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I replaced my AC compressor, and also tried to install a new accumulator/dryer. I bought this one from FCP:
https://www.fcpeuro.com/products/volvo-a-slash-c-receiver-drier-240-9131972
The problem is that the hose couplings only thread a few turns before stopping and it takes too much force to turn them. The hoses seat nicely with the new washers, but they wiggle around because the couplings cannot be tightened all the way. The fittings are clean and I even tried some PAG to lubricate the threads. No luck.
Here's a pic:
Anyone have experience with these units on a 93 240? Is there another brand I should try? They also offer the Volvo OE, but that's 3 times the cost. Maybe that one will work - not sure.
Suggestions appreciated.
Thanks.
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Hi there,
Wow that is quite a difference in threads.
The second photograph is the one I wanted you to do for your proof or provide on here.
You can see by laying one thread into the other, the pitch from peak to peak will either match or show up in a gradual accumulation.
Art mentioned using a thread screw pitch gauges. They make one for inch and one for metric. Sometimes people will not have those or one or not he other.
What you can use are taps or a known sized of bolt or screw stock.
Laying the profiles together help remove confusion despite not being able to measure the major diameters.
If you still have the FPC part that your are sending back, you can take any metric tap, irregardless of diameter and measure the pitch differences. It would be nice to know if it was a .25mm change in one from the other?
The last number is the pitch. Like .75, 1.0, 1.25 will be the distance between peaks in parts of millimeters or whole millimeters. The smaller the number the finer the thread.
English is just whole numbers divided into an inch of distance equalling a certain thousandths of an inch pitch.
Except in plumbing pipe size that's has 11&1/2 threads per inch. Must be something about water, even fire fighting equipment gets weird!
The plumbing trade can do anything they dream up! The CNC machine world has made it even worse. You can punch it any odd ball decimal and it will make it for you.
On English standard threads there is coarse and fine despite the likes of SAE which is usually a fine thread. SAE is more or less a "slang" term from years ago!
There are Many groups are responsible for Standards.
Sizing and grades of fasteners are made with certain strengths or for special purposes. Aircraft have standards as well but are out of the hands of most consumers.
Now with these other new pictures, I think I was way off thinking there had been a chipped tool or malfunctioning of some sort.
It was a straight up pitch change! Why? I have no clue other than a contracts feud among various vendors and their fittings being exclusive to one or another!
With all of those necking grooves into the hex diameters they are trying to help point out there is something different happening. The first FPC was way off base in this case.
I did not catch on to this possible communication value either!
On gas fittings that is done to point out the use of a left hand thread. Acetylene against oxygen for instance.
I see this accumulator fiasco continues!
In looking at Ron J post, with the part numbers listed, it's even more scary!
There are two more loose numbers floating around out there!
Glad to see you have it together!
Phil
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Make sure FCP sends you a prepaid label to ship back the wrong part.
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Hi,
Your eyes are sharp enough! The new ones thread overall length is longer.
Did you ever lay the to threads together to see if their pitches were the same along their entire lengths? We got to know if they're the same animals! They look it, from here.
You are correct, the lead on diameter is missing, that the other one has. A nice deep chamfer (45 degrees) might resolve that area if need be.
The bigger issue is that the right side of every "V" form has a step line about half way down the angle.
Both sides should be smooth to the bottom.
This by itself will make the bottom of the thread too tight to clear the mating thread of the nut coming in.
If you look at the grooved area behind each thread that is a relief groove cut provided to allow the nuts thread to run into a void. This area is below the minor diameter. It is usually cut after the thread was machined. The minor diameter should be down very close to that diameter.
Inside the tube, there is an internal step, that must be reachable to seat the "O" ring against.
The step should be a certain dimension out ahead of that relief groove. If it's there the fitting is still useable.
Since, You don't want to jeopardize your warranty check to see if it's correct. You can measure with a small scale to compare to the old one.
If it is....,
The alternative is to run a die over the threads.
First identify the diameter and pitch.
Locate a machine shop that has that size die or a place to purchase one and run it down the thread.
Another "UGLY" alternative is to use a thread file of that pitch and walk it around and around the diameter to get rid of that step in the bottom. Machine shop supply houses or well equipped tool stores carry them. They are a square file with several pitches on each end so you get a selection of eight. Aluminum files fast!
