Hello and greetings from Southern Idaho. I recently acquired a 1981 Rabbit Diesel. The previous owner was having issues with it and with him not being very mechanically inclined and other circumstances he decided to get rid of the Rabbit. I towed the Rabbit home today and immediately started in. Long story short, I got the Rabbit to fire and run smoothly via a glass jar of diesel directly fed to the IP in the 40 F weather we had today. This is a good thing. The Rabbit hadn't been started in over a year and so I brought it up slowly to operating temperature. There are some issues with fuel leaks from the injector return line which I am waiting for some hose to fix that. The question I have is when we shut the motor down I looked underneath the car and there was a bolt laying in the drive way which wasn't there before. I examined the engine and tried to find a place this bolt could have came from and couldn't find anything. Figured I'd upload a few photos and some measurements to see if anyone might be able to guess where the bolt came from. Hey it might be a long shot, but worth a try.
Thanks in advance for any replies.
Josh D.
BOLT MEASUREMENTS:
DIAMETER: Just over 7mm
HEAD DIAMETER: 12.5mm
There is about 21.5mm of threads and 32.5m of unthreaded bolt
Overall Length of bolt (including head) 66mm
Length of bolt (excluding head) 57mm
The Allen Head appears to be 6mm. I don't have a numbered set of allen keys so I will have to try and find some.
Welcome to the forum. VW uses lots of allen headed bolts on these cars. The approx 2" long bolt may be used to hold some accessory on, like an alternator or something like that. Most bolts are smaller for brackets etc. One item I'd look at is the intake manifold bolts. Those are about that length and that's where I'd look first.
Everybody else lists their cars here - but not me.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
The only match for that bolt seems to be for an intake manifold @ 58mm. The interesting thing is that it is for the split manifold of JP engine type say 1984.
The bolts for the 1981 big looping manifold are longer. @ 60mm. If your short bolt is 3mm shorter than spec...
"I'm not here to help... I'm here to Pro-Volke"
Be like meeee...Drive a Quantum TD
...The best work-horse after the cart...
Quantae grow on you...but Rabbits are like roses...
... girls like em ;o)
Only one Darwin, Einstein, Poe and Verne.
That is why if you listen, you will learn:
From the one and only Quantum-man,
Who sees the worms from outside of the can.
7 Quantae in 20 years; 4 dead and 3 TD's still alive [2 wagons & 1 fastback] oh and a GTD )
Thanks for the quick replies everyone. Your guesses will give me at least some more places to take a look and see if it rattled loose. I figured with the long shank and the substantial amount of threading that this was an important bolt most likely holding something important to the motor. Hopefully I can get a look this evening after work.
Thanks again and I will keep you all updated on my progress with the new car. I've wanted a VW since I was a kid and needless to say I am very excited to work on the rabbit and get it on the road.
Right, I have also seen allen head bolts on the inner CV.
More likely to fall out than an intake bolt.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
its not a cv bolt, unless the poor fellow put a replacement bolt in. the cv bolts are the same size, and will fit, but cv bolts are star/or torks(if I spelled it correct), and hardened.
its intake bolt from the looks. to get to all the intake bolts youll turn into a gymnast, and the allen socket most likely will get stuck a few times. DoNot over tighten, iirc spec is 18ftlbs. id hate to go into the amount of bolts/nuts that would be going thru my mind to check tightness.
I hope you changed oil, air filter, and especially the fuel filter before starting.(among other things)
you don't want an engine to 'warm-up slow', bring revs up slow and let it heat up. the faster you reach operating temps is better, then again engines are made to do just that.
I hope you changed oil, air filter, and especially the fuel filter before starting.(among other things)
you don't want an engine to 'warm-up slow', bring revs up slow and let it heat up. the faster you reach operating temps is better, then again engines are made to do just that.
All fluids were checked and the engine was started via a jar of diesel with a in line filter. The engine was brought up to temp normally. I was saying it was brought up slow meaning that I didn't get in it and put it under load or rev it right off the get go. The motor is running fine and will get new filters once we get to draining the tank and hooking it back up. Thanks for your comments.
Last edited by josh.d on Tue Jan 14, 2014 10:27 am, edited 1 time in total.
air-cooled or diesel wrote:its not a cv bolt, unless the poor fellow put a replacement bolt in. the cv bolts are the same size, and will fit, but cv bolts are star/or torks(if I spelled it correct), and hardened...
MK1 were allen key, Einstein.
Have a nice day.
'91 Jetta ECOdiesel TD - clean & complete (less motor/tranny) for sale
air-cooled or diesel wrote:my bad, I haven't seen a mk1 since the late '90s.
even when bottle feeding you want to run it thru the fuel filter. (new one).
Thanks for the tip. The engine running/filters etc isn't really my concern at this point. While your point is valid, this will be taken care of once I get the bolt figured out and some leaks taken care of.
air-cooled or diesel wrote:even when bottle feeding you want to run it thru the fuel filter. (new one).
Actually, I would suggest rigging up a jar of fuel and an in-line fuel filter and going right to the IP for some certain testing scenario's. This way you remove 100% of the chassis fuel system to aide in diagnosis for fuel supply issues. After you rule out anything on the engine for a source of the problem, then introduce the fuel system, or various portions of it, and continue troubleshooting from there.
Everybody else lists their cars here - but not me.
air-cooled or diesel wrote:even when bottle feeding you want to run it thru the fuel filter. (new one).
Actually, I would suggest rigging up a jar of fuel and an in-line fuel filter and going right to the IP for some certain testing scenario's. This way you remove 100% of the chassis fuel system to aide in diagnosis for fuel supply issues. After you rule out anything on the engine for a source of the problem, then introduce the fuel system, or various portions of it, and continue troubleshooting from there.
Exactly what I had in mind, and what I am doing. The new filter will be introduced when the fuel tank with fresh fuel is also introduced.
not to stir the pot but on the following cars I have only seen triple square cv bolts, never allen:
79 Rabbit German Made.
80, 81, and 82 Rabbits all US made. 82 Rabbit Pickup.
81 Dasher Wagon
Did they intermingle allen cv bolts on some years?
TylerDurden what MK1s have you seen Allen on CV bolts? Curious in case I run across one some day.
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