The 54 mm dia piston on the Escort caliper is exactly the same as the Sierra/Ka/Puma caliper used by me and many others on the "normal" TJ conversion. My Sprint also uses 254mm Passat discs with it's Puma 54mm calipers and coupled with a dual circuit standard master cylinder, stock Sprint servo, all braided S/S hoses and 5/8" bore rear wheel cylinders, all is well. There is a little more pedal travel than I expect from a well set up standard Sprint, but it's not "excessive" in any way, my MOT tester has never even mentioned it, not even in passing.
My assumption here is that the basic setup you have contrived is fine, conforms to the normal "Trackerjack" pattern and should work as advertised.
The travel issue IS real, one that has bothered some people and not others! From the dozen or more TJ conversions i've done so far, a tandem master cylinder gives a lower pedal than a single circuit one, but in neither case has it ever been, IMO, cause for concern (and i'm fanatical about brakes)
How much travel is TOO much? It's a bit hard to quantify, But I have 3 TJ converted cars on the premises here, a more or less standard tandem circuit Sprint, my own Vauxhall converted Sprint auto (spec as above, it also has PDWA delete, LSV delete and my equal length rear axle pipe conversion) and the ex FWD car which has a similar setup to my Sprint but has 239mm discs, Sierra 54mm calipers and the 1500FWD servo. If it's not pouring with rain tomorrow, i'll do some measurements, running and stationary and get back to you.
But my provisional conclusion is that if you HAVE got too much travel, something else is responsible, not the design. One thing I have noticed over the years is that the TJ system is more critical of poor rear shoe (self
![Laughing :lol:](./images/smilies/icon_lol.gif)
) adjustment, so that's worth checking.
On bigger master cylinders, I gather there is a 22mm bore Jag master available, also one from a Saab (don't know which model) and possible a Volvo one too (340/360?) But, as far as I'm concerned, you're on your own with these, I've never NEEDED to find out!
Steve