How do you change a Case 580C backhoe fan belt?

Answer 1

It isn't the easiest thing in the world to do. That being said, here we go.

READ THE WHOLE ARTICLE BEFORE PROCEEDING!! THIS IS CRITICAL!!!

First raise and block the loader arms as far as they will go. Use the safety lock on the loader arm if you have one. Otherwise cut a piece of heavy angle iron to the correct length and clamp it to the raised piston rod using heavy muffler style clamps, so it sits on top of the piston rod and contacts the upper rod arm bracket, and the lower part rests on the Piston Tube top.

Then you must remove the front radiator grille that protects the radiator. Then right below the grille bottom, you remove the lower rectangular front hydraulic pump cover on the front of the loader frame, which should have 4 big bolts on the sides holding it to the frame. The bolts do not have to be taken completely off as the cover usually has slotted attachment holes. Slide it out towards the front of the machine.

Then you loosen the bolts on the alternator brackets and remove the belt from the alternator and water pump pulleys.

Then its back to the hydraulic pump. Loosen the high pressure steel line fitting and remove it from the hydraulic pump. This is the hardest part of the job. It helps to have a rubber stopper to put in the tube or at the least a CLEAN rag to stuff in the tube to prevent it from leaking oil all over the place.

Then loosen the rubber hose clamp that holds on the hydraulic return hose to the hydraulic pump. You may not have to remove the hose, but you will have to also loosen the cross tube rubber hoses that come from the hydraulic tanks and form a Tee from which the return line to the pump hangs. These connecting hoses can be removed if you like, and you can remove the return line Tee completely, but the hydraulic oil will spill out unless you drain it first. Usually you can get the pump back far enough so you don't have to take the Tee off. Alternately you can stuff a CLEAN rag into the tubes/hoses to keep them from leaking.

When this is done, remove the two large bolts that hold the hydraulic pump to the loader frame. They are threaded right into the frame and have no nuts on them. Then slide the pump towards the front of the machine, wiggling and twisting as you go to loosen the flange of the pump which is tightly fit into the mounting hole. You may have to tap it with a drift to get it to loosen. CAUTION!! The pump body is SOFT ALUMINUM, and if you hit it hard you WILL BREAK IT! BE CAREFUL! Pumps are expensive. At this point you have removed the pump drive spline from the front pulley which connects to it to drive the pump.

There is a connector sleeve between the front pulley drive spline and the hydraulic pump drive spline. It looks like a tube. Make sure to remove and replace this spline coupler! It will ALWAYS be worn! It is made from very soft steel.

Check the condition of the front pulley spline and the hydraulic pump spline as well, and if worn, you will have to replace them. The pump spline can only be replaced with a new pump. {:o( Bad news, but true.

Now wiggle the old belt off the front pulley spline. Then get TWO, new, Gates Brand, V - belts, and wiggle them back over the front pulley spline. You only use one belt, but it is such a pain to change them, you wire the unused belt out of the way and let it wait patiently for the next time you need the belt replaced. It will be dry rotted a bit by then, but it will work for awhile until you can get the time to fix it. This is an old trick I learned the hard way. It lets you keep running if you are in a pinch.

When the belt is in and installed on the pulleys, and the spare wired out of the way, make sure to install the tubular drive coupler before doing anything else. DON'T FORGET THIS!!!. The pump won't run without it!

I have tried putting grease on the splines to make them last longer, as they move around a bit due to loose tolerances and some motor movement relative to the pump which is bolted to the frame. I have also put the removeable locktite, the blue stuff, on the splines, which seems to limit movement and still let them move when they have to. This has better results. NEVER use RED Locktite, as it will freeze the splines and break the pump!

Push the pump back in and reinstall the pump high pressure fitting first before tightening in the pump mounting bolts. The tubing nut usually is not the most perfect fit or perfectly aligned part, and it may take a little wiggling or twisting to get it aligned and started. Then you can install the pump mounting bolts and tighten them up EVENLY, so the pump doesn't bind going into the frame mounting hole. This can break the pump. Pump is soft aluminum, frame is steel.

Make sure to tighten up the fittings and hose clamps well, or they will leak air into the pump intake and ruin the pump. It is good practice to put multiple clamps of the highest quality and strength to do this. DO NOT USE CHEAP CLAMPS. It is a good policy to tighten the clamps using a 1/4 inch ratchet and socket to get them tight. If the clamps break when you do this, they are of poor quality and strength, so go get some good ones.

Make sure the hydraulic fluid is full and/or topped off at this point!

Put the front Hydraulic pump cover and radiator cover back on, and remove the loader safety lift strut. You should be back in business.