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This is my first DIY so constructive criticism is always appreciated. After much searching online and failing, I thought I’ll write up how to change an RB25DET accessory belts. That is the Air-Con, Power-steering and Alternator belts. If this DIY already exists, all good here is another one.

Disclaimer: I am not a mechanic, I try and work things out using my own knowledge and other peoples DIY to please don’t blame me if anything goes wrong.

Belts I used:
Alternator: Gates Micro-VAT 4PK850
Air-Con: Gates Micro-VAT 4PH915
Power Steering: Gates Micro-VAT 3PK835

Meaning of the numbers:

4: Belt has 4 grooves, this cannot change in the replacement belt
PK: Not sure, don’t think its important
850: Length of belt, you need roughly the same.
All pulley systems have lots of room for adjustment for size of belt so you don’t have to have the exact same one. Have a look at what is currently installed and get something similar in size.


Firstly, you need to figure out which belt/s are worn. For me, when I had the steering at full lock with a cold engine, I would get belt squeal as well as when I turned the Air-Con. Therefore I decided to change those, as well as the alternator while I was at it.

When you open the engine bay, you will see your belts such as the pics below.


The the second step is to loosen the alternator pulley which is found on the left side of the engine bay, when facing the car. This will be done by loosening the bolt numbered 1 and then turning bolt number 2. You can then push the alternator towards the engine and loosen it.


The next step is the removal of the fan. Using a 10mm spanner, undo the 4 bolts. It helps using WD-40 and then holding a pulley while applying force onto it. Once they are undone, remove the fan.

Once the fan is removed, you need to remove the belt at the very front first. This is the power steering. I believe. To remove this, loosen bolt 3 and then turn bolt 4 to bring the nut away from the holding plate. You can then push the pulley system and loosen the belt. Once loose, the belt can be slid off.


The next step is the air-con belt. To remove this, you need to get under the car and remove the underbody protector by removing the 6 screws. Once removed, you will see another bolt near the middle of the car which needs to be loosened. This will allow the tensioner to move and loosen that belt. With the bolt loose, push the tensioner. This might be really tight so use WD-40 and/or a hammer on the block circled, NOT THE PULLEY ITSELF, to move it up. Once this has moved enough, you can pull that belt off too.


The last belt to be removed will be the alternator belt. Since you have already loosen it, you can just slide that off too.

Once your belts are off, you can just need to reverse the process and put them back on.


First alternator belt, don’t tighten this. Next the Air-con belt. Tighten aircon belt tension bolt enough so that belt twists to 90 degrees and nothing more, don’t re-install the under-body protector yet. Install power steering belt and again tighten it so you can just twist it to 90 degrees and tighten the other holding bolt. Next re-install the fan. Once the fan is tight, you can tighten the alternator belt to the same tension.

Start up the car and listen for any noises. Any screeches means the belt it too loose. Power steering will screech at full lock so hold it at full lock for a few seconds. Air-con should screech as soon as you start it if it is loose. Alternator should screech at any point when the car is on.

If any screeches are heard, tighten the corresponding belt using bolts 2, 4 or 5.

Once all belts are tight, you can reinstall the underbody protection as we left it off in case we need to tighten the air-con belt.

Go for a drive and test it out. If any screeching is heard, tighten the belt which causes. Avoid belt squeal eliminators as they are only temporary fixes which make more of a mess than solve the problem.

Final Step: Enjoy your screech-less belts and pulleys :action-smiley-069:!

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  • 2 months later...

Nice write up - I looked for a guide ages ago when I did mine and couldn't find any so I just thought stuff it and ended up working it out. A guide would have been nice back then :)

Part of the reason I wrote one up. I thought someone somewhere would find it useful.

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  • 1 month later...

Hey man, to tighten the alternator belt do I loosen bolt 1 and adjust tightness with bolt 2? Which way am I suppose to be turning bolt 2 to tighten?


Sorry for late reply, I was overseas. Yeah you need to loosen bolt 1 so that the whole alternator moves then turn bolt 2. You want the whole alternator moving away from the middle of the engine so from memory and looking at the picture, it should be to the left to tighten, therefore towards the cabin of the car. It moves enough with each turn to be able to see if its tightening or loosening.

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Sorry for late reply, I was overseas. Yeah you need to loosen bolt 1 so that the whole alternator moves then turn bolt 2. You want the whole alternator moving away from the middle of the engine so from memory and looking at the picture, it should be to the left to tighten, therefore towards the cabin of the car. It moves enough with each turn to be able to see if its tightening or loosening.

Thanks mate, yeah took me a while to figure out, was turning both bolts like a mad man and nothing was happening. Had to remove my FMIC piping to get a better view and realised bolt 2 moves the alternator in the slot.

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