Author Topic: Removing the clock  (Read 9507 times)

karmannghia60

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Removing the clock
« on: June 28, 2004, 17:44:17 »
Hi
My clock stopped working so I am trying to remove it to fix it. I removed the underide of the dash but still can't get to it? What am I supposed to do? Remove the inside of the glove box? This is a RHD car
Thanks in advance
Raf

BHap

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Re: Removing the clock
« Reply #1 on: June 28, 2004, 18:40:34 »
i went through the radio opening.......
Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

karmannghia60

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Re: Removing the clock
« Reply #2 on: June 28, 2004, 18:54:11 »
That would be a nightmare with such a small openning, wouldn't it?

Richard Madison

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Re: Removing the clock
« Reply #3 on: June 28, 2004, 19:05:03 »
Have no experience with RHD car but on my LHD late 280 SL, I removed the glove box, then had easy access to the clock.

Remove Glove Box: open the box, remove the screws on top and bottom. Slowly bring the box forward with the lid open. Watch the springs on the left side, they are a bear to work with. They do not have to be removed. The lid does not need to be removed. As the box comes out, unscrew the wires for the glovebox light on a terminal board behind the box. I put the two screws back into the terminal board so as not to lose them. Then box comes all the way out.

Now you can now reach in and disengage the wire and the bracket that holds the clock.
Richard M
1969 280 SL, Tunis Beige, Euro Model (Italy).

graphic66

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Re: Removing the clock
« Reply #4 on: June 28, 2004, 19:27:53 »
Once you get the clock out you may be able to fix it. First check to make sure you have power to it by partialy pulling the plug off and checking the prongs for power. There are 3 connections, one ground, one constant power and one switched power for the illumination bulb.

If all is well there then you must remove the white plastic cover from the back of the clock. This is done by removing the very small 3 nuts on the back, one nut may possibly have a tamper evident seal in the form of a blue plastic disc fitted over one nut. I just broke it off to reveal the nut, you may be able to defeat it and not break it.
Then the white plastic cover will pull off carefully with the power wire for the light pulling tightly and still hooked up inside the clock.

When you get it open look for the small contacts that energize the solonoid to wind the clock. These are usually the problem. The contacts must be clean in order for the clock to work. I just used a small exacto knife to clean them and coated them with silicone dielectric compound. You can push the one moving contact down to check if the clock will run, as it runs the contacts will come together and energize the solonoid and kick the winder to wind the clock. This just keeps happening over and over to keep the clock wound.

If the clock runs slow or fast there is an adjustement on the back. You could let it run a while on your bench hooked to a 12 volt power source to check its operation and adjust it. Then after you put it in the car that will all change and maybee after 4 or five adjustements you can get it close. Or you could have a new quartz movement installed in the old clock and be done with it, but what fun would that be?

Also check the operation of the bulb and clock before fully assembling the dash. The clock is on the #1 fuse with the interior lights.

knirk

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Re: Removing the clock
« Reply #5 on: June 29, 2004, 00:02:19 »
Is the fast/slow adjustment accessable without removing the back cover?

Per G. Birkeland
69 280 sl aut 834
Norway

hands_aus

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Re: Removing the clock
« Reply #6 on: June 29, 2004, 06:10:47 »
Hey Raf,

The procedure for removing the clock in a RHD car is the same as described for a LHD car.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL #114, auto, ps , 717,717
best of the best

ted280sl

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Re: Removing the clock
« Reply #7 on: June 29, 2004, 06:36:25 »
Raf,
  As usual our panel of experts as provided all of the information you will probably need. I ran into an additional problem with my clock. It seems that our clocks have a built in fuse which is very sensitive and can easily be blown. I applied power to my clock and it did not work. I was able to follow the leads within the clock to find the fuse and soldered the conection closed. Material on the clock was listed on the "Pagoda Pages" several years ago. Here is the material:

Clocks of the W113 Era, by Jim Mahaffey

 

VDO subcontracted the job of building mechanical clock movements to the German firm of Kienzle in about 1958 to about 1975. There were two major patterns of Kienzle movements made. Let's talk about the common, drum-shaped movement. It's a basic Borg-wind, anchor-escapement clock, shock-mounted, built on two nickel-plated brass plates. Winding period is about three minutes (sounds like a muffled jolt.) The balance is not temperature compensated, and usually runs in one jewel. (There are rare examples of two-jewel movements.)

