How to rescue yellowed headlights

[Tom F&L GoR]

I have disassembled a Gen 1 headlight that was functionally fine, but unusable due to a cloudy, yellowed lens. In the following posts I'll outline how to do it. Mine were pretty bad; thanks to almost-neighbor viper067 for saving his from the body shop.

 

[Tom F&L GoR]

The rear panel of the headlight comes off, of course, so you can change your bulbs. There are three wingnuts that come off and a thumbscrew that will stay on the headlight back cover. It can be a time-consuming effort to pry off the back of the headlight. The back is stuck on because the gasket was once-gooey and now will be hardened.

note: the housing on the left is obviously laying upside down.

 

[Tom F&L GoR]

Inside there are sheet metal screws holding the silvered plastic reflectors, wire bundles, and an interior clear plastic section in place. There are also two sheet metal screws with heads showing on the top of the headlight body. You should then be able to remove the reflector and aimer level. There is a metal tab that is pop riveted in place from the underside that will interfere with removing the clear plastic section, but I did get everything out.

 

[Tom F&L GoR]

Before everything comes out, push the rubber grommet into the body and feed the wire inside. Also, pull out the stiff vent tube. It's just pushed in, no glue.

 

[Tom F&L GoR]

281Cammer, here is your headlight level. Hope you find those screws!

 

[Tom F&L GoR]

To get the clear plastic insert out of the body, the metal tab seems to be in the way. You should be able to push up on the black plastic housing (area circled) and pull the top of the clear part to "roll" it out over the metal tab.

note: I forgot to get a picture, but there are two more screws holding the clear plastic insert in place. The are off to the right in the image below.

 

[Tom F&L GoR]

Pretty bad, huh?

 

[Dom426h]

wow, that is the yellowest headlight i have ever seen on Any car.
How could you see at night? I assume less than 50% of the light was making its way through...

Last year, i completely sanded down my headlights with 220, 320, 400, then used the 3M kit to get them looking band new.
3M Headlight Lens Restoration System, headlight polishing kit, restore yellow headlights, 3M plastic polish

Thankyou for the detailed pics Tom.

 

[Dom426h]

newcastle brown, always a good choice

 

[Tom F&L GoR]

And thanks to KNG SNKE for the oven directions:

Bake at 300F for 12-14 minutes.
Use large flat blade screwdriver to pry between the clear plastic lip and black plastic housing, starting at the lower edge of the headlight. Once it lets go in one area, the rest seems to come easily.
The upper edge of the clear lens can be "helped" by just pushing down (and releasing) on the roof of the housing.

Then there are two... pieces.

 

[Dom426h]

In your 3rd picture. The big screw's on the bottom of the assembly(top of pic). How do you unscrew them from the bottom? I couldnt figure this out when i was attempting to take em out to make my polishing job easier.

 

[Tom F&L GoR]

These closeups will be hard to tell what part of the body you are looking at, but it shows that the black housing has a groove and the clear lens has a tongue... tongue in groove with grey sealer inside.

The grey sealer was not all that stiff after 15 years.

 

[Tom F&L GoR]

And after 30 minutes of elbow grease with plastic polish the lens looks better already. It still has a yellow tinge, though. Most of the issue was on the outside.

note: compare to post #10

So - for the real experts:
What is best way to make the lens like glass again? This one is more clear, but wavy
Is there a coating to put on so this doesn't come right back?
What is best glue to reinstall lens?

 

[Tom F&L GoR]

In your 3rd picture. The big screw's on the bottom of the assembly(top of pic). How do you unscrew them from the bottom? I couldnt figure this out when i was attempting to take em out to make my polishing job easier.

I took the front fascia off.

 

[KNG SNKE]

Pending you kept the headlights warm enough during the separation and didn't get the "String" effect on the glue you should be able to set them up next to each other, reheat the oven to the same temp, bake again, pull out and push the headlights back together. I have never had to reseal a set of headlights before and I have pulled one set of headlights apart 3 times (non viper of course) and reassembled the same way.

