UK Car Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry that you have not been helped yet. I just came online and saw your question.
Ok, any brake work done prior to them feeling spongy? If so, please list what was done
If you pump the pedal quickly several times, does it temporarily give a good firm brake pedal?
Does yours have rear drum brakes or rear disc brakes?
Please remember that I am not there and therefore rely on you to provide as much detail as possible, including what has been tried to repair it