Linear bearings loose on guide rods

[iras]

I'm working on a used Geeetech Prusa i3 Pro. The original owner assembled it but didn't really get it calibrated and had some firmware issues. All of these are fixed and it is printing, but kind of sloppy prints - nothing horrible, but not like it should.

I've determined that there is a lot of slop with the extruder assembly - I can move it a little back and forth, in and out, etc. - much more than I should be able to. It's definitely not the belts.

It seems like the linear bearings are actually kind of loose on the guide rods. If I rattle the head, I can actually see a little space between the bearings and the rods. Between this looseness on the X-axis and Y-axis bearings, I believe that accounts for the sloppy prints.

NOTE: I'm comparing the print quality to my other Prusa i3 (non-Geeetech). Those linear bearings don't have any slop and the head is pretty rigid. And yes, I'm nit-picking on print quality but this Geeetech should be able to do better. My intent is to switch to the Geeetech and install a dual extruder, but not until I can get this looseness resolved.

Any ideas? Replace the bearings? Both the bearings and rods are essentially new and look perfect - other than the looseness.

Thanks.

[Mark]

screws? are they loose? or the diameter of the rods, are they too small?

[iras]

All screws and the rod end mounts themselves are tight.

When I measure the rod diameter on this printer vs. my other printer, they are smaller - maybe .07mm smaller. Doesn't sound like a lot, but there's a visible (if you look closely) gap if I move a bearing from side to side against a rod. Figure that all 4 bearings have this problem and that accounts for why the head can be wiggled so much.

For one, I'm not sure why rods and bearings from the Geeetech kit should have this problem. I can see if I mix/match components.

Where is a good place to buy a matched set of rods/bearings?

[iras]

Ooops, a correction - It is actually the X and Z bearings that are loose. The heated bed bearings don't seem to have the same problem - maybe because they are the "short" style bearings. The net effect is in the X and Y direction when printing.

[Fluxcore]

If those bearings were not inspected by you thay may be missing balls and need to be replaced . Get your self some good bushings instead .

[iras]

I bought one set of bearings and rods to investigate one of the two problem axises. Turns out the existing bearings were find. When I changed out the rods, that eliminated the looseness. The old rods must have been undersized. I changed the other set of rods too, and the printhead wobble has been eliminated. Thanks.