Pully Wobble Problems? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ChicoSmith · 04-28-2009, 12:58 PM

I have a C20 with a 327 AC/ALT/PS Pulley system that seems to have a little play or whobble. On a red light idle I sometime hear the tink tink of the fan touching something.

I just replaced the water pump and fan clutch about a month ago. Recently threw the AC belt (from the whobble?)

Can anyone help me troubleshoot the cause or direct problem of this? Is it possible that the water pump shaft is already spunked or is a little movement here normal?

**leddzepp** · 04-28-2009, 01:44 PM

Did it also do this before you changed the water pump?

If not, my guess is that it is a bent water pump shaft. It could also be a bent pulley.

69GMCLonghorn · 04-28-2009, 06:08 PM

Sounds like a cracked crank shaft to me... This would be a great time to drop in a BLOWN 502!! I hear they have never experienced a pulley problem to this day! HAHA

**john** · 04-28-2009, 06:14 PM

Have you checked the motor mounts? Possible cause of tink tink fan noise.

**DANTIP** · 04-28-2009, 06:14 PM

I would try to watch the belts/pulleys as the throttle is opened and closed. You may be able to zero in on the problem. I diagnosed a bent pulley earlier today with this method.

Good Luck!!

ChicoSmith · 04-28-2009, 06:18 PM

Thanks guys for the quick responses, hopefully its not the crankshaft. That 502 would be nice.

I will try taking a better look under idle and see what happens with some throttle...

Thanks again.

04-28-2009, 12:58 PM	#1
ChicoSmith When in doubt throttle out!!! Join Date: Feb 2009 Location: Chico, CA Posts: 22	Pully Wobble Problems? I have a C20 with a 327 AC/ALT/PS Pulley system that seems to have a little play or whobble. On a red light idle I sometime hear the tink tink of the fan touching something. I just replaced the water pump and fan clutch about a month ago. Recently threw the AC belt (from the whobble?) Can anyone help me troubleshoot the cause or direct problem of this? Is it possible that the water pump shaft is already spunked or is a little movement here normal?

04-28-2009, 01:44 PM	#2
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,995	Re: Pully Wobble Problems? Did it also do this before you changed the water pump? If not, my guess is that it is a bent water pump shaft. It could also be a bent pulley. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man

04-28-2009, 06:08 PM	#3
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	Re: Pully Wobble Problems? Sounds like a cracked crank shaft to me... This would be a great time to drop in a BLOWN 502!! I hear they have never experienced a pulley problem to this day! HAHA

04-28-2009, 06:14 PM	#4
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Pully Wobble Problems? Have you checked the motor mounts? Possible cause of tink tink fan noise. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

04-28-2009, 06:14 PM	#5
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,882	Re: Pully Wobble Problems? I would try to watch the belts/pulleys as the throttle is opened and closed. You may be able to zero in on the problem. I diagnosed a bent pulley earlier today with this method. Good Luck!!

04-28-2009, 06:18 PM	#6
ChicoSmith When in doubt throttle out!!! Join Date: Feb 2009 Location: Chico, CA Posts: 22	Re: Pully Wobble Problems? Thanks guys for the quick responses, hopefully its not the crankshaft. That 502 would be nice. I will try taking a better look under idle and see what happens with some throttle... Thanks again.



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