Blue fan clutch mod

landtank

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History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame.

This outlines how I adjusted the timing on my clutch.

warning:none of the parts within the clutch are serviceable by TOYOTA. Be gentle with that O-Ring. If it appears to have stretched and there is a bubble when placed in the groove, simply start from the side opposite the bubble and work it back into place compressing it as you go.

Needed tools:

12mm box wrench to remove the fan/clutch assembly
10mm socket/ratchet for removing fan from clutch
#3 Philips screw driver
#2 Philips screw driver

Supplies:

2 tubes of Toyota 6000 cst oil P# 08816-06001

Attached are pics of the blue hub clutch, the thermometer and oil I used.
Blue hub.JPG
thermometer.JPG
 
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landtank

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disassembly

Once the clutch has been removed from the truck it needs to be placed hub side down so the oil will drain into the bottom of the clutch. I have always allowed this to happen overnight to be sure all the oil has migrated.

Before disassembly clean the outside of the clutch completely so no debris will enter it upon opening it up.

Start by removing the 8 screws indicated in the pic with a #3 Philips screw driver.

Once the screws have been removed the two half can be separated, there will be some suction while doing this.

Be sure to keep the clutch horizontal, otherwise the oil will run out.
Clutch screws.jpg
 
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landtank

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target temp

Once the two have been separated the half with the spring on the outside needs to be warmed to 95*.

What I've done is to place about an 1.25 inches of water in a sauce pan and heat it to about 110*. I then placed the control side, spring down into the pan and place the pan on a wooded cutting board. The cutting board helps slow down the cooling process so I have time to make the adjustment.

Since the pan with water in it will cool at the edges faster than the center where the spring is at, it's important to occasionally lift the clutch up and down to help circulate the water and minimize that effect. I did this every few minutes and then more frfequent when I got closer to the target temp.

Attached is a pic of how I had it set up.
Cooling station.JPG
 
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landtank

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adjusting control plate

Once you've reached 95* it's time to adjust the control plate.

There is 2 #2 Philips screws that once loosened the plate can be rotated.

You'll need to sight threw one of the small round holes and adjust the plates position so that half the hole is open and the other half is blocked by the valve.

If the holes don't align perfectly to each other one should be 50% open and the other should be more than 50% open.

Attached are two pics that show an open hole and one adjusted properly.

The top pic is when the temp of the clutch is greater than 95* yielding an open hole.

The bottom pic is after the control plate has been adjusted by rotating it into position once the temperature has reached 95* You can see that the valve is dissecting the hole leaving half of it open
Clutch hole open.jpg
Clutch hole adjusted.jpg
 
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landtank

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filling with oil

The last step is to drain and fill the oil in the clutch assembly.

The first pic shows how I positioned the clutch to allow the oil to drain. This will take a few hours minimum, overnight would be best.

The second pic shows where I filled it to. I basically filled it to the underside of the drive plate. Looking threw the holes in the plate you'll see some rectangular reliefs that will help you in determining when you've reached the underside of the drive plate. If you are using the OEM oil empty both tubes completely into the clutch.

You'll want to add oil to all the holes as this stuff is pretty thick and doesn't flow easily.

Now replace the top of the clutch and tighten down the screws. If the O-Ring has come out of it's groove you'll need to work it back into place. The easiest thing I've come up with is to start from the opposite side and work it in by compressing it together. Once it's in place it will stay there during reassembly.

The torque spec that I've come up with for those screws is: Good and tight!


As a last note: Before adjusting the clutch you should scribe the plate where the heads of the screws are so you could put it back to it's original location if need be.
draining.jpg
Clutch full.jpg
 
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e9999

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excellent writeup and no doubt good detective and engineer work!

quantitative results?
 

landtank

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e9999 said:
quantitative results?

Not sure what you're looking for, but on Friday I had a 2 hour drive home with a 3500 lb trailer in tow in 90*F weather and I managed to only have slight movement in my RavenTai modded gauge while getting 12.65 MPG.