These files are made just for the purpose of straightening up a beaten thread on shafts that cannot be removed for machining or the thread diameters are so large that dies are not even made for them! Hand labor and a file is far cheaper!
In this case, you have so many options so I won't go on with more of them!
I'm curious, but why you are changing the accumulator? Did you get metal particles in the system?
Phil
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Hi Phil,
I wonder, have you ever heard the expression "Occam's Razor?"
When this thread was first posted, I recalled reading about the metric vs. inch connector switchover occuring with the factory R134a versions of this CCOT system we use in the 91+ 240. It became an issue trying to find made-up suction hoses for the 93-only system, which was that first 134a-equipped 240 system. I did not respond to the post, because I had nothing in the way of first-hand real experience; only the recollection of the forum chat. I was happy to see Sean jump in and verify my memory.
Well Occam's Razor predicts the most likely answer is the simplest. My guess after looking at these latest side-by-side photos is the pitch is most definitely not the same on these threads. I am so glad to have a good set of thread pitch gauges, but they really don't work laid up against the computer monitor. Nonetheless, I think the most simple answer is the wrong accumulator was sent. And the reason the threads are not pristine is it was one which was returned by another customer running into the same problem and attempting the same fix. Perfect example of Occam's Razor. What you say? No supplier you ever used glanced at and then restocked returns? Ho ho ho.
--
Art Benstein near Baltimore
Q: What is an electrician's favorite ice cream flavor?
A: Shock-o-lot!
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Hi,
Art-definitely right about the 92 and before being SAE and 93 being metric, that's what I also remember reading on here throughout the years.
Now related to the thread I offer this warning:
Anyone who messes with the OEM Volvo R134a retrofit j-pipe (you can purchase it alone or in kit form for 91 and 92 models) will run into the same SAE vs metric thread problems.
If you buy from a Volvo dealer (on special order) you are more than likely screwed. They will not have any help for you when you tell them about how the part was machined for metric but it should be SAE thread. All you'll here is "sorry no returns" and "there's no way we can verify the part is wrong."
And good luck if you think you'll find an appropriate Volvo customer support number.
Steer clear of Volvo's R134a retrofit kit or j pipe to avoid migraines and lost $$.
Travis
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Hi Art!
I will say never heard any type of expression like that. I had to punch it into the browser to get a hint.
I admit that expression and theory was well before my time!
If he saw a newsreel covering the last 500 years he would have to revise his thinking.
Most of all, the thought that "A God" will take any logically responsibility for having control of the past or present times of mans endeavors!
I suggested he return the accumulator too. I myself could probably fix it or not changed it to begin with but he asked for alternatives.
I also have been upset at stupid models that were made up just so they would look good in a SALES catalog. All the items did the very same thing but each one had a separate part number and wasted shelf inventory capital.
I recently wrote about the car WINDOWS and their motors being left hand and right handed units.
Ideas copied off like just like our bodies are made! Since we have made billions of both on this planet it was simple to do? Ah, but it just took a few centuries to get rolling... (:-)
Do we make one opposite the other to keep it simple. Maybe, maybe not?
Use the same parts with only a rotational direction change that it can already do. Yes.
I think it be done with only a one case design. Jeez, imagine only one universal motor part for all car windows or even wiper motors?
Oh but we don't! We use all kinds makers, with their own models and part numbers, to entertain ourselves!
Is this is logical and Simple? Yes, some one thinks it must be! If you gotta keep up with one, why not ... Billions of other ones!
Imagine! What if we had been left up to making RAIN water droplets!
Would we have started with clear or a colored rain? Snow is white, looks pretty but what a mess of work!
Why yes, of course colored! That way we could be wringing out our clothes and washing off our cars just to keep us busy!
Now, Would we change the color every week, to another color as it would keep us from getting bored about which one is coming next?
A big, YES on that too!
Just Look, at the great variety of cars makes with colors and shapes that change every year!
Smaller, bigger and back smaller again.
We see this going on just to haul our carcasses around the planet.
Hey! Surprise the thread on there is different for that year. NO REALLY! Imagine that crap!
Duh, some man-made chaos and we haven't even thrown in defective parts being produced!
Defective? How many different people do we have on this planet and we think, we shouldn't have to wonder what's up!
News flash! Look out!
If SALT wasn't working so good on our U. S. highways there might be some other entrepreneurs or engineers working on making up some acid rain!
