HOW TO... Fit an alternator belt
It’s the squeal deal… That nasty screeching sound from under the bonnet probably means it’s time to replace your alternator drive belt. Here’s a quick step-by-step guide on how to go about doing it on a non-aircon mk1.
Kill that dreadful screeching sound by replacing your alernator drive belt: we show you how
1 You’re going to need unimpeded access to the front of the engine, so the induction pipe has to be cleared out of the way. Start the process by loosening the jubilee clip holding the pipe to the airbox and throttle body using a crosshead screwdriver.
4 This is where a torch comes in handy, because the alternator is buried away low in the bay. Alternators are exposed to water and road grime, and their mounting bolts can rust and stiffen. Soak them with oil to loosen them a little before getting busy with the 12mm spanner.
3 Wriggle the induction pipe free of its fixings and place it on top of the engine, out of the way. By the way, if your airbox doesn’t look like the one in the picture, that’s simply because our photographic car is fitted with a Davefab cold air induction kit.
2 At the other end of the induction pipe, use your long-nosed pliers to squeeze and loosen the clip that holds it to the control valve air bypass pipe.
6 Using a 12mm ring spanner, slacken off the bolt on the tensioner sufficiently that the old alternator drive belt can be slid off the pulleys. That done, check the condition of the water pump and alternator bearings by rotating them – they should turn smoothly.
10 Check the tension – there should be about 10mm deflection on the longest part of the belt run. Tighten the alternator mounting bolts, refit the induction pipe, and run the engine: too tight and the belt will whir, too loose and it will squeal. Expect to re-tension after 100 miles.
5 Undo the upper and lower alternator mounting bolts. The lower bolt is hidden from view on the back of the alternator and you’ll have to locate it by feel. If it’s seized you’ll have to get the car on a ramp, remove the plastic undertray, and attack the bolt from below.
8 Slip the new belt over the pulleys, starting with the crankshaft pulley, seen at the bottom of the picture. Ensure that it is seated properly in the grooves of the pulleys.
9 Tighten up the tensioner bolt again, until you can feel that the belt is stiffening on the pulleys.
7 Old belt on the right still has some life left in it, but the deeper grooves of the new belt will help it seat better on the pulleys.