Sunday, November 23, 2008

The Avanti Project - Or If at First You Don't Succeed

About six or eight months ago I received a call from a gentleman named Jim.

Jim had an original Studebaker Avanti he was restoring and he wanted the AC to work. He wanted his compressor rebuilt and his drier replaced.

The Studebaker Avanti was a sports coupe built by the Studebaker Corporation of South Bend, Indiana, between June 1962 and December 1963. It was designed by a team of stylists employed by industrial designer Raymond Loewy. The Avanti was an all new design with radical body changes. Avanti is Italian for "forward" or "advance." While Jaguar began offering production-car disc brakes in 1957 on the XK150, the Avanti was the first American mass-produced car to feature standard disc brakes. The Avanti's emphasis on safety, with seatbelts available as an option, safety door latches and roll-over protection bar, was also very advanced.

The Restored Avanti's Engine Compartment.

Well, the compressor was relatively easy. It was the original York compressor which had the vintage 1960's housing. Because we had all the necessary parts in house we were able to accomplish that in short order.

Now, the drier was a whole other story. After much searching I realized that there was nothing readily available that would drop in as a replacement so I began to look for someone to rebuild the old one. There were a few people around but none whom I would be willing to attach my name to their work.

The Plan

Not one to accept defeat gracefully, I embarked on a mission to come up with a solution. My first efforts were directed at finding a suitable inline drier and fabricate the necessary fittings and mounting studs to attach to it. I found a few driers that would work and I laid out the necessary materials to make it work. It would definitely work but it looked like a pile of junk. Jim was doing a complete and proper restoration. I couldn't do that to his project.

Views of The Interior.

A Giant Leap - Past The Point Of No Return

I decided to rebuild his old drier. This would require disassembling it, removing the old desiccant, cleaning it and reassembling it. Sounds easy.

It wasn't.

My first task was to get the thing apart without destroying it so I set out to find a shop with an induction welder. For those of you who don't know, induction welding is a form of welding that uses electromagnetic induction to heat the workpiece. The welding apparatus contains an induction coil that is energized with a radio-frequency electric current. This generates a high-frequency electromagnetic field that acts on either an electrically conductive or a ferromagnetic workpiece. In an electrically conductive workpiece, such as steel, the main heating effect is resistive heating, which is due to magnetically induced currents called eddy currents. In a ferromagnetic workpiece, such as plastic doped with ceramic particles, the heating is caused mainly by hysteresis as the magnetic component of the electromagnetic field repeatedly distorts the crystalline structure of the ferromagnetic material. In practice, most materials undergo a combination of these two effects.

The plan was to undo the brazing by using the uniform heat you could get from an induction welder. Heat the end of the drier red hot, draw out the molten solder with the heat and "pop" one of the end caps off. Unfortunately, after about 2 weeks of calling around to local shops whom I thought might have one, I realized I was not going to have any luck finding one locally.

Plan B

Undaunted, I decided I would do it in house. After all, Jim was patiently waiting so I had to deliver.

I got out the huge Oxy-Acetylene torch and began to heat the brazed joint, figuring I could heat it and methodically tap it off without destroying it. Well, after about 2 hours of varied methods of attack I realized it wasn't going to work.

So I thought to myself, "Self, your not a professional welder. Stop being stubborn and send it to Robert." Robert has a welding shop and has been a pal for about 25 years. Surely he'll know how to get this apart. No such luck.

I began to realize that when they brazed stuff together in the sixties, they were serious about it not coming apart. There was no way I would be able to get this apart without mutilating it, in which case I'd never get it back together.

Taking Out The Big Guns

I reasoned that the only way I would be able to rebuild this drier is to cut it open neatly so I could weld it back together with minimal difficulty. I had done this before with aluminum accumulators and with a few steel driers. The Avanti drier was different though. It was too long to fit in my lathes three jaw chuck and turn true reliably and I did not want to risk wrecking it.

Sal is another pal I know for about 25 years. He and his wife Kathy are like part of the family. Sal owns M&S Precision Machine and has a shop full of CNC's as well as some conventional lathes and mills. He is one of those people who can literally make anything. If anyone could cut this open nicely, Sal could do it.

