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Discussion Starter #1 (Edited)
Shalom VMFers! Just when you think you’ve been through it all Mustang throws you a curve ball.
So I decided to finally buy my own gear and charge my new A/C system.

All went well ice cold A/C but then I noticed this Sound! Thought Belt was loose and slapping something, so tighten it up and the noise got worse.

Removed the A/C belt and noise gone!
At first I thought oh hell a valve went out... then oh heck the new compressor is bad!

Loosened the belt enough to still turn the compressor no problem but a bit slack and noise quite diminished but still there.

Checked the idler bearing bolt tension, and compressor rotation and no binding or sounds. Seems to actually be more emanating from the crank pulley area. Fan/pump bolts are tight.

Vbelt is a Gates with the ribs facing onto the pulley.

Funny thing is that it ran around for weeks spinning the compressor without a sound before it was charged. Stumped!

 

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Maybe you overcharged the system? Also, wouldn't make sense since you said it ran fine for weeks before charging but are you sure the pulley's and belt are correctly aligned? It's a bit tough to tell from the pic you posted.
 

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I'd check the mounting of the crank pulley to make sure it's flat against the balancer and tight. These are known for belt "slapping" with the long span and, IIRC, a retro-fix was the installation of an idler pulley.
 

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You did evacuate the ac system before charging, didn’t you? It shouldn’t make the noise with ac off if it’s a refrigerant charge issue.

it sounds mechanical. Like a pulley is tapping or rubbing. Like the other poster suggested, check your pulley bolts for tightness.
 

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Discussion Starter #7 (Edited)
You did evacuate the ac system before charging, didn’t you? It shouldn’t make the noise with ac off if it’s a refrigerant charge issue.

it sounds mechanical. Like a pulley is tapping or rubbing. Like the other poster suggested, check your pulley bolts for tightness.
Of course! vacuumed it out for 1 hour. I used to do A/C in shops during my teens and early 20's. I even bought a digital pocket scale with my vacuum pump and manifold and measured the drop in weight on the two 12 oz cans. I got exactly 23.3 oz in there from these two 12 oz cans per the math. System calls for 24. It is ice cold even at idle. The white bucket is hot tap water. The refrigerant took minutes to go in where as took 1hr to get 5 oz in with the can sitting on top of the hot radiator. An old trick I'd long forgotten.

Noise A/C on or off. Not related to the compressor. Definitely coming from the crank pulley area.
 

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Discussion Starter #8 (Edited)
I'd check the mounting of the crank pulley to make sure it's flat against the balancer and tight. These are known for belt "slapping" with the long span and, IIRC, a retro-fix was the installation of an idler pulley.
Yes, I have since dug up a few old threads about belt slap and installation of a Ford idler pulley. I have an idler that also acts as a non-spring tensioner between the crank pulley and compressor. But was the Ford fix adding a second idler or just a single one as I have?

I've found there is wobble in the crank pulley. None on the dampener. [email protected] Chinese part most likely. I have ordered a new one from NPD. Let's hope their Chinese part has better quality control. I'll have to take a look to see if it's belt slapping or if the CP is grazing the WP pulley. The more I wrenched on the A/C belt to make it tighter the worse the noise gets! I slackened it as much as it can be slacked and still drive the compressor and noise becomes very faint.

If it was belt slap you'd think the opposite would happen? Anyhow, I'll have the new part hopefully this weekend. I love how these cars are so simple but every time you fix one thing something else breaks!
 

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Discussion Starter #9
Maybe you overcharged the system? Also, wouldn't make sense since you said it ran fine for weeks before charging but are you sure the pulley's and belt are correctly aligned? It's a bit tough to tell from the pic you posted.
As I said to JW67 23.3 oz. I used a digital pocket scale to measure the cans. Noise isn't from compressor/clutch operation nor are the idling bearings funky. In other words noise w/AC on or off.

Before the compressor was even hooked up to wires and hoses I ran it for a while with the belt to test it. Don't recall how tight but I don't leave my belts slack. Ironically slacking it is what makes the noise lessen. So it's definitely tension on the CP. I guess there's no easy fix. Will swap crank pulley and tear everything apart except the compressor.
 

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Interesting. I had a similar issue last week on my 68, started with vibration then noise. Finally figure out what was wrong as I limped it home. It became obvious with a big clank when the Crank pulley fell off! Apparently two of the bolts worked their way loose, Eventually the third sheared off. One was missing completely, one was sitting Happily in the pulley on top of the sway bar, and the sheared one was on the ground nearby.

Luckily I was only 2 blocks from the house. Drove it there before it heated up too much.

Now I have to decide If I will try to get the sheared bolt out or just replace the Balancer.

so I recommend you check the torque on the pulley bolts and consider using some thread locker.
 

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Discussion Starter #11
Interesting. I had a similar issue last week on my 68, started with vibration then noise. Finally figure out what was wrong as I limped it home. It became obvious with a big clank when the Crank pulley fell off! Apparently two of the bolts worked their way loose, Eventually the third sheared off. One was missing completely, one was sitting Happily in the pulley on top of the sway bar, and the sheared one was on the ground nearby.

