Triumph Repair: spit rear brake locks before front, caliper pistons, brake locks

Question
I am done the test on gravel and notice, that on my spit MK2 locks rear wheels before the front wheels locking. I am has changed all pads, all calipers, front brake pipes, master cilynder (single line). Brake pedal is hard. After driving also the rear wheel drums are much more hot when front discs.

Answer
Hi Andres,
The single circuit brake system does not have a proportioning valve so they depend on the size of the caliper pistons verses the size of the rear wheel cylinders to take care of the difference in pressure front to rear. If the front calipers and and pads are new and the disks are smooth then someone may have put the wrong calipers or wrong rear wheel cylinders on that car. With a single circuit master cylinder the exact same pressure is applied to the caliper as the rear wheel cylinders and if the size of both are correct then it should lock the front brakes first as that was the design so as to keep the car straight forward in a panic stop.
However if the rear drums are getting hot just driving you may have the rear brake adjusters set too tight. This may effect it some.
Also do this, jack the rear of the car up and have someone pump up the brake and hold it down hard, then have them slide their foot off of the pedal so you can hear the pedal snap back and you be trying to rotate a rear wheel. There should not be any delay from when you hear the pedal hit the back stop and the rear wheel releases. If there is even the slightest delay you probably have a swelled up flex line and it needs to be replaced and may be the cause of the dragging rear brakes.
Howard