Carb float chamber material

Technical advice Q&A

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Philippe-J.
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#1 Carb float chamber material

Post by Philippe-J. » Sat Nov 15, 2025 8:06 pm

Hi!

is there anyone here who knows what the float chambers are made of? I red somewhere it is aluminium, do you confirm?
I am asking because the central screw broke flush in the bottom when I tried and unscrewed the top nut that secures the lid. It was completely sized, and there is no access to inject WD40 so I had no option but to use force :shrug: and the shaft broke. Now I am considering brazing a new one in aluminium, in order to save my float chamber. But will it be compatible with aluminium brazing?
Philippe-J

1967 S1(.25) OTS ... coming together
https://renov-ots-1967.over-blog.com/

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mgcjag
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#2 Re: Carb float chamber material

Post by mgcjag » Sat Nov 15, 2025 10:22 pm

It's a high silicon content alloy....full details here https://forums.jag-lovers.com/t/materia ... ors/463967
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

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tim wood
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#3 Re: Carb float chamber material

Post by tim wood » Sun Nov 16, 2025 1:50 pm

New from Burlen but expensive, I’ve seen them reasonably often on eBay
Series 1 FHC purchased 50 years ago. Courted my wife in it.
Series 1 2+2 when the kids were small now sold.
Series 1.5 OTS in opalescent maroon, Californian car. My retirement present.

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Gfhug
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#4 Re: Carb float chamber material

Post by Gfhug » Sun Nov 16, 2025 5:01 pm

Isn’t there a person who has taken over David Lonsdale’s business for restoration of carbs? My quick search hasn’t given his name but he could be a source of parts and/or help.
Edited on post #11: viewtopic.php?f=3&t=21058&p=171406&hili ... le#p171406
On EBay UK there is an HD6 HD8 carb bowl for sale, could that work? Asking the experts here to say yes or no.

Geoff
S2 FHC Light Blue
S2 OTS LHD - RHD full restoration

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mgcjag
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#5 Re: Carb float chamber material

Post by mgcjag » Sun Nov 16, 2025 6:43 pm

You would need to check the AUC number under the arm that attaches to the bowl to ensure you get the correct part.....Steve
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

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Gfhug
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#6 Re: Carb float chamber material

Post by Gfhug » Sun Nov 16, 2025 7:16 pm

Is the base thick enough to be threaded? Then an aluminium bolt, cut down as appropriate, could be screwed in with a fuel proof adhesive (Sika, 3M or other good stuff) to both seal it in place and stop leaks? :shrug:
Might be a silly idea, in which case I’ll plead guilty. Just a suggestion for what it’s not worth! And not require soldering a material that isn’t compatible.

Geoff
S2 FHC Light Blue
S2 OTS LHD - RHD full restoration

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rfs1957
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#7 Re: Carb float chamber material

Post by rfs1957 » Sun Nov 16, 2025 8:41 pm

Find a second hand one.

Forget the repair.

You’re talking about brazing a highly grainy and difficult to weld alloy, chosen exclusively for its castability, in the form of a component of locally very thin sections, in an area that is inaccessibly deep inside the float chamber, so unless by some fluke you can address this repair from the outside then I would judge this to be technically impossible.

And a nonsense economically, even if some big-dick process did exist.

Plus the repair has to be fuel-tight, and it has to be as strong as new - the strain on that lid sleeve nut is not inconsiderable.

Find another one.
Rory
3.8 OTS S1 Opalescent Silver Grey - built May 28th 1962

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40GT
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#8 Re: Carb float chamber material

Post by 40GT » Mon Nov 17, 2025 7:39 am

Personally I would put an ad in the Wanted section, someone here is bound to have one. Seems ebay prices are still in the realms of the E being worth what it was 10 years ago.

Sean.
Sean

S1 2+2 1966 BW RHD
XK120 1954 comp LHD

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Philippe-J.
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#9 Re: Carb float chamber material

Post by Philippe-J. » Mon Nov 17, 2025 8:37 am

Thank you all for your advice.
During this w.e. I tried some of your technical options, none are completely convincing. Partly due to my poor mechanical skills, but not only. As a response to Geoff, yes the bottom is wide enough to dig a thread, bit not deep enough for the taper to go far deep enough :shrug: .
I am left with "buy another one" option. I wish I encountered this issue earlier, I just missed two nice offers on ebay :banghead:
Before I go to Burlen, I'll try my luck in the "wanted" section, and keep an eye on ebay. I am not in a rush, the new floating chamber can be mounted at the last minute prior to engine test, which is not tomorrow :sad:
Philippe-J

1967 S1(.25) OTS ... coming together
https://renov-ots-1967.over-blog.com/

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Gfhug
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#10 Re: Carb float chamber material

Post by Gfhug » Mon Nov 17, 2025 11:22 am

Good luck with your search Philippe and if you find one on eBay and can’t get it directly to you in France, maybe one of us could ship it for you.

Geoff
S2 FHC Light Blue
S2 OTS LHD - RHD full restoration

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