OBS to NBS Master Cylinder Upgrade REPORT

[Tony Biddle]

Yeah you cannot install any NBS master cylinder with an OBS hydro boost. If you are having trouble with a hydroboost setup I would look at other solutions. Generally speaking properly functioning OBS hydroboost setups are more than fine. Have you tried maintenance items already?

Yes I replaced the pump to boost line, and got all air out of the system. I’ll probably just replace the master cylinder with oem

 

[Supercharged111]

Yeah you cannot install any NBS master cylinder with an OBS hydro boost. If you are having trouble with a hydroboost setup I would look at other solutions. Generally speaking properly functioning OBS hydroboost setups are more than fine. Have you tried maintenance items already?

Sure you can. Folks on here have, they just end up hogging out the HB so the MC fits. I'm under the impression that the 800 mc is a 38mm bore and 400 HB mc is 39mm bore, so not sure how this is an upgrade for an HB truck. My 1500 pedal seems much improved after swapping from 800 mc and vacuum to 400 mc and hb. That and it'll put you through the windshield now.

 

[dfarr67]

Hydroboost does come in a few different sizes- look up the same year hydro for the master- I just went through this but had a spare on hand that did fit.

 

[TheAutumnWind]

Sure you can. Folks on here have, they just end up hogging out the HB so the MC fits. I'm under the impression that the 800 mc is a 38mm bore and 400 HB mc is 39mm bore, so not sure how this is an upgrade for an HB truck. My 1500 pedal seems much improved after swapping from 800 mc and vacuum to 400 mc and hb. That and it'll put you through the windshield now.

I should clarify...it wont just bolt on. Of course you can put anything on anything with a cnc machine, a welder, a grinder, and enough gumption.

Interesting that you went from gmt800 to gmt400 HB and MC. I have HB on my gmt800 escalade and it works great, especially with gmt900+ calipers and rotors now.

 

[Supercharged111]

800 HB and MC probably would be great, the 400 vacuum is what sucked so hard. 800 MC was better than the 400 stepped bore MC. 400 HD isn't stepped from what I understand.