Jumping Lever

#1: Post by **mrb** » April 2nd, 2016, 7:25 pm

Hi.

My Pavoni Stradivari has two points in the piston travel both ways where the lever loses resistance like the piston seal breaking.

I immediately noticed this unexpected functioning when using the machine for the first time but ignored it because the coffee is good. A few months later the jumping lever isn't any worse.

I haven't looked in the cylinder. Is this coffee press defective?

Thanks.

#2: Post by **forbeskm** » April 2nd, 2016, 7:28 pm

Was it purchased new or used?

Have you had the group apart?

How old are the seals?

Have the been lubed with dow 111?

#3: Post by **drgary** » April 3rd, 2016, 12:40 am

I ran into that problem on a different machine (Riviera Baby) when the portafilter didn't fully seal against the portafilter gasket. Is there any leakage around the outside of the portafilter during a pull? I've also had the situation Mike mentions just above where there wasn't any lubricant on the piston gasket, so it slipped. That was with a new Ponte Vecchio Export.

April 3rd, 2016, 11:25 pm

I purchased the machine new and have not had the group apart. The seals are the original ones and at around 3 months old.

The jumping lever happens with no portafilter in place, with a cold machine and with a pressurized machine.

The machine holds pressure without issue and group water has apparently never flowed into the boiler. I have made some hard pulls on this lever without a squeak of gas. With the backpressure from some coffee, the jumps are less pronounced.

It seems as though the jumps occur as each piston seal passes the same range of travel. I don't have experience with such machines. Do all Pavoni's do this? Is there a gouge in my cylinder wall?

#5: Post by **drgary** » April 3rd, 2016, 11:41 pm

It just looks like they failed to lube the piston seals in the ever downward spiral of quality control. If your dealer is near you they should service it at no charge and get it working right. Otherwise it's easy to service. Remove the nuts at the top of the piston rod, remove the front lever pin after unfastening one of the clips. Remove the portafilter gasket and shower screen. Press the piston down and remove it. Lube it with DOW 111 and reinsert, taking care not to tuck the piston seals, so you don't damage them. Reassemble in reverse order. If they're lubricated and there's a defect in the plastic sleeve that's an easily replaceable part.