Rebuilding the 550 A/C Compressor

I have just successfully rebuilt my A/C compressor myself, so thought I'd post the steps and parts in case anyone else wants to give it a try. A bit of background first... Due to a number of factors, the car sat without being run for around 3 years, and when it was back up and running the A/C wasn't working. Putting this down to a lack of refrigerant, I sent it to the local main dealer to recharge. When I went to pick it up it sounded like a cement mixer full of rocks! Turned the A/C off, and hear nice V12 sounds. Turn the A/C back on and the horrendous noise is back. This suggested the compressor had failed.

After a quick look at the costs of replacement A/C compressors at Ricambi ($5,800) and the costs of having the failed one removed and refitted by the dealer, I decided to remove it myself and send it for rebuild. The dealer recovered the new refrigerant and then it was over to me... While researching where and how to get it rebuilt, I came across this YouTube video, which completely changed my approach. It is a detailed (50 min) video of exactly how to dismantle, service, and reassemble a Harrison / Sanden V5 Air Conditioning compressor - exactly the same one in my '98 Euro 550. It was this that gave me the confidence to tackle this job myself. Here is the link to the video:

Step 1: Remove the Air Conditioning Compressor

The compressor is buried on the passenger side of the engine, sandwiched between the alternator and airbox, and as is often the case with these cars, getting to all of the bolts does require multiple other components to be removed first. After removing the undertray I could get a good look at the alternator and compressor.

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The passenger airbox needs to be removed, which required access from below with a 12" extension to snake up through the engine bay to get one of the nuts on the rubber bobbins. With the airbox removed I could get my first good look at the compressor.

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The hose connectors at the rear of the compressor are covered by a heat shield that is held in place by two bolts on the top. The compressor is mounted underneath a curved bracket that connects to the block behind the cam belt. For the removal I eventually managed to get all four bolts undone without removing the bracket, but for the install I had to bite the bullet and remove it. More on that later... There are four cast 'ears' on the front and back of the compressor, and these mount on the outside of the top bracket. Two from the front and two from the back. The front ones are easy to see and get to, and the nearest of the rear ones isn't too bad, but the furthest away rear bolt it partially hidden by the exhaust manifold and engine mount.

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I couldn't get my hand in from the top to put the Allen key in the bolt head, so had to come at it from below. This meant removing the Alternator and belts first. Obviously disconnect the battery before starting this.

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Once the tensioner bracket is wound back out and the belt removed, disconnect the two electrical connections from the rear of the alternator and remove from the car. There are then a couple of bolts at the front and bottom of the compressor that then need to be removed. The refrigerant hoses are connected to a block, and this block connects to the rear of the compressor with a single bolt. Once this is undone you should be able to remove the compressor.

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It was at this stage I was able to confirm it really was a Harrison / Standen V5 compressor.

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Step 2: Teardown

To remove the clutch from the compressor a special A/C clutch removal tool is required. The nut you can see in the middle does not hold the clutch on - it is on the end of the spindle and is to stop the seal pushing out under pressure. This is where Amazon came in handy as I was able to order a clutch removal kit for $21 CDN with free delivery... Two days later, following the instructions on the video, I removed the clutch assembly.

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Once the clutch was removed the ribbed pulley and bearing was accessible.

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This is a pressure fit on the electromagnet and needed a puller to remove it. I used a suitable size socket to protect the end of the shaft from damage.

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Once this is removed the electromagnet is visible.

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As with the spindle, this is a pressure fit and comes off easily with a puller. The body of the compressor is now fully accessible and is able to be dismantled. The first step is to remove the pressure regulating value, which is located in the rear compressor casing and is held in place by a C-clip and is easily encouraged out with a couple of flat blade screwdrivers.

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The six long bolts that connect the front and rear casings together, and pass through the middle section which is common to all uses, can then be removed. At this stage the rear casing can be 'encouraged' to come off the large O-ring mounted in a groove at the end of the center section.

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The reed valve plate and gasket can now be carefully removed from the center section.

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The variable displacement, five pistons of the compressor can now be seen.

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This is the collection of parts now spread out on the workbench.

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The final step is to remove the front section, leaving the center section, with all of the moving parts, intact.

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Upon inspection, the bearing in this center section felt fine, but the roller bearing in the rear section felt very stiff, so I pressed it out and purchased a new one, again off Amazon for $12 CDN. https://www.amazon.ca/gp/product/B007EDX030/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

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Step 3: Rebuild


For those of you following along at home, I have now invested a whopping $33CDN to get to this stage. Now the big spend occurred as I needed to order the rebuild kit. I went for the complete kit, which included all seals as well as the tool to put over the threaded spindle to prevent damaging the seal when it is slid down the shaft. I ordered the complete kit here: https://www.shopcenturyautoair.com/store/p137/GM_V5_Compressor_Complete_Reseal_Kit_KT-V5-SYS.html This set me back $25 plus shipping - call it $45 CDN. So total investment so far is $78 CDN.


I gave everything a good clean and then laid all the components out, ready to be reassembled.

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Assembly is the opposite of disassembly, and again, following the video, I matched up the O-rings, coated them with petroleum jelly, oiled the various moving parts and put it all back together. The final step before putting it back in the car was to fill it up with compressor oil. This is where the WSM is contradictory with regards to how much oil to put in. I had a eureka moment when I looked at the casing again and saw that the volume of oil was printed on the label! I went to NAPA and purchased some PAG-46 oil for R-134a systems, and put 265cc into the compressor. Cost of this: $20 CDN

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Putting it back in the car was a little different, as there was no way I could get the top, back bolt back into the bracket. So the bracket had to come out... Which meant the passenger side cambelt cover had to be removed... Which meant the front cover had to be removed... Which meant the driver side cambelt cover had to be removed... Which meant the driver side airbox had to be removed...

Once everything was out of the way, attaching the compressor to the bracket was a piece of cake, and it all went back together smoothly. The final step was a trip back to the dealer to have the refrigerant put back in, and voila! No noise from the compressor and ice cold air blowing into the cabin.

Would I do this again? Absolutely! The only thing I would do differently would be to remove the bracket to get to the rear bolts. Trying to take the 'easy' path cost me 3x the time it would have taken to do it properly. Lesson learned.

Anyway, this was my experience rebuilding the compressor. Total out of pocket costs, including buying tools, was less than $100 CDN, so significantly cheaper than replacing or fixing it. As a side note, I also have an 04 Maserati Quattroporte which had an A/C compressor fail a few years back, and we needed a quick fix as we were about to go on a road trip. The QP shares an A/C compressor with one other car. Care to guess which one? Wrong. It shares an A/C compressor with the Ferrari Enzo! Do you think Enzo owners get replacements at Maserati prices, or Maserati owners get replacements at Enzo prices...? If I knew then what I know now...

Cheers,

Steve

 

Thanks for the kind comments. I've gained huge value from forums like this and wanted to put something back.

Cheers,

Steve

 

I had the dealer recharge the system with the required amount, so don't have a definitive answer for you.

 

Hi. No, I was able to remove the compressor without taking the engine mount off. Cheers, Steve