Handbrake clunk
Hi Rag1873
Had a similar problem with my T2. When I released the handbrake there was a clunk and the car lurched forward/backwards, depending on whether I was going in forward gear or in reverse, when the brake shoes suddenly released.
On examination turned out to be a leaking wheel cylinder that had contaminated the rear brake shoes causing them to stick. New cylinder and shoes did the trick.
Assuming you don't have rear discs, you might try taking off the rear drums and checking the shoes for contamination.
Regards CL