Off I went, part in hand to see Sal. He took the drier, studied it a bit and chucked it up in the 3 jaw on his lathe. Even though his machine was much larger than mine the drier fit was still a bit unwieldy which made it necessary to clamp down on it with more force than we wanted to use. He cut the part open and I had a nice clean "V" shaped seam to weld. Piece of cake now, right.


The body of the drier had 3 small dimples where the chuck had held it. Thinking those blemishes could be easily covered with any filler, I took the drier back to my shop. There I removed all of the insides, glass beaded everything, inserted the desiccant bag and proceeded to weld it shut. Finished at last! All I needed to do was pressure test it for leaks, fill the dimples with epoxy or some other filler and paint it.

I pressurized the drier with 350 psig of N2 and submerged it in a tank of mineral spirits to look for leaks. Sure enough one of the dimples made by the 3 jaw chuck had a small leak. This meant I had to start all over again, fix that leak and re assemble the drier. There was no way you could braze on the body of the drier without burning the desiccant bag and causing it to rupture.

After 3 tries I realized that leak would not go away. Apparently the metal body was so old and weakened from the internal rust that even though it looked useable it was not. Disgusted I thought to myself, "What now?"

Sal To The Rescue

I drove over to M&S to find Sal setting up a job on one of his CNC's. I showed him the pile of pieces and said, "Any ideas?"

Without missing a beat the answer was "I can make that."

We needed a piece of seamless tubing, I had to remove the fitting from the old drier and Sal could make the two end caps to seal off the tube.

Unfortunately, seamless tubing could only be purchased in 18 or 20 foot lengths and was cost prohibitive. What I did was purchase a length of regular ("seamed") tubing, weld a flat plate on both ends, one with a 1/4 male flare access in it and pressure test the seam on the tube. No leaks and we were in business.

I took it back to Sal where we cut it to size and he gave me the end caps he made. They fit perfectly and had a nice chamfer on the edges to facilitate the flow of the brass.

I took it back to my shop where I drilled the hole for the body fitting, brazed the mounting studs to it and brazed the second fitting on the appropriate end cap. Next I brazed all of this together, let it cool and after inspecting the welds, inserted the dessicant bag. The only thing left was to braze the other end cap on, pressure test and paint it.

It was not without some anxiety that I pressure tested this drier. As I connected the fittings I was trying to will the thing to not leak. At 50 psig I submerged it. Good so far. Then 200 psig, and finally 350 psig. Success, no leaks! But wait. This can't be. So much had gone wrong on this project I thought I had better do it again to be sure. Success again. No leaks.

I removed it from the tank, wiped it down with some wash thinner and brought it to the spray booth. The nightmare was finally over and I had a part I could ship to Jim that would be appropriate for the restoration he was doing. Plus, Jim had the patience of a saint. He understood that I could not simply drop all to do this and that I had to squeeze this in when I could. After all that I could not let him down. Thank you Jim.

The Drier (Left) Mounted on the Condenser

Jim, being the consumate gentleman he is sent me this wonderful thank you note and the pictures used in this blog.

Friday, October 24, 2008

You sent me a bad compressor. It does nothing when I turn it on.

This is something we hear from time to time, especially when dealing with DIY'ers or with people working on older cars. This usually stems from a lack of understanding of how these systems are energized OR a particular nuance about a specific vehicle.

About a month ago I received a call from a customer to whom I sold a BMW Behr Bosch wing cell (rotary vane) type compressor. The complaint was "My mechanic installed it and it worked fine for about an hour and then it quit."

"OK, what is the compressor doing?"


"Nothing at all? Does the clutch engage when you energize it?"


"OK, tell him to disconnect it from the system and jump it direct from the battery."

"He tried that. It doesn't work."

"OK, tell him to test it with an OHM Meter. If the coil is open it is bad. If it reads between 3 and 5 ohms it is good. Also, tell him to check the in line diode and make sure there is continuity through it."

After a day another call came with the news that it still doesn't work.

"OK, send it back and we will check it. If there is a problem we will replace it."

The compressor was returned, and, as I suspected, there was nothing wrong with it. To be on the safe side, we replaced the coil because the potential for erratic or intermittent failure, though rare, is possible and erring on the side of caution is the preferred choice.

A week passed and a second call came in.