Whoops!
I'll have to check the server, to see if that was in a classified e-mail, somewhere among the worlds politicians.
I've been "occaming" too long Art! (:-)
Have Good simple day!
Phil
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I'm with Art on this one. If the part number in your OP is a Volvo part number then it's the wrong one for a 93. The part number for a 93 would be 3537542. Up to 92 the part number would be 1388667 and if you use a kit to convert your pre 93 car to 134A the part number would be 9144329.
Ron J
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Hi Phil,
You're right with that question --> Why need to change the accumulator?
Nowadays I don't normally replace the accumulator IF:
1) the refrigerant oil inside is clear or just slightly cloudy
2) there's no any metal particles inside
We all know that its the desiccant bag is the ONE that needed replacement, so I would get me a small desiccant replacement package like those used for the new type condensers (with a tubular replaceable desiccant attached to its side).
I use Toyota's desiccant bag. Its about $3. The size is about 0.5 x 7 inch. And its for R134a. I'll cut the bag open, throw some desiccant pellets out and stapler the cut end. Next I would "stuff" this reduced sized bag into the inlet of the old accumulator. Need to do this otherwise the full sized bag won't fit into the inlet.
Next service time around I would "fish" the bag out with a hook and put another new one in. The bag would just "stand" there inside the accumulator absorbing all the leftover moisture there is. No more accumulator replacement!
Regards,
Amarin.
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Hi there Amir, long time no chat. I hope things are going good with you.
Thanks for telling us about the desiccant trick. I was not aware of that setup as a possible work around, instead of having to replace the whole unit.
I was thinking about suggesting an idea on here.
This one means you could take the accumulator out of the car, like he did, but heat the whole unit up to say a 200-250 degrees Fahrenheit for an hour or so in a oven. This would drive or boil off any moisture inside the desiccant.
What do you think of the idea?
I know that we can pull a vacuum and use a heat gun on the car as well. I have never done this on any dryer let alone a Volvo. We just replace them in the field.
I don't know where the package is located in the chamber of a Volvo accumulator. Top, bottom or a certain side. Do you? Be nice to know where to put a heat gun.
I changed out one on a friends late 70's Corvette. That unit separated from a split line in the housing from the bottom so you could change the package. It was a pain to get to just like most everything on Corvettes. This one you had to remove the right front tire and fender shield underneath the firewall where there was a cubby hole for it.
Totally out of sight and out of mind of techs.
The reason I got to change it was because of its off and on cooling from excessive moisture overload.
It's a real shame the thread was messed up on his new unit.
After seeing the thread better in the photo, I believe that the thread was done on a machining center type of CNC. They use a single point tip and probably cuts the thread in three passes in about four seconds.
I'd say the right side of the tools edge either got chipped or a missed in-feed from the triangulation code of tool movement. That's why it left the step on the right land of the "V" form.
To many reflections down the slopes says something is going on there.
You called it right about the thread from the get go!
Thanks for telling us about your neat trick too! .
5 X 7" sounds perfect. Cutting the end and removing some I suppose makes it more Bendable get around the corner of the fitting.
I will definitely keep this in my memory bank!
Amazing what you know about different automobiles parts that fit somewhere else.
You must network well with others in your neighborhood!
Have a good day,
Phil
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Phil,
"This one means you could take the accumulator out of the car, like he did, but heat the whole unit up to say a 200-250 degrees Fahrenheit for an hour or so in a oven. This would drive or boil off any moisture inside the desiccant."
I think that's a tough one to answer. Firstly I've never tried that. Secondly there are plastic parts inside i.e cable tie and some filter screen at bottom of the J tube on some accumulator design. The dessicant package inside is already soaked with refrigerant oil. The oil could also got "cooked" (most PAG oil suppose to flash at 360F but what happens before that?) in the process if the temp was not properly controlled. This would coat the desiccant pellets inside leaving making it harder to absorb moisture next. All these are theoritical you see ha ha..but it could happen.
"I don't know where the package is located in the chamber of a Volvo accumulator. Top, bottom or a certain side. Do you? Be nice to know where to put a heat gun."
I've sawed thru two accumulators and find the desiccant packages were cable tied to the J tube at half-way down their height. The bottom was clear of any parts maybe not to meddle with the refrigerant-oil mixture. If the "heating" project going to be carried out I suppose heating should be directed towards the middle of the aluminium can.
