A common job that i get asked to do is a Bernina 707 cam gear replacement repair. The plastic gear inside gets old and develops a crack. The tell tale sign is that the machine gets jammed or it will run for a few stitches and then stop. The crack in the gear makes the teeth open up therefore making it stick. Here is a step by step guide on how to replace it
Bernina 707 cam gear replacement
Here is a nice brand new shiny replacement gear!
You can see the round, dark hole in the gear and above that another hole. Both holes have a screw inside which need to be loosened.
After the screw’s have been loosened the cam shaft needs to be removed. Start this off by using a screwdriver to gently push the shaft. There is an exit hole for the shaft on the rear of the machine.
Here you can see the shaft sticking out slightly from the back of the machine.
You may need some tweezers or pliers to start pulling out the shaft but be careful not to damage the end. Pull the shaft all the way out taking a note of the position of the groove.
Now the complete cam assembly can be removed from the machine.
Both of these screws need to removed as they hold the plastic gear in place.
The gear can get a bit stuck onto the cams so gently prise them off with a screwdriver
Give the cams a bit of a clean up but keep the order the same!
Align the cams in the same order and position on top of the new gear. There are two holes drilled into the metal part of the gear which should be positioned anther the two holes in the cam.
Tighten the screws a little bit on each side and keep alternating until its nice and tight.
Reposition the gear and cam assembly into the machine.
Re-insert the shaft until it is flush with the rear of the machine and then tighten up the two screws to hold the can assembly in place!
Thats it!
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9 thoughts to “Bernina 707 cam gear replacement”
Hi,
This instructional guide is exactly what I was hoping to find, it’s brilliant, thank you!
Could you please let me know where I can purchase this gear?
Kindest regards,
Stacey
Hi Stacey,
As im not sure where you live its difficult to suggest any suppliers but try googling and see what comes up.
Tim
If you haven’t gotten a gear yet, I got mine at SewingPartsOnline.com it fit perfectly. And these instructions are great.
Hi sorry to bother. I have a Bernina 707 with a broken cam gear… Today the replacement arrived but when I tried it on it was slight bigger… After some work it fitted nicely but the zig zag was messed up… The needle moves while it’s still in the fabric… I’ve re mounted back the broken gear and the needle is perfect when zig zagging… Any advice? Thank you
Lorenzo
Hi Lorenzo,
are you sure the replacement gear was correct? When you say “bigger” was the metal part deeper than the one you removed? If so then it sounds like it’s incorrect. Also when replacing the gear you can knock out the pendulum motion which means that the needle doesn’t go up and down at the correct point. Firstly i would double check the gear size and get back to me again when that’s confirmed
Tim
Hi,
I replaced the cam gear with a new one, but now the zigzag doesn’t work. It’s probably the pendulum motion as you mentioned. Any idea how to fix this? Thank you for helping.
Beejay
Hi Beejay,
if you check out this video by Neil Lund he explains a really good way to re set this.
https://www.youtube.com/watch?v=yNff83zFdDM
Tim
Hi, I am just after buying an old Bernina 807 which is frozen . While I am slowly & steadily able to “ unfreeze “ part by pat , my problem is “around the clutch to engage the bobbin winding “ . It is “ stubbornly frozen “ to the extent no matter what ever I do I am unable to “ dismantle “ the clutch “ wheel . It is really a frustrating situation, let alone “the imminent danger of the plastic wheel breaking “ due to its age . I should be immensely thankful & greatly indebted if you could give me few tips to fix this problem please. I look forward to hearing from you at your earliest convenience. Regards & thanks, Ramana , London.
Try lubricating with WD-40 or Try flow .
This usually does this trick!
tim