What Master Cylinder?

[ehjorten]

Okay...so my '91 Crew has a little bit of a drooling problem with the master cylinder.  I'm going to replace it with a stock 1-5/16 ACDelco Master for my hydro-boost system, but...I really like the more modern M/Cs that are an aluminum body with a plastic reservoir.  Does anyone know of a M/C that will fill this bill?  What model and year?

Reasons why I like them better: 1) lighter weight, 2) won't rust from brake fluid dribbling down the side everytime you take the cover off to inspect or top-off the level, 3) you can see the level without taking off the cap.

Seems this one could be a pretty easy swap like from a few years newer chevy truck or something.

[ehjorten]

Looking at RockAuto.com it seems that a 1999 K3500 M/C might work.  It is a 1-1/4" bore vs. the stock 1-5/16 bore, so that means a little more pedal travel and slightly stiffer pedal, but it has the same size front and rear ports.  Only thing I don't know about is the push-rod cup design.  Gonna go to Olympic Brake to day and compare them side by side.

[Captkaos]

you should be able to modify the travel based on the location if it isn't something seriously different.
MP Brakes should be able to give you the info on what would work with your existing setup.

[ehjorten]

Little snafu at the brake store...they didn't get the correct one transferred to the store I was going to on Friday.  Went there today and the one they transferred they said is the correct one, but it clearly isn't.  Guy tried to argue with me and tell me a '91 V3500 is a suburban and that they didn't make a truck like that in '91.  Never been too that perticular location before.  The one close to work is much better.  Took some measurements of the '99 master that I want to use.

[ehjorten]

Went to NAPA tonight and measured a stock replacement to compare to the measurements that I made from the '99 K3500 one.  The dimensions are identical and the pushrod hole measures very near identical to the stock one.  Gonna go pick-up the '99 K3500 one w/Hydroboost, bench bleed it, put it on the truck, and see what happens!  I'll let you know!  Probably not going to get it on until after the weekend.  Gotta take the whole family up in the snow for my son's 6th birthday this weekend and the last thing I want is to run into some problem and not have the truck back together by then.

[Captkaos]

Post back what you find.