I replaced my radiator and cap because I cracked the neck of my old one leaning on it!

So..I noticed today my upper and lower radiator pipes are swelling, like enough to leak at the clamps. Its like the system pressure is to high, but the cap is the correct 16lbs, but I'm wondering if its a bad cap..I shut the car off and it takes about 20 mins to relieve the pressure, the pipes are litteraly swollen and have a pressurized feel when you squeeze them..

Someone give me any insight on this?

 

the hoses are old and need to be replaced.. they buldge under pressure when they weaken from the heat cycles, and rot from the inside out.