Stripped Threads on A/C compressor
Thread Starter
Instructor
Joined: Dec 2010
Posts: 233
Likes: 6
From: Lake Charles LA
Stripped Threads on A/C compressor
Well, this has been a fun weekend. I just picked my car up from the shop on Friday, after having the A/C compressor replaced. I started the car Saturday morning and the (3 month old) alternator belt broke and flipped the A/C belt upside down on the pulleys. Not sure why that happened, unless the shop did not install the belt properly.
So, I went to get a new belt and replaced it. When finishing up, all I had to do was tighten up the A/C compressor and the bolt just kept turning. I didn't put any undue pressure on the wrench, but the bolt would not tighten. I must say the the bolt was tight when I loosened it. When I backed it out, some metal threads came out with the bolt.
So, am I screwed here or is there a way to fix this? I really hate to bring it back to the shop. Hoping I didn't ruin a brand new compressor.
So, I went to get a new belt and replaced it. When finishing up, all I had to do was tighten up the A/C compressor and the bolt just kept turning. I didn't put any undue pressure on the wrench, but the bolt would not tighten. I must say the the bolt was tight when I loosened it. When I backed it out, some metal threads came out with the bolt.
So, am I screwed here or is there a way to fix this? I really hate to bring it back to the shop. Hoping I didn't ruin a brand new compressor.
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
Well, this has been a fun weekend. I just picked my car up from the shop on Friday, after having the A/C compressor replaced. I started the car Saturday morning and the (3 month old) alternator belt broke and flipped the A/C belt upside down on the pulleys. Not sure why that happened, unless the shop did not install the belt properly.
So, I went to get a new belt and replaced it. When finishing up, all I had to do was tighten up the A/C compressor and the bolt just kept turning. I didn't put any undue pressure on the wrench, but the bolt would not tighten. I must say the the bolt was tight when I loosened it. When I backed it out, some metal threads came out with the bolt.
So, am I screwed here or is there a way to fix this? I really hate to bring it back to the shop. Hoping I didn't ruin a brand new compressor.
So, I went to get a new belt and replaced it. When finishing up, all I had to do was tighten up the A/C compressor and the bolt just kept turning. I didn't put any undue pressure on the wrench, but the bolt would not tighten. I must say the the bolt was tight when I loosened it. When I backed it out, some metal threads came out with the bolt.
So, am I screwed here or is there a way to fix this? I really hate to bring it back to the shop. Hoping I didn't ruin a brand new compressor.
It involves drilling out what's left of the old threads, then tapping threads for the Heli-coil to screw into, and voila! good (or even better) than new! (Heli-coils are sometimes used in racing engines as the coils offer more surface area to the block and provide a smooth uniform thread surface to the threads of the head bolts - promoting uniform pre-load.) I just recently had to do a couple on my wife's L46 when I was installing a new cam in it. A couple rusted bolts broke off (rusted off?).
Its easy. I believe AutoZone has a kit which included the proper size drill bit along with the tap that comes with the kit.
P.
Last edited by Paul Workman; May 1, 2011 at 03:28 PM.
Melting Slicks
Joined: Aug 2005
Posts: 2,359
Likes: 15
From: Confusion
Most likely a piece bolts to the compressor to provide the mounting points, bolt does not go directly into the comp. Replace the piece bolted to the comp, bracket or brace and forget about heli-coils
http://www.docrebuild.com/dr-r-web/AC-COMPRESSOR.HTML
http://www.docrebuild.com/dr-r-web/AC-COMPRESSOR.HTML
Thread Starter
Instructor
Joined: Dec 2010
Posts: 233
Likes: 6
From: Lake Charles LA
Most likely a piece bolts to the compressor to provide the mounting points, bolt does not go directly into the comp. Replace the piece bolted to the comp, bracket or brace and forget about heli-coils
http://www.docrebuild.com/dr-r-web/AC-COMPRESSOR.HTML
http://www.docrebuild.com/dr-r-web/AC-COMPRESSOR.HTML
This is another mounting point to the right of the first hole. This one won't work with the bracket that I have. Looks like it just screws into the housing to me.
This is the mounting hole that is stripped.
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
I put a new compressor (not reman) on my '79 last summer. I found that the newly manufactured compressor was made with metric threads and fasteners. I almost stripped out the hole with the original fasteners when I put it on. The bolt just didn't seem to start correctly after a turn or so. I realized the SAE to metric issue in time. The adjusting slot on the original mounting bracket was also too narrow for the metric fastener. I had to grind the slot wider to accomodate the metric diameter of the bolt.
Racer
Joined: Dec 2006
Posts: 281
Likes: 0
From: Nashville Tennessee
St. Jude Donor '10
Commonly repaired with a Heli-coil which you can pick up at just about any auto parts place worth it's salt.
It involves drilling out what's left of the old threads, then tapping threads for the Heli-coil to screw into, and voila! good (or even better) than new! (Heli-coils are sometimes used in racing engines as the coils offer more surface area to the block and provide a smooth uniform thread surface to the threads of the head bolts - promoting uniform pre-load.) I just recently had to do a couple on my wife's L46 when I was installing a new cam in it. A couple rusted bolts broke off (rusted off?).
Its easy. I believe AutoZone has a kit which included the proper size drill bit along with the tap that comes with the kit.
P.
It involves drilling out what's left of the old threads, then tapping threads for the Heli-coil to screw into, and voila! good (or even better) than new! (Heli-coils are sometimes used in racing engines as the coils offer more surface area to the block and provide a smooth uniform thread surface to the threads of the head bolts - promoting uniform pre-load.) I just recently had to do a couple on my wife's L46 when I was installing a new cam in it. A couple rusted bolts broke off (rusted off?).
Its easy. I believe AutoZone has a kit which included the proper size drill bit along with the tap that comes with the kit.
P.
That's the way to go...Please don't ask how I know.
Bobby
Thread Starter
Instructor
Joined: Dec 2010
Posts: 233
Likes: 6
From: Lake Charles LA
I put a new compressor (not reman) on my '79 last summer. I found that the newly manufactured compressor was made with metric threads and fasteners. I almost stripped out the hole with the original fasteners when I put it on. The bolt just didn't seem to start correctly after a turn or so. I realized the SAE to metric issue in time. The adjusting slot on the original mounting bracket was also too narrow for the metric fastener. I had to grind the slot wider to accomodate the metric diameter of the bolt.
I was wondering because the bolt went in easy and there was no resistance that you might expect if cross threading. I think I will have a little talk with the shop tomorrow.
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Safety Car
Joined: Jun 2004
Posts: 4,362
Likes: 221
From: Beecher Illinois
A friend's 78 had the 7/16 fine thread bolt replaced with a long 3/8" thru bolt with a washer and nut on the other end.
I replaced that with the proper bolt. At the time I originally thought it had been stripped out.
But the longer bolt with the nut had worked fine, just wasn't 'correct'.
I replaced that with the proper bolt. At the time I originally thought it had been stripped out.
But the longer bolt with the nut had worked fine, just wasn't 'correct'.
