Rear roller replacement with ball bearings. There are several ways to do this but I went this way as it was the easiest and lowest total cost. I would not recommend using any plastic for the shims.

Shims (1 package)
http://www.mcmaster.com/#catalog/121/3255/=ze3s5j
98055A106

Bearing (3)
http://www.mcmaster.com/#standard-ball- ... gs/=ze3suh
7804K112

The shim must be drilled out to fit the pin and the OD reduced to allow the outer bearing race to turn freely. The stack width must be about 14mm so the lever does not bind on the group. You have to measure this and adjust for each machine. At least 1 shim and better 2 between each bearing and the next then shim both ends of the assembly so that the stack it tightly clamped when assembled and there is adequate clearance between the sides of the lever clevis and the group. Light oil in each bearing and they are good to go for a very long time. Do not use 3-In-1 oil as it wil promptly oxidize to a hard varnish.

These parts will build the low friction rear bearing assembly. The total bearing width is 12mm and the nominal total width of the assembly is 14mm so you need to have 2 shims on each side of the center bearing minimum and 3 will be a better bet. Using 3 shims on each side of the center bearing them each outer end will then have 2 shims each. You can hold all of this together with a good sticky grease. Silicone based grease will not serve for this. Assembling this can turn into the mechanical equivalent of a greased pig contest at the county fair.

Do you favor any type of bearing on that spec page? For instance I saw some that are pre-lubed and have a buna rubber seal. Also, if not 3M, what light oil do you recommend?

The part number I specified (7804K112) is the only one that fits. A single drop of plain 30 weight engine oil and it is lubed for life unless you wash it in the dishwasher. The open bearing will have the lowest friction and roll easiest.

I've ordered those parts and will post here when I rework the lever pins.

Sounds like a plan is coming together.

Gary, any update on this? Oldnuc, I see the bearing you specified is only 4mm wide; is one enough? or did you Siamese 2 of these side by side? I've been looking at mine and there's way too much slop, was thinking of making some plain bushings to tighter tolerances but found this thread... Also, there is way too much side to side play in my lever. I know Oldnuc solved this by using longer pins that are threaded and threw in shims to tighten up the slop; I have to admit I like the idea of a Teflon shim in there as I will occasionally get a 'rub' feel while doing half pumps that I really don't care for.

aloha,
walt

Hi Walt,

Parts came in, haven't gotten to it. Coffee hobby comes second to my day job as I get my new practice off the ground.

walt_in_hawaii wrote:Gary, any update on this? Oldnuc, I see the bearing you specified is only 4mm wide; is one enough? or did you Siamese 2 of these side by side? I've been looking at mine and there's way too much slop, was thinking of making some plain bushings to tighter tolerances but found this thread... Also, there is way too much side to side play in my lever. I know Oldnuc solved this by using longer pins that are threaded and threw in shims to tighten up the slop; I have to admit I like the idea of a Teflon shim in there as I will occasionally get a 'rub' feel while doing half pumps that I really don't care for.

aloha,
walt

3 bearings with sufficient spacers that bear against the inner race only to make up a stack the is just a couple thousandths wider than the group body. The clevis is pulled down tight against the spacer-bearing stack. At least 1 spacer on each outer end or they do not roll. Generically the group body is 14mm thick at the slot and the bearing stack is 12mm. The shim # I listed must have the OD reduced and it may also have to be drilled out on the ID, just do not remember but the pin will be 6mm OD.

drgary wrote:Thanks, Rich. Please tell me again what lube you use? Until I jump down the rabbit hole of getting a lathe and learning to use it I'll try a new lever pin that should fill that hole a bit better.

Cv axle grease is the stickiest best lubricant I have ever seen. Wouldn't take much, don't want it in your food, but might just be the ticket as a light coat for the lever pins and roller?

http://m.oreillyauto.com/mt/www.oreilly ... &ppt=C0139

The roller usually does not roll, no matter what you lube it with and neither do the pins. That is why ball bearings instead of the roller and pin joke. That is also why I used a high pressure polymeric grease on the front pin and a light weight lube on the sliding surfaces of the rear bearings.

If you want sticky try ISO 1000 steam cylinder oil or worm drive oil, same thing mostly. They are H-1 and everyone should go look up what exactly H-1 certification means.