"It still doesn't work."

"Then something is wrong with your system or with the way your mechanic is proceeding."

"Would you please speak to my mechanic for me."

"Be happy to. Have him call me."

Louis called me about ten minutes later and assured me the compressor had a good electrical connection with adequate voltage. I in turn assured him the compressor was thoroughly tested and good.

"Well, Louis, when you have power to an otherwise good component and it does not function my first thought is that it is not reaching ground. Are you sure it is grounded?"

"There is only one wire on this coil."

"OK, so the ground is through the body. Does the bracket have bushings on it?"

After a pregnant pause the answer was "Yes."

"Is there a ground strap on the compressor or the bracket."


"Well that is your problem."

"But, but ...."

"Louis, I am sure that is your problem. Ground the compressor and it will work."

Some older vehicles, most notably Volkswagen's and BMW's, used two piece brackets which incorporated small rubber bushings between the bracket pieces. The bracket bolts passed through the center of these bushings which effectively isolated the bracket and compressor, preventing them from reaching ground. To overcome this a ground strap was used. Obviously, in this instance the ground strap was either missing or damaged.

There are many other reasons, too numerous to mention here, why an otherwise good compressor won't turn on. For more information on this topic please visit our FAQ's at:

I hope this helps some of you who are working with or restoring older vehicles.



Wednesday, October 8, 2008

Why Can't I Get This Schrader Valve Out?

A guy came into the store the other day wanting to purchase a new hose or have us fix his old one.

Looking at the hose I asked "What's wrong with it?"

"It leaks right here at the valve" and he pointed towards the hoses R134A high side access port.

"So why don't you change the schrader valve?"

"I can't. It doesn't come out......Never saw such a stupid design......The @@##$#% want you to buy a new hose instead of changing the schrader valve."

I picked up the hose and looked at the high side access port. As I suspected, it had a what is called a primary port adapter......and before you ask, I have no idea why they named it that because there is nothing primary about it and it doesn't work as an adapter for anything. Its' only purpose is that for which it was apparently intended, to make something simple complicated and convoluted. Pictured here is a GM high side Primary Port Adapter. You can identify it by the fact that the schrader valve is non removable. When you look into the opening of the port instead of seeing a pin type depressor with a shoulder that can be turned with a standard schrader valve removal tool, you will see a round plastic ball type depressor that cannot be turned or removed. Also, notice that above the oring there is a lip of sorts. This lip mates almost seamlessly with the female threaded housing in the hose, making it appear to be one piece and non removable. Because of this, and because we are used to dealing with easily removable schrader valves, ones' initial reaction is there is no way to fix the leak and therefore you must replace the hose.....a very pricey error to make.

Replacement and removal of these ports is quite simple. First you must remove all of the freon from the system. Be absolutely certain you have all of the freon out of the system and there is no pressure in it. Failure to do so could cause serious injury or death. The port can violently shoot out of its housing with the force of a bullet releasing freon and oil with it.

Once you are sure there is no pressure in the system, simply use the appropriate sized wrench or socket on the port while holding its' female base (the part in the hose) with a second wrench. This is very important because if the threads bind you will turn the housing instead of the threads and possibly ruin the hose.

Next clean the housing threads, put a little bit of oil on the oring, insert the port into the housing and turn it by hand as far as it will go or until the oring seats. Then snug it up using the two wrenches as described above until the gap above the oring disappears and it once again gives the illusion of being one piece.

Remember, this is an oring seal and does not need to be tightened with super human strength. Once the oing is seated it will seal and hold pressure. The ONLY reason to use a wrench is to tighten it enough that it won't vibrate loose.

That's it. The repair is complete!

I hope this saves some of you a bit of grief should you encounter this.

Until the next time, thanks for reading.


Monday, October 6, 2008

Pinned By A Volkswagon or Just Because It Looks Like a Duck ...

About 2 months ago I received an inquiry about a Sanden SD7V16 control valve from a customer in Malaysia. After exchanging a few emails the order was placed and the product was shipped.

The Sanden SD7v16 is a variable displacement compressor used by several different manufacturers, most notably certain Volkswagon and Audi models. Here is a very nice article explaining how variable displacement compressors work.

But, I digress ...

