Fixing up the instruments on my 1940 56S (long!)

[Daves1940Buick56S]

I've said in several previous threads that I have been working on the dashboard and the instruments. This will be kind of a summary of what I did and how I did it, along with some pictures to illustrate this in hopes that future users may take advantage of some of the things I learned.

What I started with:

The first thing you have to do, obviously, is to get the instrument panel off. I suppose that you could get the instruments out and leave the panel in, but it would seem to be exponentially more difficult. The panel has four studs with nuts holding it on to the dashboard. There are two on the right side, another in the lower left corner, and the last one about in the center of the curve on the upper left side. This is as you are looking at it from the dashboard. The easiest thing to do is to pull the grill, and if you have it, the radio. This way you can get to the two right-hand bolts really easy. Also, it's a little bit easier when you're working on the wiring and getting the speedometer and other things out to go in from the right side through the grill area. Now, getting the grill off can be a little bit tricky, because they are square studs held on by Tinnerman nuts. Once you get those pried off, you can put them back with rubber grommets and that will hold them firmly in place so that you don't have to go through that again. So once you get the grill off, you can easily get the two right-hand nuts off. The lower left-hand nut is a little bit more difficult because it's right in the middle of a metal structure but you can work your fingers in there. The hardest one is the one on the upper left side. The important thing to remember is that the dashboard kind of curves around up at the top so you actually have to put your fingers above where that metal curves in. Once you get those off use a grommet or something so you don't have to go through the mess with the nut.

Once you get the panel loosened, you can just pull it forward a couple of inches and you will have access to all the instruments. I took the right-hand instrument pod, the one containing the gas gauge and the oil pressure gauge, off first. The gas gauge was just held on by a couple of wires, and the oil pressure by a metal pressure line which can be loosened using, I believe, a 5/16 inch wrench. Once you get the wires and the oil line off it's easy just to pull the 2 nuts on the backside and remove the pod. The speedometer has four lights, two of them instrument illumination lights and two of them bright light indicators. Once you pull those and the speedometer cable, there are 3 nuts to remove and in the speedometer just comes out really easy. The left-hand pod contains the ammeter and the temperature gauge. The wires for the ammeter are easy to remove, but in my case I just removed the pod from the instrument panel and just kind of left it hanging in place could as I didn't want to go through the hassle of pulling the temperature sending unit at that point and the tubing through the firewall. So I just kind of did all this with that pod still in place.

Original instruments and wiring:

So the first thing I did was to work on the right side pod. In the shop, I undid the tabs holding the bezel of the pod to the back plate. Basically you can pry up the corners with a screwdriver and then bend in the rest the way up was square jaw pliers. Once you do that you can pull out the back plate and along with that should come the metal backplate of the gauges, a rubber gasket, plexiglass containing the engraved white painted numbers, another gasket, and then the cover glass. So separate all those out and you should have the two gauges or instruments themselves in the back plate assembly. The gas and oil instruments are both held in place with a couple of screws. You can remove those and the instruments come off pretty easily.

Next is replacing the plastic backs for the gauge faces, which I got from a vendor that was for a 1941 - 47. They will all work on a 1940 except the chapter ring is not correct for the speedometer. But I decided to go ahead because what I had was pretty bad so I needed something. The plastic faces are glued into a metal shell that is riveted onto the instrument frame and getting them off is a is a little tricky. To remove the rivets you have to use small drills and in my case I put them in a pin vise and not in an actual electric drill. That way you have a lot more control over what you're doing. I use three small drills ending with the number 33, each drill larger in size than the previous. So once you get the rivets drilled out you can kind of pop the back plate assembly loose and twisted around 180° and pull it away from the indicator needle. When you do this you will see how it works.

In my case the old plastic face just crumbled away so I cleaned it out and then I used a wire brush on the metal backing plate to clean off the old glue. I then mounted the new face in place and held it with a little bit of RTV. The rivets that I had previously pulled out I cleaned up and I had to countersink into the plastic a little bit since the rivets have to go in slightly deeper since you don't have as much rivet to work with as they had originally when they assembled this. So once you do that they'll stick out far enough. You may have to clean out the original rivet holes a little bit and enlarge them slightly. Again, a 33 drill works nicely. Once that was all done I remounted the plate and held in place with some Elmers Stix-all glue. I made sure that everything was parallel so that so that nothing was leaning forwards or backwards and it would mount properly in the gauge back assembly. Once it was all dry I put some papers on top of the plastic face to protect it and painted the needle indicators a nice red color to restore that. Also, the plastic doohickey that is attached to the metal backplate is held in place by a metal "circle and spear" that is in turn riveted to the backplate. Drill out the rivets as described above.

