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1.6N/A Crankshaft bolt
by
ffgb
on 23 Apr, 2010 15:20
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I have a 1984 rabbit diesel engine code JK. I am rebuilding the motor. The crankshaft bolt is missing. Where can I get the appropriate bolt? Is it a dealer only item or can I go to a hardware store like ACE, and get the correct size and strength bolt there?
Thanks
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#1
by
Vincent Waldon
on 23 Apr, 2010 15:48
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Special bolt... torque to yield... and very bad things happen if it breaks.
Dealer or OEM VW parts supplier is your best bet.
If we knew your actual location we could be of more help.... pretty sure this has been mentioned before in fact.
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#2
by
ffgb
on 23 Apr, 2010 15:54
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I am in southern california. I just spoke with timmons volkswagen, and the representative said that there are 3 only left in the united states, and that If I ordered it, the bolt would be coming out of New Jersey.
This sucks, because I am finally putting my motor back together, the machine shop lost my bolt, and I am finally realizing this after 2weeks!
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#3
by
ffgb
on 23 Apr, 2010 15:57
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I just found out that the bolt size is M12x45. What is so special about this? Especially if you can get the bolt with at least 10.9 grade.
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#4
by
ffgb
on 23 Apr, 2010 16:50
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Problem solved. After contacting 3 local dealerships, and getting 3 different part numbers, I ended up driving to the local dealership and talked to someone in person and look at the screen with the parts numbers I had written down. One was for a gas model, the second one was for CR engine code diesel, third was a M12x45 that was NLA. I saw on the screen JK engine code, and what do you know, the bolt does exist! I ordered it and it will take 2 days to get here. Oh well, I guess I have to wait, but at least I know I am getting the right part. I can't believe 3 different dealerships had all the wrong part numbers, even though I told them year make and model I had, also what engine code I had, weird!
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#5
by
burn_your_money
on 24 Apr, 2010 05:29
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Glad to hear your local dealerships were able to figure it out.
Did they give you a 12pt or 6pt? The 6pt is suppose to be NLA and has superseded to the 12pt.
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#6
by
ffgb
on 25 Apr, 2010 07:57
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I haven't received it yet. The bolt will be here tuesday. The parts person said it was a hex head, according to the description on the computer. What is the difference? I know on my original bolt, it was a hex head. Are the torque settings different? Why couldn't someone just buy a hex head bolt the exact size as the original in 10.9 grade?
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#7
by
burn_your_money
on 25 Apr, 2010 08:12
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The 6pt ones are reusable while the later 12pt ones are TTY
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#8
by
vanbcguy
on 25 Apr, 2010 10:48
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As to why you can't just get a regular high-strength bolt and call it a day, VW has this designed for a very specific amount of tension.
Most higher strength fasteners don't stretch as much as lower strength fasteners which can result in them coming loose in some applications. That's why VW doesn't just use the highest strength fastener in every application - there's some times where you want the fastener to have some 'elasticity' in order to soak up changes in temperature, load or vibration. All three of those pretty much describe the crank bolt to me.
I think VW used something very specific with the crank bolt - otherwise they'd just sell you a regular bolt and they'd have gazillions of them in stock. IE they used some particular combination of size and alloy that provides exactly the "right" clamping force and has the right elasticity. It's another one of those things where you have to figure for them to have done the engineering and decide that they needed a special non-standard bolt, that's a big deal. They made millions of these engines - if they could have saved $1 per engine by using an off the shelf fastener, well...
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#9
by
ffgb
on 25 Apr, 2010 11:49
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While searching through another bucket of bolts for my car from the machine shop, I came across a bolt that looks like the crankshaft bolt and washer. I will post pics ASAP. I hope this is it, because going to ACE hardware and picking up odds and ends like washers for the oil pump bolts that the machine lost is driving me crazy.
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#10
by
ffgb
on 25 Apr, 2010 11:56
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#11
by
Rabbit79
on 25 Apr, 2010 12:49
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I have my crank bolt sitting on the desk in front of me as I write this. My motor is also an 84 with a JK engine code. The only difference I see is the washer and the top of the bolt. The top of my bolt is not recessed, just flat across the top, so no significant difference there. The washer on mine is stepped down to a smaller size though, so it's way different. My crank gear is the type that's held in place by a woodruff key. I understand there are differences on the type of gear that pulls the timing belt? so check that.
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#12
by
ffgb
on 25 Apr, 2010 14:40
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Yeah, I don't have a woodruff key on mine. There is a slot on the crank, where the timing belt sprocket has a built in quasi "woodruff key". I grabbed some calipers and measured the bolt, it did measure out to be 14mm x 55mm. I don't know what other bolt on the engine has this exact size?
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#13
by
Vincent Waldon
on 25 Apr, 2010 15:00
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Even if it is... my vote would be to toss it out and spend the 6 bucks on the new-and-revised 12-point bolt from the dealer.
As Burn says, the six-point are NLA from VW, and that usually means they had problems and revised the design.
Huey helicopters have a "jesus bolt" that holds the rotor on to the mast... it's named that because you'll be calling to Jesus for help if it breaks. The crank sprocket bolt is the "jesus bolt" of VW diesels...6 bucks is pretty cheap piece of mind imho.
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#14
by
Rabbit79
on 25 Apr, 2010 18:48
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Hmmm....I've wondered about the crank on this engine. The way I understood it they changed from a 22mm to a 31mm crank nose in 83. But mine definitely has the 22mm nose, hence the differences in our sprocket setup. I don't think this motor has ever been re-built so I wonder if they had some 22mm cranks laying around that they needed to get rid of and decided I was getting one.
