It's plausible. Over the years I've heard of some cases where a brake hose collapases internally and causes brakes to remain applied.

If the brake calipers, rotors, hoses etc are original....and considering 9 years of storage which plays hell with hydraulics (and other things as well).... I'd brace myself for a full system overhaul.

Be ready for gas tank rust as well, and replacement of fuel hoses, all new fluids and filters, etc as part of the recommissioning process.

For general buying advice thre's a Buyers Guide at the top of this section....in one of the sticky threads.

Cheers
DD

 

That happened to my xk 150 with the bakes, not a hard fix I don't think you have to drop the rear end to replace, but not sure.

 

There is only a single flexible line on the rear brake line, connecting the pipes on the subframe with the pipe from the master cylinder. Whilst this could be collapsing internally, I suspect a stuck/sticky caliper piston.

I had a Series 3 like yours, (although the six cylinder engine), and had a rear caliper piston seize up and cook the seals. As Doug says, get ready for a lot of work. It would be best to replace all lines with cupronickel pipe, and brass fittings, and overhaul all calipers. The rear suspension is best done by first removing the whole rear subframe as there is little/no room to get at things with it on the car. It is not too difficult to remove, but you need a trolley jack with a fairly high lift, plus stands for the body to rest on.