Overtensioned AC belt tensioner on defender

[moorey]

Recently had main belt shag itself on my 95 130, had it replaced by a mech, and within 2 months it was shagged again. Replaced it myself this time, and found that the (seemingly) non adjustable tensioner was putting huge tension on it. Had real trouble getting belt on, but managed. within another few months it is virtually shagged again, but the pressure has taken the water pump bearings with it. Never had a problem with it over the 100,000kms with it prior to this.
Am I missing something with the tensioner? There seems no way to adjust it.
Then again...i am the king of screw ups:angel:

Any advice?

[isuzu110]

Have you got the right length belt ? I recall there are several possible lengths for the 300TDI (eg. dayco 7pk 1595 and 7pk 1580 and possibly another)

[weeds]

there are two engths depending on which size alternator pulley you are running

being a 95 defender you should have the small pulley fitted, not unless you have upgraded your alternator to the higher output version a disco runs as i did, the disco alternator came with a larger pulley therefore i now need to remember to purchase the larger belt

is your tensioner siezed?

[nice1guv]

There is no way to adjust the main belt tensioner, it is spring loaded and just puts a predetermined amount of tension on the belt.

As the tensioner wears out it looses tension and will generally jump around more.

The tension is high. ;)

To get them to move especially when they are new you normally need a spanner (I use a ring one for this) with a half metre pipe or beaker bar over it.

Just using a spanner it is very very difficult to even budge the tensioner.

Even with a long extension on the spanner, it is still a difficult task to get the belt back on by yourself.

I believe OEM tensioner is Dayco, maybe your new one was a cheap brand.

[p38arover]

I remember when I bought the 300Tdi Disco, the belt that had been fitted was too short and was as tights as...

A new (longer and correct) belt, tensioner, and new bearings fixed it.

[moorey]

I seeee..... good advice all round. I didn't upgrade alternater since owning it, and unsure if it was done before....
As stated, yes, there is HUGE force required to move the tensioner any great distance, but no, it isn't seized....the longer belt must be the answer to my woes...thanks again, all you oracles.., you fonts of knowledge:D

[moorey]

A quick call to good old roverparts, and sorted......The one I got last time (not from shaun:angel:, but from Bursons..in a hurry) must have been for a 1996 onwards, and 15mm shorter:(

[weeds]

A quick call to good old roverparts, and sorted......The one I got last time (not from shaun:angel:, but from Bursons..in a hurry) must have been for a 1996 onwards, and 15mm shorter:(

err, now i'm confused cause i thought the late 300tdi defenders and disco had the longer belt and your had the shorter (if original alternator is still fitted)

my guess is if you need the longer belt you have a disco alternator fitted

[p38arover]

you fonts of knowledge:D

Or even founts of knowledge. :p

[moorey]

err, now i'm confused cause i thought the late 300tdi defenders and disco had the longer belt and your had the shorter (if original alternator is still fitted)

my guess is if you need the longer belt you have a disco alternator fitted
:eek:Shaun says 95 and earlier had longer belt? Damned if i know, as long as the one i pick up tonight fits...:confused:

[nice1guv]

err, now i'm confused cause i thought the late 300tdi defenders and disco had the longer belt and your had the shorter (if original alternator is still fitted)

I know late Disco 1s, from VIN TA onwards, had a smaller pulley and hence shorter belt - cause I have a 98 D1 and it takes the shorter 1580mm belt.


:eek:Shaun says 95 and earlier had longer belt? Damned if i know, as long as the one i pick up tonight fits...:confused:

The belts I have used have always had the length etc stamped on them, but they do wear off over time.

Eg: 7PK1580 or 7PK1595.

The relative positions of the alignment markings on the tensioner can also help you tell whether you have the right belt and also how much it is worn/stretched.

According to Incisor in this thread http://www.aulro.com/afvb/technical-chatter/33403-serpentine-belts-long-short-300tdi.html the markings should read 5 to 12 with the back marking being 12.

[weeds]

I know late Disco 1s, from VIN TA onwards, had a smaller pulley and hence shorter belt - cause I have a 98 D1 and it takes the shorter 1580mm belt.



The belts I have used have always had the length etc stamped on them, but they do wear off over time.

Eg: 7PK1580 or 7PK1595.

The relative positions of the alignment markings on the tensioner can also help you tell whether you have the right belt and also how much it is worn/stretched.

According to Incisor in this thread http://www.aulro.com/afvb/technical-chatter/33403-serpentine-belts-long-short-300tdi.html the markings should read 5 to 12 with the back marking being 12.

looks like i had it around the wrong way.....thanks