Introduction: Repair/Adjust/Clean Canon 17-55mm F/2.8 - Dropped and Slipping Focus

I dropped my main lens, the famous Canon 17-55mm f/2.8 IS, and broke the focus mechanism. Af wouldn't work at all, and the manual focus ring did nothing.

Repair costs are said to be very expensive, so I decided to accept the risks (as you will too if you choose to open your lens) and try it myself.

This instructable also tells you how to stop that annoying focus ring slip, as there is an adjustment inside.

Enjoy

Step 1:

Unscrew the 4 main screws, then the 2 tiny ones indicated by the red arrows.

Step 2:

Unclip at least 2 of the 4 plastic tabs underneath the steel lens mount, indicated by the green arrows. Be careful not to pull too hard on the ribbon cable connecting the electronics terminals.

This releases the plastic ring insert, which allows the terminal block to be released.

This will expose the circuit board and next layer.

Step 3:

Unscrew the small screw that secures the circuit board in place, and carefully unplug the ribbon cable as indicated. It just pulls out with moderate force.

Step 4:

Lift the top housing up vertically to remove. Be careful not to snag any other ribbon cables.

Step 5:

Lift the manual focus ring off.

Step 6: Keep It Tidy and in Order

Keeping your workspce tidy will help you with re-assembly. Also, laying out all the parts in the same order you remove them will save you time. Try to keep the sets of screws separate from each other, and with their relevant parts.

Step 7:

Undo the clips on the other ribbon cables. Do this with a very fine slotted screwdriver, or an exacto knife, as shown in the picture. The clips are hinged, and need to be lifted up to release the ribbon cable.

Do not pull the cable with any force. If it does'nt almost fall out, it isn't unclipped properly.

Step 8:

Undo the 6 screws marked with the green arrows. Then carefully lift the ribbon cable off the black plastic frame. It is adhered with double sided tape. Be careful not to kink it or yank it.

Step 9:

Lift the black plastic frame off, carefully freeing the ribbon cables as you do.

Step 10: The USM Focus Tension Assembly

The green arrow in the first picture shows the wave spring that keeps the USM motor under pressure against the full-time manual focus assembly. When this becomes weak, or experiences a jolt from a fall, it might not be putting enough pressure on the assembly to keep the MF ring engaged. The next step shows how to adjust this.

Step 11: Adjust the Manual Focus Ring Pressure

The green arrow indicates the flite that a tab on the silver steel ring screws into. From the factory, mine was about halfway along this flite.

After the fall, the blue loctite had released, allowing slop in the assembly, and causing the MF mechanism to not press hard enough to engage the focus mechanism.

Turn the Steel ring clockwise as indicated to increase the pressure on the wave washer, and the whole AF/MF assembly. You may not need to turn it all the way into it's thead, so test to see if you have enough pressure by replacing the MF ring and checking if it turns the focus mechanism. Then re-apply some quality loctite, or medium superglue. I used a toothpick to apply the super glue. It doesn't need much, as all it is doing is stopping th steel ring from unscrewing.

If you only needed to adjust the MF due to the focus ring slipping, then at this point you can re-assemble everything in the reverse order. If you want to also clean the front element, skip to the 2nd last step.

Step 12: Continue Disassembly to Make Repairs

Unscrew the 3 screws indicated by the green arrows, then lift the lens out. When replacing this lens, you must be careful to keep the black ribbon cable out of the way so it doesn't get pinched, and carefully align the lens with the plastic pins. It only fits in one way, so be careful not to force it.

Obviously, you should clean the elements as you re-assemble. This is a quote from https://www.instructables.com/id/Using-Ultra-Fast-Lenses-on-DSLR-Cameras/step2/Clean-It/    

"Clean the glass by first giving a few puffs from a blower to remove dust (which might otherwise scratch the elements). If there are greasy fingerprints, use lens cleaning wipes or a swab moistened with alcohol to remove them. I like to do final touch-up using a lenspen.
Through all that, you should never have the lens elements or body wet -- using too much of any liquid can allow that liquid to seep inside the lens."


I suggest you do your own research on lens cleaning before attempting anything yourself. You can ruin a lens by using the wrong method.

Step 13:

Unscrew the 3 screws indicated by the arrows in the first image, then carefully lift the main housing up vertically, and slowly, making sure you don't catch any rippon cables.You should not need to use force. As you can see in the second image, 2 ribbon cables stay in the other piece.

Step 14: The Repair

The red box indicates the part that was damaged in the fall. The left hand side of the plastic tab was broken off. Fortunately, it fell out of the lens as I disassembled it. I glued it in with some quality medium superglue (CA), then waited for a couple of hours to let it flash off completely. I didn't want any CA fumes damaging my glass.

The second image shows the metal tab that engages with the plastic part that broke. When you re-assemble, ensure this is engaged again.

Step 15: Re-assembly

The other side has the focus actuator tab. It must engage with the focus element. Both are indicated with green arrows.

