T3 Headlight Mod for H4 Bulbs
 

I finally got fed up with my reproduction T3 Bulbs blowing. Ive lost (2) bulbs in about a little over a year and I only use my headlights a handful of times a year at best. At $170 a set on ebay, I cant be replacing bulbs once a year.

At first I decided to give a set of H4 ecode headlights a try. You can actually buy a really high quality set of Japanese ecode 7" headlights from your local toyota dealer for only $20. Its a ridiculous low price and includes (2) koito ecode headlights, a full harness with all the relays and an apology letter from Toyota to FJ Owners for dicontinuing the sealed beam version. Part number 81110-60P70. List price is only like $23. I called one local dealer that quoted me $40+ but a call to another dealer and I scored them for $20. They fit really well, Have a very thick glass lens, and a stainless rear ghousing. Plus the bulbs are held inplace with a locking ring rather than the cheesy Spring clip like most. I didnt use the relay harness, but I only kept the 55watt bulbs. If installing higher wattage, I would use the relay harness. I just couldnt stand the look of the Flat lens so I started researching cutting the lens of the reproduction T3 Sealed Beam bulbs and grafting them onto the Koito H4 housings. Thats what I ended up doing.

Re: T3 Headlight Mod for H4 Bulbs
 

I found only (2) threads after searching the internet showing this mod and I really had to look so I documented my process.

I used a Dremel Tile Blade EZ545HP and its Arbor EZ402 setup in a drill press. I bought a 2-1/2 Qt Paint mixing bucket and this was the perfect size to hold the sealed beam light somewhat level. I set the Drill press on a medium speed. I tried the slowest setting but it wasnt cutting very well. I used a spray bottle with water to keep the glass dust down, Turned the drill press on and spun the bulb around slowly until cutting the lense off. There is somewhat of a seam already on the edge of the bulb to follow. I will say the bulb glass is very strong, I dont think you need to worry about it shattering. At one point the blade grabbed and threw one bulb from my hands and still nothing happened. Just go slow, wear gloves and use medium pressure to cut the glass.

Re: T3 Headlight Mod for H4 Bulbs
 

Onening the Koito H4 Bulbs was a little tricky at first. I heated the bulb in the oven at 240* for 20 minutes to soften the factory glue. That let me scrape the glue out from around the edge with a pick but I still couldnt get the glass to release. I ended up spinning the bulb face down and heating the back edge of the metal housing with a heat gun. This worked way better. I was able to work the tip of a right angle pick under one edge of the glass. Once I did, the glass was easy to pop off the housing. Wear gloves and eye protection. I did splinter small pieces of the glass lens off while doing this. I then scraped most of the factory glue off of the housing with small flathead screwdrivers, rinsed the housing out and dried them with compressed air.

Re: T3 Headlight Mod for H4 Bulbs
 

Both of the write-ups that I found doing this mod previously used a 2 Part epoxy to attach the T3 Lense to the H4 housing. I had the 3M DP100 epoxy on hand but after seeing how Koito had their lens attached I decided to use a Butyl Rubber tape instead. I found a Gray Colored Butyl tape at my local home depot for $6. I figued gray would hide better inside the glass rather than using a black butyl like the newer plastic headlights and I was right. I formed the butyl into approx a 1/4" rope and set it in the groove on the housing. I pressed the T3 lens in place. Than I re-heated the back edge of the housing with the heat gun and pressed the lens deeper into the glue. I probably didnt have too but after that I filled the edge that was left with some Clear Rubberized Silicone.

The first lens dropped right into the housing with a nice fit. The second lens was a little too tight so I had to spread the outer lip on the metal housing a little by lightly tapping outward around the perimeter.

Re: T3 Headlight Mod for H4 Bulbs
 

afterletting them set for an hour or two I installed the completed bulbs back into the truck. The rubber boot around the back of the bulb is a tight fit into the hole in the factory bucket but with a little dilectic grease it slides into place nicely. The factory headlight retainer rings are a tight fit around the new metal H4 housing. I had to file the edge of the metal H4 housing on the one side that I spread open a bit to make the trim ring fit, so keep that in mind and dont spread that open any more that you need too fitthe glass. Once I get a chance I will take it outside in the dark and to check the beam pattern and adjust.

With the H4 Housing one could install Higher watt Output bulbs, led options and such. Personally I just wanted to keep the OEM look and be able to replace the bulbs themselves rather than order $170 headlights everytime they fail. I like the Original Yellowed Dim look that it has.

Re: T3 Headlight Mod for H4 Bulbs
 

Nice work. Does the butyl tape harden or set up? I thought it was supposed to stay pliable.

Re: T3 Headlight Mod for H4 Bulbs
 

Excellent job, I can't wait to try this myself.

Re: T3 Headlight Mod for H4 Bulbs
 

It does stay soft. Its easier to squeeze into place, seal and stick together with a little heat. its what they use on the New Lexan Style oem type headlights so I figured it would be acceptable. That $6 roll from Home depot was enough to probably do 50 headlights.

