Air conditioning belt keeps jumping off?
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=123353
Printed Date: 24 Jul 2025 at 8:07pm
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Topic: Air conditioning belt keeps jumping off?
Posted By: Ron(AB)
Subject: Air conditioning belt keeps jumping off?
Date Posted: 14 May 2016 at 10:40pm
|
I've put the air on the last two days while doin' fieldwork, and each day the belt jumps off. This is on a 8070 with the old style gm compressor. First time the belt went into the fan, got a few bites taken out, and then got spit out. Second time, it jumped onto the alternator belt, sort of, and wore both belts before I noticed. Two belts junk! The ac does work good when the belt stays on properly… Its the weekend, and I need new belts, and I have field work to do in hot weather - 70 above F. What's causing this? |
Replies:
Posted By: MACK
Date Posted: 14 May 2016 at 10:52pm
| Replace the fluid damper on front of crankshaft. MACK |
Posted By: DrAllis
Date Posted: 15 May 2016 at 6:57am
| X-2 !! get that fluid dampner replaced before it breaks the crankshaft !! |
Posted By: jkoby
Date Posted: 15 May 2016 at 8:55am
|
Without ac, wouldn't you have more power? More power means moving a little faster? Faster speed means more wind? Open the windows and feel the breeze! Some of us don't have ac! |
Posted By: SteveM C/IL
Date Posted: 15 May 2016 at 9:33am
| Doc and MACK agree with me |
Posted By: littlemarv
Date Posted: 15 May 2016 at 9:37am
|
How does a damper throw a belt? ------------- The mechanic always wins. B91131, WC23065, WD89101, CA29479, B1, Early B10, HB212, 416H |
Posted By: DrAllis
Date Posted: 15 May 2016 at 10:13am
| Because it isn't working. Too many harmonics going on making the belt act like a guitar string twanging. |
Posted By: Leon B MO
Date Posted: 15 May 2016 at 12:03pm
|
This is info that I need to store somewhere in the back of my head. I would have never came to the conclusion that an 8070 throwing the AC belt is due to a bad dampener. The information available here never ceases to amaze me. Leon B ------------- Uncle always said "Fill the back of the shovel and the front will take care of itself". |
Posted By: DrAllis
Date Posted: 15 May 2016 at 12:53pm
| 7080-7580-N5/N6- 8070- 4W220 |
Posted By: Ron(AB)
Date Posted: 15 May 2016 at 2:16pm
|
Thanks everybody. The tractor is parked in the shed until the damper is replaced. Now I just have to get a new one and figure out how to get the old one off….? |
Posted By: Lynn Marshall
Date Posted: 15 May 2016 at 3:32pm
| The dampener is not the pulley. The pulley is solid on those models. The dampener just bolts to the pulley with 6 7/16 capscrews. Easy as pie, except the part where you have to pay for it. |
Posted By: tbran
Date Posted: 15 May 2016 at 8:37pm
|
when we have this we also check to see that liquid Freon is not getting to the compressor and locking it up - replacing the expansion valve and drier usually fixed.
------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: SteveM C/IL
Date Posted: 15 May 2016 at 9:52pm
| Good point Tim....for others,it's not just viscous dampers that go bad.If the rubber ring gets bad on those without a viscous damper you end up with BAD harmonics there too. My uncle's 190 was wrecking alternators and throwing belts before he noticed the ring wobbling some. |
Posted By: Ron(AB)
Date Posted: 16 May 2016 at 1:49pm
|
Ouch! $1680.00 Can to replace… Ahhhh but we love allis tractors… Orange is a beautiful colour….. |
Posted By: Stan IL&TN
Date Posted: 16 May 2016 at 2:47pm
I'd want to make darn sure the old one was bad before writing that check.  ------------- 1957 WD45 dad's first AC 1968 one-seventy 1956 F40 Ferguson |
Posted By: DougS
Date Posted: 16 May 2016 at 3:43pm
There is a thread lurking here in the archives where getting the damper rebuilt by a guy in Salem, Oregon was discussed. He was able to do it for a fraction of the cost. ETA: Here's the thread: http://www.allischalmers.com/forum/forum_posts.asp?TID=96740&KW=damper&PID=844184&title=426-harmonic-balancer-dampner-front-pulley#844184" rel="nofollow - http://www.allischalmers.com/forum/forum_posts.asp?TID=96740&KW=damper&PID=844184&title=426-harmonic-balancer-dampner-front-pulley#844184 |
Ron(AB) wrote:Posted By: DrAllis
Date Posted: 16 May 2016 at 4:39pm
| That's for the rubber mounted style, not the viscous style. |
Posted By: SteveM C/IL
Date Posted: 16 May 2016 at 5:42pm
| I assume viscous dampers are sized to the engine ie displacement and or stroke etc. The ones on my class eight trucks are much larger than my 8070.I just remembered my 6-71 Detroit had a pretty lrge one and it was 426 two stroke. |
Posted By: randy
Date Posted: 16 May 2016 at 6:27pm
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I am going to guess that if you price one for a Deere or a Caseih they are quite pricey also! ------------- CA WD WD45 D17 D17 Diesel 7060 8050 8070 |
Posted By: SteveM C/IL
Date Posted: 16 May 2016 at 10:11pm
| Can you purchase direct from Fluidamper? |
Posted By: LeonR2013
Date Posted: 16 May 2016 at 10:12pm
| You can check the damper with a mic. Just polish the damper on four points and see what the measurement is. When the viscous material starts to harden then the very thin metal on the front starts to bulge as the viscous starts to gang up on one side. You should have been getting a vibration by this time. I personally wouldn't even start it again until it's fixed. Leon R Cmo |