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Float chamber retaining bolt and washers

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Hi all. One of the H4 carbs is leaking fuel from the float chamber retaining bolt. I've read this is quite common and replacement washers are readily available. My question is can I replace the washers by simply unscrewing the bolt from the carb body and withdrawing it complete with washers (and the float chamber assembly). Does it just bolt into the body or is there something likely to fall off inside! I can't make out the diagram but it looks like the bolt screws through the body and fuel throws through the hole in the bolt and then on to the carb. When tightening does the torque of the bolt matter?


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It is simple to unbolt and replace the washers. But to get a tight seal is more difficult If you have a shouldered bolt you can cure a leak with an extra copper washer. A mobile mechanic came out to my car and showed me how to do it. 

A better fixing is the stud with no shoulder AUC 1387 which I now have.

There are some "o" rings which will offer a seal if you are having trouble. Finding the right ones is harder.

Good luck Richard & B..

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Hi Richard thanks for the reply. I've just removed it and there is a steel washer and then a rubber ring/grommet underneath and a matching grommet at the top. The grommets look immaculate (only done about 1500 miles since professional rebuild). The steel washer is very slightly bowl shaped. I guess that is by design to aid holding the bottom grommet? The bolt appears to be the earlier AUC 1335 (closest spanner is a 1/4 whitworth). Can you remember what position you put the extra cooper washer?


Also when removing I could hear the float rattling about inside the float chamber . I guess that is also normal? I haven't had any problems apart from the this leak from the float chamber.

Thanks again Archie


UPDATE: Just about fixed it with a Halfords fibre/sealing washer between metal dish washer and the rubber grommet. A very small film of fuel was noticile though (on both float chambers in fact) this morning after letting the engine go cold following a 25-30 mile run. So may try to get some suitable cooper crush washers.



Edited by AtLast
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