Re: T3 Headlight Mod for H4 Bulbs
 

Good job and a great write-up. A couple observations / questions if you don't mind. Curious about the high- and low- beam patterns, since they are determined by both the reflector and the lens.

Also, you're using H4 bulbs, I believe -- so why do the lamps appear somewhat yellow? All in all, a very original, vintage sealed-beam look! :chevy:

Re: T3 Headlight Mod for H4 Bulbs
 

Yes Ill post the Beam Patterns once I get it outside in the dark and get some adjustments dialed in. The stock H4 Bulbs that came with the Koito toyota lights are a standard 55/60 Halogen bulb and still have a very yellow look to them. I do like it as they look very original when lit up. there is a large reflector inside the Koito Light housing that reflects light back to the "bowl" these likely could have been removed but I left them in place. Werid one of my reproduction sealed beam T3 lights had a similar reflector sheild over the filiment and the other did not. Not sure why they had two different setups but maybe just manufcaturing differences. The Koito lens did have a nice cut off line even with the halogen bulb. Im sure that is gone with the T3 Lens but Ill report back soon.

Re: T3 Headlight Mod for H4 Bulbs
 

Interesting! The only ones I have seen were clear. I know that some have a blue coating, but that's usually a bad idea.


I believe those shields are intended to help create a sharp horizontal cutoff on low beam. We'll see what you end up with.

Re: T3 Headlight Mod for H4 Bulbs
 

I have done this with my gmc 4 headlight 5 3/4 inch set up. At 1st I did it with smooth reflectors but I didn't get the pattern I desired so after I used ribbed ones and it made a huge difference how wide the pattern got. But being that you have larger 7 inch bulbs that may not be a problem for you. I too hated how the flat glass destroyed the look of the front of my truck and thats what drew me to do this conversion.

Re: T3 Headlight Mod for H4 Bulbs
 

Thanks for your original thread that was one that I used for inspiration and to build the courage to cut the bulb in half!

Re: T3 Headlight Mod for H4 Bulbs
 

I really like this idea. I do not like the look of most updated aftermarket headlights, and I think this will give me a nice light that fits with the feel of my truck.

My kit just showed up today. It was $17.74 plus $15 shipping. Can't beat that! Now I just need it to warm up enough for me to get back in the shop and install them.

Re: T3 Headlight Mod for H4 Bulbs
 

I got my headlights installed yesterday. A complete write up will be in my build thread, but I will say it was very easy. The hardest part was enlarging the holes in the back of my buckets to accept the rubber seal that comes with the new headlights. I had previously updated my headlights to run on relays, so I didn't need to do any wiring from that standpoint. I did end up cutting the connectors off of the harnesses that came with the headlights and used them on my truck because they connected a lot more securely than the ones I had on the truck.

The pictures are of my lights shining on my shop door both before and after. The before one is the picture with 2 different light intensities because my left light was newer than the right one.

Re: T3 Headlight Mod for H4 Bulbs
 

That kit is such a great value.
I put one in my 74 harness and relays everything. Direct fit.

Bright. Glass lenses. Even comes with bulbs.

Props to the work swapping the lens.

Re: T3 Headlight Mod for H4 Bulbs
 

I just bought two pairs from a dealership in Ontario: I am a little concerned that they might become unavailable... or that the manufacturer will finally clue in to the fact that collectible car owners are buying more of them than Toyota owners.

I already see them being resold at a 400-600% markup on some websites.

Cost me $79 Canadian, shipped ($58 USD). That's cheaper than buying four Sylvanias, you can't lose.

Re: T3 Headlight Mod for H4 Bulbs
 

I've had the same thought about availability. I think I'm going to order a second kit and throw it on the shelf. I'll likely need one someday.

Re: T3 Headlight Mod for H4 Bulbs
 

https://a.co/d/hMUEvDV


I put these in my Hella lenses and have the correct beam.

Now wish id seen this before I threw my old cibies out

Re: T3 Headlight Mod for H4 Bulbs
 

thanks for a great write up!
I was thing of the jeep lights myself!

Re: T3 Headlight Mod for H4 Bulbs
 

Thanks for the sharing the info,Those look great.

I recently replaced my big square headlights in my 85 truck.

When I took the old ones out, The front part fell off taking it out.

I thought someone could use these because the hard part (separating them) is done.

I will put these in my Swap-Meet stuff and see if there's any interest.

Re: T3 Headlight Mod for H4 Bulbs
 

I got me mine!

I actually cancelled the above order and found them even cheaper.

Re: T3 Headlight Mod for H4 Bulbs
 

Great thread! Thanks! IS there a thread on wiring if you choose to install relays?

Re: T3 Headlight Mod for H4 Bulbs
 

Amazing! Great work fellas. Kudos to all who have done this.

Re: T3 Headlight Mod for H4 Bulbs
 

Here's a diagram that I saved from another thread on this site several years ago. It helped when I installed my relays before I did the headlight upgrade. Installing the relays into the headlight circuit is fairly straight forward.