You are probably here because you’ve got a Cat 312 water pump, and you’re looking for some useful tips on its disassembly and rebuilding. You know, with every service job that we do, there is a high probability of us needing to open up the old girl like a can of sardines. These pumps are extremely common in nature, however hardly anyone knows about their functioning and servicing. In this article I’ll try to cover everything that we need to have an in-depth look into these pumps, from their anatomy to disassembly and rebuilding procedure.
remove the fan belt
The removal is not complicated. I have 3 pictures of the cat 312 fan belt being removed. The first picture shows the front of the fan belt with the cat logo on it, and the second one shows you that it has a small hole like a key hole, and the third picture shows the back view of it. Just line up the key hole in the center of the belt with the key hole in the center of your fan belt, and you can use this to remove it.
remove the pulley and fan shroud
Remove the fan shroud. The shroud is held in place by three bolts and nuts on each side of the radiator. Loosen these bolts and nuts until you can easily remove them. When you have removed all six, gently lift the shroud off the radiator and set it aside.
Remove the fan. The fan is held in place by three bolts and nuts that go through the pully assembly into the block behind it. Loosen these bolts and nuts until you can easily remove them. When you have removed all six, gently lift the fan and pulley assembly off of the block, being careful not to damage any of the hoses connected to it.
disconnect the water lines
1. Disconnect the water lines from the inlet and outlet ports of the radiator core by loosening the hose clamps at both ends of the hoses with a screwdriver. Remove the water hoses from both ports.
2. Disconnect the two water tubes from the back of each water pump by loosening the hose clamps with a screwdriver. Slide both hoses off of the water tube fittings on the pumps.
3. Disconnect the water temperature sensor electrical connector at the front of the radiator tank by squeezing its locking tabs on each side of the connector and pulling it straight off of its fitting on the radiator tank once you have released its locks.
4. Disconnect one end of each heater core pipe from its fittings on either side of the firewall by loosening its hose clamp with a screwdriver and sliding it off of its fitting.
5. Disconnect one end of both heater core pipes that run through the inside of your vehicle’s cabin by loosening their hose clamps with a screwdriver and sliding them off their fittings at either end of your vehicle’s heater core under its dashboard.
remove the water pump pully bolts
No one will be able to answer this for you with any certainty as it is not possible to tell what state of repair your machine is in from the short description you have provided.
The first step is to remove all the bolts holding the pulley on. You do this by rotating the pulley until a bolt head lines up with a slot in the pulley. You then insert a screwdriver into that slot, and push down against the engine frame so that all the torque from the nut removal (counter-clockwise) is going into turning the pulley. You should now be able to remove that bolt easily with an impact wrench (or socket and ratchet). Repeat for all 8 bolts.
If they don’t come out easily, you will need to put them in a vice and twist off the heads, then drill out the remains of the bolts.
Once that’s done, you should be able to remove the pulley with no issues.
remove cat 312 the water pump
Water pump service is one of the most common jobs performed on a Cat 312 excavator. This video will walk you through the procedure for removing the water pump on a 312 machine.
This is a very simple process that only requires about 15 minutes of your time.
The first step to remove the water pump is to drain the coolant from the radiator. Use a drain pan and remove both radiator drains at the bottom of the radiator.
Next, remove the bolts holding the rear cover onto the machine. You can also use this opportunity to clean any debris off of your oil cooler with some compressed air.
To disassemble a cat 312 water pump you need to remove the fan belt, pulley and fan shroud, disconnect the water lines and remove the water pump pully bolts.