About 2 weeks after I shipped the control valve, our part number EX 10067, I received an email from our customer with "Wrong Item!!" in the subject line. The customer then proceeded to explain how we had erroneously shipped him an Ex 1210 which fits an SD7V12 rather than the EX 10067 he needed.

Taking the attitude that since he had it to look at and I didn't and that it was quite possible the product was mis boxed, I simply shipped him a replacement part after I had verified with the manufacturer that I was indeed shipping the correct part and not one that was incorrectly packaged or labeled. Problem solved!

Or so I thought.

Two weeks or so go by and I receive an email with "Wrong Item AGAIN!!!" in the subject line. I think to myself "how could that be?" I verified I shipped the correct part with the manufacturer, so I send a return email questioning the customers reasons and logic.

He replied that if I look at the images I will note that the image depicting EX 10067 has a different "pin" coming out of its end than the image of EX 1210. The part I shipped him resembles the image of EX 1210, not that of the part he wanted, EX 10067.

Note that the valve on the left has a "pin" whose tip is smaller than the overall diameter of the rest of the pin and the valve on the right has a pin with a blunt end.

The customer was correct. What could be going on?

Puzzled, I decided to disassemble an intact compressor to see what was in it and confirm my suspicion that possibly the images were incorrect. No such luck! The images conformed to what my customer was telling me.

Now, both confused and irritated because I had specifically asked a supplier who also happens to be the manufacturer to confirm he sold me the correct valve, and he stated such was the case. I then purchased valves from 3 other suppliers to get to the bottom of this. All of them were the same.

Well, after an ungodly number of emails and phone calls I learned that the type of end on the valves "pin" doesn't matter and for reasons unknown to me or anyone else, the engineers decided it was OK to use the same pin in all valves of this type. My guess is that the pin differences were for ease of identification on the parts shelf because that pin end is non functional, that is, it does not interact with any other component in the compressor. It merely sits in the open space between the valve plate and the rear head, as can be seen in this exploded view diagram of an SD7V16 compressor.

To his credit, my customer accepted my explanation and is going to use the valve. He also promised to report back on the results when the job is complete. I in turn wll note the outcome here, all of which only goes to prove that sometimes, even though it looks like a duck and quacks like a duck it might still be a chicken.

Thanks for listening.


Thursday, October 2, 2008

Bearing Down on Things

Yesterday my old friend and neighbor Rob came in and purchased a pulley bearing while I was out visiting a client.

Change a pulley bearing on a General Motors compressor ..... piece of cake, right.


Rob took the bearing and gave it to one of his employees instructing him to change it. This is a relatively simple task if you know how to do it.

A few hours later Rob returned with a clutch assembly in hand and said "it worked perfect before. All we did was change the bearing and now it slips.....Can you check it out for me?"

"Sure Rob. Be happy to."

The first thing I did was check the coil with an ohm meter.

"Coils good."

Next I looked at the pulley.

The first thing I noticed was the bearing seal was damaged, obviously from the way they installed it.

"Rob, look at this."

"Whoever did this used the wrong tool. You never put pressure on the face of a bearing seal."

Rob replied, "I know Joe, what did they do?" all the while with a look of disgust on his face.

I said, "Look ....." and I proceded to peer across the face of the pulley and show Rob what had happened.

His employee used the wrong tool to install the bearing and damaged the bearing seal. Then he did not support the pulley properly and proceeded to bend the "face" of the pulley so it was now concave. Of course the perfectly flat "hub" or "drive plate" which mates to this was slipping. It had to because it was only grabbing on the outer edges of the pulley's circumference.

So ....

Here are a few useful do's and don'ts about changing a pulley bearing.

The first rule to remember when installing a new bearing is to never put pressure on the inner race. This stresses the ball bearings and will ultimately cause the bearing to be noisy. When installing a bearing the tool must rest on the outer race so it does not put pressure on the ball bearings or the inner race. Remember, the whole assembly is held together by polished steel balls riding in a polished groove. Damage the balls or the groove and the bearing becomes noisy or, worse yet, it comes apart.

Removing the old bearing is a whole other matter. In most instances, you are forced to put pressure on the inner race to remove it. But that doesn't matter since you are changing it any way.

