How to Lubricate Your E61 Group
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Maintained properly an E61 group should give many years of service before requiring the maintenance service detailed elsewhere in the Wiki. This maintenance service is inexpensive and renews all valves and springs within the E61, allowing to work "good as new" again.
There are 3 culprits that contribute to cam follower (cam pins) wear
Backflushing With Cleaner
A backflush with cleaner gradually removes any lubrication from the group, over time this lack of lubrication wears the cam followers on the upper and lower valves (the inlet and preinfusion valve)….the cam being bronze (or a harder alloy of brass), not brass , does not wear as much as the pins….but still wears a little. We are told that any stiffness of the lever will soon go as the coffee oils start lubricating the area again, but Coffee oil really is not that effective a lubricating agent…I used to think it was, but experience has taught me this is not the case. I backflush with cleaner every 1-3 months depending on use and on the taste/colour of the cooled water drawn from the group.1
Descaling being acid based also tends to strip the oils from the lever mechanism and again you may well end up with a stiff lever mechanism
Over time any food grade lubricant within the group gradually get washed out and it begins to run a little dry. The self lubricating nature of brass does help a little, but without regular lubrication components will wear.
We are told that any stiffness of the lever will soon go as the coffee oils start lubricating the area again, but Coffee oil really is not that effective a lubricating agent…I used to think it was, but experience has taught me this is not the case. In addition to the cams and pins sometimes the valve mechanism becomes "rough feeling" where the pins slide within the groups components, if this happens extreme stiffness of the lever can result in much increased wear on the pins and cam.
You do need to lubricate regularly with the right product. I tend to lubricate the cam and pins after every backflush with cleaner (pulycafe). If I think the lever has remained too stiff i will even dismantle the group and lubricate the valve pins where they slide within the group body! It's easy to do (ensure the group is cold) by first removing the lever as shown in the pictures. Then remove the entire E61 part that supports the cam and contains the cam lever gaskets as a single assembly marked by the black square in the picture below. The white Teflon gasket can be reused many times if you don't overtighten things. The nut you need to get your spanner on is identified by an arrow. Important, lock the portafilter into the group and use it to provide counter torque when undoing this nut to prevent undue twisting of the group.
The product I personally use to lubricate the E61 group is Dow Corning MolyKote 1112 http://www.dowcorning.com/applications/search/default.aspx?R=393EN. You can buy it at http://www.bes.co.uk/products/094.asp and it costs around £8.67 plus delivery for a 100g tube, this amount should last you forever as only a small amount is required. It's also useful for lubricating balljoint steam and water wands!
Click on the thumbnail below to view the datasheet for Molykote
The actual lubrication is done with a Cocktail stick (as the stuff is hard to wash off fingers) and is in the places marked with the red arrows. It is also a good idea to remove the cam itself (it just snaps out) and lubricate the area at the back of the cam, it should be obvious when you remove it. The reason the barrel is lubed and not the spindle is to prevent excess lubricant being pushed off the spindle into the cam chamber and hence into the coffee. It's also the reason why you only lubricate the inner 1cm of so of the tube with a cocktail stick and do it at the side shown! If you suspect the movement of the pins which open and close the infusion and pre-infusion valve (A and B), is not free, especially under the slight lateral force exerted by the cam (temporarily place the lever on the end of the cam spindle and move the cam to determine this). Try a very quick spray of pure silicone oil, move the lever so a pin is depressed and try to spray past the pin into the area where the valve pin slides (infusion and pre-infusion valve). This will gradually wash through and help free up the valves. In time they will free up, but this can accelerate the process (a few clean water backflushes and a bit of water run through the group will remove a lot of the excess silicone oil3
2 IMPORTANT TIPS The surfaces being lubricated MUST be dry, otherwise the MolyKote will simply slide off!
If you are servicing the whole group the procedure would be different to avoid damage, but if your just trying to refit the cam spindle and have not disassembled the lower preinfusion valve assembly….simply fit the lever temporarily, this will help you to "wiggle the cam into place" with the lever in the "halfway" or 45 degree position.. I do it this way each month or two when I lubricate the cam, pins and spindle, you will find it will go in easy.**
Common signs of these cam followers on the valves wearing is some or all of:
- Lever drops down on it's own sometimes when pulling a shot (top valve follower worn)
- Lever rises on it's own from resting position, sometimes a lot (bottom follower worn)
- When lowering lever to depressurise group, sometimes residual pressure (small amount is left in group, or group doesn't de-pressurise very violently, or lever has to be pushed home harder than usual. (bottom follower worn)
- Lever action is "notchy" (one or both pins worn)
Have a look for yourself…both pins are worn, the bottom much worse that the top. Coffee oils didn't help, this machine was backflushed with cleaner every 3-4 weeks, but NOT lubricated with a proper lubricant…the wear on the bottom pin is obvious and the top is slightly worn as well…machine 2.5 years old
These are the new pins that needed replacement in the group above. As you can see the faces are flattish with slightly rounded edges. Although these pins are very cheap, they can be very difficult to find and there are two sizes required for proper operation of the E61 group. One pin is 10mm and the other is 12mm (I think from memory the 12mm one goes on the bottom "preinfusion valve"). If they are not placed properly the group may not work as designed. Even then your problems are not over, it's quite likely that the combination of heat and shearing forces will cause the old pin to snap the thread holding it when you try and unscrew it from the valve, this of course then necessitates replacement of the whole valve assembly. Again this is not too expensive, but it will be annoying, as you have to order another very hard to get hold of part. These parts are hard to get hold of because very few dealers stock them!
Even if you don't have an E61, but the principles of requiring lubrication is a sound one, ensure any parts that need lubrication on your machine are maintained.