Luckily I was only 2 blocks from the house. Drove it there before it heated up too much.

Now I have to decide If I will try to get the sheared bolt out or just replace the Balancer.

so I recommend you check the torque on the pulley bolts and consider using some thread locker.
It's definitely possible! CP is a newer one from NPD which means it was rebuilt. Threads might have been chased and loosened up. I recall the fit and torque being very tight. But anything is possible ;) If they are loose you can bet money I'll put blue threadlocker on them. But I'm hoping - praying it's just wobble in the CP causing the longer side of that belt to slap or grazing up on the WP pulley when things are very tight. As I recall there is only tiny clearance between those two pulleys. Wish I didn't have to wait 3-5 days for a part every time this happens. Oh well. Better than not having parts.
 

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Make sure the crank pulley bolts thread in far enough to pull the pulley tight. Maybe they bottomed out and allow the pulley to wobble.

It could be rust keeping it from tightening but I think you said you chased the holes.
 

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Discussion Starter #13
Make sure the crank pulley bolts thread in far enough to pull the pulley tight. Maybe they bottomed out and allow the pulley to wobble.

It could be rust keeping it from tightening but I think you said you chased the holes.
No it’s tight trust me!! It wobbles because it’s a crappy low quality knockoff that Classic Auto Air/Restomod Air used in the AC kit. New Pulley coming from NPD on Monday. I got so fed up with trying to get someone on the horn and playing phone tag I just went to NPD because they have good quality control and fast shipping. Not waiting a long time just for another junk part.

Balancer is a quality rebuilt from NPD. So no rust. Was shiny metal I primed and painted with high temp black last year. It does not wobble 😉
 

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Discussion Starter #15
Ok so it was the crank pulley piece! Took forever to get here due to all the unrest, but no biggie. No point/too lazy to upload before and after videos. But before the swap took off the power steering and water pump belts, removed water pump pulley. Ran just the A/C belt before the swap. Noise & tapping like crazy. Even after tightening down.

Swapped the crank pulley to the new one that came in today, ran it the same way and NO sewing machine and clacking noises whatsoever. Totally quiet. So THAT part is fixed. Strangely don't see any problems w/old crank pulley. I guess it was just eggshaped cheap junk that didn't fit right on the damper. This new one looks like a quality piece from NPD made like the original one with a heavier steel reinforcement in center and more carefully balanced.

NEW problem tho :) Water pump pulley does not clear the crank pulley any longer. Current one is probably 5 7/8 its almost 6". So now I have had to order a new dual groove water pump pulley that is 5 3/4".

Strangely the old lower quality crank pulley cleared it but just barely. I needed a feeler gauge to measure the clearance. New crank pulley bulges up just a tiny bit more. So 5 3/4" should give a good 1/4" clearance. Part will be here in 2 days.

At this point I've bought or had every pulley on the car replaced some 2x and now 3x. Oiy. Hoping to be driveable again this weekend without something else popping apart :p:giggle:
 

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When adding AC I had to switch the Pulleys for the same reason. Ford had different matched sets depending on which accessories you have
 

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So yours is a '68. I have a '67 (which had 4 different AC pulley setups for SBFs).
Here is the one on mine, and it appears original as it says fits 67 Mustang or Cougar:


5-5/16 inches in diameter. Just in case you need one smaller...….

Jason
 

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Discussion Starter #18 (Edited)
So yours is a '68. I have a '67 (which had 4 different AC pulley setups for SBFs).
Here is the one on mine, and it appears original as it says fits 67 Mustang or Cougar:


5-5/16 inches in diameter. Just in case you need one smaller...….

Jason
Jason,

Bit of frustrationville here but it's kind of my fault. I'm glad you said something because now it seems 5/16" is my only option!!!The 5 3/4" WP pulley I got is the same as my previous one o_O. It's sort of my fault because I didn't measure exactly correctly that night and thought I had a 5 7/8". So this one has to go back at a loss.

Weird thing is that 5 5/16" isn't reproduced by anyone anymore!! So how can NPD be selling a crank pulley for a 289/302 68' A/C car and has an interference fit with the 3/4". Grrrr.

I don't want to pay $80 for a used one and wait for shipping from Classic Cougar all the way on the West Coast to Virginia. Hope the belts will still fit!
 

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Discussion Starter #20 (Edited)
Dug around...one MFR making a new under drive pulley 5.25 (5-1/4) that actually speeds up the pump so they say. That might not be a terrible thing at idle as long as it doesn't speed it up too much. Prices is ridiculous tho! No one repro's for the 5-5/16. ARRRGH.

Edit: Found one much closer and much cheaper than Classic Cougar. NE Performance Mustang. It's the C6OE-8509-B 5.32" (5-5/16"). Lord...remind me never to try and restore a Cougar.

....aaaaaaaaand waiting game again :D. I guess I'll put it together with old parts and no A/C for the weekend :cautious:

Am going to make CAA send me a new part JUST TO MAKE THEM PAY for this hell even though I won't need it.
 
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