2.5 aux belt shredding issues

[andmcit]

Car is a 95 Exclusive saloon:


One of my more recent purchases, I've not been able to even dismantle to try an tackle a
continuous problem the previous owner had with it where the AC aux belt continually
shredded despite a correct length belt being fitted by an experienced Cit Indy/specialist.
Everything looks aligned properly but the belt seems to shred a few mm in from one edge
and tears into strips which would suggest an idler pulley is out of kilter.

Said specialist had the car a few times and whilst there has fitted a new timing belt but
finally suggested a new damper spring as the pulley it supports seems to check out fine.

Where do I begin to tackle this!? I cannot get access onto the Allen head drive to loosen
the spring loaded tensioner pulley for a start - is there a special tool available? I'm effectively
halted at the first hurdle. I am led to understand the set up is the same principle if not
identical as the 2.1 sprung tensioner which is shared by the 1.9 Td Xant AC one
The 2.5 spring is a different design on one end and appears a Cit only part?

The car has barely covered any mileage since it had it's last MOT but because it was so
unreliable and let the previous owner down so badly (embarrassingly) its sat unloved
awaiting it's fate and I volunteered to try and tackle the problem.

Any suggestions/pointers would be great as I'm now desperate for a decent legal tow
car as my usual choice isn't likely to work anytime soon and may even be terminal.

As yet, I'm totally blind to the nuances of 2.5's although I do like driving them as well
as the hydraulic clutch. I could forgive this black car being a diesel if its damned belts
worked properly!

heyulp!!!

Andrew

[XMX]

Hi Andrew;

Where do I begin to tackle this!?
Andrew

PM Sent,

XMX

[xmexclusive]

Hi Andrew

The 2.5 aircon aux belt can be a real sod.
You cannot check the alignment of the pulleys visually.
You cannot fit a non aircon belt as the hydraulic pump is in a different place.
On-the-Cut replaced his spring with a slotted metal plate.
This takes some of the snatch out of the belt drive.
Most people blame a weak spring and the bearing wear in the idler arm bearing.
I have a theory that the more the belt snatches the worse things get.
This puts a permanent set in the idler arm, offsets the idler wheel far more than bearing wear ever will.
It then runs the edge of the belt just over the sharp edge of the roller.
First ridge of the belt is flexing over that sharp edge. The outer rib is still under heavy tension but not supported by the roller so it wraps round the edge of the roller tearing at the thin belt strip so the outer rib starts to break away. If left this process will shift the belt over until it starts again on the next rib.
A crankshaft pulley with split rubber can also cause similar belt operation. That needs checking before you rush out and replace the idler and spring.
The idler is a one off but I think the spring is also used on the later HP20 V6.
I bought a couple of new idlers from AEP. Have seen the springs fairly regularly on Ebay for around £40.
The adjuster just needs a shortened allen key unless some kind (ah)sole has fitted a Torx bolt as I eventually found on one of mine.
Have an engine out to design a more reliable system much closer to the non a/c 2.5 and the later Xantia's where there is no idler arm.

John

[robert_e_smart]

The aux belt does a lot of flapping on my 2.5. Its a nuisance, I'm going to change the belt after I get it MOT'd and investiage the spring loaded tensioner. I am blaming the tensioner, but haven't investigated it yet.

[onthecut]

Hi Andrew.

Heres a copy of my post when I had this issue, if it's any help. Can't remember now whether I had to drop the engine a little to extract the main retaining bolt.

'Essentially, a very simple mod. Took off the whole assembly to start with and it was immediately apparent that the key wear was in the main pivot point where the arm is Allen keyed into the block. (this lets the spring loaded gubbins push and tilt the tensioner pulley to the extent it starts slicing the belt up on its outer edge)
I established that by rotating the pivot bearing seat through 90 deg. I could achieve an acceptably play - free situation, using the existing pieces. Instead of re-using the spring tensioner, I cut a suitably thick piece of steel (abt. 5mm); drilled a hole at the top to bolt it onto the pulley arm, where the spring device was fastened and then milled a slot at the bottom to allow some manual adjustment and clamping by use of a bolt, into the original hole used by the spring device. Tensioned it up using a pry bar placed on top of the centre boss of the pulley (not the outer face) and levered against the chassis leg. Not pretty, but gets a result. A bonus of using a reasonably thick piece of steel, is theat when fastened up, it tends to true up the pulley arm, relative to the block, even more.
Guessed at the tension, but when I dismantled it all to do the belts, there were no signs of distress on the belt it had been running. Anyway, happy enough with the result to continue using it now'

MIke.

[terry g]

the idler shaft bearings have gone, where it mounts to the block, they are noodle roller bearings, sorry needle roller, and they wear the shaft and the whole pully assembly ends up out of line and the belt runs off to one side of the idler bearing then slips over the V grooves on the other pullys, then it looses a rib and it flaps around usualy taking some of the bonnet insulation with it, ill bet your belt has moved over to the left hand side looking from the front and there is one or two empty v,grooves showing on the pump pulley? a quick fix is to loosen the whole assembly from the block and turn the bearing shaft 180% then refit it and it will work for ??? mine has been working for two years now,?? be warned that this wiil not stop the belt from flapping at about 1200 rpm? and pollishing parts of the subframe

[andmcit]

I appreciate all your replies so far - thank you.

So what you guys are all saying is this is a design "characteristic" of AC 2.5's?
I'm pretty blind to the reality of the set up and the noodle bearings so was
pre-arming myself with good info before battle commences.

Bottom line then - a new idler at whatever no doubt eye watering expense
is required or are set up issues now built in which will never be renewed or
built out by fitting new? I like the idea of a plate instead of the damping to
cut down the resonance - there is a significant throw on the belt at idle,
that's for sure.

Andrew

[robert_e_smart]

Mike,

Do you have any pictures of what you done? It sounds like a better solution than fitting a new spring tensioner thing. The belt resonance is really annoying, and I would like to eliminate that.

[onthecut]

Hi Robert.

Sorry --- afraid not. Patience was stretched to limit doing the s*****g job. Once you get your access to the pieces it's pretty self explanatory, as all you do is replace the spring loaded gubbins with a suitably butch, flat plate with an adjustment slot. The surprising bit is how much force you have to apply to get a satisfactory tension on the belt. Did seem to make a permanent fix though.

Mike.