Soliciting suggestions - removing corroded light-bulb access cover plate screws - Page 1
Forum section: electronics / general

author: Rick Law
author_rank: Super Contributor
timestamp: March 16, 2021, 06:44:30 am
content: I am hoping for some suggestion... I am trying to remove a downward facing access-opening cover plate screws to change a light bulb. The light bulb access cover plate faces the ground, held by four screws that screw in upward. Three of four screws are very corroded and seem very firmly affixed to the cover plate.My go-to solutions for these kinds of problem are screw-remover bits and if that doesn't work or doesn't fit, WD-40.The screw remover bits never failed me before. It just bites into the screw-head gripping it enough to unscrew. But this time, the screws are so corroded it is firmly "glued" in place. The screw-remover bit merely cuts a smooth and shinny small pit on the screw-head as I turn.So, WD-40... Well, the screws go in upward, that means the head faces down. However much I spray the WD40, it just drips away and dries out in moments. The lights bulbs are car license plate/tag lights, and the access-cover is screwed on to the car. So, turning it over so that the screw-head faces is not an optionMy last-resort solution is to drill the screws out. But before I do something as drastic as giving my car a drilling, I like to see if there are solutions that I missed...Any suggestions are appreciated and welcomed.Thanks.

author: Cyberdragon
author_rank: Super Contributor
timestamp: March 16, 2021, 07:07:43 am
content: Take a small dremel and cut slots into the screws.

author: Alti
author_rank: Frequent Contributor
timestamp: March 16, 2021, 01:31:32 pm
content: Screws are usually driven into plastic so I am not sure if this method applies here:If the screws are mild steel (I guess they are if corroded) and if there are no plactic things in proximity that you care about, you could take a mild steel non-galvanized nut and weld the head of the screw through the hole in nut. I use regular stick welder, 1.6mm (1/16") rod. Mind that I have never done that with screws but with rusted or twisted bolts this is super easy and worked every time for me. Last month I was removing rusted M6 seized inrivnut.Remember to replace the screws with brass ones.

author: SeanB
author_rank: Super Contributor
timestamp: March 16, 2021, 02:40:35 pm
content: Likely the lights are using self tapping screws that are going into clip on locking plates in the inside of the vehicle. If you can get access to the interior there you can see them, and then you can try using a pair of vice grips to turn the screw loose from the inside. Failing that you are left with drilling them out, and using new fasteners into the body, hopefully this time with a nice coating of heavy grease on the threads to keep them from corroding fast.Failing that try heat, either using a soldering gun to heat up just the screw, using a 100W plus soldering gun, or a hot air paint stripping gun, though if there is plastic around you will melt it. WD 40 on the screw head on a small pad will hold it there, giving time for it to wick up into the gaps, though your chances of it working with it already not budging to gentle force you will probably have to be less gentle, and accept that you will probably be buying 2 new light assemblies, after butchering the existing ones to avoid damaging the rest of the car.

author: David Hess
author_rank: Super Contributor
timestamp: March 16, 2021, 04:45:44 pm
content: I have done what Cyberdragon suggests before; use a Dremel to cut slots into the screws so that a flat head driver can be used. Now I also use an impact driver instead of a manual screwdriver because it is less likely to allow the driver bit to strip out of the screw. I did this last year to remove the very rusted screws holding a garbage disposal in place.

author: Rick Law
author_rank: Super Contributor
timestamp: March 16, 2021, 07:48:03 pm
content: Quote from: Cyberdragon on March 16, 2021, 07:07:43 amThanks for the input.Unfortunately, two of the screws are mounted in recess - the screw hole sunk in about 1-2cm with a tunnel for the screw driver. The cutting tool will not reach the surface of the screw top.Quote from: Alti on March 16, 2021, 01:31:32 pmQuote from: SeanB on March 16, 2021, 02:40:35 pmYeah, when I did my initial research on how to get to the license plate bulbs, I saw on a youtube video with the cover plate removed and I saw the four plastic clip screw receiver in there.I was looking for that video again to confirm that it was indeed plastic screw receivers that I saw before I post this re-reply, I found a different video that took me down a different path... wiring. The bend-point where the wire goes into the truck is a another very likely failure point.Either bulb or wire problem, I will still have to remove that cover plate...Time is a problem for me now. That failure indicator show up two days ago. My car inspection (by the State) is due in two weeks at end of month, but I am unavailable much of the next two weeks... I have to do some planning here, and then execute fast.Thanks folks, you folks do not disappoint! Very useful input here.

author: ajb
author_rank: Super Contributor
timestamp: March 16, 2021, 07:56:22 pm
content: If the screw extractors just spin and ream out the drilled hole, you may need to switch to a different size drill bit or try applying more pressure into the screw with the extractor. This may be tricky if the screw isn't mounted in something solid. A larger hole will allow a larger diameter of the extractor to engage the screw, which means lower tangent force on the extractor's ridges. This will require a deeper hole so that the extractor doesn't bottom out before engaging, of course, which is another pitfall you'll need to be careful of. An impact driver may help as well, if you can get one into the right position.In lieu of WD-40, there are other penetrating oils designed specifically for removing fasteners like this you might try. It's okay if some drips out, as long as enough stays on the surface to wick into the interface you're trying to dislodge.

