The Stovebolt Site Forums The Parking Lot Tons 'o Fun Master cylinder/booster upgrade?

Will one of the master cylinder/booster bolt in upgrade kits for a 1/2 ton fit in a 1 ton? Are the pedals and linkage rods the same between a 1/2 ton and 1 ton? Are those kits generally a pretty simple installation without much modification?

I'm getting ready to put the 14 bolt rear under the truck and figured I might as well go ahead and upgrade to the dual master cylinder with booster, and plumb new lines to the back. Anything bad about using DOT 5? It's supposed to not absorb water like DOT 3 does.
Thanks.

I guess it depends on what you mean by 'fit'?

The frame and brackets, pedals and mechanism are all very similar so a properly designed 1/2-ton kit should bolt into a 3/4- or 1-ton just time. Depending on the other modifications you might be making sometimes the 1/2-ton kits won't fit right in a 1/2-ton.

I recognize your name but don't remember the details of your truck and project so can't comment on what problems you might need to expect.

The second set of issues is that the 1/2-ton master cylinder is not as large a bore as the 1-ton. You really want to maintain that bore size to get proper braking performance. Since you are changing the brakes on the rear that makes the problem more complicated. You want the right bore size to provide enough fuild displacement to activate the rear brakes, and you want it to happen in sync with the front brakes.

I forget what you are doing on the front.

If you search for DOT 5 you'll find a number of threads debating DOT 3, DOT 4 and DOT 5. Personally I've ended up on the DOT 3/4 end every time I've looked at the issue, but others are convinced DOT 5 is the right answer.

If you keep your system sealed and replace the brake fluid as recommended by the manufacturer I can't imagine DOT 5 having any advantages over DOT 4 in a street vehicle. It does have disadvantages.

Thanks for the response OldSub.
My project is a 54 1-ton dually with dump bed. Currently it has the original single master cylinder. I am wanting to put a dual master in with boost but wasn't sure what to expect. I'm going to have drums all the way around (original front, 14 bolt rear on back) for the time being though. I just thought that a brand new modern dual master with boost would be far better than the antiquated single master. I better do more research in the case you are describing.
Thanks

What size are the wheel cylinders on the 14-bolt compared to those on the Eaton? If they are the same size then a dual master with both sides having the same bore as the original would be the easy answer.

For my '54 1-ton I'm using a 14-bolt in the rear and a C-20 IFS with disks in the front. Essentially my brakes front and rear will match factory configurations available in the mid-70's. My plan is to buy a dual master for a truck that had the same brakes front and rear as what I have.

I'm going to trust that the GM engineers knew what they were doing. While we all know from seeing/reading news of recalls that factory engineers are not infallible, I think we can follow their lead in sizing things like brakes and expect to come very close to the right combination of parts.

The wheel cylinders on my 14 bolt are 1-1/16 inch bore. Not sure what the eaton ones are, as they're still under the truck and in-use.

I bought everything new for the 14 bolt brakes with the exception of the adjuster stop and the emergency brake arm. All of the parts for both sides (shoes, bearings, seals, wheel cylinders, spring kits) only came out to about $160 at O'Reilly's. I was surprised it wasn't more expensive than that. It was strange that a wheel cylinder rebuild kit was $7.00 and a whole new wheel cylinder with internals was only $12.00. So at least now I have a nice solid build on the rear brakes.