What a CLA actually involves

Most people who shoot film have heard the term CLA. Fewer know what it actually means. Here's what happens when a camera comes in for service, from the initial inspection to the final shutter speed verification.

What CLA stands for

CLA stands for clean, lubricate, and adjust. It's the standard service procedure for a mechanical camera that hasn't been worked on in years. The clean part means removing old lubricant, dust, and contamination from the mechanisms. The lubricate part means applying fresh lubricant in the correct places in the correct amounts. The adjust part means calibrating the shutter speeds, rangefinder alignment, and other mechanical functions.

A CLA is not a repair. If a camera has a broken part, a CLA won't fix it. A CLA is preventive maintenance -- the equivalent of an oil change and tune-up for a car. You do it to keep a working camera working correctly.

Initial inspection

When a camera comes in, I start with a visual inspection. I look for obvious damage -- dents, scratches, missing parts. I check the light seals. I check the shutter curtains for pinholes or damage. I check the lens mount for wear.

Then I test the shutter speeds with a tester. I record the readings at every speed. This tells me what's wrong and gives me a baseline to compare against after service.

I check the rangefinder alignment on rangefinder cameras. I check the meter on cameras with built-in meters. I check the film advance and rewind. I check the self-timer if there is one.

Disassembly

The extent of disassembly depends on the camera and what it needs. For a basic CLA, I remove the top plate and bottom plate to access the main mechanisms. For a more thorough service, I may remove the front plate and the lens mount.

On Leica M cameras, the top plate removal gives access to the rangefinder mechanism, the shutter speed dial, and the film advance. The bottom plate removal gives access to the slow-speed governor and the shutter cocking mechanism.

I photograph the camera before disassembly and at each stage of the process. This is useful for reassembly and for documenting the condition of the camera.

Cleaning

The cleaning is the most time-consuming part. I use naphtha (lighter fluid) to dissolve old lubricant. I apply it with cotton swabs and allow it to work into the mechanisms. I cycle the shutter and film advance repeatedly to distribute the solvent and carry away the old lubricant.

The slow-speed governor is cleaned carefully. It's a small escapement mechanism with tiny pivot points. I apply naphtha with a fine brush and work it in gently. The governor is the most sensitive part of the camera to contamination.

The shutter curtains are cleaned if they're contaminated. On cloth curtains, I apply naphtha with a cotton swab and allow to dry. I never touch the curtains with my fingers.

Lubrication

After cleaning, I apply fresh lubricant. The lubricants I use are specific to each part of the camera. Molykote DX paste for the slow-speed governor. Tribolube 22 for the shutter curtain rails. Light machine oil for pivot points.

The most important rule is: use very small amounts. Excess lubricant migrates. It gets on the shutter curtains, causing them to stick. It gets on the rangefinder optics, causing haze. Less is always more.

I apply lubricant with a fine brush or a sharpened toothpick. The amount at each point is barely visible. After applying, I cycle the mechanisms repeatedly to distribute the lubricant.

Adjustment and calibration

After cleaning and lubricating, I test the shutter speeds again. I compare to the baseline readings from before service. The slow speeds should be within 30% of the marked speed. The fast speeds should be within 20%.

If the speeds are off, I adjust. The slow speeds are adjusted by changing the amount of lubricant in the governor or by adjusting the governor spring tension. The fast speeds are adjusted by changing the curtain tension or the gap between the curtains.

On rangefinder cameras, I check and adjust the rangefinder alignment. I replace the light seals. I check the meter calibration if there's a built-in meter.

Final verification

After all adjustments, I test everything again. Shutter speeds at all settings. Rangefinder alignment at 1 meter, 3 meters, and infinity. Film advance and rewind. Self-timer.

Then I run a test roll through the camera. I shoot it in a variety of conditions -- bright light, low light, close focus, infinity focus. I develop the film and check the exposures and focus accuracy.

A CLA takes three to four hours for a Leica M. Simpler cameras take less time. More complex cameras take more. The test roll adds another day for development and inspection.

In Florida, I do CLAs on cameras I use regularly every ten to fifteen years. The humidity here accelerates foam deterioration, so I check the light seals annually. The mechanical parts of a well-maintained camera can last indefinitely.