All in all I'm very satisfied with both the cooling and MPG numbers. Last year I was recording highway MPG numbers in the low 16s. Once I get a few tanks of highway use under my belt, I'll have a better idea how much this adjustment impacted that.
 
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Beowulf

 
 
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Rick,

Step #4 is a little confusing to me. The pics of the 2 holes appear identical and the explanation has me a little confused.

Is the "desired" relationship of the 2 holes at 95* with the 50% overlap? ... or perfectly aligned (no overlap)?

-B-
 

landtank

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Yes Dan, those are the ones you loosen to rotate the plate and the plate was no where near center when I first opened it up. It would be only a guess if I was to make one but I really didn't move it that much as far as distance goes. But the move was in the counterclockwise direction when looking down from the top.

In that other thread Tools posted a pic from when he opened up his and if you compare them they look pretty close visually.
 

cruiserdan

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Based on the way Toyota does stuff I would hazard a guess that the variances from clutch-to-clutch would be minimal and a guy could just open one up and move it about what you did and have very similar results.

We need to have OZcal call his local Toyota agency and ask them what the part number is for a 1FZ clutch. It would be interesting to see if it's different. Also, what color the hub is.
 

Rookie2

 
 
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Rick,

Nice write-up. It's hard to tell from your cook picture, but I presume the spring half of the clutch is fully submerged in water? What did you do to insure all the water was out of the unit before reassembling?

Thanks,
Rookie2
 

landtank

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Rookie2 said:
Rick,

Nice write-up. It's hard to tell from your cook picture, but I presume the spring half of the clutch is fully submerged in water? What did you do to insure all the water was out of the unit before reassembling?

Thanks,
Rookie2

The unit is only placed in water, contacting the outside of the clutch, but the spring is submerged. The water isn't high enough to actually enter the area that would be inside the clutch once re-assembled.
 

landtank

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cruiserdan said:
Based on the way Toyota does stuff I would hazard a guess that the variances from clutch-to-clutch would be minimal and a guy could just open one up and move it about what you did and have very similar results.

I'd expect that as well, maybe if a few more go through this we might be able to shortcut the cook all together. But I was thinking that maybe something on mine shifted since the factory and if that were true than the amount might be different for different clutches.
 
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landtank

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LandCruiserPhil said:
Rick Why 3000cst? Seems like the break down of the fluid is one of the main reasons for performance loss of the blue.

That is what looked to be installed in the first place. In my case I don't think it was break down at all, just not coming in soon enough. But I did add some oil to the fill in hopes that by increasing the volume I might provide some additional cycle time to help in cooling it. Also keeping the rad temps down helps in this area as well.

If someone thought it was simply a case of spent oil, they could buy just the oil and drain and refill. It was around $12.00 a tube IIRC. 3 tubes might do it but I can't be sure.
 
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cruiserdan said:
Based on the way Toyota does stuff I would hazard a guess that the variances from clutch-to-clutch would be minimal and a guy could just open one up and move it about what you did and have very similar results.

We need to have OZcal call his local Toyota agency and ask them what the part number is for a 1FZ clutch. It would be interesting to see if it's different. Also, what color the hub is.
If the OZ contact could find out what oil is the "A" code, most popular there, I hear it's 10,000 cst?

On the valve, some when opened are even on both holes, others are slightly off, one hole open a little more than the other, this isn't a problem. The idea is to get them about half open between the holes, If one is 40% open and the other is 60% or whatever that's OK, it's not that critical just an indicator to set the opening temp by.

Rick's clutch is relatively new, so his oil is probably good. If your clutch is older and is weak the oil is probably broken down, this is the number one cause of clutch failure. To change it pull the clutch apart invert the half's over a preferably disposable container and allow to drain, wipe clean and refill. The fluid is available from Dan, three tubes are the factory fill.

Rick has shown that the clutch can be slightly overfilled and still operate correctly. If your in a hotter area where the truck operates at 100+ often and your going to add fluid, I would top it off with a tube of 10,000 cst.
 
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