HodakaGuy's FJ40 Thread

Hodakaguy

Adventurer
Gauges - 2nd time's a charm! Getting the Temp & Fuel gauge working again on the 40! And lets not forget that oil pressure gauge.

After cleaning the connections on the circuit board last time the fuel & temp gauge started working again....for a bit. On the first drive the gauges quit again shortly into the drive...came back on....then quit again. Time to investigate.

After some internet sleuthing it looks like the voltage regulator on the back of the fuel gauge is the most likely culprit. Time to take the gauge cluster back apart again.

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Disassembled. Now that the gauges are out of the housing I can inspect the suspect Fuel Gauge.

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The fuel gauge is supplied by 12v that feeds a built in voltage regulator, the voltage is then reduced to 6v to run both the fuel gauge and temperature gauge. If the regulator is malfunctioning both the fuel and temp gauges will stop working. The regulator is a bi-metallic unit and when current flows through the regulator the unit heats up, expands and opens a set of contacts breaking the circuit, it then cools down again the closes the contacts. This cycle is continuous and the average voltage equals 6v.

The rear of the fuel gauge.

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Here you can see the voltage regulator (The U shaped flat metal piece) and it's contact points. If these points get dirty over the years the regulator can stop functioning correctly (see Below).

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Testing the voltage regulator: I tested my regulator and found that is was performing inconsistently. I ended up dressing/cleaning the contact points and the unit re-tested nice and consistent. Perfect!


Video showing the testing procedure in action along with a better description of the voltage regulator.



The test setup.

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Back together we go.

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Now to get the original oil pressure gauge up and running. I grounded the sensor wire under the hood and powered on the gauges with the key....the oil pressure gauge went all the way to High.... Perfect! The gauge itself is working! Next up I removed the tubing that runs to the aftermarket mechanical gauge that the previous owner installed and installed a proper new oil pressure sending unit in it's place. I ended up completely removing the mechanical oil pressure gauge and tubing.


Video of the oil pressure gauge testing process:



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Yeah buddy....all the gauges working great now! Drove around a good portion of the day and they all operated smoothly and consistently. Nice having all the OEM gauges working!

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Hodakaguy
 

jgaz

Adventurer
Nice work and excellent explanation of the voltage regulator operation.
it’s been a looooong time since I dress the points on a regulator.
 

Zeep

Adventurer
Such a nice find. My uncle had one just like yours, back in the seventies.
You had the gauge's that far down, I would have touched up the needle's a bit.
 

Hodakaguy

Adventurer
Such a nice find. My uncle had one just like yours, back in the seventies.
You had the gauge's that far down, I would have touched up the needle's a bit.

That crossed my mind. But didn't have the correct stuff on hand to make it look good so left it alone 👍

Hodakaguy
 

Hodakaguy

Adventurer
My E-brake is talking to me...

When I purchased my 40 the E-brake was adjusted waaaaaay loose to the point it wasnt functuoning. I adjusted it back where it should be but when driving you could hear the brake scraping/rubbing when you come to a stop/take off from a stop. I loosened it back up with a plan to look at it soon.

Fast forward to this weekend....ran to town and started hearing the rubbing noise again when coming to a stop. Noticed if I pulled the e-brake handle just a tad when the noise was happening it would go away, confirming that it's the e-brake causing the problem. When I got home and looked under the rig the e-brake drum was HOT....smoking hot! I threw a fan on it with a plan to investigate in the morning.

Next morning I pulled the drive line and removed the E-brake drum. Yep there's the problem! The driver's side retainer pin was missing and the retainer clip was loose inside. This was allowing the back side of the driver side brake shoe to scrape on the back side of the drum, and causing the right shoe to wear away on the drum.

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With a Sunny weekend calling the 40's name I removed the E-brake shoes & hardware then re-assembled the drum & driveline. I'll install new components soon along with a double seal on the output shaft.

Snagging some fuel on the way to lunch.

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Pops trying it out. He loved it!

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Hodakaguy
 

YetiX

Active member
So glad I caught this early on! This thing is already beautiful. This is inspiring me to get some work done on my Land Rover.
 

Hodakaguy

Adventurer
Did the previous owner tell you where he sourced the front seats 💺?

The seats are Bestop Trailmax II high back buckets. They are mounted using Hell for Stout seat tracks (HFS51255).

I have the original seats that I'd like to restore and re-install. At some point these seats will be available.

Hodakaguy
 

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