1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Leaking fuel intake to Carb + rounded bolt

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Old 08-11-17, 06:12 PM
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Leaking fuel intake to Carb + rounded bolt

1983, stock nikki carb.

I rebuilt the carb recently and just installed it today. Car runs fine now, except there's fuel leaking from the bottom of the cylindrical things circled in this picture:



Is there a washer or O-ring or something that I missed. I'm not about to put gasket compound directly in the fuel stream.

Also, as a side note, I had no clue what size bolt this was (12mm I think) and, like a complete idiot, tightened it down so far I couldn't loosen it again. Long story short, I rounded it out completely. Does anyone know what this bolt is called/where I can get a replacement?





Thanks!
Old 08-13-17, 12:07 PM
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Old 08-13-17, 02:59 PM
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Those are all fuel inlets to carb. The bolts are called"banjo" bolts. They use crush washers to seal fuel inlet pipes to carb. Each bolt takes two crush washers to seal. One under head of bolt & pipe,the other between pipe and air horn (top of carb). Normally the crush washers can be reused after annealing,which is heating them til red hot & letting cool. In your pic they appear to ,over tightened to point of deformation and need replacing. You can source them from Mazda or an auto parts store catering to import vehicles. A third place would be a motorcycle repair shop. They are very similar in dimension,12mm,to crush washers used to seal brake lines to calipers & master cylinders. Take the bolt and a crush washer with you to match up. You want aluminum washers like what you have. There are copper,brass washers normally used as gaskets for oil pan drain plugs,refrain from using them as they need more torque to deform and seal than aluminum. The extra torque needed for these may damage threads or warp/ distort air horn on carb-neither are good. Regarding the bolt head you" stripped" from overtihhtening-was this done to stop fuel leaking also,do you have a pair of crush washers on it? You can still remove/reuse that banjo bolt. Instead of the wrench or 12 point socket you used on it,use a 6 point socket of correct size. I think it's 14mm,might be 12,i can't recall at the moment,away from home for several days. I can look at a carb when I get home. Maybe someone else here can chime in. Once you have correct size socket,put it on bolt and with palm of your hand push hard on head of ratchet toward bolt head to keep socket on bolt and loosen bolt. Last,torgue bolts "snug" when reassembling with new washers.
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Old 08-13-17, 08:48 PM
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The one between the two gas lines in the second image, is 12mm.
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Old 08-13-17, 10:30 PM
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Thank you guys!

I was beginning to wonder if I needed a washer on both the top and the bottom. I must have dropped it while I was taking apart/putting the thing back together. Yeah... 12 point sockets kind of suck. I got it off, though. Everything seemed to be fine. No stripped bolts or anything. The fuel wasn't leaking from that bolt either, so I didn't tighten it down more than I needed to. For some reason, though, it had gotten tightened down so hard I ended up bending some of the brass. oops.

Anyway, like I said, thanks for the help!
Old 08-14-17, 10:25 AM
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I like to use six point line wrenches for those bolts that you know are going to be a problem.

https://www.harborfreight.com/hand-t...set-61357.html
Old 02-19-24, 11:38 PM
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the stripped bolt

what is the bolt that is circled in the second pic. called i have to get a new one due to the fact that when i tried to remove it when i first got the car it broken off inside but no fuel is leaking from it should i just leave it alone or replace it and if needing replaced where can i get the bolt

Last edited by Shadow7803; 02-19-24 at 11:41 PM.
Old 02-20-24, 07:29 PM
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it's called the fuel inlet bolt:

https://www.flickr.com/photos/glazedham42/4772448365

how long have you been driving with it broken?

ultimately, it's probably best to replace if you can. however, i'll leave the urgency/timeframe to do so, up to you.
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