To repair a freightliner’s fan clutch can cost you approximately $2,500.00. Gordon Robertson demonstrates how you can conduct a truck repair and save money by cleaning the fan clutch and applying grease. 

To get started you should place a piece of cardboard between the truck’s fan and the radiator so that your hands don’t get damaged by the radiator. If you are having difficulties placing the cardboard from the top or the side of the fan, try placing it at the bottom area of the truck’s fan. 

In order to remove the bolts to get the fan clutch of the engine’s block you will need a 3/8″ drive extendable ratchet to reach into those tight places, the appropriate bolt socket sizes for your truck’s model and wrenches. 

Detaching the Fan from the Fan Clutch

Removing the Fan to perform truck repairs

Proceed by removing the fan bolts to get the fan detached from the fan clutch. The fan bolts pass through the channels of an aluminum spacer, so depending on the space you’re working with you should remove the center top bolt last in order to have stability when removing the other bolts.

Although the fan becomes detached from the clutch it still may be difficult to have access to remove the fan clutch to conduct repairs due to the limited spacing area between the two parts. You can use straps to keep the fan from moving around while you continue  with the repairs. Now that the fan is loose you need to detach the fan clutch hose fitting.

How to Remove the Fan Clutch to Begin Repairs

Continue by loosening the bolts behind the fan clutch which are attached to the engine’s block. If it is difficult to reach the bolts with one wrench, you can use a double wrench to extend your reach. For the purpose of this big truck repair a 19mm wrench is used to loosen the top bolts and an 18mm wrench is used for the bottom bolts. 

Big Truck Repair Removing the Aluminum Spacer

To get full access to clean the fan clutch seals you will need to remove the aluminum spacer with a pickle fork and a hammer. When the aluminum spacer is off, remove the fan belts by loosening the adjustable fan tighter and the fan adjusting bolt on top to get them off. 

Now that the belts are off you need to loosen the bolts behind the part which you need to repair. It will be easier to get access to the bolts at the bottom as opposed to those at the top because of the pulley.

Reparing the Fan Clutch

You will need to open the top area of the part in order to get access to clean the seals inside. Depending on the model of your truck the part may look differently to the one shown above.

Truck Repair Troubleshooting

If you blow air into the hose and the clutch does not release you should continue along with the process of repairing the fan clutch. You can also try spraying some WD-40 in the hose and blow air into it again and see if the clutch moves. If that does not do the trick move on to the next step . Remove the part on the top so you can see the crown nut. There will be springs holding the clutch together so you need to be careful when removing the crown nut.

Using C-clamps for Fan Clutch Truck Repair

Using a power gun, loosen the crown nut with care so that you do not completely remove it. You need to be very careful at this point since you do not want the springs to be released unexpectedly. Use C-clamps to keep the parts together and prevent the springs from flying apart. Gradually loosen the crown bolt and C-clamps simultaneously to see how the part unfolds. For this big truck repair demonstration and model it is possible to take it apart without using the C-clamps. However, as a precautionary measure, you should use the C-clamps.

Taking It Apart

Truck Repair - disassembling the fan clutch on a big truck

Remove the hub, the air hose and the springs to continue with the fan clutch repairs. Once again, blow air into the area where you removed the hose. You should feel air blowing properly through the center area. This is an indication that the problem is not in the vicinity of the air hose area, but the core center area itself.

Truck Repair - disassembling the fan clutch outer hub on a big truck

To clean the hub you need to seperate the inner piece of the hub from the outer hub by using a hammer if they are stuck together. Also, if you have any brokern o-rings you can simply replace them.

Clean the rust around the machine area or the center area where the clutch release cyclinder connects. These two parts may have been rusted and stuck together and prevented the fan clutch to function properly. You can clean up the mechanical parts using a Scotch Brite cleaning pad and diesel. Remember to take apart and clean the piston as well.

Applying bearing grease to the fan clutch for big truck repair

You can use any light bearing grease and apply it to the inner part of the piston and then put it back together. Also apply some grease to the center area or where the piston connects or fits itself onto. If the bolts coming through the hub are damaging the inner part of the hub you should place some washers on the bolt to space them out. This will prevent any further damage and allow the hub to bottom out in the drum.

Getting Back On The Road

After you have cleaned and greased the necessary parts you should put all the parts back together again. Now that you have reassembled the part in order to complete the big truck repair some further testing must be done. You must once again put air pressure in the hose connection area to ensure that the clutch is operating correctly. Once the fan clutch is releasing properly when you input the air you can go ahead and install back the air hose.

Using the fan belt on a big truck repair

Remember to file the edges of the aluminum spacer if there were any damages to it by the pickle fork when it was removed earlier. Now we need to place back the part in the engine which is actually the reverse of how it was taken out. First make a choker using one of the fan belts and tighten it on to the fan belt’s pulley. Also, use a piece of metal pole to keep the part steady and at a workable height. This contraption is to be used as a handle to make it easier to re-insert the bolts of the clutch.

Congratulations, your truck repair fan clutch problems are over!!! Put your key in the ignition and start your engine. You are now ready to be on the road again without breaking the bank.


Doing the truck repair yourself will save you a lot of money!!!


Depending on your truck’s model you may encounter problems to remove and place back the fan clutch due to the rigid spacing area in your engine.

If you find this repair job interesting check out how to repair a damaged fiberglass hood of a truck.