i just bought a set of manifold gauges

http://www.harborfreight.com/cpi/cta...emnumber=92649

and a can of r134a

to recharge my 95 f150 which the ac kinda works on the highway but it could be alot colder so i hook up the guages and test the system pressure and get 45 low and 180 high so i go to charge the system but cant figure out how to tap the can and when i screw the yelow hose on its like the threads are to short because the hose is still lose even though the fiting is tight, i did this last year but used one of the single gauge setups and didnt have a problems but this year i figured id get the gauges to see high side pressure and i know i have a leak but its slow and its going to have to wait for right now i just want to get it working again for the summer

are the guages not designed to be used with the cans or do i need another fitting to tap the can thanks

 

You can get a can tap at most auto parts the fitting on the guages is for hooking to a big cylinder.