Kenmore sewing macine cams #1 (26841) and #2 (26842)

This video will probably be handy, although not quite your model, it should be very close. Generally, your machine should be able to do straight & zig-zag stitch without cams. Cams were usually for decorative stitches.

Kenmore 158 17550 Sewing Machine Tutorial

Parts: https://www.sewingpartsonline.com/kenmore-158-17600-sewing-machine-parts.aspx?sort.ss_cat_sort=desc&index=64

Manual: Kenmore 158 manuals 3

Hmm, cams will generally not transfer from one machine to another. I found some for my old 158 Kenmore on eBay. Since the machine is at least 30-40 years old, it's not likely Sears is going to carry them. Your best option is finding them used.

https://www.ebay.com/sch/Machine-Parts-Attachments-/41248/i.html?_dcat=41248&Brand=Kenmore&_fsrp=1

http://www.searspartsdirect.com/partsdirect/part-model/Kenmore-Parts/All-Products-Parts/Repair-Maintenance/Questions-Answers/OwnerInstruction-manual-for-Kenmore-1588/Model-158850/0582/1200000/357492?modelNumber=158850 ..try this site you might find it there

May be best to visit a Sears parts store and see if you can get a parts list.

...

http://www.hypereon.com/Kenmore_12-Stich_Manual.pdf

The closest manual I could find was for 158.1355, which is here.

Found using a google search of: Kenmore sewing machine 158 1358 filetype:pdf

You will have to get part numbers from the supplier or manufacturer, they are normally stamped on the cams.

Take this link to sears.com and click on view manual.

http://www.managemyhome.com/mmh/owner_manuals/search?sid=MMHMxSearsx00019&query=15817572+KENMORE

kenmore 158.132.01 manual