ptt

1990 AC oriface tube question....

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I finally got started on the 90 convertible AC problems starting with the orifice tube replacement.  Got the lines opened and to my surprise...NO ORIFICE TUBE!  Is it possible to run the AC system without an orifice tube?  I'm sure I opened the correct line.  The one at the top of the firewall...smaller of the two and has the dimples a few inches back from the end.  Also, does the short end of the orifice tube go towards the evaporator or does the long end? 

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3 hours ago, ptt said:

Is it possible to run the AC system without an orifice tube?

 

Yes, it can be "run", but it would never get cold.

 

3 hours ago, ptt said:

the short end of the orifice tube go towards the evaporator

 

599ee6b8351ea_ORAFICETUBEDIRECTION.jpg.d42b90d0e362a1cf27b36a2a739e0072.jpg

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My initial attempt to insert the orifice tube had it stopping with about a half inch of the long end left sticking out of the line.  I didnt force it.  Maybe it needs to be twisted slightly to get a little further past the dimples?  I'm replacing green o-rings as I go and using silicon paste.

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Yes...I used a flashlight and theres nothing in the line.  I will try and align it correctly and get it to to seat.  I sure need to pick up the pace or I will be shoveling snow...but I'll have AC...  Next is getting to that 15mm bolt holding the hoses on the compressor that go to the accumulator....any way to get to it without radiator removal?

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That may be fine......the design may be that some sticks out so it can be grabbed and pulled out for replacement.

doesn't really matter if some of it is in the mating line.  The biggest problem I had was getting the correct "o" ring for the

connecting tubes.  I purchased two different "O" ring kits before finding the correct size......don't ask me what size is needed.........the darn kits were no help.

The small kit had a picture of the sizes and number of each in the kit....the large kit had nothing, I even called the company that made them and they could not tell me

what was in the kit.

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7 hours ago, ptt said:

I will be shoveling snow...but I'll have AC

 

The AC compressor also runs while in DEFROST mode, to dry the cabin air in Winter, because your moist breath will frost the inside of the windows.

 

None of the Orifice tube extends beyond the tubing, when fully installed. That is why you need an extraction tool to remove one (or long, thin needle nose plires).  Note length of tool. It is universal for all Orifice tube applications.

 

5811289-1__ra_p.jpg.0c8bbdac8bd7b33f9d9c13b32834a984.jpg

 

 

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The flat end is what should be the last in. That way you can use a pair of small needle nosed pliers to pull it out.

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The aluminum line going thru the firewall to the evaporator appears to have an ever-so-slight curve and only allows the new orifice tube to go in to where about a half an inch remains out of the line.  It seems to be seated as far as the orifice tubes o-ring is concerned.  I don't see how it can migrate any further.  New O-rings are being installed as I work my way towards the ACCUMULATOR.  I think I'm resigned to having to pull the radiator to access the back of the compressor to remove the 15mm bolt holding the hoses to it. 

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I would disconnect the evaporator totally, a shoot a can of non-chlorinated brake parts cleaner in, then compressed air.

 

2 hours ago, ptt said:

The aluminum line going thru the firewall to the evaporator appears to have an ever-so-slight curve and only allows the new orifice tube to go in to where about a half an inch remains out of the line

 

You are putting it in backwards. The SHORT FLAT end goes in the tube, facing the drivers side. Please- take a clear photo of the tube area, and post it here.

 

I AM VERY SORRY- MY PHOTO WAS INCORRECT.

Edited by 89RedDarkGrey (see edit history)

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89Red...I believe you had it right the first time if my 1990 FSM is correct. It illustrates on page 1B-4 that for orifice tube replacement "install with shorter screen end toward evaporator and use new o-ring seals" 

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I was going by an '89, and how the end with "tabs" that the removal tool latches onto- should be recessed in the tube, not protruding at all. An '89 AC metal tube has 2 dimples, pointed to the drivers' side. They are "shoulders" that the flat end goes into, and rests on, when fully inserted. Maybe the '90 is reverse of that? The Orifice Tube should not be jammed up against a curve in the metal tubing.

 

Could you please take and post 1 photo of your tubing- before proceeding any further?

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89Red....your pic of the 1990 evaporator (ROCKAUTO) is what my evaporator plumbimg looks like.  As the 1990 FSM states "...the short screen end of the orifice tube inserts towards the evaporator ..."  So your original answer is the correct one for a 1990 system!  Short screen end always towards the evaporator and long screen end always towards the condenser for 1990 systems.  I wonder why they needed to switch it up like that?  

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You're very welcome:) I just want you to get it working correctly. So- when inserted properly- does the Orifice Tube protrude from the metal line at all? If the flat end is lined up, it should push in completely, and be recessed- as in the video.

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As I posted previously it appears the tube going to the evaporator has an ever-so-slight downward bend to it.  Its enough to stop the new orifice tube and leave the long screen end with about 1/2in sticking out.  Possibly the PO had yarned on it for some reason or other.  The fitting and tube surface showed no distress marks except for that slight downward curve.  Maybe the fact its bent has something to do with the fact no old orifice tube being present when I separated the fitting?  Someone had obviously been into it.  Going to do the evaporator flush suggested next.  Thanks to 89Red and all for hanging in there!!!!

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Are you able to look in the tubing? Can you feed a length of wire into it- then pull it out, and measure how deep it went in? There shouldn't be a curve in the correct line for the Orifice Tube- it should be straight. I really do wish you could get a photo of your setup.

 

EVAP-02_jpg_16103ca2dd402726f79593369b7b5156.jpg.c023938e4f3260830cfdb1586b00dc7e.jpg

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Ive been incapacitated with an injured knee and one of the other convertibles and havent gotten back to the Coupe.

Edited by ptt (see edit history)
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