available, and the ABS bleeding process is impossible without a snap-on scan tool, it made the most sense to remove the unit. I lost all trust in the ABS system. The ABS part of the unit worked, but something failed in the valving part. All the wiring is intact. I took the whole unit out, and removed the fuse. I ran a T connector to the front brakes and integrated an adjustable proportioning valve on the rear. Honestly, the truck stopped better than before. I also grew up driving older trucks without ABS, so it wasn't a big deal. I actually prefer a vehicle without ABS.

How 'bout the holdoff valve, and the safety switch?

 

[kylenautique]

I'm replacing the pump. I can feel in the steering in a parking lot that its lost some power. Trying a Napa brand pump this time.