I used clean mechanics gloves to push back together so I would not burn myself and did it really fast.

 

[Tom F&L GoR]

No string effect, but it didn't really seem like that kind of glue. It is 15 years old so it has aged a lot, but it now seems more like a caulk. Even when warm, it doesn't feel that sticky, either.

 

[KNG SNKE]

When it cools it does not feel sticky really. When you get it to full temp should be fairly sticky. Always worth trying. I tried to look up replacement glue with the same properties but I was unable to.

 

[Dom426h]

And after 30 minutes of elbow grease with plastic polish the lens looks better already. It still has a yellow tinge, though. Most of the issue was on the outside.

So - for the real experts:
What is best way to make the lens like glass again?

forget about that plastic polish for now. that is the Last step.

You need to start with a clean slate by removing a decent amount of plastic. This cannot be done with an abrasive liquid, it must be done with an abrasive paper.

As with polishing any type of material, each increasing grit of sandpaper removes the scratches created by the previous step. You will want to start with atleaset 320 then work your way on up (i started with 220 to make certain that i would get past All the deeper scratches, and wanted to completely sand off the raised lettering)

This is what i would reccommend:
(using a combination of sandpaper and the 3M Kit)
3M Headlight Lens Restoration System - Auto Geek Online Auto Detailing Forum
1. 320grit by hand
2. 400grit by hand
3. 500grit 3Mrotory
4. 600grit by hand
5. 800grit 3Mrotory
6. 1000grit by hand(wet)
7. 3M Trizackt Disc
8. 3M Liquid Polish
9. SyntheticWax/Polish(like Nufinnish)

That is for lens in bad condition. Mine had 50K miles on em(for reference)
If your lens already look pretty good and you just want to polish em up some then starting at step 3 or 4 would be fine.
Spend alot of time on the first step to make sure youve got a good base and take your time on every other step as well if you want a glass like finish.

 

[Ricketts]

281Cammer, here is your headlight level. Hope you find those screws!

My Hero!! Guess I could've got off my lazy butt and tried to take it apart myself. I'll give it a whirl this weekend. I appreciate it sir.

 

[GTS Dean]

Tom,

As usual, you have provided a reference work on the subject. Many thanks for the effort!


There's an anti UV coating on the headlights that gets sanded off with the refinishing process. It it possible to obtain this coating product for a complete DIY project?

 

[Kevan]

This is what i would reccommend:
(using a combination of sandpaper and the 3M Kit)
3M Headlight Lens Restoration System - Auto Geek Online Auto Detailing Forum

That's what I used on the maize headlights on Rachel's Jag.
Worked great, but I wish it came with more polishing compound (and a resealable container).

 

[got one]

yup...time to add this to the illustrated section Tom, hanks for the help! Us older Gen 1 guys who actually put miles on our cars GREATLY appreciate this!!!

 

[Simms]

Great write up! Thanks for posting.

 

[Tom F&L GoR]

yup...time to add this to the illustrated section Tom, hanks for the help! Us older Gen 1 guys who actually put miles on our cars GREATLY appreciate this!!!

Ha, I wish Tom Hanks would help. Anyone have input with the UV issue?

Here is a link to a video training clip from 3M. At the end they do not mention anything about a UV coating.

Logging in

If that doesn't work, start here:

3M™ Headlight Lens Restoration System - A fast and easy way to restore the clarity back to headlight lenses that have become dull or cloudy over time US 3M

 

[2000_Black_RT10]

Good job! Glad it came apart.

For aftermarket UV coatings.. i.e. GlassyLite ™ - Premium Headlight Restoration Treatment

 

[Ricketts]

Thanks Tom!! All better now.

 

[Zentenk]

Oh, I need those pictures. My lens has scratches on the INSIDE... SO STUPID!