In 24V and 12V V6's, the idler wheels are solid metal, with a smaller bearing attached to the block with a very
As for the bearings themselves - several posts on here to do with the idlers of the polyrib v-belt indicate that for the cash strapped Alfisti an option exists for doing several things - if cheap enough replace (which has been the most standard route). If too expensive, another option is to turn the bearings while listening to them with a screwdriver as stethoscope. A clean bearing will have a sound like an old-fashioned roller-skate wheel, and all is well. One on the way out will have small bits of impurity within, and this can be heard as small gritty sounds, as though there is fine sand within the bearing - which there is, sort of - these are microscopic rust fines, much like the sands of Mars. Ultimately, they will cause a seizure and tooth-hopping results.
It is possible to recondition a bearing - sounds impossible, but it is surprisingly easy, and I have both seen it done, and done it myself, with a lot of care and attention.
Tools you will need :
1) Micro-screwdrivers - usually NZ$ 2 -> 4, so a cheap throwaway, commonplace in electronics
2) Grease - I would recommend the Molybdenum Grease used in CV's
3) A spraycan of Degreaser
4) A tray to work in - because this most likely will involve bearing bits coming loose, and you do not
want to loose them. Something about the size of an oil capture tray is ideal, and definitely one which does not have any holes !
5) a small plastic cup, and a plastic model (Tamiya make the nicest ones) paint stirrer/spatula, and a pair of tweezers
6) The suspect Idler Wheel
It is highly unlikely that the bearing can be safely removed from the wheel, but that is no matter.
First, gently prise one of the bearing seals off - they look like a black plastic ring surrounded by two annular metal rings, when viewed with the wheel lying in the work tray, and that's because they are
. The micro screwdrivers come into play - its a bit like taking a bicycle tire off in micro - and you may need three or more flat-edge micros in action at the same time, but with care and a bit of forethought, removal is fairly painless (but just wait till we get to putting them back in
) At this stage you will now be able to see the balls swimming in a sea of grease. Not so visible may be the little flecks of rust - but fear not, for we now come to....
or - flush the buggers ! With can of degreaser, all of the ball bearing is now going to be thoroughly degreased.
spray away - and the next part will creep you out, guaranteed. Turn the wheel so it rests in the tray, so that you can direct a jet of degreaser into the bearing cavity. This will not harm the seals, btw. It is likely that (unless the balls are raced) there will be a flow of grease out of the bearing, carrying the impurities with it - and possibly some (if not all!) the bearings with it. fret not - once the cavity is cleaned out, degrease the balls that have escaped, and with a tweezers, replace them with the wheel lying flat in the tray. at this point we are ready for....
or - putting it all back together. Using a plastic cup containing moly-grease, slowly pack the bearing using the Tamiya model-paint spatula. This tool is really great for this kind of fine work, since you can use the spoon end for ladling the grease into the tiny cavity, and the stirrer end for smoothing the grease bed down. At this stage, be on the lookout for missing ball bearings in the tray, as you do not
want to miss one !
Once the bearing is well re-greased, gently re-insert the seal, being careful to not excessively nick any of the outside and inside edges as you go.
Test the bearing, being sure that its running well, and it should be after all this labour. Re-insert into engine. (much cursing and moaning). Clean up work area to avoid domestic squabbling. Wash hands.
So , for about NZ$50 outlay, you save on buying an NZ$300 part that could go south anyway....
I have done this before, with no overall improvement in performance, but certainly not the even worse fall in performance !
A skilled mechanic with experience in Alfas will generally test these as a matter of course during a belt change.