In the case of the oil gauge there was a couple of hinge points that the Bourdin tube uses to move the pointer. I put just a little bit of clock oil on those to make sure they were lubricated. The gas gauge kind of swings loose so I just put a little tiny bit of oil where the pivots are. Also, my gas gauge indicator needle armature was actually physically brushing up against one of the coils so I was able to bend it down a little bit. That is why my gas gauge always maxed out at only three quarters of a tank so that is now repaired. I check continuity all the coils, and just to be sure I re-soldered where the small wires go, and then double checked it with freeze spray to make sure I had a good hot joint. Once all this was done I remounted the instruments into the pod back.

I was trying to figure out what to do with the metal backing plate since it had oxidized to a greenish color. I know they are steel with some kind of anodized copper coating. I thought about trying to replate them but I understand that that is difficult to do and the surface has to be absolutely pristine or it will not work. So I decided the easiest thing to do was just to paint it. After looking around I found a Rustoleum color called Sienna Mist that is very close to the original so I painted the plates with those. This was not only for the right pod but the left pod, the speedometer and the clock. On the pods, the new plastic doohickey is attached to the front of the backplate after the paint has cured. The rivets have been drilled out but there should be enough left to act as a guidepin, and the assembly can be glued in place with Stix-all. The plexiglass was a little bit marred and I polished it up as best I could. In some places the lettering had actually come out of the places where the numbers and letters were cut in reverse in the plexiglass so it was just simply a matter of getting some light ivory model enamel at the local model store and then filling in the letters and numbers where the paint was missing. It matches pretty close it looks really good. So basically that was it for the right pod.

For the speedometer, I already had another thread detailing the work on that. It was kind of a mess because it is a lot a little tiny parts, almost like working on a clock. But I was just a pretty simple matter of keeping everything straight and cleaning everything up and lubricating it properly when reassembling. Pay especially close attention to the pivots of the cup. Just put a little tiny bit o'clock oil on each one just to make sure it will swing free. My odometer was actually in pretty good shape. I just had to clean a little bit of the old grease out of the driven gears and apply some fresh grease. The reason why the odometer was stuck was at the trip mechanism gear was interfering with the operation of the odometer. I fixed that and now it seems to be working pretty well. I tested the speedometer with a drill at 300 RPM with a square drive and it looks pretty good. The one trick with the speedometer that I had was that someone had replaced my 0 to 110 mile-per-hour with a 0 to 120 mile-per-hour, which is more correct for 1941 and later. So I managed to get a speedometer face-off eBay with the correct 0 to 110 mile-per-hour plexiglass. A little bit beat up, but it looks better I think than the original as far as being correct plus I have 2 bright light indicators and the 1941 plexiglass covered one of them up. The colored filters on the bright light indicators had all faded, and I replaced them with some red acetate that I got at a local art supply store. It took several layers to approximate the Ruby red that was there originally but I was able to make it work.

I have reached my image limit so stay tuned for Part 2!!

Cheers, Dave

[Daves1940Buick56S]

Part 2:

The left pod was a little trickier since it was still in the car, but everything went pretty much as the right pod as far as drilling out the rivets cleaning everything up and putting the new faces on them and putting it all back together.

The turn signals were a bright green originally and they had faded as well. I matched the original green to a green color separation filter, Kodak Wratten 61. I managed to get one on eBay for a few bucks, and it took two layers on each side to get the proper density of green. But it looks pretty sharp now.

