The parking brake is essential but mine did not work even when new. I figured it was due to a factory problem and began a series of adjustments that never lasted more than 5000 miles (van has 340,000 miles on the odometer) and even then I don't trust the parking brake to hold the van. I had the same problem finding a cable when I installed a full floater. I was lucky in that I found a small wrecking yard that had several Econoline vans in the back. The other problem is the clearance between the "hat" and shoes has to be adjusted to less than 1mm without a feeler gauge. Even when adjusted correctly, mine quit grabbing iron after about 5000 miles. Remembering to release the parking brake is another matter. Unless you are lucky enough to locate the cable online best bet is to pick through a junk yard. Ford built millions of these rigs so there has to be one you can cannibalize somewhere in the sagebrush east of LA. The ends are unique to Ford so improvising is a bit more difficult. The cables have little to no stretch in them, so it is preferable to use OME if you can. Ultimately, the real problem shows its ugly head is when parking on a hill. If someone, a kid or a dog pops the transfer case lever out of gear, you got a whole lot of other problems to deal with. The only solution I've given any thought to is installing a wraparound "shoe and caster wheel brake" and lever onto the rear driveline. It will take a drive line shop to weld everything in place and rebalance the driveline. It is an old school solution but the kits are still available.