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bnam
Samba Member
Joined: July 02, 2006
Posts: 2936
Location: El Dorado Hills CA/ Bangalore, India
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 Posted: Wed Oct 30, 2019 8:47 am Post subject: DIY P45t to P43t adaptor |
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I've been wanting to experiment with LED bulbs on my Beetle, but I've not found ones offered with a P45t base which I have on my 71 Super. These bulbs were common on Euro cars with the multipart H4 headlight set up which was used at least until 73.
My thesis is that I could take the mounting ring off the P45t H4 bulb and that the smaller P43t bulb could be made to fit inside the larger P45t base.
Here's the P45t that I'm going to sacrifice for this experiment. I've marked the alignment of the top pin as that is critical for proper bulb functioning. The mounting ring is attached to the bulb with 4 spot welds which I dremeled off.
In order to fit slip the P43t H4 thru the P45t mounting base, I will have to enlarge the opening in the middle to at least 26mm. Perhaps larger if the dia of the LED is more.
The inner dia of the back of the P45t mount is 43mm which is the OD of the P43t base. Here's I've inserted the P43t bulb into the P45t base (though in reverse as I've not yet enlarged the hole as I can't find the right size step drill amongst my tools).
My theory is - I enlarge the hole. Then insert theP43t bulb into the P45t base aligning the big tab with red mark that I made. Then, mark the locations of the other 2 tabs. Grind the edge of the P45t base at the tab locations so that the tabs sit flush. For added stability I may need to print a 5mm tall ring as a sleeve with 43mm OD and 38mm ID. That's the theory. Will see what difficulties I run into.
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1971 1302LS Convertible (RHD) owned since '74
Click to view image
1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL |
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Meiang
Samba Member
Joined: September 27, 2016
Posts: 656
Location: Perth, Western Australia
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| Posted: Thu Oct 31, 2019 7:33 pm Post subject: Re: DIY P45t to P43t adaptor |
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| Why not buy a P45T to P43T converter. It allows installation of a P43T bulb in a P45T housing. |
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bnam
Samba Member
Joined: July 02, 2006
Posts: 2936
Location: El Dorado Hills CA/ Bangalore, India
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| Posted: Fri Nov 01, 2019 1:39 am Post subject: Re: DIY P45t to P43t adaptor |
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$30 per adaptor = $60 The bulb that I sacrificed was $1.If I have to print a sleeve or 2, it'll cost be another couple of $. For<$5 I could have pair. And if it doesn't work, I can still buy.
_________________
1971 1302LS Convertible (RHD) owned since '74
Click to view image
1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL |
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Meiang
Samba Member
Joined: September 27, 2016
Posts: 656
Location: Perth, Western Australia
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| Posted: Fri Nov 01, 2019 6:02 am Post subject: Re: DIY P45t to P43t adaptor |
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| Not sure where you get you costing from. The going rate on Ebay is about 8 UKP (UK pounds sterling) per pair plus less than 3 UKP shipping. |
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