How to: NBS master cylinder swap for firm brake pedal

[Knuckle Dragger]

I'm not running a 'residual valve' on my swap. If you are sucking air through your wheel cylinders it means they are compromised and need to be replaced. No residual valve needed and my brakes are working fine. I am using the MC off an 03 Silverado.

Really, why do they run them from the factory on drum brakes then?

 

[dave_erald]

Residual pressure valves are used on drum brake only lines to help keep fluid in the wheel cylinder, the factory springs and designs on most setups will pull the pads back far enough away from the drum that you need to refill the wheel cylinder on the next reapply of the brakes (refill so to speak). Basically there to keep the brake shoes close to the brake drums.

Again depending on the design, age and recent service of the brakes, and how tight you adjust them (and if the automatic adjuster is working at all) some people need a residual valve, some dont

 

[Dylan1991_1500]

I don't have one from the factory. I have the OEM prop valve which I kept when I ditched the rear ABS but that is it. The star wheel adjuster should be what sets the distance of the shoes from the drums, not the wheel cylinders. Once the wheel cylinders are bled there really should be no chance for air to enter the system unless there is a leak.

 

[dave_erald]

Dylan is right, though I wasn't meaning air getting in, what i was getting at is the star wheel keeps the bottom of the shoes adjusted, but the return springs on the top can pull the shoes together strong enough in some cases to collapse the cylinder and push fluid back up the line.

You could be right though about our trucks not having external ones, but i was sure they were built into the factory master cylinder design. Somebody should find a blown up schematic

 

[Knuckle Dragger]

Now I remember why I don't post, dumb ***** with no formal training trying to show everyone how smart they are on the internet.

 

[Jrgunn5150]

Now I remember why I don't post, dumb ***** with no formal training trying to show everyone how smart they are on the internet.

I fail to see exactly what you've contributed here? Other than to ask a spiteful, baiting question, and then hurl an insult.

 

[dave_erald]

???

Uh... licensed 310s Automotive Service Technician for the better part of ten years, and would you like a textbook explanation of the purpose for a residual valve then?

Sorry if I misplaced that valve...**** I know I had it here somewhere ...walked away again

 

[dave_erald]

Sorry, getting off topic there.

NBS master cylinder. Good

 

[Stepside_fever95]

I had an issue with the adapter when I tried to swap in a nbs master. The line didn't seem to seat properly and the thread bottomed out before it was even close to being tight on the adapter. I just ended up replacing it with another obs master instead.

Sent from my SM-S920L using Tapatalk

 

[TopdaT]

Knuckle,

I was wondering about this, too. Did any of the 99-06 come with disc/drum setup? I vaguely remember that they went back to rear drums in the later year models.

Did you end up having to bleed the ABS unit?

EDIT: Looks like they went back to drums on the 2005 1/2-ton pickups with the lower GVWR. AC Delco and rockauto show two designs for the vacuum booster disc/drum on the 2005 Silverado 1500, the difference being in how the reservoir attaches (which I don't think would matter to us) and the connection point at the booster--which would matter, the first design extends further into the booster than the second design. First design part is Delco #174-1011 the second is Delco #174-1169. I think the second looks like the GMT400.

I did the NBS master swap on my truck with a 2003... After reading this I'm thinking of swapping it out for a 05 like the one talked about here.. Has anyone tried one yet?