Help tightening loose T90 breech mounting : LUSENET : Canon FD : One Thread

My T90's breech/bayonet mount has been getting loose through many lens changes, actually thought it was my lens until I grabbed the mount and it jiggled. How big a job is it to access the screws etc. to tighten it back up? Exactly what must be removed to get to them? I have jeweler's screwdrivers to do it, should the screws be Loctited? Or should I leave this one to a good repair tech?

-- Gary Kitchen (, February 26, 2002


Hi Gary! I think this is a job for a specialist.It's not only to tighten the screews on the mountring. It will probably also be necessary to adjust the optical axe

-- Jomar Haktorson (, February 26, 2002.

Gary, The screws for the mount are easily accessible after removing the front cover of the camera. Loosen the two screws on the latch for the back about 2 turns. DO NOT remove this latch assembly since there is a small spring underneath. Remove the 3 screws on the front cover, 2 on the bottom and 1 on the top just above the lense mount. Lift the latch assembly up enough to pull the front cover away. You will see the screws that hold the mount are now in view. You can probably use a very small amount of loctite if you want. After you tighten the screws and put the front cover back on make sure the front cover is underneath the hand grip and everything looks flush. Be sure to tighten all of the screws in the cover and the latch assembly. Good Luck!

-- Terry Taylor (, February 26, 2002.

Gary, I did forget one thing, when you put the front cover back on, before tightening the screws, make sure the stop down lever functions properly. It should be all the way to the right when the cover is installed.

-- Terry Taylor (, February 26, 2002.

Hello again Gary, If you want I can send you a 30 second video clip I made some time ago from a Canon service video. The clip is in windows movie format and you need windows media player 7.1 to view it. The clip shows enough of the removal procedure to be helpful. Let me know. (the file is about 900K).

-- Terry Taylor (, February 26, 2002.

Terry Taylor has posted some good instructions. Since I had already written out the same procedure in more detail by private reply ( was down that day), and since the idea of this forum is to archive useful bits for those yet to come, I'm going to be presumptuous and stick my redundant answer here as well. I hope Terry doesn't think I'm being pushy. Information is good, right? [TT: Are such T90 video clips posted on line anywhere?]


There is no way to 'align the optical axis' in the T90. The four screws just go in or out. That's it. No side-to-side adjustments are possible. That said, here's how to make the repair.

In manuals, the camera has two sides: The 'release' side or 'take up' side, where the shutter button is and the 'supply' side where the film spool sits. Never say 'left' or 'right.' Now you speak camera tech.

Lock the cat out of the room.

Lay out a cotton dishtowel to provide a static-free cover for your work surface and so tiny parts won't skitter around.

Set the camera on your work table in good light on a second folded cotton dish towel to give it a soft resting place.

Use a 00 or 000 Phillips screwdriver (flat blade jewler's or eyeglass screwdrivers will mar and eventually destroy the screws). Loosen the two screws on the spool side of the camera, above and below the film door latch mechanism, approx. two turns -- no more. [If you go too far, you'll end up hunting in the carpet for the tiny spring from the latch mechanism.] Work the body panel containing the latch mechanism away from the camera so it's away from the camera and out against the heads of the two screws you loosened.

Remove any lens or body cap. Remove the screw immediately above the lens mount.

Remove the two screws to either side, just below the lens mount. [Note: These are a different size than the one from above. Don't confuse them.]

Lift the front panel of the camera, starting at the film spool side. It will easily come free and has no attachments to the camera. Set it aside.

Take some time to gaze into the wonder that is the T90. With no covers, it looks like an FT with Borg implants all over it. Don't get frisky in there: Those tiny wires break easily and don't have any extra length to aid resoldering. Fire off a few shots on 'bulb' (it's safe -- just don't go ANYWHERE near the shutter when firing) with the film door open and watch the parts move. Say "Hey, Honey, come look at this!" Understand when no one else shows any interest. Get back to the business at hand:

The lens mount is (was) held down by four screws at its corners. They were once each fixed in place with a dab of paint (glue?). Tighten each. Don't ask me what torque to use, just know you'll be back near 'factory spec' when the (now broken) glue dabs realign with their original positions. Fix them down for another 15 years with fresh paint or model cement or other glue or what-have-you but I DO NOT advise using LocTite on threads this tiny. Just a fresh glue dab on the heads.

Put everything back in reverse order. Make sure the front cover goes in and seats under the slight lip beside the hand grip (release button end) and also make you have properly engaged the depth of field preview slide inside the camera with the lever on the front cover. Test the lever a couple o' times.

Replace the three screws around the mount (tiny tweezers help the fat- fingered) and tighten the screws above and below the door latch. Done.

-- Robert Segal (, February 27, 2002.

Thank-you everyone. I had to figure this out for myself 2 years ago and was terribly worried at the time that I would break something or not get it back together. I left my T90 with one minor scratch and unfortunately did not know about gluing the mount. In the next couple of years when I have to do mine again I will know where to look for the proper directions. ( I was too scared to marvel at my naked camera - just wanted to get it back together! )

John Crowe (

-- John Crowe (, March 08, 2002.

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