Master cylinder no work, no more

I need to rebuild the master cylinder on the "L-185" The cylinder looks ok but needs new seals. there isn't a rebuild kit avalable. The truck shop in town says " I can order seals for the size of the bore. Then just put it back together and there you go".
Is it that eazy or is there more to it than that?

I don't know where you get your info but...

The MC goes by Chassis number but since there's only two it can be I'll post both. Easy to tell one from the other by the casting number.

Master cyl. 1-1/2" bore
56509R91 IHC <FE-2652> (<casting #)
11120 Bendix
MC2657 Raybestos
MC2652 Wagner
M2657 Dorman

Kit
64837R91 IH <FC8448>
MK135 Raybestos
MK8448 Wagner
UP135 United/Napa

48175H IH (w/o RCV) <FE 661> (<casting #)
MC661 Raybestos
MC661 Wagner
Kit
121401HB IH <FC3622>
MK39 Raybestos
MK3622 Wagner
UP39 United/Napa

The truck has a aftermarket air-over-hydraulic. Brake system by Wagner. Surprisingly the air system still works.
I finally got the master cylinder of the truck. I had to cut the bolts. All good now.
Anyway the master cylinder says "Wagner Lockheed 777''. The pamphlet I bout that explains everything, says that it is a 1 3/4" bore dia.

IH used that MC also,very common on Loadstars which used the "661" too.

55070R91 IHC
11122 Bendix
MC2842 Raybestos or Wagner
M2842 Napa

Kit
64838R91 IHC
MK175 Raybestos
MK8449 Wagner
UP175 United

Here's a link with pic & specs.
http://www.raybestosbrakes.com/magnolia ... ber=MC2842

On a standard system on a 2 1/2 ton truck.Would you have a master cylinder and then a hydro boost or a hydro boost then a master cylinder? Or just a master cylinder?

First of all there is a difference between a "Hydro-Boost" and a "Hydro-vac",the former is a MC & vacuum chamber in combination and are mounted on the firewall in most cases while the later is a separate unit usually mounted on the frame.

With a Hydro-vac system the MC is alway's before the HV and "feeds" the slave cylinder of the HV, which in turn accuates the the vacuum assist curcuit.
If you watched the YouTube video I posted in the other thread you started it plainly demonstrates how it all works.

I believe, that Hydro-boost refers to a hydraulic (power steering fed) type brake booster. At least, that's what I've seen in my time as a mechanic. Hydrovac, refers to a frame mounted vacuum booster, and a firewall mounted vacuum booster is just called a vacuum brake booster, or power brake booster.
https://www.google.com/search?q=hydro-b ... kgodE2UMPQ

IH called the FW mounted vacuum units a "Master-Vac",just to show they are called many things. I have also seen many times the hydraulic type that use a PS pump called "Hydra-Boost",which makes sense as it uses the 1st 5 letters of hydraulic. Hydro has never made sense to me because it's usually associated with water power.

The difference between hydra and hydro may be a due to one or the other being copywrited name. The same system comes up in a google search under either name.

This has been so much fun!!!
Amazon has the master cylinder all ready to go for less than $100.