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 16, 2021, 08:10:37 pm
content: Drill is probably your best option. Left hand bit if you can find one. Be careful not to go too deep and through the plastic. Then grab the stubs from the other side with pliers and try to get them out that way.I'm assuming we're talking about the style where the screw is a sheet metal type going through a thin plate, if it's a machine screw with many threads of engagement you'll probably need to drill them out of the plates and replace both the screw and clip nut. Auto parts store will probably have something close enough.

author: Rick Law
author_rank: Super Contributor
timestamp: March 18, 2021, 12:03:57 am
content: SUCCESS!After thinking it through last night, I came up with the plan to drill a small hole to around the depth of the screw head, and switch over to the screw extractor. Plan was to then use the extractor to strip more metal to break the head off. That would serve the purpose of releasing the cover.So, I started with the smaller drill bit, as it got near to the depth of the screw head base, I switched back and forth - screw extractor and back to drill. After a few switches, the screw came loose before the screw head did.The small hole at the center actually helped the screw-extractor tip to go deeper. So, the cutting edges of the extractor bit bite into the screw better. That was the trick.First one was hard, the next three were easy. After I got the cover off and got to the bulb, there was no question the bulb was blown. I quickly got to the local part store and got the right bulb. It came in pair so I got both license plate bulb replaced.Thanks guys for the input. It certainly helped me overcame my initial reluctance to take a drill to the car...

author: Gyro
author_rank: Super Contributor
timestamp: March 18, 2021, 11:53:04 am
content: Quote from: Rick Law on March 18, 2021, 12:03:57 amAnyone else remember the days when you had to steady your nerves enough to drill and file a big hole in the front wing in order to fit a car radio aerial?

author: LaserSteve
author_rank: Super Contributor
timestamp: March 18, 2021, 05:18:13 pm
content: After mentioning putting antennas into Car Fenders (Wing?) and Roofs, you can pay for my counseling bill now..."Son, you DID WHAT?" That was 20 years ago, but still painful. Thou shall not mess up the factory upholstery in the roof.Steve

author: ajb
author_rank: Super Contributor
timestamp: March 18, 2021, 06:48:36 pm
content: Quote from: Rick Law on March 18, 2021, 12:03:57 amWait, were you not drilling a hole for the screw extractor before? If so that would explain why it wasn't doing the job! You may be able to get enough purchase just on the head as-is in some cases, but extractors are generally designed to engage in a hole drilled into the fastener first. It's why they have shallow tapered sides, so that as the spiral ridges engage with the walls of the hole they pull the extractor in and the taper wedges the ridges further into the screw to provide the required grip. Without that hole and the resultant lock-in of the taper a screw extractor is really just a bad left-handed drill bit, and the only extraction force it provides is based on the cutting pressure of the ridges on the material, which won't be very much because that's not what they're designed for. You'd get better results from a real left-handed spiral drill.

author: duckduck
author_rank: Frequent Contributor
timestamp: March 18, 2021, 08:06:48 pm
content: Make sure to use stainless screws when you replace the cover!

author: Rick Law
author_rank: Super Contributor
timestamp: March 18, 2021, 09:58:35 pm
content: Quote from: ajb on March 18, 2021, 06:48:36 pmYeah, I did NOT drilling a hole first. I've been using that extractor bit set for years and never had the need to drill a pilot hole first. These extractor bits have ends that fit my hand held wrenches and screw driver, whereas my drill has round-ended drill bits. So I never did associate those bits with drills.I learned something new with this experience.Quote from: LaserSteve on March 18, 2021, 05:18:13 pmYour's, and most other folks on this forum give counseling and advice that is well worth the money. I would gladly buy fellow eevblog forum member a cup of coffee if they happen to be in town, and of course only after the lock down.Funny thing about growing old... I became more risk averse. I did a lot to my car in my younger days, but this car is different. This is an old and worthless car financially speaking, but it has great sentimental value to me. That may be the reason I was so reluctant.

author: Gyro
author_rank: Super Contributor
timestamp: March 18, 2021, 10:10:41 pm
content: Quote from: Rick Law on March 18, 2021, 09:58:35 pmYes, I think that's a common problem. I find that I really have to psych myself up sometimes for jobs that I wouldn't have given a second though about starting a few years ago. Overthinking things beforehand has become a major mental block.

author: james_s
author_rank: Super Contributor
timestamp: March 18, 2021, 10:18:41 pm
content: WD-40 is ok as a water displacer but it's pretty worthless for most of the other uses it gets touted as being good for. I've been using some stuff called P'Blaster for years and have found it to work very well. Smells kind of foul though.

author: MikeK
author_rank: Super Contributor
timestamp: March 18, 2021, 10:50:37 pm
content: Quote from: james_s on March 18, 2021, 10:18:41 pmTests have put PB at or near the bottom of the list of effectiveness for rust penetrating, with Liquid Wrench at #2, and homebew 50/50 ATF/acetone at #1 (which needs to be mixed ad hoc or kept in an airtight container).