935 Type Boost Gauge Rebuild

[Doug Smith]

Has anyone disassembled their boost gauge and refurbished it? The reset clutch on my tell-tale needle is very loose and the plastic gauge face is scratched. I'm considering replacing the face with glass and tightening up the clutch. Any experience with any of this to share? I guess the first step is to remove the bezel to access the internals. Is there a "least-damage" method to do this? For anyone who has had a gauge rebuilt by a vendor, were they able to remove the bezel and re-install it with no sign of damage? Thanks for any insight. Doug

[Doug Smith]

Here's a photo of the suspect.

[xbmwguy]

north hollywood speedometer does a great job

[turbobrat930]

Yep, NHS is THE place to go for anything VDO related!!!!

[Doug Smith]

I usually like to do all my own work but this is one case where I may need to rely on someone else. I'll call NHS and talk to them about it. Thanks!

[krasuskyp]

I removed my speedo bezel (shutup, Ronnie) to replace my odo gear w/o any sign of intrusion

my VDO tell-tale was in the exact same shape, and now my NHS version has THE most Chinese water torturest annoyingest 'jingle' at off-throttle / slight maintenance throttle... arrrghhh it's annoying - anyone ever fix THAT???

I'd give the boost gauge a DIY try before farming it off to NHS, but that's just me 8-)

[JFairman]

I've had mine apart to replace the black ring bezel because it was bent from a previous owner or mechanic.
To make the "jingle" that sounds like a trunk monkey with a tambourine you take the vacuum/boost hose and tie a knot in it. Get a longer hose it's not long enought
Seriously, thats how you do it.
Not too tight a knot, just snug enough to dampen the minute air flow going through the hose to operate the gauge.

I have some pictures of the inside of my gauge somewhere.. I'll post them if I find them.

[krasuskyp]

^nowai?

THANKS JIMBO! If that works, damn man... that's HUGE!

It's soooooooooooooo annoyyyyyyyyyyyyyying. Trunk Moneky heh heh... classic.

[JFairman]

Pics of the insides of it. Mine works great. The clutch is adjustable but I never had to adjust it.
The clutch looks kinda like brass wavy washers in there under light compresion. The green stuff looks like glue to keep the tension adjustment on them from coming loose.

[JFairman]

Originally Posted by krasuskyp

^nowai?

THANKS JIMBO! If that works, damn man... that's HUGE!

It's soooooooooooooo annoyyyyyyyyyyyyyying. Trunk Moneky heh heh... classic.

Worked for mine.. no more gauge jingle. I forgot where I got that tip.. it was from a phone call to NHS or someone posted it and I tried it.
Now there's no more tambourine in the trunk.

Those trunk monkey videos on you tube are hilarious!

[krasuskyp]

UDAMAN - as usual - Jim... thanks

[Doug Smith]

krasuskyp, mind telling me how you got your bezel off and back on without damaging it?

[krasuskyp]

dunno, really - it's kinda like a bra strap... you just twang it and it flies off!

kidding aside, I just used a really small flathead if I recall and OH SO CAREFULLY pried under the edge

Sorry, it was many years ago not long after I'd gotten my POS so I don't exactly recall - however - I'm no technowiz by ANY means... and... it was easy, even for ME

soooooo...

good luck 8-)

[JFairman]

Yup, short stiff knife blade or something similar and pry the folded over edge up a little more than half way around and wiggle it off. You can reuse the one you removed or buy a new one from NHS and fold the edge over to put it back on.

To fold that edge over on a new or reused bezel I put the gauge face down on a towel and while holding there with one hand I used a 930 wheel spacer and pushing down hard on it while rolling it along that edge with my other hand it rolled and folded the edge down like a factory job.

[Doug Smith]

So really, I'd be better off buying a replacement bezel and installing it instead of trying to re-use the one I take off. I suspected that was the case. I'll call NHS and see about getting a new one.
Another thing, my lens is plastic. Is that typical. I thought I'd replace it with glass. I'm assuming the other gauge lenses are glass but now that I think of it, I don't recall ever checking.

[WPOZZZ]

Just use Meguiars PlastX and polish the lens while it is apart.

[JFairman]

I've done this to other gauges in 912's and other cars and if you're careful you don't have to replace the bezel.
When the gauge is installed the back of the bezel is pushed up against the soft rubber insert in the dash so if it's a little buggered up you don't even see it.
I replaced some of mine because the person that installed the white gauge overlays in my car before I bought it bent some of the bezals.
They all ad some scratches and surface rust and needed repainting so I bought the shiny aluminum rennline bezel overlays and sanded them with 400 grit paper and spray painted them satin black enamel before installing them with black silicone glue.

The gauges in our cars come with glass in them and you can buy those from NHS too.
The VDO/NHS mechanical boost gauge has a plastic lens.. probably because there's a hole drilled in the middle for the telltale reset key. I'm sure you can buy a new one of those or try wet sanding and polishing any scratches out while it's removed.

[Doug Smith]

I'd rather have a glass lens. My objective is to replace the plastic lens with a glass one and tighten up the tell-tale needle clutch. The large scratch you see in the picture of my gauge is actually a crack. And since these things are so pricey, I'd prefer to have it look as original as possible once I'm done. I think I'll look into buying a replacement bezel because I know I'll screw this one up trying to get it off. I think I can roll the edge back down easily to re-install a new one. Like everything else with this car, this simple task is turning into a big project. I guess that's why I love my 930 so much. I'm never bored for lack of a project... I appreciate all the information and advice. I'll post some pictures as I get into this.

[Ronnie's.930]

Originally Posted by krasuskyp

I removed my speedo . . . (shutup, Ronnie) . . .

Paul removed his speedo and put it on this Ken Doll - notice it fit perfectly!