Step 16: Clean the Front Element

NOTE - You do not need to disassemble the whole lens to do this. You can start this whole instructable from this step if all you need to do is clean the front element.

Use something fine to catch the edge of the decorative ring with the writing on it in the front of the lens. It is secured with double sided tape.

Someone suggested using a toothpick. I think it's a safer option than what I used. It's up to you.

Before unscrewing the 3 screws, mark from the lens carrier to the threaded filter ring to ensure correct alignment upon re-assembly. The lens is NOT symmetrical and can fit back in other incorrect positions.

This is a quote from https://www.instructables.com/id/Using-Ultra-Fast-Lenses-on-DSLR-Cameras/step2/Clean-It/

"Clean the glass by first giving a few puffs from a blower to remove dust (which might otherwise scratch the elements). If there are greasy fingerprints, use lens cleaning wipes or a swab moistened with alcohol to remove them. I like to do final touch-up using a lenspen.
Through all that, you should never have the lens elements or body wet -- using too much of any liquid can allow that liquid to seep inside the lens."


I suggest you Do Your Own Research on lens cleaning before attempting anything yourself. You can ruin a lens by using the wrong method.

Now, re-assemble everything in the reverse order. and you're done!

Comments

author
timhowan made it!(author)2016-02-25

Thank you for this write up. Very detailed and helpful. I attempted to rotate the silver retaining ring back in and now the manual focus is beautifully engaged. However, I now encountered another problem. Auto focus is now behaving in a very strange way. It is less responsive and a bit choppy at times and I have to press the shutter several times to make it worked. I am not sure if insufficient or excessive pressure is the problem.

I dismantled the lens again and rotated the silver ring a bit backward and it has improved a bit but still not like before. I hesitated to open up the lens a third time. I worried about breaking the flat cables.

Before I go further, is there any info regarding how to adjust the pressure of the USM to make the AF working again.

Thanks.

author
snowman_ed made it!(author)2015-12-07

Created an account just to say thanks for the helpful guide. I dropped my lens and it felt tough to focus and wouldn't focus sharply at the 17mm end.

I followed your guide to step 11, played around with the focus tension, put it back together - and now it works as well as before... so thank you!

author
ins30546 made it!(author)2013-09-10

Hi,

I'm trying to fix a bad zoom creep problem with my 17-55mm lens, and the first step is to figure out where the friction is actually created.

I slipped off the large rubber zoom ring and noticed that the zoom barrel has three slots, and in each slot is a screw with a brass round spacers/collar around it.

Is this where the friction is created? Or is there another part internally with a friction element on it? If so, is this part visible in any of the pictures in your guide?

I figured that since you disassembled yours, you would have a good idea about the inner workings of this lens.

Thanks

author
canon4lyf made it!(author)2013-10-24

Hi,

To make any adjustments to the friction you will need to disassemble this lens further than this guide describes. The inner zoom assembly consists of two rotating barrels with multiple helical screws. This is a similar example:

http://martybugs.net/gallery/photos/IMG_A18156_600.jpg

If you are game, I would advise you to get some Helimax XP Helicoid Grease - it's made for telescopes and cameras and is much cheaper than the other Japanese greases commonly recommended. I applied the tiniest amount with a very fine brush to the sections of the barrels that rub against one another, as well as the helical screws that move the lens elements. It's now smooth and stable in both the zoom and focus rings

http://www.ebay.com.au/itm/HELIMAX-XP-Camera-Telescope-Optical-Instrument-Focusing-Helicoid-Grease-w-PTFE-/271194713421?pt=LH_DefaultDomain_0&hash=item3f2476ed4d

author
kinetica made it!(author)2012-01-14

Hi, my lens started showing the err 01 message and from further investigations, it seems like my IS unit is not functioning properly. All I can't seem to take photos with apertures f2.8 and above. Apparently some of the lens element is spoilt as well. If I were to remove the IS unit, would the lens still work? Any idea if I can just make this into a manual focus lens? I'm not willing to repair it at canon for 450 euros..thanks!

author
coffeegeek made it!(author)2012-01-16

Sorry to hear you're lens is borked. I really couldn't say whether it is an IS problem or not. But, if you removed the IS system, you would have a dead lens, as one of the lens elements is integral to the IS system.

All the best.

author
kinetica made it!(author)2012-01-16

I sent my lens for diagnosis at canon and they said my IS needed a replacement..not sure if I can get the replacement parts myself?

author
coffeegeek made it!(author)2012-01-16

If that link doesn't work (try cut and paste), you can search ebay for item number 220923949568

author
coffeegeek made it!(author)2012-01-16

You sure can! Try this... http://www.ebay.co.uk/itm/220923949568?ru=http%3A%2F%2Fwww.ebay.co.uk%3A80%2Fsch%2Fi.html%3F_from%3DR40%26_trksid%3Dp5197.m570.l1313%26_nkw%3D220923949568%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1

;)

author
gnif made it!(author)2011-06-02

Wow, thanks for this information, my brother dropped his lens and he was able to follow your steps exactly and repair it, saved him a bundle.