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Roger, I don't know if anyone else on the forum has had this happen, but I had it happen once and a friend had it happen as well:

The primer pump is a very simple thing, you pull the knob out and it sucks fuel through one dime size little check valve, and when you push it in it pushes the fuel out through another identical little check valve. The difference between the check valves is that one sits upside down from the other. When the engine is running and the plunger is pushed in and locked the fuel comes up through one and flows down through the other.

Occasionally, somehow, one of the check valves can get flipped over, which results in the fuel flow stopping, or restricted, causing the engine to either die or barely keep running. The primer pump mounts on with two bolts, one with a 7/16ths head and one with a 3/8ths head if memory serves. This is so that it cannot be installed backwards. If you remove it and look at the two check valves, and they look identical, then one has flipped over. With a bit of observation and blowing through the check valves it is easy to figure out which is wrong.

I know that this happens very rarely, but it is a five minute fix if this does happen to be the problem and sometimes it pays to check it out before pursuing other problems.

Where your fuel filter was full this is probably not the problem, but it could save hours of headaches if it is.

By now you probably have it fixed, but I thought I would mention it just in case!

I hope this helps!:usflag
 

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990 Posts
Discussion Starter #145
Yes!!!!!!!!!!!!!!!!!!!!!!!!!! And thank you Ret423!

Here is a link to one for sale on Ebay with a pic
1W1700 1W 1700 Fuel Transfer Pump Replacement Caterpillar 0R3008 3406B 3406C Cat | eBay

Verify the part number to be sure but they are a pretty quick fix if that is your issue.
At long last I'm resuming my restoration efforts and on Wednesday Morning 11/11/15 the new ebay transfer pump will arrive in Mayfield, Kentucky where instructor Doyle Howard will supervise installation and proper tuning. Thanks for the info Ret. And I mean that..
 

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Discussion Starter #146
Hello gentleman! A fan clutch broke apart and a piece of it almost stuck a mechanic I'm informed. Larry at the Peterbilt Parts Counter, Sikeston Mo. had a replacement on the shelf. To be installed. Restoration resumes. Best to all.
 

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Discussion Starter #147
Mechanic has told me that a fan clutch is not essential to a 3406c's safe operation; That it's absence will result in the fan constantly running but little else. Is this guy running some BS by me? I know he'd as soon see my Pete roll out the door and free up his bay. Apparently replacing a fan clutch is difficult work and time consuming. Anyone ever replace one before? How long should it take? Thanks for any insights...
 

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Every 3406C I have seen defaults to fan off if the clutch fails, not fan on continuously.

I also have never see one fly apart when idling in a shop, I have seen mechanics leave things in the path of the fan which breaks the fan blades and shroud when the fan kicks in though.

It sounds like they may have screwed up and broke your fan, and it sounds like they intend to cut off some of the opposing blades to get it balanced enough to send you away.

I would look closely at your fan and shroud, if they are damaged it was an error by the shop; not your fan clutch failing Naturally.

Fans are not cheap on Air to Air motors, if they broke yours you deserve a new one.

As far as changing the fan hub is concerned, it requires removing the upper radiator hoses and radiator braces, disconnecting the hood catch and leaning the radiator forward enough to remove the fan and shroud. About an hours work.

Then you remove the belt, the air hose and the 4 mounting bolts to lift the old hub out. Another hour or so.

If you rebuild the old hub (I do this, cheaper and better than trusting a reman) it takes about an hour of bench work (or less).

Reassembly is a little quicker so maybe an hour and a half to make smoke again, I don't know your shop rate but that's about how long it takes me on a Saturday afternoon to do this job.

Good luck, hopefully your fan clutch is fine and they owe you a fan but you need that fan clutch to work properly; if it is always on your fuel mileage will be much lower, your belts will break much sooner and the noise will drive you crazy.
 

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515 Posts
Really good to hear from you Roger! I have often wondered what happened with you and your project. Keep us posted a little more often. Merry Christmas!
 

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Discussion Starter #156
Hello everyone. I plan to spend a bit more of my time at "The Diesel Garage" Any one ever make it to Washington DC or nearby, stop around and lunch will be on me.
 

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Hey Roger! Ever get that Pete moving under it's own power? Just haven't heard anything out of you for a while! Update please.
 
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