Bosch orbital sander repair

[pop-pop]

This morning my orbital finish sander slowly stopped moving.

A bit of disassembly revealed a locked up orbital bearing. After a douche with brake cleaner here is the bearing ready for greasing and re-assembly.

And ready for attaching the pad.

One of my friends calls this operation a "ZDR" which stands for Zero Dollar Repair

 

[Raymond]

Hey, if the operation works, than a ZDR is best option.

 

[bob vaughan]

Attempted portable power tool repairs don't always end that well. Congratulations.

 

[Herdfan2005]

I recently thought my Bosch ROS was on its way out. It would take forever to try to come up to speed. I too decided to investigate and found a loose screw like the one pictured.. A couple turns and I was back in business.(I'm guessing it was the problem) ON a hunch, I check my old Ryobi who was having a similar but different issue and lo and behold, it was loose as well. Now I'm back to two functioning sanders.

I was very close to just getting a new one and so glad I waited.

 

[pop-pop]

I meant to mention how to open a "sealed" bearing.

The seal on a suffix "2RS" bearing on the right can usually be easily popped out using the point of a sharp knife. A thumb press will usually reinstall it.

On the left, the shields on a suffix "ZZ" bearing is not removable (note the staking). However, there is a small gap between the shield and the inner race so that a bit of light oil can often be worked in to soften the hardened grease.

i

 

[bob vaughan]

The process is, of course, correct, but the suffixes are switched. ZZ means metal shields as on the left. 2RS means two rubber seals.
Showing the knife blade at the outer race is very good form. Its easier to pop the seal if the knife blade is stuck under at the inner race but that will ruin the seal in short order.
As a matter of protocol, the interior of a bearing should be about 40% grease and 60% air. Otherwise a grease dam will occur and bearing failure is likely. When I first started trying to repair portable power tools, I crammed a bearing full of grease. It went on a router. I got probably got a few minutes of run time before the bearing froze, spun, and ruined the router.

 

[pop-pop]

The process is, of course, correct, but the suffixes are switched. ZZ means metal shields as on the left. 2RS means two rubber seals.

Fixed, thanks.

 

[bob vaughan]

There is an excellent point being made here. If the tool is not working, give fixing it a try or at least dig into it to see if you can discover the cause of the problem. Most of the time it is something simple. Most of the time, but not always.

some sanders are easier to work on than others. Below are three types of construction viewed from the top and side. As you can see, the one in the middle is built more like an industrial router. That one is the Porter Cable 330 speed block. The bearings are enclosed in metal not plastic. That's why we often see a 330 that's decades old. I still have the one that I photographed and that photo was taken in 1985.

 

[junquecol]

There is an excellent point being made here. If the tool is not working, give fixing it a try or at least dig into it to see if you can discover the cause of the problem. Most of the time it is something simple. Most of the time, but not always.

some sanders are easier to work on than others. Below are three types of construction viewed from the top and side. As you can see, the one in the middle is built more like an industrial router. That one is the Porter Cable 330 speed block. The bearings are enclosed in metal not plastic. That's why we often see a 330 that's decades old. I still have the one that I photographed and that photo was taken in 1985.

View attachment 196895

I also have several of the Speed Blocks. All were bought used.