Pajero

[V8Ian]

2012 Pajero diesel, occasional use 80k on the clock. Regularly serviced on a time basis (every 6 months) rather than kilometres traveled.
A couple of years ago the fanbelts (matched pair) developed a slight chirp, under load. As the car was over serviced and mechanically wanting for nothing, when the female owner took it for its next (unneeded) service, she asked for the fanbelt to be adjusted or replaced.
The car was returned with no fanbelt noise. Within 10 kilometres the noise had returned. The car was taken back for the belts to be readjusted. Rinse and repeat, the noise returned.
Belt adjustments were requested at every service for the next couple of years.

Fast forward to a point where I had to borrow the car, thanks to the legendary reliability of Land Rover and Range Rover.
The battery suddenly went flat in a shopping centre carpark. RACQ came to jump start the car and diagnosed a non-charging alternator. I took the car to my auto electrician, who immediately diagnosed loose/worn fan belts. The belts were replaced and I thought that was the issue fixed, apart from a retentioning of the belts in 200 kilometres. Within that 200k, the battery went flat again. Again the RACQ came to jump start the car and retentioned the belts. Within another 200 k, the battery was again flat. I took it to a mechanic (known competent), explaining the protracted issue. He replaced the belts again and checked pulley alignment. Initially everything seemed normal, but on closer scrutiny with the engine running an intermittent wobble of the alternator was noticed. Cause was found to be the lack of a nut on the main mounting bolt. The car was returned with instructions to retention the new belts in 150 kilometres. This I dutifully did and know it was done correctly.
200 kilometers later the belts are again totally worn, for some reason the adjuster is not holding its position. I was going to add a locknut to rectify, but on disassembly cannot workout how this adjuster is supposed to work.

20240427_110244.jpg

The long bolt adjusts the tension on the belts, obviously. I thought the shorter bolt locked the adjuster, but unless something is missing, no. The central lump is threaded where the adjuster passes through, enabling the adjustment. The smaller bolt passes through loosely, apparently merely stopping the nuttesque lump from turning during adjustment.
The long bolt is not long enoug to add a locknut.
What am I missing?

[V8Ian]

I think I've got it sussed, but will await opinions of them what is more cleverer than me, in these matters.

[spudfan]

You might be waiting a long time...

[BradC]

My experience is an alternator adjuster is there to allow "adjustment" of the belt tension. It's not there to hold it, so after setting the tension all the slide/pivot bolts need to be tightened up. In fact I used to lock it in place then back the adjuster off a turn to make sure it wasn't being subjected to tension.

Edit: Not on a Pajero, but other cars.

[V8Ian]

Somehow i doubt it, Spud.

What initially appears to be the lock bolt, buried deep in the bowels of the engine bay and well covered by the bottom radiator hose, only holds the adjustment "nut" on the front of the alternator. The adjustment bolt is machined below the head, to locate it into a slotted, stationary bracket. This creates a monkey for the adjustment. It obviously needs a locknut to prevent loss of tention.
The locknut was probably lost by the same incompetent jobsworth who forgot to put the nut on the main mounting bolt.
It's no wonder motor mechanics are the least trusted of all trades. Paying premium rates for ham fisted incompetents, who deliver a car back to the owner in a worse condition than before they started servicing or repairing it!

[loanrangie]

Strange that a 2012 vehicle still has a manual adjuster and not a spring loaded tensioner like near on every other vehicle on the planet, there must be a set deflection measurement to setting it correctly.