504 fan electrical problem

geodon

geodon

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The fan on the 504 motor in my ute project does not engage when power is supplied.

As I understand it, a temperature sensor on the radiator (when the temp rises to a pre-set point) powers up the feed to a carbon brush touching a slip ring on the water pump/fan pulley.

This activates an electromagnetic clutch which then engages & makes the fan & water pump turn as one.

Now one would NOT expect that slip ring to be earthed but that is the case here; when I hook up a pilot to power & then, with the other lead, touch the slip ring, the brush or the wire feed, the light comes on.

So there is a short circuit in the clutch.

Is the pulley clutch accessible for repairs?

Are new ones available?

If not do I have to somehow pin or bolt the fan to the water pump so it turns all the time?
 
George,

There is a clearance measurement between the hub and clutch mechanism. What is it, I'm not sure? Not sure if the thermo fan set up is covered in the 404 manuals I sent you. They are definitely covered in a 504 manual but alas, I don't have any of them. Wiser heads on here, may be able to help.

Cheers,

Dan
 
Dan, the Haynes 504 manual only mentions testing the clutch with an ammeter and battery. There's not much info there at all.

There isn't even a schematic diagram of the mechanism.

Dan[/QUOTE]
 
Air gap should be .3mm (.012"). Presumably. it's the same for a 404.
 
Make sure the carbon brush surface sits flat on the hub surface and there is spring tension pushing the carbon brush onto the hub.

Here is a diagram on fan adjustment

Once adjusted properly, turn on your ignition and grab the two wires that are plugged into the temp sender in bottom of the radiator. Removed the wires and touch them together. You should here a click from the fan hub. This is the fan hub engaging.

You can lock the fan by tightening the adjusting screws, but this might not be a good idea during a cold Melbourne winter...it's ok for us QLDers.
 

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Before you go to the trouble of fixing it, I went to put an electric fan on my 1800 404 ute motor and the shaft for the fan was dangerously long and getting very close to the 504 radiator fitted. Originally a fixed fan with my water pump.
Is your radiator fitted ?
 
Not sure the test light shouldn't come on since it's just an inductor, no resistor. The manual says you want to see 0.8A when 12V is hooked up, I think that's the best test. If you get the right current, getting the air gaps right should do the trick. FWIW, I stuck an Ohmmeter over an old 504 one just now but it came up with an implausible 1500 Ohms. Surely wouldn't get 0.8A through that.

I doubt you could find anyone to repair one. You *can* close up the gaps to keep the fan engaged all the time, but it will still slip on sudden changes of engine speed and will wear out after a while. Best to track down a new one or a decent second hand one if yours fails the test.

Have fun,

Rob.
 
Bob D said:
Before you go to the trouble of fixing it, I went to put an electric fan on my 1800 404 ute motor and the shaft for the fan was dangerously long and getting very close to the 504 radiator fitted. Originally a fixed fan with my water pump.
Is your radiator fitted ?
Click to expand...

G'day Bob!

If I can't sort it out an electric fan is my preffered option.

Rad (505) is fitted.

I can't see any fitting problems if I get a pusher fan on the outside of the rad.

There's heaps of room bet the rad & the grille

A 14 inch unit with curved blades is rated at 1650cfm. & draws 10 amps.
 
geodon said:
G'day Bob!

If I can't sort it out an electric fan is my preffered option.

Rad (505) is fitted.

I can't see any fitting problems if I get a pusher fan on the outside of the rad.

There's heaps of room bet the rad & the grille

A 14 inch unit with curved blades is rated at 1650cfm. & draws 10 amps.
Click to expand...

in my 505 i fitted a mazda 626 electric fan on the engine side, but had to cut the water pump shaft.
 
I dont have a circuit diagram but i should imagine that the coil that activates the clutch has to have one end connected to earth to work .if the active is introduced by the brush the other end has to be earth for it to work ,your test light is finding its earth through the coil .pugs ,there is also some 10 mill bolts that can be locked up to by pass the action of the clutch .
 
I have locked up fans for years. There is a school of thought which says that you lose a few horsepower in doing so, but I maintain that by doing so I have eliminated one weak link in the chain....electromagnetic hubs stuff up regularly when they get older.

There are 3 small bolts with lock nuts in the central part of the fan. At least you could do this until you fit an electric fan.

BTW, sucking is more efficient than blowing, but I guess that if you get a dedicated blower fan, this may make up for that. And it won't matter if you don't have air-con to put extra strain / heat into the system.
 
Sorry I may not have explained it well enough: when I supply power either via the wire/carbon brush or direct to the slip ring I get a few sparks (& even a tingle!) but I don't hear the clunk of a clutch engaging and the fan is free to move independently of the pump.

The test lamp going on indicates the current is going thru to earth via the coils of the electromagnet but the clutch is not engaging.

I'm taking the rad & fan off tomorrow to check the air gap
 
I put a 505 electric fan in mine in front of the radiator. Plenty of room if you have a ute grill. Very, very tight to fit one with a sedan grill.
Works off the radiator switch through a relay.
 
If the coil was completely burnt out its likely it has shorted to earth giving you the result you have ,i recall meeting a guy in balina who used to remove the wire from the electo fan on his 404 when traveling interstate overnight ,he said his wife could tell when he was speeding by the pitch of the fan ,he would make good time on the trip and his wife was blissfully unaware,pugs
 
Bob D said:
I put a 505 electric fan in mine in front of the radiator. Plenty of room if you have a ute grill. Very, very tight to fit one with a sedan grill.
Works off the radiator switch through a relay.
Click to expand...

Nice one Bob!

I'll also add a manual switch to make it go. One can normally tell when the need arises

I've done this in the past with chronic over-heaters eg MG Midgets
 
2pac said:
in my 505 i fitted a mazda 626 electric fan on the engine side, but had to cut the water pump shaft.
Click to expand...


2-pac I had to smile at your location!

It's nearly impossible to watch a Middle East doco without seeing a 404 ute in the background!
 
I have had fan clutches fail on several 504s I have had including my current cab and I have just tightened the screws to have the fan locked on and there is no problem after this
 
julian c b said:
I have had fan clutches fail on several 504s I have had including my current cab and I have just tightened the screws to have the fan locked on and there is no problem after this
Click to expand...

If you don't mind losing 10-12 bhp and the engine running very cold on a trip (Basically no heater) plus a bit more engine noise, it's not a bad remedy! :crazy:
 
Dont lock it. If anyone who has fitted a fan override switch will tell you. Flick it on going up a hill and it is like throwing out an anchor.
A 504 diesel with the 8 bladed fan and the impact is even more dramatic.
BIGR is 100% correct.
 
All good!

Air gap was about 20-25 thou!

I closed it to 12 & it works fine.

Actually the 12 thou corresponds to the exact tipping point of drag/no drag so it's logical.
 
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