VDO bezel and glass removal

23e Heure · Post by **23e Heure** » Mon Dec 05, 2016 10:18 pm

VDO bezel and glass removal... Is there a trick to doing it yourself?

Or is it a case of needing the (special) tool for the job?

Are later gauges easier, and if so from what year?

I have a couple of SC oil gauges:

They seem to have a tab to push to allow the ring off:

What do i press down on them with, a wide screwdriver?

I want to open one up and stick a silver dot on it, to make it consistent...

23e Heure · Post by **23e Heure** » Mon Dec 05, 2016 10:43 pm

Oh... does anyone know where I could get hold of a silver dot?

jtparr · Post by **jtparr** » Mon Dec 05, 2016 10:48 pm

Small flat head screwdriver...say 2 or 3 mm wide..insert carefully under the crimped rim and then work your way around easing back the rim bit by bit
Slightly nerve wracking as you will worry about scratching the bezel...so wrap it in masking tape to protect should you slip....
All quite doable...just be patient...ease a little all round...then go back and start again...easing more...don't try to simply bent it back in one go

Jp

inaglasshouse · Post by **inaglasshouse** » Mon Dec 05, 2016 11:05 pm

Jonathan,
How about the reverse process, when you want to crimp the rim back on? Have always assumed that some kind of jig would be useful / necessary (to push the entire rim back inwards in one go, as opposed to working on small sections). What would you recommend?
Cheers, Richard.

nj1052 · Post by **nj1052** » Mon Dec 05, 2016 11:28 pm

When I was rebuilding the instruments on my Laverda I fitted a circa 1" o/d standard ball bearing onto a bar which I mounted on a lathe tool holder. I then mounted the assembled instrument in the chuck, held in place by the tail stock, and gently pressed the bezel rim back onto the housing a very low speed. It worked perfectly.

jtparr · Post by **jtparr** » Tue Dec 06, 2016 12:14 am

inaglasshouse wrote:Jonathan,
How about the reverse process, when you want to crimp the rim back on? Have always assumed that some kind of jig would be useful / necessary (to push the entire rim back inwards in one go, as opposed to working on small sections). What would you recommend?
Cheers, Richard.

Originally I am sure it would have been crimped on one go...but not having access to such machinery I reversed the process and used a blunter screw driver to re form the opened metal...a 2 or 3mm flat faced metal punch would also suffice...with the unit sitting front face down at my study desk..i.e. the clean desk..not the garage work bench..!..again..slowly and smoothly all round..bit by bit....we are lucky with these instruments as the rubber mounting ring conceals the back edge of the crimped metal retaining ring...so minor creases from pressing the metal back into shape are concealed

sladey · Post by **sladey** » Tue Dec 06, 2016 6:47 am

James I'm interested in doing something similar to my later gauges, and therefore interested in whether anyone knows re the silver discs.

One other thought though - I'm not convinced that there is a silver disc on the temp/oil gauge?

23e Heure · Post by **23e Heure** » Tue Dec 06, 2016 7:07 am

The silver discs sound like a simple job for 3D printing.
Surely someone must be "doing" these already?

Mark: Do you mean to say you are not sure if early oil gauges had silver dots?
If so, ponder no longer: they certainly did.

Lightweight_911 · Post by **Lightweight_911** » Tue Dec 06, 2016 7:46 am

As an amendment to Jonathan's method, I use a short length of wooden dowel (approx 8mm diameter) to press the rim 'overlap' back into position on the rear of the gauge.

Darren C · Post by **Darren C** » Tue Dec 06, 2016 8:28 am

This is whats required.

http://rennlist.com/forums/attachments/ ... zetool.jpg

Removal is by carefully prying up the return fold. Without a special tool you can get away with 2/3 fully pry up and manipulate the glass out the remaining 1/3 I used a beech wood (hardwood) wallpaper edge roller about 1" wide to roll the edges back on my 914 gauges (you can see the result in the 914 section on my resto thread) while resting them face down on some sheet rubber. The clock is the hardest as its got the adjustment knob through the glass and needs a hole in what ever you rest it on. Make sure the sponge rubber seals are fitted correctly in the bezel and not damaged. The edges of the bezel need a good roll flat treatment to compress these seals as VDO gauges are notorious for steaming up, especially at this time of year.
If you're painting the bezels, use a plasticiser as the paint will crack/flake when you refit and "roll" the edges.

inaglasshouse · Post by **inaglasshouse** » Tue Dec 06, 2016 9:13 am

Darren C wrote:This is whats required.

http://rennlist.com/forums/attachments/ ... zetool.jpg

Excellent, love it:

I think we need a DDK special tool lending library!

911hillclimber · Post by **911hillclimber** » Tue Dec 06, 2016 9:23 am

I've done this on several 911 and motorcycle gauges and bike headlamps, and as described, 'easy easy' does it for taking all apart, and same in reverse but applying pressure to compress to some small degree the rubber washers sandwiched in the assembly.
A wooden dowl will ease the nerves when crimping back, and of course get the inner face of the glass super clean but also all other surfaces or that one spec of dust will be visible....

The bezels will have been rolled over to set them in the factories.
As for the conical silver centre discs, ebay for some scrap 911 gauges maybe?

23e Heure · Post by **23e Heure** » Thu Dec 08, 2016 5:43 pm

Related topic: pegging your speedo.

I really fancy fitting a 120mph speedo to the car.
Yes the car will be capable of a significantly higher top speed, but on the road I should never get near that <ahem>.

But I am likley to use the car in germany on unrestricted routes, and also have plans to do a few track days.

I have googled and got confused about "pegging" mechanical speedos.
Research results range from "Exceed the top indicated speed and your speedo is broken forever"..
...through "You can exceed the max, but calibration will subsequently be buggered"...
...all the way to "Only some speedos don't like being max-ed, your one might just bounce at the top and then return to normal when your speed drops".

Can anyone give me accurate experienced advice, hopefully directly related to mechanical VDO speedos for early porsches?

If indeed exceeding the max is a no-no for our speedos, is there any mod available that acts as a protection mechanism?

Lightweight_911 · Post by **Lightweight_911** » Thu Dec 08, 2016 6:00 pm

Why not have 2 speedos - 120mph version for road use (if, for some reason, you prefer that style) & a 150mph version for de-restricted roads & track outings (quick & easy enough to swap) ?

Personally I'd fit a 250kph speedo ...

23e Heure · Post by **23e Heure** » Thu Dec 08, 2016 6:09 pm

For some reason I quite like the idea of having a 120mph unit fitted.
It helps that I have one going spare, just needs the bezel painting, the face I like with its faded needle and yellow numbers.

Although I can't pretend that a 120mph unit would render the car "understated", what with it sitting right next to a 10k tacho.
Oh and fitted to a car that - according to some people - is going to be festooned with stickers

I also have a (later, non silver dot) 150mph one, and I could swap that in for hoon sessions.

Still interested to learn about the risks - or not - of pegging one of the early speedos...

DDK - Die Deutschen Klassiker