Stratasys J3 Series User Manual page 88

Stratasys J3 Series User Guide
15. Make sure that along with the head, you remove the four (4) rubber O-ring
Important
If the seals are not removed with the head, they are probably stuck to the
print block housing. If so, remove them.
DOC-19001 Rev. G
seals.
Figure 4-85 O-ring seals on the print head
Figure 4-86 Making sure the O-rings are not stuck to the print block
4 Operating and Maintaining the Printer
4-60