Looking for largest bore rear wheel cylinders for my truck!

[gregamorton]

Guys my drivers side rear wheel cylinder was leaking this morning and need to fix. Im wondering what the largest bore I can get and what there off of that will fit my 1979 f350 frame. Dana 60s in front and back. This is my 71 bodied dually.

[tnlprt]

I do not know which ones you need

But increasing the bore size will require more pedal effort to apply the brakes as you have to supply more fluid to do the same work

[gregamorton]

I bought the one at ABC that called for it. It was a 1" bore. The one I took off was only working on one end and that was the one leaking. My shoes on that corner look at least 1/2 wore down so I ordered new shows for both sides on rear. I also had a broke spring on that corner too so I ordered a hardware kit to replace all parts. After I get the rear rebuilt on both sides and bled if I am not happy I will check into the master cylinder. There are different bore sizes on those and I know a bigger bore will make it stop more.

[tnlprt]

A larger master cylinder bore requires more pedal effort to do the same thing


http://www.markwilliams.com/braketech.aspx

[gregamorton]

So why would some trucks have larger bores if it does not create more force to the brake drums? Sometimes technical jargon just goes over my head!

[tnlprt]

They probably have a different pedal pivot point which will increase or decrease the amount of effort to stop the vehicle

[ultraranger]

So why would some trucks have larger bores if it does not create more force to the brake drums? Sometimes technical jargon just goes over my head!

While pressure and volume are related, they are also independent of each other.

A small bore MC will put out more pressure, for the same amount of leg force put on it, as a larger bore MC.

A small bore MC will have more pedal travel and the pedal won't feel as firm.

A large bore MC will move more volume of fluid but, at a lower output pressure. Pedal travel will be less and give a firmer feeling pedal.

A MC bore that's too small will make the brakes overly sensitive. A bore that's too large will make it difficult to get the vehicle to come to a stop.

Small MC bores generally aren't good with brake boosters and large bore MCs generally aren't good if used without a brake booster.

MC bore size is a compromise between output pressure, comfort to the driver being able to apply the brakes and sized to quickly bring a vehicle down from speed in the shortest distance, in the least amount of time, without locking up the wheels.

[1 Crummyshooter]

Somewhere the thread changed from "Wheel Cylinders" to "Master Cylinders".

Increasing the bore size of the wheel cylinder WILL increase the pressure on the shoes. It will also require more pedal travel.