Early movements have all brass gears; later movements have plastic escape-wheels with coaxial aluminum flywheels. There are some basic case patterns: 115 (short case), 114 (long case), 113, 107 (SLs have internal lighting and connector blocks on the back), etc...

Adjustment is with a jeweler's screwdriver though a port on the back, covered with a paper tape, usually labeled "VDO." To adjust, set up the clock on a bench with a 12-volt power supply. Make EXTREMELY small movements of the adjustment pinion, and allow the clock to settle for at least 24 hours between adjustments. To get a really fine adjustment can take a week, and it will be spoiled as soon as the car heats up inside. An inability to achieve adjustment indicates wear on the plates.

Altitude compensation for the case is provided by a labyrinth vent, hidden under the plastic tape with fuse specs. One of three nuts on the back of the case is warranty-sealed with a two-part plastic lock.

Normal failures are as follows:

The thermal fuse. This fuse is installed as a rivet, made of bismuth/tin alloy, and is intended to prevent fire in the rare event of a failure of a flat, phosphor bronze spring on the wind clapper. These fuses eventually fail out-of-specs. A bronze spring separates the electrodes, and the remains of the fuse are usually evident somewhere in the case. I suggest replacing the fuse with lead-tin solder, with the warning that this voids the purpose of the fuse.

Points. Causes stalls at the end of the wind cycle without solenoid meltdown. The precious-metal points can become burned or distorted. Lubricant evaporates and is burned to soot in the points, and this can cause overheating. Metal can also sputter and migrate from point to point. Dress the points with fine abrasive.

Flywheel bearing failure. Causes uneven force on the first wheel and stalls between winds. The heavy steel flywheel on the solenoid plate should not wobble on its bearing. For some reason these things wear out prematurely on some cars, particularly on SLs, and it may be high-frequency vibration related. It is held on its shaft by an E-clip. On later models the clip is built with a bronze tail, so you can't lose it. Replace the flywheel. Lubricate this bearing.

First and second wheel bearing failure, back plate. Causes the clock to stall between winds. The first wheel takes a severe side load from the winder, and this will eventually doodle out the back bearing. The second wheel can also lose its back bearing. Replace the back plate (with attached balance), or repair the bearings. The bearings respond to shrinkage under a staking punch (with subsequent reaming), or to bushing. As good back plates are becoming rare, I find myself resorting to staking punch more and more.

Setting knob (rare). The rubber suspension goes soft, and you can't reach the hands with the setting knob clutch. Use the clock for parts.

Front plate bearings (very rare). The wheels wobble on the front bearings. Use the clock for parts.

Weathering. Red rouge on a cloth wheel can do wonders for the plating on the brass bezel, and even for scratches on the plastic crystal.
Cracked or smashed crystal (very rare). Use the clock for parts. Assure the owner that they're all just alike, and he won't notice the difference if he buys a new one.

Previous repair work (more common). Note extra stickers or the absence of the nut seal. Note a promiscuous use of lubricant. Stalls in mid-wind. Clean it thoroughly.

Salt water immersion. (More common than you'd like to think.) Excellent source of parts - the brass bearing plates are unaffected. Springs will be ruined.

Only seen once: Winding pawl worn out. Clapper spring breakage. Clock possessed by demons.

Suggestions:

Be careful of the cleaning fluid you use to remove old, oxidized lubricant. Most organic solvents will play havoc with the various plastic components. The best is freon, which to my utter dismay is no longer available. Professionals advise the use of detergent in water. Lubricate conservatively, using only fine watch oil. Silicon-based oil is certain not to harm plastic components.