I think the reasons for me not replacing the accumulator are its cost (of course!) and design. Many accumulators I tried before were of Chinese origin (this car had long lost its OE accumulator) and they have their J tube having smaller diameter, its lower bend being too restrictive near the bottom and the mouth open up too close up the roof. All of these causing reduced flow thus a rise in suction pressure degrading the AC performance. My current one made by ATCO looks satisfactory and performs well.
That aside...another "trick" up the sleeve is about the alternator bushings. After a few years of use I see that these bushings are skewed towards a side as a result of prolonged pull by the belt. I would later install these 180 degrees (half turn) so that these skews could be counter-acted. So this doubles up its useful life!
That's all for now. You have a good day too Phil!
Regards,
Amir.
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Hello there,
The other poster talking about metric and English threads are a good possibility. There are those out there you just cannot leave things the way they were!
The two different threads will interact act just like you said. Or a bad thread will start but get tight right way.
The picture, that does not show me a good background profile as I would like. It seems there maybe a problem with the form of the thread.
From the picture, the root of the thread appears to be too wide.
I judged this, from looking at the thread on the left, looking down into that thread.
I compared those flats on top of the same thread to the bottom of the thread.
I'm suspicious if the major diameters are the same, there maybe a problem with the actual "V" form.
You can have a wider flat on top but not in the bottom. A wider flat on top of male and on the inside of females.
This hurts nothing but gives extra clearance for dirt and oils. Threads are design with 75 percent of full depth engagement to start with due to the torque amounts required for taps or dies!
Of course, excessive amounts will weaken the threads tensile strength. That thread looks thin regardless of OD & ID's.
A wider bottom means excessive clearance due to bad thread form, a shift in pitch spacing. The lead or the part or tool could have moved.
Just from these reasons I would want to send it back!
One way to check the the pitch is to put the the two diameters together.
Using the old accumulators thread, Lay the two thread profiles together.
That is, by Placing one within the inside other's. Outside to outside. They're should match pitch to pitch as well as the depth top to bottom with very little light or space at the roots of either.
Compare the thicknesses of the "V" threads.
It is possible the die that cut this thread had either had a chipped tooth or its teeth became loaded.
Metal can wad or become welded onto ts upper lands.
This can either gouge the bottom widths thereby removing some ot the "V".
The excess pressure strains the dies closure mechanism. This can start to trip the die open to soon. Only a few thousandths is all it takes.
With aluminum, that's most likely what happens if the cutting fluid was not flooding the stock at the moment of engagement. There are several causes for this with automated machines.
Low supply, moved nozzle from last setup or a delay from the "G" program code to start the pump soon enough over many cycles. Or just too many parts were ran on the same die.
I suggest you do not force things together as that nut will be harder to repair, to remove mashed aluminum deposits. Replacing that nut you just don't want to go down that road!
When you get the threads to the nut relationship square away, I would use a little refrigeration oil on the threads to help prevent galling and possible corrosion. You will want some on the "O" rings anyway.
Phil
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Thanks for the replies. Before tackling the the AC system repair, I picked up this nice set of wrenches from Harbor Freight:
I have wrenches up through 19mm, and these pickup from there and I used about half the set for the various large fittings. Worked well.
I'm really afraid to crank down HARD on these fittings since they are aluminum on the dryer and steel (I think) on the hoses. And the torque specs for those connections are less than 35 lbs:
I think I'll take the plastic caps to HD/Lowes and see if they are metric or SAE.
The first few turns are pretty easy, and then it locks up pretty tight after that. In my experience that means a thread mis-match. Before I crank down too hard on these, I'll check the fittings.
Thanks again for the timely advise. Not sure where I would be without the forum members.
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They may have sent you a '92 accumulator - remember that in the '93 model year (and in '93 alone) all fittings were metric. FCP did the same to me, once.
...or it could just be tight...
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Hi,
Compare the threads on the new accumulator to the old one. If they are the same then don't worry. There will be no cross-threading here. New accumulators are KNOWN to have TIGHT fitting threads.
Use two big wrenches - one on the nut on accumulator and one on the hose. The wrenches should be about 1 foot long (or more) because you'll need the length for extra leverage.
Regards,
Amarin.
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