Above I mentioned that when installing the new bearing the tool must rest on the outer race.

Hmmmm .... this could be a problem for the DIY'er......

Well ..... not really.

Of course, you could get on line and go to your favorite Auto AC parts and supplies dealer, Polar Bear, Inc. and spend a lot of your hard earned dollars with that nice guy Joe over there. This in an of itself is always a good idea ....

but,.... if this is a once a year or once in a life time project, it kind of defeats the purpose of doing it yourself. So, consider ..... what will fit perfectly over the outer race of your new bearing?

How about the outer race of the old bearing?

Simply clean any grease or grit off your old bearing and line it's outer race up with that of the new bearing. Line both bearings up perfectly straight with the bearing housing of the pulley and use a flat piece of metal to press it in.

But .... nothing is as easy as it sounds.

You must be careful to keep everything straight. If the bearing cocks to one side it will jam and cause you problems. It might even damage the bearing or the pulley. All of which brings to mind Rob's original problem ....Notice that the bearing in the pulley pictured below presses out from the rear.

You simply lay the pulley on its face and press the old bearing out of the pulley (or drive it out with a special tool and a hammer). Then wipe it clean and install the new one doing the reverse using your improvised old bearing and scrap metal tool.

Well, .... not exactly. You must be sure to support the bearing housing when you install the bearing. If you support it from the outer edges, as Rob's employee did, you will collapse the face of the pulley, making it concave and rendering it useless.

Keep in mind also that if you use the old bearing as a tool in order to install the new bearing you will usually have to drive part of the old bearing into the housing. It will probably get stuck. As long as it does not to go too far into the housing you can remove it by holding the pulley and tapping it with a small hammer. If the bearing sits too deeply in the housing you will either have to buy the correct tools or bring it to a properly equipped shop. Another thing to know is that most automotive bearings are secured in place by either a snap (or lock) ring OR they are staked. When working with a snap ring you simply remove and replace it. You need the appropriate snap ring pliers. When working with a bearing that is staked you will need to "re stake" (if there is such a word) the bearing. If there is no snap ring, you will notice a series of "punches", "indentations" or "dimples" on the open side of the bearing housing. These punches slightly collapse the wall of the housing over the outer race of the bearing. When you remove the bearing you expand those "collapses" (another new word) so when you replace it you must stake the bearing again. You do this with a small, very pointy punch and a hammer. Place the punch next to or on one of the original marks on the pulley and give it a sharp rap with the hammer. Do this following the old marks until you get them all and the bearing is now "staked".

While we are at it ... A word of caution about presses.

Even the lowly manual arbor press exerts several tons of force when you use it. A hydraulic press exerts much more....* Any* hydraulic press, even the bottle jack style. When you stack objects such as these be aware they can fly out of the machine with deadly force when not perfectly straight. Never stand directly in front of the machine. Always stay to the side and try to use the frame of the press as a "shield".

So, the lesson learned here is that Rob, a seasoned pro, didn't assess the job with respect to the resources he had available. Obviously, his employee was not familiar with changing this type of bearing in this type of part. In terms of time, lost opportunity, damaged parts and wasted labor, Rob would have been better off changing the whole clutch OR, bringing it to someone who has the proper tools and fixtures to do the job.

As a DIY'er, it is critical you think this way since as a general statement, you do not have a complete shop or a network of shops you can bring your mistakes to and get professional help. When in doubt feel free to call us (1800-365-3516). We will tell you what is involved in doing the job and if you need special tools. And, when we don't know, we are not ashamed to say so. But, we will find out for you.

So, till the next time something worth discussing happens, thanks for reading this.


Thursday, September 4, 2008

Repair Price Shock and Searching For The Deal

You brought your car in for diagnosis and just got the repair estimate from the dealer. After you regained consciousness and the heart palpitations stopped you decided to do a little research and see if you could get a better deal. But how and where?

Well a deal is only a deal if you do in fact need the service. I'll relate a true story to make the point.

First let me state that we were never in the actual repair business and that our expertise has been in rebuilding compressors and fabricating custom components and systems, so when Shelton, one of the truckers who regularly picked up outbound freight at our warehouse asked me to look at his car I was a bit reluctant but agreed to do so only as a friend who would diagnose his problem and then send him back to his repair facility. I told him to bring the car by on Saturday when I would be supervising a crew working overtime to push out a large order of rebuilt compressors.

