Rookie mistake on fan belt?

Paul L · 10-19-2004, 02:40 AM

Did I make a rookie mistake in replacing my fan belt? I had a belt pop 6 months ago. I replaced it and figured out what the spacing washers were for. I adjusted it tighter a few weeks later. 2000 miles later another one breaks. I get a new one and install the same as the first one. Now a few weeks later I go to adjust it tighter and notice the removable half of the pulley doesn't seat on properly. The special fit hole in middle is starting to get rounded out and there are metal shavings in the area. I continue to examine and notice that the fan has a key slot yet nothing is in the key slot. The fan can turn around the hub without the hub moving.

2 questions
1) what did I do to screw up the pulley or is this abnormal wear and tear that sometime occurs?
2) should the fan be able to spin on its hub without the hub spinning?

aj88cab · aj88cab's Garage

You should have a key in the slot to keep the pully from spining on the atlernator shaft. Sounds like the pully has worn from spinnig on the shaft. I think you will need to replace the pully and worst case the alternator too if the shaft is worn also.

Good luck
Andrew

Rot 911 · 10-19-2004, 05:13 AM

I agree with Andrew.

Wil Ferch · 10-20-2004, 05:36 AM

Typically a result of not using the full set ( 6) of shims...in whatever proportion you need to get it tight. The unused ones MUST be installed...but behind the nut and not under the pulley-halves. Worst thing...throwing away the "unused" number of shims and only using the few that you need between the pulley halves. Doing this won't allow full seating of the outer pulley half and the rounded-end rectangle will get "hogged" out over time...apparently what happened here.

Wil

Paul L · 10-21-2004, 07:32 AM

Rookie mistake for sure! I never had 6 to begin with. I had 4 then lost one!

Any suggestions on where to find a new or used pulley. Does this sponsor sell them? What about more washers?

I think the alternator shaft is part of the alternator. I'd hate to replace a functioning alternator. Believe it or not, it is working fine with all these grooves in the pulley and key element missing. The belt is quiet and appears (at idle) be spinning everything fine. Is there any danger to the engine in me running it like this? Another stupid broke rookie question.

Wil Ferch · 10-21-2004, 07:41 AM

You need the key ( half-moon "woodruff" style), and if its the outer pulley half that is damaged...you can get a replacement here from our host or used. If the damaged part is the other, mating part, then you have an alternator problem, most likely.

Wil

Gunter · Gunter's Garage

Wil said it. Get the shims and key and let someone who is familiar with the proper installation look at your pulley. It maybe re-usable. You are not the only one who has misaligned the pulley and not used the right configuration on the shims. Get a Bentley manual and Wayne's book. Unfortunately, the shaft may be beyond salvage. A belt should last easily 2-3 years. You say it's working fine, but you also say the pulley spins on the shaft. Two belts braking, something is wrong. Get someone to look at it and use the proper wrench in your tool kit for belt replacement. Do not hold the fan with a screw driver like someone one this board did and broke the fan blades. Get the books.