Club 80-90 Forums

I've always had a problem with the fan belt slipping but just put up with it - every time I've had it in the garage for some reason or other I've always asked them to sort it but the dreaded squeal always comes back. Anyway I've just had to replace the alternator and swapped it out myself and sure enough the fan belt is slipping again.
I've had a look on ebay and the adjusting bolt looks like this for a T25, so obviously the ratchet type thingy (I'm not very technical) must tighten the fan belt when you tighten the bolt?

But my bolt isn't like that (no ratchet thingy) and there's no notches in the bracket thing it goes into? Anyone got any ideas?




Thanks

Two things cause a squeal, crappy belt or wrong tension.
If your battery is caned it will cause a squeal as the alternator tries to stop the engine.

Make sure ALL the alternator bolts are very tight.
10mm of belt movement up and down on the longest run.
The bolt you show merely makes adjustment easier.

Get your spanners out and bollok them bolts up

Make sure the belt is suitably tensioned, it may have become too stretched. You should be able to twist it about 1/4 of a turn.

As Kev stated, ensure bolts are f.t.

If your pulleys are particularly rusting, they can insert the rust into the belt and it looses friction. Quite rare in a car for that to be an issue though, common on boats!

I believe a belt continually loosening is a symptom of a knackered water pump bearing. Not sure if that is applicable to the t25 motors?

kevtherev wrote:Two things cause a squeal, crappy belt or wrong tension.
If your battery is caned it will cause a squeal as the alternator tries to stop the engine.

Make sure ALL the alternator bolts are very tight.
10mm of belt movement up and down on the longest run.
The bolt you show merely makes adjustment easier.

Get your spanners out and bollok them bolts up

Thanks Kev. Are the bolts usually like the one in my photo? Mines just a normal bolt with no ratchet bit. I've had another look at the bolt and it might be the wrong size? I think the head of the bolt should be captive (in that it fits in a slot in the alternator?). This one seems too small and spins when I tighten the nut, and it's hard to get a spanner on it because of the slot it sits in. I'm going to go out to get another one and then tighten everything up.
The battery isgood (only changed last year) and the belt is in good nick as well, as far as i can see.

Smosh wrote:Make sure the belt is suitably tensioned, it may have become too stretched. You should be able to twist it about 1/4 of a turn.

As Kev stated, ensure bolts are f.t.

If your pulleys are particularly rusting, they can insert the rust into the belt and it looses friction. Quite rare in a car for that to be an issue though, common on boats!

I believe a belt continually loosening is a symptom of a knackered water pump bearing. Not sure if that is applicable to the t25 motors?

Cheers Smosh, I hope it's not the water pump bearing. Replacing the alternator has wiped me out for this month

Smosh is right and you do need to check the pump. Its easy enough. Remove alternator belt and grasp water pump pulley. I put this up a while ago for reference: https://www.youtube.com/watch?v=LghNy400HzI" onclick="window.open(this.href);return false;

Also check that the lower bracket is securely fixed to the crank case. It's held on with two studs, and where they go into the crank case can be a bit of a weak spot. On mine, one of those two studs was loose due to a damaged thread, so the bracket wobbled, which made the belt squeal. I had to helicoil the damaged thread.

Cheers lads. I've had another look and it's actually the bottom belt slipping, the one to the water pump.
Looks like you can tighten it by removing some spacers behind the pulley?