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MG MGF Technical - 1996 vvc drive belt adjust (air con)

trying to adjust the tension on the drive belt to stop the racket. looked at couple of links but not give clear pictures or instructions...well not clear enough for me apparently...any help?
peelie

Hi, are you sure that the tensioner is not on the way out? How long since it was changed? Noise can be a precursor(sic) to failure and engine damage,

Cheers Alan
A.J. Mackew

how do you know if its on its way out? just had the car 2months dont know wen was last changed. dont even know if am at the correct bit. diagrams i've seen show the tensioner at bottom of altenator (but wer non air con) , i can see a round thing facing the outside of car wich i asume is the tensioner. is a bit of movement in it n not sure if thats ok or if is ment to bix fixed hard with no play
peelie

Sorry I thought you were refering to the camshaft drive belt, Alan
A.J. Mackew

Pictures of Dieters shows this side of engine.
3903 shows the position of the idler. I believe the tension adjustment is via moving the alternator?

http://www.mgfcar.de/wreck_engine/dkcp_3903.jpg
http://www.mgfcar.de/wreck_engine/3817engine_left.jpg

Dave

More pictures. AC parts catalogue.

http://www.mgfcar.de/epc/988.htm
Dave

".. i can see a round thing facing the outside of car wich i asume is the tensioner."

Correct, there should be a 13mm nut in the centre of this tensioner pulley - Slacken this off a couple of turns. Look beneath the tensioner, you should see the exposed thread of a bolt, follow that down to the bolt head which is on the lower side of the bracket (this is the ajuster mechanism). If you turn this bolt head clockwise (tighten), it will move the tensioner pulley downwards, increasing tension on the belt. Once you have adjusted to the correct tension, tighten up the nut in the centre of the pulley to 25NM.

I have a theory that the position of this tensioner makes it prone to picking up dirt into it's bearing - I replaced mine (£30) when it started to squeel one winter (started after driving on salted roads) but the one that came off didn't seem that bad on inspection (and after a drop of 3 in 1 oil, it sounded as smooth as its replacement!). This year I've noticed the replacement one is sounding a little 'gritty'. Not that many people have the aircon version but even so there are a few threads in the archives which suggest that these pulleys are prone to this.
Mark

thanks for input alan , dave and mark it is really appreciated. yours seems to be spot on mark, although it wont tighten is like its at max adjustment, not sure if the tensoiner is knackered or if its the belt...the belt looks to be in good cndition n doesnt look that old so dont know if the belt is streched or the wrong size was fitted, but there is a little movement on the tensioner (can wobble it like you would your wheel bearing) but dont know if thats ment to be there or not...you do know am gonna be on here for loads info in the future.lol...thanks
peelie

The pulley is clamped against the backplate by the tightening of the centre nut - The pulley tends to stick against this plate and can give the impression that it won't adjust. I normally unscrew the adjuster bolt a bit and then hit it which breaks the grip and allows the pulley to travel up and down easily.

It's quite simple to take off the pulley wheel (just remove the centre bolt completely) to get at the mechanism behind - Underneath the pulley is a backplate with a slot in it (This is held on with 3 bolts, easy to remove). Passing through the slot in the backplate is a threaded bolt which is tack welded to a small plate which locates against the back of the slot. There is a threaded section on this small plate and the adjuster screw connects to this. Turning the adjuster screw causes the plate with the spindle to travel up and down the slot.

A couple of weeks ago, I tried to slacken my pulley to adjust the belt and snapped the spindle, so I've very recently taken it apart. The spindle plus a new nut cost me £11.22 from my local Xpart (and I know that the pulley costs approx £30). Once you take the pulley wheel off all will become apparent... You said you had noise from there? The pulley shouldn't wobble if the centre bolt is tight, may well be a worn bearing (or perhaps the centre bolt is loose?)
Mark Clayton

thanks for that mark..unfortunately its bit late to have look now but will get lights out n try dismantling it tommorow after work n let you know how get on, havent noticed any noise from tensioner just belt slipping n battery light coming on
peelie

Peelie, here are the pages from the workshop manual.

J.H McLeod

Sorry only loaded one page.


J.H McLeod

This thread was discussed between 08/11/2008 and 11/11/2008

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