older 1993 GFI vs todays GFCI

My house built in 1993, has in my garage a GFI protecting my two bathrooms, two separate outdoor outlets and two interior garage outlets. It is a 20A S/R GFI. The wiring to the GFI is the incoming load (hot). It is connected to the bottom ground side of the GFI and the common wire (white) is conneted to load side of the GFI. The top connections are the same. This connection has never been changed and is at present working fine as wired. Recently I had a problem with the breaker not reconnecting after using my pressure washer for a hour or so. I purchased a new Leviton 15A GFCI, wired it exactly as the old wiring. It wouldn’t work. I then reinstalled the old GFI and now it is working with out any problems. What is happening here?? What problems would there be with switching the incoming wiring to a new GFCI receptical??? I don’t want to make any major wiring changes as long as the present GFI works.
Thanks for your reply.

If you wired the new one as the instructions that came with it say, I’m thinking you received a bad on from the supplier…but, that is just a guess, since I can’t see what you have there.

Your FIRST mistake is attempting to replace a 20A GFCI with a 15A GFCI. Why? To save $20?

Call an Electrician!

First off I’m an electrician of 14 years becoming and inspector. Second off your better to call an electrician. But newer gfci’s line load are opposite of the older generations. But I would definitely install a newer gfci in my own house as they test with micro volts .0001 when you press the reset button as opposed to the older style that hit the line with the 120 volt. Identify the line and load and you should be fine.