Alternator belt tightening - too tight?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu Jun 18, 2020 11:08 am

ps. We all love the Jazz!

Scott560 · Post by **Scott560** » Sat Jun 20, 2020 3:36 pm

Whipped the PS belt off, started it up, still had the noise.

Whipped accessory belt off, started it up, noise gone. Good good, in the right ball park, alt or aircon it is then...

Removed alternator, it span smoothly, in fact freer than than the new one. At this point I was worried I misdiagnosed. No detectable play in any direction or notchiness when spinning at all.

Checked the aircon pulley whilst it was free of the belt tension. No up or down play, but a little bit of in and out play. At this point I'm worried its the aircon pulley. The in and out play though j could see was the clutch mech, not the actual pump part, so still hopeful.

Wanged the new alternator on. Tightened the belt and rigged up a bucket with 10l of water to give me the 98N force required for the deflection test (wife gave us a hand). Range is 9.5mm to 12.5mm , came out 10mm in the end so happy with that.

Fired it up, noise gone, all good. Diagnosis correct, just as well!

Put the PS back together and a quick test drive, all good.

Things to remember!

Undo the bat neg terminal! Don't wanna pop your main fuse or weld your socket/spanner to the alternator nut. Manual says to write down the customers radio presets , made me LOL.

Don't overdo the + terminal on the alternator. Last one was hard to remove. 8NM is the spec.

Before trying to shove any belts down to the crank pulleys, make sure the wheel well access port has its tabs pushed out the way or you'll end up getting the belt caught on one of the fingers and get very annoyed.

Overall quite high on the fiddly job scale. Very limited space for the alternator bolts, needed to use a few different combinations of ratchets adaptors and sockets, a different one for every bolt! It was near impossible with a standard halford pro large toolset, had to rummage my spare socket box...

Make sure you clip the orange abs power connector back onto its mount. I've lost a few mm where it rubbed on the PS pulley from last time. Same goes for the PS fluid which just lifts off.

Another job done , shouldn't have needed to do it but obviously was going to happen at some point.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sun Jun 21, 2020 1:17 pm

Glad all sorted.

Scott560 wrote: ↑
Sat Jun 20, 2020 3:36 pm
rigged up a bucket with 10l of water to give me the 98N force required for the deflection test (wife gave us a hand). Range is 9.5mm to 12.5mm , came out 10mm in the end so happy with that.

This is dedication to accuracy!
(would love to see pics of the lashed up water application!)

Scott560 · Post by **Scott560** » Sun Jun 21, 2020 2:03 pm

Sometimes I discount written instruction and go with the flow, but since the accidental over tightening I decided to be sure to be sure this time. I always take the mindset that if someone took the trouble to write it down, its probably important, and since they design and build millions of cars and I don't, it should probably be followed.

It is actually completely impossible to set the tension as the manual describes. Technically you cannot put the force on the belt either perpendicular to it, or in the middle of the pulleys, because the sodding engine mount is in the way. Even if you do try, you would need to factor in the moment of force and add more accordingly as the belt is not sitting level to the ground.

In the end, I did the PS belt by eye. The angle is even steeper and engine mount even more in the way.

Still, the sound is gone, and one of my metallic rattles at start up also seems to have gone - so perhaps there was a clue it was on the way out for some time.

Sadly no pictures taken - but a neighbour passing by probably did wonder what was going on and where the old priest was

Scott560 · Post by **Scott560** » Sat Mar 06, 2021 6:09 pm

Just for the completeness of the post, over the last few months, the car was giving me a chirp from the alternator belt in the following conditions:

Heavy electrical load (lights+fogs+fan+rear demister etc) when revving out of idle.
Going through a puddle on the left hand side.
Or just when starting normally.

Whilst the Honda manual states the belt is no longer 'new' after 10 minutes of running, I suspect the newer aftermarket belts are harder, and take a little longer to stretch/wear in. Obviously the previous adjustment was too slack, so had to adjust the alternator tension again today. Still a fiddly job due to no space.

I removed the ABS connector off its mount, pulled up the PS fluid pot and moved it aside a little. I then slackened the 2 barley visible bolts that mount the alternator (13/14mm at the top of the alt under the PS pump and 12mm (i think) post under the alternator - this is the tricky one to get to right opposite the front chassis leg), nipped up the adjustment 10mm bolt facing the front of the car 2 full turns clockwise, and then tightened everything back up. Hopefully 2 turns wasn't too much. I then also remounted the tiny little bracket that holds the wire harness clip which is held to the alternator with an 8mm nut which I left off last time.

no chirping now when under full electrical load and give the throttle a blip at idle. I can see why auto tensioners were invented!

Also noticed that my battery terminals have shrunk slightly, probably from being clamped too hard, I can now move the clamps around by hand. No danger of coming off the top, but tricky to rectify. Thoughts on a postcard!