I currently have a 69 FJ40 with a 76 disk brake front axle and a 76 booster and master cylinder setup. I am looking at putting on rear disk brakes and have been doing some research on if my existing master cylinder will work for this or not. I have come accross an aisin master cylinde sold by JT Outfitters that they claim they put on there conversions. Has anyone tried this product or is it better to stay with the master that I have. Thanks in advance for any input.

The Master Cylinder that you have will work fine with rear discs after you remove the residual valves. Assuming that you are using Mid size GM calipers.

Jeff