Technical 2.5td 1991 how to adjust generator belt tension?

[Cyberkul]

Hi! The belt needs to be re-tensioned often, for some reason. The upper generator bolt for the sliding adjuster is difficult to reach, and there is very little room for a ratchet or other tool to loosen/fasten the bolt. The 19mm nuts on the lower fastening bolt is ok to reach, when raising up the vehicle with a jack. I guess the two bolts in the middle is just the fixed mounting bracket for the alternator? (see picture) Anyone know a better procedure for this adjustment? Does it exist a better mechanism that can be used? My Skoda has a flat multi belt with a spring tensioner. Never needs adjustment, I think it has never been changed, and the car has about 250000km..

 

[Communicator]

Hi! The belt needs to be re-tensioned often, for some reason. The upper generator bolt for the sliding adjuster is difficult to reach, and there is very little room for a ratchet or other tool to loosen/fasten the bolt. The 19mm nuts on the lower fastening bolt is ok to reach, when raising up the vehicle with a jack. I guess the two bolts in the middle is just the fixed mounting bracket for the alternator? (see picture) Anyone know a better procedure for this adjustment? Does it exist a better mechanism that can be used? My Skoda has a flat multi belt with a spring tensioner. Never needs adjustment, I think it has never been changed, and the car has about 250000km..

It is a long time since I adjusted a similar system, and that waa on a 1990 Talbot Express where the alternator was on top of the engine.
General principle is to slacken all three points. Alternator pivot, slotted stay clamp, and slotted stay pivot. I had a piece of wood (oak) to use as a lever pulling belt tight, then tightening sliding clamp point first. Belt should be OK if you can deflect it by about 12mm on longest span between pulleys.

Perhaps @bugsymike has other suggestions as his experience is broader than mine.

 

[bugsymike]

It is a long time since I adjusted a similar system, and that waa on a 1990 Talbot Express where the alternator was on top of the engine.
General principle is to slacken all three points. Alternator pivot, slotted stay clamp, and slotted stay pivot. I had a piece of wood (oak) to use as a lever pulling belt tight, then tightening sliding clamp point first. Belt should be OK if you can deflect it by about 12mm on longest span between pulleys.

Perhaps @bugsymike has other suggestions as his experience is broader than mine.

All as you say.
It may be that due to age of the vehicle, the pulleys if it has been slipping a lot have got polished up or can even be out of alignment so unless a really good quality belt of the correct A shape to fit in the V groove the problem will persist.
It is the main reason manufacturers went to multigroove belts as they are better able to handle the effort needed on high output alternators etc.
Inbetween during transistion they tried "cogged" belts which are basic V groove belts but have notches in them, this isn't to provide drive , but allow the belt to twist more in form with the pulleys.
I had a Nissan Cabstar that used twin V groove belts, but even then they could slip and of course could only be replaced in matching pairs.
"Cogged belts have slots that run perpendicular to the belt's length. The slots reduce the belt's bending resistance. Cogged belts can be used with the same pulleys as equivalently rated V- belts. They run cooler, last longer, and have an efficiency that is about 2% higher than that of standard V-belts."

"

 

[Cyberkul]

Thanks for great answers I adjusted the tension again yesterday. I losened the three points, but not the stay clamp pivot. After losening the three points I used a crowbsr between the engine mount and a solid edge on the alternator. Little force was needed to get tension on the belt, and I also was able to tightening the stay pivot bolt before removing the crowbsr, and tightening the two alternator pivot nuts from the underside. I think the tension is now about correct, but there is some give, so i'm not sure. Also, i'm not sure if the torque on the pivot clamp nut is enough. There is only room for a short ratchet down there. It could perhaps be done from the underside, with an extender of the correct lenght. I hear no noise from the belt when it is relatively tight. But the experience have been that when i hear squeeking noise when cold, a little bit above idle, the belt is slack again. We'll see if the same happens again. Maybe it is as simple as not enough torque on the pivot clamp nut?

 

[bugsymike]

Thanks for great answers I adjusted the tension again yesterday. I losened the three points, but not the stay clamp pivot. After losening the three points I used a crowbsr between the engine mount and a solid edge on the alternator. Little force was needed to get tension on the belt, and I also was able to tightening the stay pivot bolt before removing the crowbsr, and tightening the two alternator pivot nuts from the underside. I think the tension is now about correct, but there is some give, so i'm not sure. Also, i'm not sure if the torque on the pivot clamp nut is enough. There is only room for a short ratchet down there. It could perhaps be done from the underside, with an extender of the correct lenght. I hear no noise from the belt when it is relatively tight. But the experience have been that when i hear squeeking noise when cold, a little bit above idle, the belt is slack again. We'll see if the same happens again. Maybe it is as simple as not enough torque on the pivot clamp nut?

Don't overtighten bolts they are only M8s on adjuster bracket from memory.
Generally if all bolts tightened correctly they do not need to be "violently tight" .