Aux belt resistance- alternator clutch or ac compressor?

corndog

Active Member
Nov 14, 2014
47
0
Hi Folks

My pd100AXR is a little shakey when pulling away in 1st (especially so when cold) and the transmission/engine seems to lurch a bit when i let off the accelerator quickly.

I started it up and wend for a quick drive without the aux belt and it seems considerably smoother

I've checked the alternator pulley centre spins independently of the outside only in one direction. It can be done by hand but is perhaps a little bit stiff to get going. Should it should be very easy to spin the inside and outside separately?

The tensioner spins nice and easy and doesn't feel to have any play when belt is off

The AC compressor spins nice and easy but has no refrigerant due to a cracked pipe (been like that for almost 3 yrs (don't know where the clutch/engagement is in this. Any ideas?)

I'm hoping someone can point me to it being one of these or what further tests i can do?
I wonder if things are different when under tension?


So i'm thinking it is aux belt related but it could also be something else. I did do a cambelt and waterpump replacement about a year ago which may have improved the issue slightly though i think my belt is not quite under the right tension (tension indicator slightly outside the marks) so i may need to re do it. Timing is currently ok based on VCDS readings. Had a look under the camshaft cover and didn't see any obvious damage but i need to have another look

Thanks for any help!
 
Last edited:

RUM4MO

Active Member
Jun 4, 2008
7,784
983
South Scotland
I can only answer about the AC compressor, it does not have a clutch, it is always driven, so the pulley has a rubber shear coupling so if the compressor seized, it would shear that coupling and disconnect the inner from the belt driven outer of that pulley to allow the rest of the auxiliary bits to be driven.
 

corndog

Active Member
Nov 14, 2014
47
0
Interesting stuff, thanks RUM4MO!

Half thinking AC delete anyway as i've never really needed it but finding a good guide is hard. Obviously need a shorter belt but i think the tensioner may need moved/changed in that case
 
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RUM4MO

Active Member
Jun 4, 2008
7,784
983
South Scotland
If you look in the on line parts catalogues you should be able to see what changes you need to make to leave out the AC compressor.
 

corndog

Active Member
Nov 14, 2014
47
0
Ok still pondering this one...

AXR engine

I think based on looking at real OEM and various other places that i may need a 780mm belt (that would fit just the alternator to the crankshaft pulley) Various things suggest i may or may not need a tensioner. possibly this one :https://www.amazon.co.uk/INA-534015010-Luk-Tensioner/dp/B00AJXD3R0

Measuring around crankshaft pulley then around alternator pulley looks much more like 980mm rather than 780 as suggested.

Trying to decide if i should just buy a stretch belt that is 980 without tensioner or some other option.

Any ideas?

Thanks!
 
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