Installing a siren...

Paul Steinberg

Paul Steinberg

PCS Life Member President
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Everyone knows that an ambulance needs to have a real siren, not some dinky little burglar alarm type stuffed under the hood. For this reason, I borrowed a vintage Federal WLR from Jim Staruk to see how I liked the look on my Chevrolet. After having it sitting on the roof, I decided that a siren with a front light would be the correct thing for this car. After procrastinating all week, I decided to do the install today.
I started by finding the exact center of the roof, by measuring up from the windshield molding 11" and taping a cloth measuring tape to the inside of the drip rail, and pulled the tape to the other side. I then put a piece of tape on the roof at the 72" mark, and then measured to that mark from the other side using the same method. I added the two figures together, and divided by two, and place a mark on a piece of tape that was put on the area of the roof center. Then I repeated this procedure 8" back from where I originally started, and put a mark on the center like I did the first time. Using a piece of cardboard, I drew a line between the two marks, to have a continuous centerline on the roof.
Next step was to determine the center line of the bracket. This was a lot easier, since I could hold the bracket in my hand and measure. I determined the center line by measuring from the left edge of the front left hole to the left edge of the right front hole, and divided this by two. I now knew the center line of the bracket and put a piece of tape on the front of the bracket and marked it. I did the same with the rear of the bracket, and then cross checked both lines diagonally front to rear. My marks were dead on!
Next I placed the bracket and centered it on the roof, and using a small torpedo level, I moved it toward the windshield until it was level. I also checked the center of the roof first to make sure that the car was sitting level. This picture is a "test fitting" of the bracket. I have had this chrome bracket for a number of years, and am glad that I never parted with it. It is the only one that I have ever seen, since all that I have ever seen are the cast aluminum ones.


Next I marked the location of the hole centers on the tape, and taped the entire bracket to the roof. I had already determined the size of the front and rear bracket holes, and true to most production items, the front holes were larger diameter than the rear holes. Using the drill bit that matched the rear hole, I made a small drill mark on the roof that was centered in that hole. I then proceeded to use small drills, moving up in size as each one broke thought the roof skin until I had a hole that would accommodate a 5/16" threaded bolt.


Here you can see the hole that I drilled and the center line. I moved the bracket to the side to remove the metal chips, and to check the hole with the bolt for clearance.


Next I bolted the bracket securely to the roof, and checked my alignment of the bracket to the center line. I could see that the rear mark was perfectly aligned, but I couldn't tell if the front one was because of the angle I was working from. For this, I used my camera as a telescope, and found that the alignment in the front was off.




I gave it a nudge, and checked again....... I got it right this time. Taped the bracket down again, and drilled a hole for the front right bolt. Put the bolt in, and double checked my marks again, and everything was still lined up correctly. I then secured the front right bolt, and proceeded to drill the last two holes.


Once I had all 4 holes drilled, I once again unbolted the bracket, removed all the chips from the roof, and removed the tape. I then put the bracket on the roof and used rubber washers under each bolt hole, and secured the bracket to the roof. Once secured, it was time to fasten the siren light to the bracket. I thought that this would be easy, since it only requires one bolt at the rear to secure it. I could have used another hand to hold the siren, and then inserting the bolt would have been easy. I finaly got it done, without dropping the siren, but I was sweating it for a while, fearing that it was going to fall and get damaged. Not a good thing to happen to a borrowed siren.

 
Now that the siren mount is installed, the next step is to remove the mount, and install a reinforcing plate under the siren. I had a 14 gauge steel plate cut, and bent to the curve of the roof, that is large enough to brace the roof from vibration cracks caused by having the siren mounted up there, but small enough to fit through the zipper opening in the headlining. This will be the next step, however, I am going to wait for a cooler day to start this next phase.

A few things come to mind that I didn't mention in the above post. I had checked the headlining to roof panel clearance, and it seemed to be sufficient that I didn't need to worry about the drill going through and damaging the headliner, however, I didn't want to take any chances. For that reason, I folded up a large towel, and placed it between the roof panel and the headliner as a safety precaution. I figured that if the drill were to hit the towel first, it would protect the headliner. I am happy to report that I didn't damage the headliner.

Last week, I ran 4 wires up the drivers A pillar to supply current to the roof lights, siren, and siren light. A single 12 gauge wire goes to each torpedo light, and is connected to a flasher under the hood. A 10 gauge wire goes from the siren solenoid to the siren itself, and there is another 12 gauge wire that will supply power to the siren light.

I haven't decided exactly what type of siren that I am going to ultimately install on the car, since I know that I have a few that will work, but they are presently hiding from me somewhere in my garage. That is the problem when you put things into boxes, don't label them, and then move everything around in an effort to clean the garage.
 
Paul,Thank you for that great post !!:clap:

Very helpful when doing a mount......as far as the siren goes....it LOOKS awesome !!...what the heck just leave it up there and wire it !!

just tell Jim you decided to use it and will put the $100 in the mail .....:yum:
 
A quilt or thick blanket on the windshield....

I've put Q's on most of my ambulances. I put a quilt or heavy blanket on the windshield, then shut the front doors on it. This was to protect the windshield from scratches in case it got away from us. Always had two people present. I put an L bracket against the metal roof of my Suburban because the Q, along with the 2 CP speakers caused some buckling. These brackets come with holes in them and I recall having at least one bolt from each CP go through the bracket. At this time we hadn't put the ceiling fabric in yet.
Thanks for sharing, Paul.
K
 
this was the most important step
"I also checked the center of the roof first to make sure that the car was sitting level"

one other place to check that might have been better would be to open the doors and set it on the rocker sill. use a frame jack to level the car. left and right place it in the rear door.

the best drill stop I have ever use was a heavy cardboard tube that slide over the bit . you just cut it to length. I think I used one once.

if you really can't decide if that siren is what you want. make a cut out and play with it a little. because once you drill the first hole your kind of committed.

come on now Paul step back and give us a shot of the whole car so we can see.
 
For me, I'd start with:

Step 1 - buy a siren.

And I like Kevin's suggestion with the blanket, though I suspect that, if you drop the siren, scratching the windshield would be the least of the worries and the blanket would probably go through the windshield with the siren... :657:
 
had I known that I would have keep it here!! I'll make you a copy of the key for his 69 so you can have some leverage.
 
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