I'm trying to clean my gaggia classic. Got the

Hi There,
Try descaling - sounds like the the solenoid is blocked with lime - don't use vinegar! Try that 1st.
If machine is more that 2 years - not regularly descaled or no water filter replaced regularly, it probably the solenoid.
It the machines is 4 years + replacing both would be a good idea. Gaggia classic solenoid Vibration pump Gaggia Rancillio

Remove the screw and screen and clean. Burn out coffee from screen using an open flame or stove.

Do mean backwash like Cleaning out?Normally we use the Vingar Cleans it out.Depends on size of maker,you can run one cup of vingar/1-cup of water to clean system out,then run only water on next step fill your pot run it again.Do this couple times.Hope this answer your question.

try to clean the group shower which it can be ansrew by one cetrer screw and if you can you can open the machine and remove to clean also the coffee group solenoid valve. Bothe the valve and shower can be full of dry coffee that can blocked the way of water coming to the grounded coffee.
If you manage to clean everything above and the machine work ok so from now on in order to avoid the problem again try to flush water from the group many times without any coffee. With this is like you wash the group shower and valve from any remai coffee.
Good luck

You will have to reseat or replace the head gasket.

Try descaling the unit with citric acid(scalekleen), make sure that you rinse about 3 full tanks of fresh water before using.

It could be the steam solenoid or the small hole in the group head next to the screw holes gets blocked up as well.

Take it off, and heat up a pan of boiling hot water and add 1 cup of vinegar to two cups of boiling water. Once the water starts to boil, shut off the stove, and put the head in the pan, cover the pan and let it sit for about 30 minutes to 1 hour. Afterwards wash it really well then you will be good to go. The head does twist off

try this website http://www.bluebox.com.au/jcrayon/gaggia/

One question before I make any suggestions: If you remove the shower screen and screw, do you get a nice flow of water or is it still steam?
If you get a nice flow of water, then check your screen hold it up to the light and you should be able to see through the tiny holes, if not, get a pair of needle nose pliers and being very careful hold screen over an open flame like the stove burner. The coffee will burn before the anything happens to the metal. When it is cooled screw into group and see if the flow of water is better.
If you get nothing but steam then it is time to descale the machine.