3 replies to this topic

[driftz]

Upgraded my drums to Fiesta disks. and currently have a new .70 bore single line master. The system is well bleed but the pedal travel is still more than I would like.

 

I am looking at using a Tilton 74 series master cylinder, as they are cheaper and come in a wider array of sizes than stock. For those running larger sized calipers, what size would you recommend. The potential sizes are 7/8, 7/10, 5/8, 3/4, 13/16, 1", 1 1/8.

[Leonrjohnson]

The bigger the master cylinder diameter, the less pounds per square inch line pressure is achieved, but more fluid displaced per linear movement. So if you increase the bore to say 7/8, you may need to fit a booster, otherwise you may find yourself pulling the steering column out trying to stop. In other words, the bigger the master cylinder bore, the less the pedal will need to travel, but the  force on the pedal will increase in order to stop.

[Spider]

Upgraded my drums to Fiesta disks. and currently have a new .70 bore single line master.

 

Why not try a stock 0.75" Cylinder? I don't think you'd need more than that and if you did, as Leon has suggested, you'd be looking for a booster too

 

Or wrapping the steering wheel around your ears trying to get enough pressure in to the pedal

[driftz]

Yes I understand how the mechanical advantage is changed by increasing the bore. I have played with brakes quite a bit in the past. I'm more so looking for experience from people with similar sized brakes as to the optimum size for the master. I'm leaning towords the .75" bore but since there is also a slightly larger size available I wonder if that would be better for the larger than stock calipers size. I'm looking for quite a firm pedal, (my old rx3 race car had such a setup and I enjoyed the feel/extra effort compromise) but obviously I don't want to be standing on it to make it work.