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BillFrog
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Joined: February 02, 2008
Posts: 15
Location: London, UK
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 Posted: Mon Jun 28, 2010 3:46 am Post subject: |
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I was planning to post an update after I'd had a chance to give my solution a good long test; so far it's holding up well but I've only done a hundred miles or so, so it's maybe a bit early to tell. Anyway, the full gory details of what I ended up doing are:
(a) I filled in the chipped-away part of the crankshaft keyway slot with JB Weld, to leave a clean slot for the key. However this was only done in order to keep the key snugly in place during assembly, to locate the hub accurately on the shaft. JB Weld is *not* a replacement for steel, whatever it claims, and I would never rely on it for strength in this situation.
(b) I then lightly lapped the hub onto the crankshaft with coarse valve grinding paste, to get the worst of the shaft surface roughness out. (I rigged up a contraption with a right-angle drill chuck so that I could use a variable-speed electric drill to spin the hub.) This left me with a pretty smooth metal-to-metal contact between the hub and shaft. (Sadly, it also revealed that the hub was sitting so far back on the shaft that the back rim of the hub was contacting the outer surface of the crankshaft bearing. So I had to rig up *another* lathe-like contraption to allow me to spin the hub and evenly Dremel a half-millimeter or so off the rear hub face, after which the hub sat nice and tight on the crankshaft taper.)
(c) I smoothed off the outer face of the hub (where the washer sits) with a file, to get rid of the worst of the weld remnants and provide a good even surface for the washer to bear on.
(d) I then reassembled it all, using Loctite 638 adhesive to secure the hub onto the crankshaft, and tightened the securing bolt as much as I dared. Loctite 638 is specifically designed to secure metal-to-metal taper joints; JB Weld isn't. Because of the of the fact that the hub was sitting further back on the taper than it should have been, I left out the O-ring that is supposed so sit behind the hub, because I wanted nothing there that could reduce the force of the centre crankshaft bolt. All the O-ring does is prevent oil seeping down the keyway, anyway, so I put a thin film of gasket sealant under the washer and head of the crankshaft bolt to stop any leakage.
Since then all has been fine (touch wood!). The new oil seal is doing a great job and I have no major oil leakage any more. In fact, the bus is running better than ever because when the PO welded the hub, I think he didn't get the alignment spot-on and so the timing mark has been about 5 degrees off ever since. Now that the woodruff key is back in place and the fan timing marks are therefore lined up properly, the engine is definitely running more smoothly than before.
This summer we're taking the bus for a week's camping in Amsterdam, so I really hope it all continues to hold together... but I'll post an update if anything exciting happens (!). |
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FlowerPowered
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Joined: December 22, 2005
Posts: 389
Location: Montana
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| Posted: Sun Jun 27, 2010 8:59 pm Post subject: |
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| ftrdds616 wrote: |
| Billfrog, what did you finally do to fix the chipped keyway slot? I was wondering if whatever you did to fix the problem actually worked. I have the exact same problem and was planning on using JB Weld. I was thinking of JB Welding the chipped piece back into the crank. I would love to get a response from you or anyone else who has faced this issue. |
I ended up selling it to my niece, with the understanding it needed the problem fixed. She replaced the engine. However, I wish I had thought of this solution first, cause I loved the car, but that was 15 years ago and I was (more) ignorant:
| SGKent wrote: |
| I would have a quality weld shop TIG in on the nose of that crank where the key tore, dremel it again to fit a new key and run it. Replace the crank when you have it apart. |
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busboy73
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Joined: April 03, 2010
Posts: 70
Location: Edmond, OK
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| Posted: Sun Jun 27, 2010 8:41 pm Post subject: |
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| Billfrog, what did you finally do to fix the chipped keyway slot? I was wondering if whatever you did to fix the problem actually worked. I have the exact same problem and was planning on using JB Weld. I was thinking of JB Welding the chipped piece back into the crank. I would love to get a response from you or anyone else who has faced this issue. |
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FlowerPowered
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Joined: December 22, 2005
Posts: 389
Location: Montana
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| Posted: Thu Apr 15, 2010 7:20 am Post subject: |
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| busdaddy wrote: |
| FlowerPowered wrote: |
Some years back I had a chipped main pulley key on a Rabbit, and I discovered JB weld was not a successful solution. It lasted on a few days until it was pulverized to dust. Apparently the continuous shocks of combustion was just is too much for it to withstand. I eventually sold it and the new owner replaced the engine. However, a Rabbit crank pulley is driving the cam, so perhaps for an AC engine it may hold. |
Does the rabbit pulley attach to the crank with a taper joint or just a straight shaft and a key? You are correct though in saying that pulley has a bit more going on, but not by much as any engine produces power pulses and that's what chews them up if they get loose. The advantage with a type 4 is the taper, when it's correctly torqued the key almost becomes redundant (other than as an initial locating device). |
Yep, it was straight. Also as a last resort I had a pro try to weld it, but the darn pulley was like pot metal, that didn't last long either before the weld broke.
