What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Does a newer MC fit under our hoods?

nutt7

nutt7

1/2 ton status
 Premium
Joined
Dec 30, 2010
Posts
839
Reaction score
471
Location
Ahwatukee, AZ -> JBLM, WA
I going to do a hydroboost swap and I want the MC that matches my needs. The one that I want has a tall reservoir and I'm worried it may not clear the hood. This unit fits express vans 2003-2007 or so and various and one tons from 2001+ or so. Very similar ones are also on the 2500s and suburbans of similar years. It looks like this:



Also, does it have a divider inside the reservoir or is it one huge chamber?
 
Make sure to check if the pilot fits into your hydro boost. I tried doing a similar MC and it matched the mounting for the studs but the pilot at the rear of the new MC was too big. I ended up using an MC for a 1983 Chevy P30 box van with a 6.2L diesel and hydroboost and rear disc brakes. It had the correct port fittings and bolted up to my hydro boost just fine but it is set up for rear discs and also has a larger piston size than my factory one and it has a larger aluminum res on it. I should have pics and better info in my build thread.
 
Truckman4life said:
Make sure to check if the pilot fits into your hydro boost. I tried doing a similar MC and it matched the mounting for the studs but the pilot at the rear of the new MC was too big. I ended up using an MC for a 1983 Chevy P30 box van with a 6.2L diesel and hydroboost and rear disc brakes. It had the correct port fittings and bolted up to my hydro boost just fine but it is set up for rear discs and also has a larger piston size than my factory one and it has a larger aluminum res on it. I should have pics and better info in my build thread.
Click to expand...

Well, the master is designed for hydroboost, but maybe I can go to a parts store and check.
 
nutt7 said:
Well, the master is designed for hydroboost, but maybe I can go to a parts store and check.
Click to expand...
Yeah I was going to upgrade to an MC from something like a 2004 2wd 3/4 ton with hydro boost at first. It had the correct port sizes and a larger piston but when I got it and tried to test fit the pilot that fits into the booster was too large. I did some research and came up with the P30 one since my blazer is already a 6.2L diesel with hydro boost. I just wanted to change to a larger piston and also get the proper one to match my rear disc conversion. Napa and rock auto have some decent specs online but it helps to have really knowledgeable parts guys at my local Napa.
 
Yeah maybe you can run a newer style hydro boost booster and then the new style MC but that might just open up a whole new can of worms.
 
Truckman4life said:
Make sure to check if the pilot fits into your hydro boost. I tried doing a similar MC and it matched the mounting for the studs but the pilot at the rear of the new MC was too big. I ended up using an MC for a 1983 Chevy P30 box van with a 6.2L diesel and hydroboost and rear disc brakes. It had the correct port fittings and bolted up to my hydro boost just fine but it is set up for rear discs and also has a larger piston size than my factory one and it has a larger aluminum res on it. I should have pics and better info in my build thread.
Click to expand...

Subscribed for later use. Thanks
 
After more research, it appears my hydroboost won't fit a newer MC anyway. It's mc "accepting hole" measures about 41mm or 1.61". Too small. I also prefer not to shim down the booster. I think the hydroboost also sticks out further (I may be wrong) than the vac booster, which would make clearance more of an issue. It seems the one @Truckman4life recommended will be the best and easiest solution.
 
i used a master from a 93-94 ish c1500 with 6.5 turbo diesel on my 2wd buildup . got me the aluminum body / plastic resivor. my hood shuts no problem .

I used this one for slight bigger piston bore size and I was still doing disk/drum . and I hate cast iron masters . most of them I have ever had wont seal worth a crap and leak .
 
JoshHefnerX said:
Is there a reason you're doing hydroboost rather than just vacuum?
Click to expand...

Found a good price on a hydroboost and eventually I plan to go diesel...

sweetk30 said:
i used a master from a 93-94 ish c1500 with 6.5 turbo diesel on my 2wd buildup . got me the aluminum body / plastic resivor. my hood shuts no problem .

I used this one for slight bigger piston bore size and I was still doing disk/drum . and I hate cast iron masters . most of them I have ever had wont seal worth a crap and leak .
Click to expand...

It seems strange that some fit and some don't in the same body style.
 
I believe the mastercyl I used was from a diesel truck. And I believe all of the MC snouts from 81 and later are all the same size if that helps at all.
 
Yeah not sure why they are different. I have the pump, steering gear, master cylinder, and hydroboost off my old 1977 chevy 1 ton camper special 2wd 454 that I cut up sitting around still. Not sure why but that truck had the best steering ever. You could spin the wheel sitting still on dry pavement with your pinky and it was like there was nothing attached to the steering column. It pretty much had zero resistance. My buddy I used to hang out with said he had a 4x4 that was that same way once upon a time too. I'm saving it for a crossover conversion someday on something.
 
JoshHefnerX said:
I believe the mastercyl I used was from a diesel truck. And I believe all of the MC snouts from 81 and later are all the same size if that helps at all.
Click to expand...

I don't think they are. I *think* (aka, someone on the net said) gm uses a 37.5mm and a 45mm nub or register or whatever it's called depending on the bore of the mc
 
I swapped my vacuum booster from an 80 to 81 and that size was large enough to work on my 04 hydroboost mc. That's why I was thinking they were all similar or at least compatible.
 
I bolted a 1974 GMC vacuum boosted master cylinder onto my '82 K2500 diesel with no issues,used it for a few years till it leaked out the rear of it,then got the "correct" one listed for it...which looked the same to me..:dunno:

My truck seems to steer easier too,I think the power steering pumps for hydroboost are higher output & pressure than the gas jobs with vacuum assist..
 
You must log in or register to reply here.

Latest Posts

Top Bottom