What is the trick to installing new fan belt?
 

Got myself a new OEM fan and outter pulley. Figured I add a new OEM fan belt.

The belt is a Genuine Porsche belt 9.5 x 710. I can't even get the outter pulley to mate with the fan. It is really close though.

The newness of the pulley and fan make for a very snug mating fit which is adding to the difficulty ... but they do fit b/c I tested prior to trying to install the belt.

Is there some way to make the belt more pliable? Can it be heated up? What is the trick? My tech warned me that it would be difficult when I bought the belt on Friday.

FWIW: Previously I was using a Contitech 10 x 710 belt which I installed new a few years ago. After a year I was only using 1 shim inside of the pulley and 5 on the outside. I tried to install the Contitech with the new fan and pulley but it is too loose even with 0 shims in and 6 shims out.

Thanks,
Craig

EDIT ============ > the ContiTech belt DOES in fact fit with 1 shim in and 5 out. Intitially I thought it would be too loose prior to fully seating the belt and tighening the fan nut.

Here's one method



How to change a VW fan belt - Car Videos on StreetFire

^^^^^^^^^^^^ I expected that ^^^^^^^^^^^^^

Now onto finding a solution ....

It's very tricky installing a belt. What works for me is tape.
I put the shims where I want them, and then tape them in with masking tape.
A lot of jiggling and wiggling and eventually it goes.
I hate it. Those shims drive me crazy.

Yea, but in my case the shims aren't the issue. Even if I delete all shims (just for test fitting) I can't get the pulley to mate with the fan.

At least the fan install was easy. Took 5 mins. Hit the woodruff key on the first try.

Hmmmmm, Maybe get it started cockeyed, and turn the top pulley with your pulley wrench.
I know your frustration. It should slide on the bottom pulley.
It is a difficult process.

It would be nice if that nut on the alternator was longer so you wouldn't lose the shims in the pulley.

Put the belt and pulley on and tighten a little then turn the fan by cranking the engine for second , then go back and tighten the rest of the way. Maybe if it is really tight you will have to turn the fan and tighten a couple of times. I wouldnt heat it up.

Yeah what Dipso said I hadnt read his post. Sorry

Craig, this procedure does take some practice. I like to use a thick heavy grease such as Bosch grease on the pulley shims to hold them in place. I think there should be 7 of them to make all work properly but this doesn't sound like your main problem. I also like to put the belt in the crankshaft pulley and pull up hard on it to seat it in the lower pulley better which might help gain some room at the top. Then put the upper pulley in place at an angle but seated in the slots to make sure it is aligned, put the shims and nut on and slowly tighten while turning the pulleys and engine to make sure all is OK. Hope this helps, Tony

seems the prob is that belt is too tight

I'd probably try to install the old belt to confirm no mechanical issues

wild guess, although I've never seen it, is that belt is mislabeled

Thanks fellas.

Well I think I got it. Won't test it today b/c it is raining. I'll post results tomorrow.

I managed to get the pulley on with 6 shims inside and 0 out. I tightened the alternator nut to 30 ft-lbs while holding the fan pulley with the pulley tool. I then turned the engine over using the pulley tool and pressing on the right side of the belt in order to get the belt to ride up and seat.

Everything seems to be in order ... but dang ... that belt is tight. The deflection calls for 5mm or .2 inches. I am sure that I am in that range but as we all know this measuring technique is subjective.

I hope that it loosens up after I run it for a few minutes.

It is okay to have 6 in and 0 out right? As long as there are 6 total?

The old Contitech belt was too loose even with 0 in and 6 shims out. Again it was a 10 x 710 which seems to be an issue for many of us.

The new belt I got matches my spare original belt. Same part numbers and both 9.5 x 710. I used to run 4 shims in and 2 out when I had that belt on when I bought the car.

while you're out test-driving it, listen closely for any slight whining or grinding noises...usually a telltale sign that the belt is too tight, and causing strain on your alt bearing.

i was trying to say that maybe the new 9.5 x 710 is mislabeled and is too short

that wild guess figures that you know how to do a good install. It can be a pia doing it

excellent point

i install as loose as possible

if I quickly whack the accelerator linkage and the belt isn't flapping it's tight enough for me

I am starting to second guess myself now.

It just occured to me that I have never really had to "torque" the alternator nut. I have always tightened it until it stopped - without strong arming it of course. Always used the nut to turn the engine during valve adjusts too.

But right now the nut will still turn. Suggesting that the belt will continue to rise up and get tighter. I need to go back out there and check it again.

Yes, my biggest concern is damage to the alternator or even the fan (scraping on the housing).

"It is okay to have 6 in and 0 out right? As long as there are 6 total?"

Probably a little atypical, but not wrong.

Aside from the minor difficulty of keeping the shims in place while installing the outer pulley half, I always find that I have to install that pulley half so that it seems to be pinching the belt, then turn the crank and re-tighten the pulley nut, maybe even several times, but the belt will be forced to assume its proper position. It will be forced to "ride up" the pulley.

Thanks.

This is exactly how I have always done it. Belt is pinched and then turning the engine over causes it to seat properly. At this point my biggest concern is the tension. New fan + new pulley 1/2 + new belt. It is tight - I also don't want the fan housing it to crack. Those are pricey.

Going to do some searching now and see if anyone else has had a similar issue.

If you have the belt seated properly and the nut torqued to 30 ft.-lbs., it should only deflect five mm, which is slightly less than a quarter-inch. That's pretty minimal deflection, and the nice thing about the deflect-with-thumb test is that we all have pretty much identical thumb strength, as long as you're not putting a Schwarzneggar's worth of upper body behind it. So press it hard with your thumb and if a quarter-inch is all you can get out of it, you're fine.

I thought the magic number of total shims was 7
any combination but always 7