1/2 ton truck master

BlackBetty

Well-known member
Joined
Dec 28, 2008
Messages
91
Location
Alabama
Im currently running a 3/4 bore Wilwood clutch master cylinder. I was using it in conjunction with my Ram hydraulic throwout bearing on my T5 trans setup. Im switching to a t56 trans setup. Not really crazy at how the wilwood mounted. Is the truck master a large enough bore to power the T56 hydraulic throwout bearing? Anyone know the bore size?
 
I was just gonna go to advance auto parts or somewhere and get a new one. Do you know what year and make your master is from?
 
The master I have is Wagner PN CM110273

Chev Blazer 1994-1991
Chev C10, C20, C30 Pickup and Suburban 1985-86
Chev K10, K20, K30 Pickup and Suburban 1984-86
Chev R10, R20, R30 Pickup and Suburban 1987-88
Chev R1500, R2500, R3500 Pickup and Suburban 1989-91
 
Got that one here in a hydraulic throwout bearing setup, works fine
 
How did you find out it was 3/4 bore? I looked everywhere when I did my T5 swap and ended up buying a wilwood.
 
How did you find out it was 3/4 bore? I looked everywhere when I did my T5 swap and ended up buying a wilwood.

Hope I caught you before you bought one. I always thought they were 3/4 inch but your question made me check. It's actually 11/16 bore, doh!
 
I remember 11/16 now. Ha. I wonder if it would still work. Im running a 3AN line with the wilwood and would run that same line with the truck master. the -3AN line is much bigger than the stock ls1 setup anyway. Twin T says hes running one himself. Anyone know what size bore the stock clutch master on an fbody is?
 
I think Im going to stick with my wilwood. Its 3/4 and has 1" 3/32 stroke. The stock ls setup is 3/4 and 1" stroke. Im running a bigger line which normally solves any hydraulic issues with these. I want to remount my wilwood though. It has a flat mounting surface and I basically just have it shimmed out. I would like to make the correct angled spacer, so it mounts flush. If the truck master would have been 3/4 I would just use it since it mounts perfect.
 
I just looked at Rock Auto (they list the bore sizes for most). It looks like the Camaro 82-up is 3/4 bore but the mounting flange might make it a bitch to mount. The C5 master is 3/4 with a rear mounting flange, it might work.

I would really like to use a hydraulic throwout bearing. Does the Ram bearing you are using have specs for required master cylinder bore x travel?

.
 
The T5 hydraulic throwout bearing from RAM required a 3/4. Im pretty sure most of the HTBearings ive looked at require that size. I just read in a post on ls1tech in the conversions forum where a guy was trying to use a 5/8 bore and it wasnt working with his t56. The 11/16 may work depending on the stroke and what size line you run to the HTbearing.
 
For whatever reason it makes a huge difference on ls1 applications. They call it the drill mod. I did it myself on my 98 TA. Take the stock hydraulic hose and drill out to a larger size, but the stock master is 3/4, so I guess it just optimizes the system.
 
What size is the LS1 stock line, and exactly what does the mod improve? Not familiar with the mod, or the reason to do it. How do you drill out the hose? Do you mean the hose end? Is the hose end by any chance smaller ID than the hose itself? It would make no sense if not, simple bottleneck principle.
 
Its been years since I researched the drill mod. Now I remember it just being a type of restrictor and the end of the hose on the master cylinder end. Thanks for that article!
 
Just as I thought some kind of restriction...why that would be a good idea...dunno. GM sometimes amazes me with the things they do.....
 
Just as I thought some kind of restriction...why that would be a good idea...dunno. GM sometimes amazes me with the things they do.....

That is the one thing that is fascinating about working on shit, don't matter who made it, just taking stuff apart and staring in open eyed wonder at how in Christ's name they ever let it out the plant, let alone off the drawing table that a way....:banghead::banghead::rofl:
 
Hey guys, in reference to this master cylinder; does it come with a reservoir or are you doing a remote reservoir? Where can one find a remote if that is the case?

I wound up with blackbetty's tranny going into my '82. Parts gathering mission today.


thanks
tt


The master I have is Wagner PN CM110273

Chev Blazer 1994-1991
Chev C10, C20, C30 Pickup and Suburban 1985-86
Chev K10, K20, K30 Pickup and Suburban 1984-86
Chev R10, R20, R30 Pickup and Suburban 1987-88
Chev R1500, R2500, R3500 Pickup and Suburban 1989-91
 
The Chev truck master needs a remote reservoir. You can use the reservoir off on just about any car.

You will probably have a problem with the truck master because it is 11/16 bore with about 1 1/8 inch travel. The Wilwood is 3/4 bore with 1 1/2 inch travel and is about the same cost as the Chevy truck master (~$50).

Looks like BlackBetty said you will need the 3/4 bore with the RAM throwout.
 
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