Saturday came and Shelton showed up with his relatively new Nissan Maxima at 9:00 AM as planned. He also brought a $1685.00, computer generated, detailed diagnosis and repair estimate from the Nissan Dealer for which he paid about $100.00 Of course, that fee would be deducted from the repair bill should he opt to have the dealer do the work.

I studied the estimate for a minute or two and saw he was being told he needed a new AC compressor, a new receiver drier, an evaporator and an expansion valve. Of course common sense kicked in and I thought "Why not just replace everything in the car. Then the AC will surely work." But, I said nothing. I went inside and got my manifold gauge set so I could see what was going on in the system. For those of you who do not know, there is absolutely no way you can effectively diagnose an AC system without high and low side gauge readings. For more on this subject, read this brief article:


But I digress ..... We allowed the car to cool down while we had a cup of coffee and chatted local politics and then I connected the gauges. Hmmmmm .... equalized pressure 125 psig (engine off and cool, ambient temperature about 70 degrees) .....original complaint....."AC not blowing cold".

"Shelton, do you mind if I tinker with this a bit?"

"No, please do."

"OK, sit in the car while I connect another machine to it.....start the engine.... turn on the AC and put your hand in front of the vents."

"Getting cold yet?"

"A little"





"Yeah! .... Wow, it's freezing. What did you do?".....

I did nothing more than remove a little bit of freon. The system was over charged. More is not always better, especially when charging an AC system. Once the optimal charge is reached there is a diminishing return on any added gas until it becomes so over charged the system simply won't work. For a brief tutorial on how to charge a system read this article:


So what really happened here?

Shelton brought his relatively new car into the dealer. A dealer trained technician with minimal real world experience diagnosed the car. After connecting it to a diagnostic computer which most probably told him the problem could be one or all of several things, he opted to err on the side of caution. Rather than under estimate the job, which we all know will infuriate the customer and backfire on the technician, he opted to "fix" all of it and insure a good out come.

Was this an attempt to scam or defraud Shelton? I doubt it. People with bad intentions rarely put their misdeeds on paper where it can come back to haunt them.

So what was my point here? I guess it is to emphasize that things are not always as they seem. Before you run out and purchase parts be certain your problem is correctly diagnosed. I cannot even venture to guess at how many "bad" compressors have been changed for want of a blown fuse.

We routinely get people who want to buy components and when asked why they need the part the answer we get is "Because it doesn't blow cold."

But that is fodder for another day.


Wednesday, September 3, 2008

Information Is Power

As I state in my BIO, our purpose here is to arm you with the necessary information to either service your own automotive AC system or procure the services of a *QUALIFIED* ac technician.

First, you must realize that because your mechanic is a brilliant engine or transmission technician does not mean he is qualified or knowledgeable in the repair of an air conditioning system. Human nature being what it is, we like to think we can do it all and while he may sincerely believe he can perform your repair with the excellence he uses on everything else, it behooves you to have at least a rudimentary knowledge of how these repairs need to be done.

AND SO ....

I will bestow on you the magic words that will help insure a good repair.

A high quality repair must always result in A CLEAN, LEAK FREE SYSTEM

No matter what is wrong with your AC system, you must ultimately drive away with one that is both clean and leak free or you will be repeating the repair and possibly paying twice for it.

Moving parts (your compressor) create friction which in turn create wear (read dirt and residue). This is normal. When the dirt becomes excessive it wreaks all sorts of havoc within the system because it acts as an abrasive (creates more dirt) and causes obstructions within the system.

The solution is to chemically flush the system. For a detailed explanation read these two articles:



After reading this you might ask, "So why leak free?"

The answer is refrigerant oil must be "miscible" (a term in chemistry that refers to the property of liquids to mix in all proportions, forming a homogeneous solution) with the freon and travel with it. Ergo, when you lose freon you also lose oil, and we all know what that causes.....More friction and more wear of course. Intuitively you must realize that simply adding freon without oil accelerates the demise of your system and adding oil with the freon over time will lead to a situation where you have no idea how much oil is in the system, which will also cause problems.