Potomacduck

I am replacing the Fan Clutch in my '99.

I have read the following in several sources: Toyota 4Runner V6 4WD 5VZFE MUST follow mftr. torque specs when reinstalling the fan clutch, pulleys, and water pump housing!! Most common reason for water pump bearing failure i s overtorqueing during this process.

Most write-ups indicate that the four 10 mm bolts should be tightened to 65 IN/lbs and no tighter.

Yet the fan clutch is bolted to the fan bracket which appears to be completely isolated from the waterpump housing and bearings. See pictures:

http://www.4x4wire.com/toyota/mainte...elt/tbr_03.jpg

http://www.4x4wire.com/toyota/mainte...elt/tbr_04.jpg


How could tightening these bolts possibly affect the waterpump or bearings?

What am I missing?

Elton

all you have to do is take off the 4-10mm bolts more than likely have to remove the fan shroud too then when u reinstall it just get the nuts snug then give them a little turn

Potomacduck

I agree 100%, that's what I was thinking also.

But there are all sorts of warnings about torqueing the nuts to only 65 inch/lbs or else you'll damage the waterpump bearing..........I can't understand how that would happen.

The fan bracket seems isolated from the waterpump/bearing.

.

TheDurk

I agree. I think the warnings are generic for all water pumps/fans and are written for the more common case of a fan mounted directly on the same shaft that drives the water pump. We probably are at risk of damaging the fan bracket (aka 'fake water pump') bearing rather than the water pump itself. There is nothing in the FSM about this, other than the torque spec itself.

I just did it (see the other thread): no need to pull fan shroud, it easily slides out after you remove the 12mm repeat 12mm nuts that hold the clutch to the fake water pump. The nuts that hold the fan to the fan clutch are 10mm.

Potomacduck

12 mm ............yes, 12 mm.

wyoming9

iTrader: (1)

i am not sure how you measure your bolts be they metric or sae

I just changed my fan clutch Unless you all have different engines which could be the case .

i did not have any 12mm or 10 mm hardware.

I did have some M8 and M6 hardware perhaps I am doing something wrong

CLin9383

thedurk, did you loosen the belts or only the 4 12mm bolts?

J2F42C

He loosened the belts (ALT, PS) to prevent any movement of the #1 and #2 fan pulleys that attach to the water pump shaft. Otherwise, the pulleys could come off with force. That is what the 4 12mm nuts are for besides attaching the fan clutch shaft to the water pump.

The reason one does not want to torque the heck out of the fan clutch is that it can damage the bearings, causing the water pump to exert more force to move, excellerating wear. It is analogus to overtightening a miter saw blade (one can hear the motor exert more energy at startup to turn the blade). If the fan clutch is overtorqued a little, I think there is no problem. Try not to put more than 6ft/lb of torque on each 10mm fan clutch bolt.....

TheDurk

Actually, I just loosened the PS belt. I took the fan and clutch off with the belts tight, but the No.1 sheave shifted as soon as I pulled the fan free. Only way to get it back on was loosen the PS belt. Alt and AC belts stayed in position. I think if the fan had not been off recently, I might be able to sneak it back on. Just be aware it may twist on you from the belt pressure.

Wyoming9, we are all being lazy/incorrect and talking about the bolt size by the socket size needed to turn them, as people want to know what wrench to use/have available. Bolts are indeed sized by the thread diameter, but that's not the most useful info when you are just talking about taking things apart. You are right, we are all wrong.

Gerdo

Bolt head/nut/wrench size not shaft size.