Author Topic: Speedometer & Tach - Is there a step-by-step rebuild guide??  (Read 3064 times)

prefervintage

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Hi guys....yesterday, my tach center disc fell off...looks awful sitting at the bottom...my eye goes there now every time I get into the car! Now that I'm committed to removing the tach to fix that, I might as well clean the glass, and add new gaskets - and LEDs...of course then, while I'm there might as well do the center cluster...then while there, looking at the speedo...well, you get it. When we undertake such things, might as well do cables, lights, glass, gaskets, everything so we never have to go there again in this lifetime, given the time it takes! So...has anyone seen a step-by-step process for disassembling and rebuilding our style tachs and speedos? I couldn't find on this site. The outside shops I've been quoted nearly a $1000+ for each instrument...I'd like to set up to do this as a side service at my business...so now I want to be gathering info on parts sources, lubricants, and procedures...such a source would no doubt be also of interest to those who may which to try this themselves on a spare gauge, although without custom jigs, may be a challenge, but with a yoga class and a lot of patience, doable...thanks in advance all on any thoughts!

Jordan

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #1 on: June 24, 2020, 19:01:40 »
Can't help with the guide but I think the hardest part will be getting the chrome bezel off the gauge and then back on so it doesn't look like you used a screw driver to do it.  The specialty shops have a special tool or contraption for removing the bezel without creating dents or creases.  I have sent gauges to some of them and I'm always amazed at how good the back of the bezel looks, just like it came from the factory.  Even being patient with a screwdriver it never looks good.
Marcus
66 230SL  Euro 4 speed

hansr433

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #2 on: June 24, 2020, 19:29:28 »
The same happened to me and drove me nuts.  Unless you have tools and the know-how, leave this to the specialists.  The chrome bezel will never look right and your keen eyes will always be drawn to the bits you messed up.  Here are 2 US based companies with good reputations for rebuilding VDO instruments:  https://www.nhspeedometer.com/ North Hollywood Speedo
http://www.paspeedo.com/ Palo Alto Speedometer Repair

In Europe, I can recommend: www.ka-ja-tacho.de KA-JA Tachodienst.  They rebuilt my instruments.  The tach is now rock solid without the constant fluctuations.

While you are at it, replace the cables.  I did not, and am now suffering because I have the remove the speedo due to a noisy cable.



Hans
1963 220SE Cabrio (Exterior: Navy MB 332, Top: Haarz Navy, Interior: 482P Sahara Beige)
1963 BMW R69S

Jordan

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #3 on: June 27, 2020, 00:50:13 »
There is also Seattle Speedometer (http://seattlespeedometer.com/).  It is a one man operation (Buz) so you may get a better return time.  Best to call to see what the back log is with all of them.
Marcus
66 230SL  Euro 4 speed

specracer

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #4 on: June 27, 2020, 11:41:38 »
With regard to getting them out, something I did, take out the drivers seat, then a piece of plywood to span across the cross member and a 4x4 up near the pedals. This creates a flat surface to lie on.

col320ce

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #5 on: July 06, 2020, 06:54:34 »
I carefully took mine off from behind with a screwdriver... Going around multiple times to straighten up the folded over bit of metal. Not levering it off but gently twisting the screwdriver.
I don't think you can tell from the front (you can from the back)
Col

1964 230SL
1965 250SE coupe
1993 320CE Sportline

perry113

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #6 on: July 06, 2020, 18:47:20 »
Not for the faint hearted.
More to it than the special tooling to remove the bezel.
Morris Mintz at West Valley Instruments is the best man for the job for the most reasonable price.
https://www.westvalleyinstruments.com/contact/
Peter Perry
1970 911T Bahia Red
1972 911T Albert Blau
1963 220seb coupe barn
1965 230SL Light Ivory automatic
1966 230SL Havana Brown 4 speed Barn Find
1970 280SE living 3.5 donor car

Alex D

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #7 on: July 06, 2020, 18:59:19 »
If you decide to send out the speedo, make sure you tell them tire size you have especially if they are not 185/14 or if getting new tires soon let the speedo shop know, other wise you speedo will be off and you will go crazy trying to figure out why.
Alex D
1967 250 SL
Original 140K mi
181 Light Beige, with  112 Turquoise Interior

doitwright

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #8 on: July 06, 2020, 20:30:26 »
I am not sure about how they do it now but in the past, the Speedo shop wanted you to count the number of Speedo cable revolutions over a given distance maybe 1/20 of a mile with the tires you plan to use. They would use that information to calibrate the instrument to your car.
Frank Koronkiewicz
Willowbrook, Illinois

1970 280SL Originally Light Ivory - Now Anthracite Gray Metallic

prefervintage

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Re: Speedometer & Tach - Is there a step-by-step rebuild guide??
« Reply #9 on: July 19, 2020, 20:34:14 »
You are right...any mistake on messing up an instrument, and one's eyes go straight to it! I took the advice here, and bit the bullet and got a replacement rebuilt tach off of ebay for $500 and will send out my original with the rolling bezel to a rebuild shop where someone with more patience than mine can repair it, clean it, and check it for proper reading. I'm testing the new one now with LEDs...see my post under White or Green LEDs in instruments...the green looks really bright and I will probably change everything to that...