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GusC2it
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Joined: June 23, 2005
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Location: Orlando, Florida, USA
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busdaddy
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Joined: February 12, 2004
Posts: 52927
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Thu Apr 15, 2010 6:40 am Post subject: |
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| FlowerPowered wrote: |
Some years back I had a chipped main pulley key on a Rabbit, and I discovered JB weld was not a successful solution. It lasted on a few days until it was pulverized to dust. Apparently the continuous shocks of combustion was just is too much for it to withstand. I eventually sold it and the new owner replaced the engine. However, a Rabbit crank pulley is driving the cam, so perhaps for an AC engine it may hold. |
Does the rabbit pulley attach to the crank with a taper joint or just a straight shaft and a key? You are correct though in saying that pulley has a bit more going on, but not by much as any engine produces power pulses and that's what chews them up if they get loose. The advantage with a type 4 is the taper, when it's correctly torqued the key almost becomes redundant (other than as an initial locating device).
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GusC2it
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Joined: June 23, 2005
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Location: Orlando, Florida, USA
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SGKent 
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Joined: October 30, 2007
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| Posted: Thu Apr 15, 2010 6:12 am Post subject: |
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I would have a quality weld shop TIG in on the nose of that crank where the key tore, dremel it again to fit a new key and run it. Replace the crank when you have it apart.
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FlowerPowered
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Joined: December 22, 2005
Posts: 389
Location: Montana
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| Posted: Thu Apr 15, 2010 12:00 am Post subject: |
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| busdaddy wrote: |
| When you do the final assembly JB weld the key into the slot ... |
Some years back I had a chipped main pulley key on a Rabbit, and I discovered JB weld was not a successful solution. It lasted on a few days until it was pulverized to dust. Apparently the continuous shocks of combustion was just is too much for it to withstand. I eventually sold it and the new owner replaced the engine. However, a Rabbit crank pulley is driving the cam, so perhaps for an AC engine it may hold.
| dan macmillan wrote: |
Cut a new keyway 180 deg from that one. Mark your fan timing mark 180 deg from the orig. mark. |
I wish I would have thought of this back then. I'd still have the Rabbit (it was a convertible and a blast to drive).
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busdaddy
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Joined: February 12, 2004
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Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Wed Apr 14, 2010 8:45 pm Post subject: |
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| GusC2it wrote: |
| busdaddy wrote: |
Nice work with the Dremel! That looks salvageable. You might want to get the face of the hub where the washer sits trued up, any machine shop with a lathe can do that, you don't have to get every grind mark out but it should have an even surface. You'll also want to file that nick off the edge of the seal bore on the case.
When you do the final assembly JB weld the key into the slot and give the entire taper a light coat, twist the hub clockwise so the key seats against the good side of the crank groove as you tighten the bolt and leave it to set for a couple hours.
You have little to lose. |
BD, Don't you think that JB Weld may be too thick for that tight tapered connection? I would be afraid that JB may prevent a tight fit. I may be wrong. I was thinking Loctite stud and bearing mount. |
Perhaps, I've done similar redneck fixes with JB sucessfully in the past (forklifts, tractors), if you get it tight before it starts to harden it all squeezes out of the taper (except the damaged areas). My thinking with the JB was mainly to fill the worn area around the key slot but Phil's suggestion has merit and would be a better long term fix. Either way lapping the taper would be time well spent.
I guess it all boils down to the tools and skills Billfrog has available, he's definitely talented with a Dremel 
Edit: I meant to say Dan's suggestion, although I like Phil's too
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Last edited by busdaddy on Thu Apr 15, 2010 6:31 am; edited 1 time in total |
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GusC2it
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Joined: June 23, 2005
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Location: Orlando, Florida, USA
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| Posted: Wed Apr 14, 2010 8:04 pm Post subject: |
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| busdaddy wrote: |
Nice work with the Dremel! That looks salvageable. You might want to get the face of the hub where the washer sits trued up, any machine shop with a lathe can do that, you don't have to get every grind mark out but it should have an even surface. You'll also want to file that nick off the edge of the seal bore on the case.
When you do the final assembly JB weld the key into the slot and give the entire taper a light coat, twist the hub clockwise so the key seats against the good side of the crank groove as you tighten the bolt and leave it to set for a couple hours.
You have little to lose. |
BD, Don't you think that JB Weld may be too thick for that tight tapered connection? I would be afraid that JB may prevent a tight fit. I may be wrong. I was thinking Loctite stud and bearing mount.
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whip618
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Joined: October 16, 2002
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Location: Albuquerque
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| Posted: Wed Apr 14, 2010 7:29 pm Post subject: |
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Nice work, do what busdaddy recommends then during your next rebuild you can have the crank welded and the keyway recut.
Phil
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VDubTech
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Joined: December 29, 2002
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Location: Syracuse, NY
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| Posted: Wed Apr 14, 2010 6:48 pm Post subject: |
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Wow--damn nice work with the Dremel!
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| borninabus wrote: |
| a measurement of your rod would be extremely useful. |
| notchboy wrote: |
| my dad wasnt a belittling cock when he tought me how to wrench on cars. |
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10 photos = douchebaggery |
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dan macmillan
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Joined: October 19, 2003
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Location: Northern Ontario, Canada
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| Posted: Wed Apr 14, 2010 6:42 pm Post subject: |
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Cut a new keyway 180 deg from that one. Mark your fan timing mark 180 deg from the orig. mark. The biggest problem is cleaning the crank taper to be the same as the fan taper. If there is not enough contact area on the taper you will never get it to stop sheering keys. Also any play between the key and the keyways will result in a sheared key.
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Last edited by dan macmillan on Thu Apr 15, 2010 3:59 am; edited 1 time in total |
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SGKent
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| Posted: Wed Apr 14, 2010 4:27 pm Post subject: |
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I think that you can use the dremel to clean up that keyway and get a key in there that will hold.
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Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice" |
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busdaddy
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Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Wed Apr 14, 2010 7:40 am Post subject: |
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Nice work with the Dremel! That looks salvageable. You might want to get the face of the hub where the washer sits trued up, any machine shop with a lathe can do that, you don't have to get every grind mark out but it should have an even surface. You'll also want to file that nick off the edge of the seal bore on the case.
When you do the final assembly JB weld the key into the slot and give the entire taper a light coat, twist the hub clockwise so the key seats against the good side of the crank groove as you tighten the bolt and leave it to set for a couple hours.
You have little to lose.
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Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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BillFrog
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Joined: February 02, 2008
Posts: 15
Location: London, UK
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| Posted: Wed Apr 14, 2010 7:19 am Post subject: |
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An update on progress - some careful work with the Dremel has produced quite a satisfactory result:
The hub is in perfect condition - the keyway is clean and undamaged. I got a new woodruff key and it fits snugly in the hub keyway. However the keyway in the crankshaft is not so nice (this pic taken looking up from underneath):
What's the opinion on this? I'm inclined to go ahead and reassemble with the new key and tighten it all down well; I can't see how the hub could slip on the crankshaft even if the key does move a little. |
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BillFrog
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Location: London, UK
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| Posted: Sun Apr 11, 2010 12:14 am Post subject: |
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VDubTech - the engine has been washed, that's why it's so clean. Basically the whole rear of the engine had a layer of oil. When the fan came off, the case was covered in oil from the breather box down to the mountings, and pretty much evenly on either side of the hub across the whole rear face of the case. The inside of the fan shroud was completely covered in oil sludge though some of that could have been old. I'm guessing that oil has been leaking through the seal onto the fan, and being blown everywhere from there.
I'm also guessing that the other candidates for leaks (oil cooler seals, dipstick boot) wouldn't have spread so much oil around so evenly?
SGKent - I wonder if the PO (in Australia, sadly, so no chance of money back) melted the seal when welding the hub... I don't want to do the same myself. |
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SGKent
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| Posted: Sat Apr 10, 2010 9:16 pm Post subject: |
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what does heat from welding like that do to the #4 journal and the seal?
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George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."
Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice" |
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VDubTech
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Location: Syracuse, NY
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| Posted: Sat Apr 10, 2010 6:17 pm Post subject: |
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| SGKent wrote: |
| you may find the key is toast when you get there and that is why it is welded |
If it turns out that is the case and that's why it was welded, I'd replace the seal and reweld the hub back on....but that's just me.
To the OP:
That seal doesn't appear to be leaking to me....where exactly is your oil leak and why are you looking at the fan hub seal as the culprit? If it was leaking your engine case would look like this-yours looks for too clean to be leaking from that seal.
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First Trip in the RustyBus:
http://www.thesamba.com/vw/forum/viewtopic.php?t=279077&highlight=
| borninabus wrote: |
| a measurement of your rod would be extremely useful. |
| notchboy wrote: |
| my dad wasnt a belittling cock when he tought me how to wrench on cars. |
| EverettB wrote: |
One photo = good for reference.
10 photos = douchebaggery |
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