M5driver
MUD Addict (Ret.)
Now that I have had the Blue Mule running for several weeks, I have a few niggling mechnical issues I need to address. The work will have to wait until the truck is back in the States (Mar-Apr?), but I would like to get some advice here on what I should be looking for when I start to sort these things out. Besides, getting in immediate contact with the Washington DC area Mud/LC groups, of course 
1. Vibration. I think I have developed a driveline vibration. The vibration starts at around 40mph and gets worse as the speed goes up from there. There is no transition, like often happens with tire balance issues. To eliminate that possibility, I had the tires spin-balanced when I switched to the winter shoes. The vibration persists, but seems slightly less (!) when the front hubs are locked. I have not attempted to have the new rear drums balanced, because this would be a rare problem. It is possible the driveline(s) need to be reassembled 180 degrees from where I have them now, although I assembled them the same way they were before teardown, and this matches the FSM. The front hubs were replaced, I shimmed the front axle 4 degrees to eliminate the bump steering and hunting (works great!), but did not shim the rear axle. Drag link was rebuilt, center arm rebuilt, new tie rod, relay rod with new ends, new TRE for the drag link to center arm, new steering damper; the steering is nice and tight again - almost like new I also removed one leaf (#3) from each of the OME springs (2.5" lift) that I put back on. Driveline (or whatever) vibration had not been a problem prior to the rebuild.
2. Slight afterburn/backfire when shifting. I still have a bit of problem with this. Going slightly rich on the idle mix reduced the afterburn from howitzer to hand cannon to pop gun now, but I still get some afterburn when I wrap the engine up a bit before shifting, and an exhaust burble on deceleration in gear. The burble has been around since I swapped the original muffler with a Dynamax, and is not really a problem. The afterburn is worst if I cut the choke completely off before the engine is fully warmed up. Even after reaching operating temp, I can still induce a pop gun effect if I wind the engine hard before shifting. I will need to address this before the mule goes for the breath test - I expect to visit a good tune-up shop, or connect with some 2F tune-up masters in the DC area before taking the mule to smog testing. NB - there are no detectable vacuum leaks (15 inches rock-steady), and no leaks detected around the manifolds or carb base or exhaust flange.
3. Hard hot starts. This problem was reduced considerably when I set the mix a bit richer. The carb cooling fan helps as well. I have it to the point that it is close to what it used to be - crank and touch the accelerator pedal slightly for a good start. If I don't add a bit of fuel (or crack the choke), the start is very hard still. Carb tuning expertise will likely resolve this issue.
4. Paint and seam sealing. Not mechanical, but something still to be done. I can do some of this work myself of course, but will need a bit of touch up, and perhaps some pro help. I'll be looking for recommendations for a good paint shop.
5. Quiet. This is very strange.
Even my 
has commented that a 40 is supposed to make noise. As it is now, I seem to have no squeaks, rattles, groans, knocks, etc., even over rough terrain, and the engine is so quiet at the idle, that if I have the windows up and the Zim AC vents closed, I keep thinking the engine dies when it goes to idle. I think this problem - at least the squeaks and rattles part - can be readily resolved with a few really good off road runs 
which I am looking forward to. But I don't do rock climbs. The mule is a more or less stock daily driver, working truck, especially when the is hauling garden supplies.
6. Need
. 'nuff said.
1. Vibration. I think I have developed a driveline vibration. The vibration starts at around 40mph and gets worse as the speed goes up from there. There is no transition, like often happens with tire balance issues. To eliminate that possibility, I had the tires spin-balanced when I switched to the winter shoes. The vibration persists, but seems slightly less (!) when the front hubs are locked. I have not attempted to have the new rear drums balanced, because this would be a rare problem. It is possible the driveline(s) need to be reassembled 180 degrees from where I have them now, although I assembled them the same way they were before teardown, and this matches the FSM. The front hubs were replaced, I shimmed the front axle 4 degrees to eliminate the bump steering and hunting (works great!), but did not shim the rear axle. Drag link was rebuilt, center arm rebuilt, new tie rod, relay rod with new ends, new TRE for the drag link to center arm, new steering damper; the steering is nice and tight again - almost like new
I also removed one leaf (#3) from each of the OME springs (2.5" lift) that I put back on. Driveline (or whatever) vibration had not been a problem prior to the rebuild.2. Slight afterburn/backfire when shifting. I still have a bit of problem with this. Going slightly rich on the idle mix reduced the afterburn from howitzer to hand cannon to pop gun now, but I still get some afterburn when I wrap the engine up a bit before shifting, and an exhaust burble on deceleration in gear. The burble has been around since I swapped the original muffler with a Dynamax, and is not really a problem. The afterburn is worst if I cut the choke completely off before the engine is fully warmed up. Even after reaching operating temp, I can still induce a pop gun effect if I wind the engine hard before shifting. I will need to address this before the mule goes for the breath test - I expect to visit a good tune-up shop, or connect with some 2F tune-up masters in the DC area before taking the mule to smog testing. NB - there are no detectable vacuum leaks (15 inches rock-steady), and no leaks detected around the manifolds or carb base or exhaust flange.
3. Hard hot starts. This problem was reduced considerably when I set the mix a bit richer. The carb cooling fan helps as well. I have it to the point that it is close to what it used to be - crank and touch the accelerator pedal slightly for a good start. If I don't add a bit of fuel (or crack the choke), the start is very hard still. Carb tuning expertise will likely resolve this issue.
4. Paint and seam sealing. Not mechanical, but something still to be done. I can do some of this work myself of course, but will need a bit of touch up, and perhaps some pro help. I'll be looking for recommendations for a good paint shop.
5. Quiet. This is very strange.
Even my has commented that a 40 is supposed to make noise. As it is now, I seem to have no squeaks, rattles, groans, knocks, etc., even over rough terrain, and the engine is so quiet at the idle, that if I have the windows up and the Zim AC vents closed, I keep thinking the engine dies when it goes to idle. I think this problem - at least the squeaks and rattles part - can be readily resolved with a few really good off road runs which I am looking forward to. But I don't do rock climbs. The mule is a more or less stock daily driver, working truck, especially when the is hauling garden supplies.6. Need
. 'nuff said.
I have about 5 more days to work on it before it goes in a box 
I figure when I have it back in the US, I can drop the front shaft and see if that resolves the vibration. If so, then I'd have to suspect the 4 degree shims on the front are a little too much, especially since I took one leaf out of each spring. Maybe I need a 2.5 degree shim... I have a second pair of 4 degree shims I could try in the rear, if the angle is off. I don't have a protractor to measure that angle right now, tho. I figure I'll be OK until I get back, since drivng around town here is usually low-speed - under 40 mph.
