Bulb Mounting Tips
How to mount large or mini bulb to your horn
These tips work for almost all bulb horns.

Want to get the most from your bulb horn, or even change the tone? See Bulb Horn Tips

We currently offer replacement bulbs in two sizes: Large and Mini. Large Bulb fits our Circular, Large, Small and Straight horns plus virtually all vintage car, taxi, antique, old-brass and clown horns. Also fits Dobani product code: BULL, BULS, BULH, BULD, and BULO. Large bulb does not fit Double Bell or Mini horns. Large Bulb Mini Bulb fits our Mini Bulb Horn plus various "bicycle-size" car, taxi, and clown horns. Also fits Dobani mini bulb horn product code: BULBM. Mini Bulb These bulbs fit most vintage bulb horns with no problem. Just screw on the bulb and start honking. But the screw fittings on some bulbs and horns are close, but don't quite match, and can be a little fussy. If you need a rubber bulb like original equipment, then you will want to find a shop that specializes in vintage auto parts. Some of those shops offer premium priced reproduction car horn bulbs manufactured for your specific horn. Prices start at around twenty-five dollars. But if our bargain priced rubber bulb does not quite fit your horn and you want to save a little time and cash, below are tips from customers who describe a few easy ways you can attach the replacement bulb to make that old horn squawk like new again. Both Tubes Same Size, or No Threads? If you want to attach the horn tube to the bulb tube, but they are both the same diameter (i.e. one will not fit inside the other), then try an inner sleeve splice. This surprisingly easy solution fastens both tubes using a tube within a tube. "Extremely simple, 5/8" (15.9 mm) diameter nylon spacer fit inside the tubes like a glove," reports Alan in California adding, "nothing else was needed." Need to Splice Mini-Bulb Tube to horn tube? Try 1/2" (12.7 mm) diameter nylon spacer wrapped with electrical tape. Same Size? Try Innersleeve Splice Bulb Tube Diameter Too Big? This is the easiest fix for most situations. Try wrapping your horn threads with teflon tape. That's the stuff plumbers wrap around pipe threads to prevent leaks. If teflon tape won't work, then try electrical tape. But if tape won't work, then consider attaching the bulb permanently using epoxy putty, solder or other adhesive. A better alternative might be to remove the brass tube and replace it with your own, which is described below. Wrap Threads with Teflon Tape How to Convert Regular Bulb into a Plain Bulb in 2 Easy Steps: If you already own one of our large or mini Spare Rubber Bulbs, feel free to swap it for a Plain Bulb. But if you want to save time, then you can convert your regular bulb into a plain bulb. How? It's easy. All you have to do is remove the brass collar and tube. 1. Remove Brass Collar Remove brass collar using small screwdriver with 1/8" blade (e.g. shirt-pocket screwdriver). Carefully pry rim crimp open. Push up and outward. Lift collar off. Re-attach later or discard. Pry Off Collar 2. Remove Brass Tube With the collar off, push screwdriver down between tube and rubber neck to loosen adhesion. Wiggle the tube and twist it out. Locking pliers work well. Important: Be sure to twist metal tube clockwise. That's because the end of the tube inside the bulb is crimped with sharp fluted edges. The tube end might flare out and rip the rubber bulb hole/shaft when you remove it. So to prevent damaging the bulb, simply twist metal tube clockwise. Twist Tube Clockwise Tips: "I applied some oil on the old bulb threaded tube as well as the new, where it attaches to the rubber bulb," says a customer from Pennsylvania. "I was able to use the old tube in the new bulb. The first time I squeezed the bulb, my cat almost jumped through the ceiling. The horn works fine!!" Oil helps remove bulb from tube. Let oil penetrate. Remove oil residue with rubbing alcohol after tube is extracted. Apply a small amount of "thin" or penetrating oil at the tube/rubber neck. WD-40 oil has also been recommended. Clean off any residual oil or alcohol after removal. "I was able to remove the tube in the bulb by cutting 4 slots and collapsing it, then was able to turn off," reports a customer from from Saint Louis. "My tube fit snug into the bulb, sounds great and will be a nice piece to hang on the garage wall." Plain Bulb Mounting Tips Our plain bulb is a rubber bulb with no hardware (i.e. no brass collar and no brass tube). The plain bulb is available in two sizes: large and mini. The large size fits most vintage bulb horns. The mini fits small bicycle-size horns. Below are hole/shaft dimensions and instructions on how to install your horn tube into the plain bulb. Plain Large Bulb The large Plain Bulb hole/shaft diameter is 9/16" to 5/8" (14.3 mm to 15.9 mm). Plain Large Bulb should work if your tube OD diameter is 5/8" to 11/16" (15.9 mm to 17.5 mm). Plain Mini Bulb The Plain Mini Bulb hole/shaft diameter is 1/2" (12.7 mm). Plain Mini Bulb should work if your horn tube OD diameter is 1/2" to 5/8" (12.7 mm to 15.9 mm). How to Install Horn Tube into Plain Bulb in 2 Easy Steps All you need to do is plug your horn tube into the bulb and attach a collar if you got one. 1. Insert Horn Tube Carefully insert (twist) horn tube through bulb hole/shaft opening. Tube not snug enough? Then wrap end of tube with electrical tape to increase diameter. Or apply a little contact cement or superglue (cyanoacrylate) on tube to create a tight seal. Some customers insert a thin basswood shim to improve the fit. Tube slightly too wide for bulb? Then increase hole diameter with sandpaper or round metal file. 2. Attach Alternative Metal Collar if Desired This bulb is designed for a crimp-style collar. Position collar over tube and bulb neck. Use flat blade of small screwdriver, manual press, or other tool to compress collar rim firmly into bulb neck. If crimp-style collar won't do its job, then a ring collar might work if you have one that fits. If tube is secure enough without a collar, then you are probably good to go without one. But if tube is unstable, and if looks are not important, then trash the collar and secure the tube with a hose clamp instead. Now you're honkin'!™ Questions? Give us a holler.