One of the things that was messed up in the car originally was at the wiring was in bad shape behind the instruments, which is why I started this to begin with. So I basically cut out all the bad wiring and where necessary, replaced with modern wire. Since this is a driver I was not too worried about keeping it original, I was more worried about safety. If you are restoring your car and your wiring was as bad as mine then I would recommend a new harness. Once you get the instruments out and take it all apart it really doesn't look like it would be that difficult to replace the harness. But I patched everything up, and in many cases, especially for the lights, I extended the wiring and connections so that there would not be as much pressure on the wiring putting it back together. This way I was able to loom everything very nicely with everything out of the way and make it really easy going back together. I also fixed some problems that were there originally, such as the map light not working. So basically all the wiring patch ups were done. Also use some F4 tape for cleanup.

So once all this was done I mounted all the instruments back onto the instrument panel then connected all the wires and put the lights all back in and then mounted the panel back on the dash. It was kind of a big job but it was worth it and I think that way I don't have to worry about what's going on behind the dash anymore.

In my case, I wanted to add a few things, like the power for the add-on heater, and power for fog lights, and anything else I might want to add later. So rather splice in new wiring since the 1940 doesn't have a convenient fuse panel, I went ahead and created something myself. I basically took some terminal strips and glued them together to make a kind of a bus bar. One section of the bus bar was for chassis ground, another section for the 6V illumination power, another section for 6V power, and then the third section for 12V power. The reason I wanted 12V is I have an old 12V tach that I wanted to use that requires it. The response is not linear at all if you use 6V with this tach, at least not mine. To get the 12V I got a 6V to 12 V DC module off eBay for about 10 bucks and it provides up to 3A so if you want to run a small transistorized radio or something like that there's plenty of power. To power the 6V portion of the bus bar I mounted a 6V relay on the firewall by the voltage regulator. I ran a line from the switched part of the ignition switch out to the relay to drive that, and then brought in higher current capacity from the relay to the 6V bus bar. I use this to power the heater fan and also the electric fuel pump and power to the fog light relay. All of this is fused of course. I have another relay on the firewall for the fog lights so the heavy power is strictly under the hood for those. Yes, I know it's not original, but I wanted to be safe and since this is a driver that is more important.

All done (for now!):

I also did quite a bit with the clock but I will put that in another thread since I put a new design piece that may or may not be of interest.

Cheers, Dave

[Barney Eaton]

Good information.....keep it coming

[danhar1960]

Well done Dave !! Love your work. :)

Danny

[Daves1940Buick56S]

Thanks Danny and Barney!

[Mark Shaw]

Great Job Dave....!

[MrEarl]

Great thread, giving it 5 stars right now.

[Buicknutty]

Excellent looking work!

Keith

[Daves1940Buick56S]

Thanks Mark, Lamar, and Keith! I will post a thread on overhauling my clock later in July after we return from Colo.

Cheers, Dave

[Guest BigDogDaddy]

Umm, has anyone heard of the Buick Bugle ? Maybe Pete would like this for an article in the Bugle.

Phil

[Pete Phillips]

That's a technical article in the Bugle, if I ever saw one!. Dave, can you get me larger blow-ups of your photos? This is excellent.

Pete Phillips

pphillips922@gmail.com

[Daves1940Buick56S]

Pete:

I sure can. Also, let me clean it up a bit. I originally did it using Dragon, so it is more "conversational" than I usually write. I will email it to you in a few days.

Cheers, Dave

[kingrudy]

Very nice thread, I have one question about the Speedometer. I purchased my car in 2007 and the speedo and the rest of the gauges looked pretty. I purchased the kit to replace all of the plastic and I was warned the plastic for the speedo was for 120 mph and my 56S had a 110 mph dial. May be it had been changed before I got it, but it already was set up for 120 mph. I have not verified that it is reading accurately. I'm sure you have more experience than I do on this.

 

Mike

[Morgan Wright]

The 120 MPH speedo (from 1941 to 1947) is the same as the 110 MPH (1940 only) internally,  they just added the 120 after the 110 on the glass. They didn't change anything to the calibration of the part of the scale that goes from 0 to 110. Imagine having a 13 inch ruler. The first 12 inches are the same as the 12 inch ruler.

 

No need to calibrate anything!

 

Well, I can't guarantee it's accurate. Mine reads a little slow, it says 55 when I'm going 60. Depends also on your tires.

[Morgan Wright]

This topic has lots of good information. I had a huge struggle fixing up my dashboard last september: