Oriface tube pop quiz

[crashfirepm53]

Any reason why my 91 burb has a Blue Ford A/c oriface tube for the front A/C?? The Gm white/black tube wasn't even close to fitting.Very different.Also where is the rear A/C oriface tube at??

 

[99firehawk]

Possibily after market ac conversion? ID ont know about the rear orfice........if there is one.

 

[crashfirepm53]

Well Auto zone sells a rear oriface.I've taken every connection apart pretty much and no rear oriface.A/c is Factory.The rear lines o-rings are still black.I'd guess they are the old ones.So much for a quality conversion job.Now the bad news the small rear line where goes thru the rear floorboard unfort. was corroded and the line snapped off at the fitting.Does the whole line need replacing or can It be fixed?

 

[imiceman44]

[ QUOTE ]
Any reason why my 91 burb has a Blue Ford A/c oriface tube for the front A/C?? The Gm white/black tube wasn't even close to fitting.Very different.Also where is the rear A/C oriface tube at??

[/ QUOTE ]

Do a search here, it's been asked before and someone posed an exploded view that shows where it is.
/forums/images/graemlins/dunno.gif

 

[unclematty]

I always thought it was in the low pressure line at the junction on the firewall inside the tube /forums/images/graemlins/thinking.gif it's been awhile since I replaced one, so I might be wrong.

 

[crashfirepm53]

The exploded view I can only see one listed.That was the front that The Blue Ford tube went in.You can look under "oriface" in the search.

 

[Blue85]

I heard that the Blue Ford tube works better for R-134a. The white GM tube is for R-12. 134 likes a slightly smaller tube.

Since you're tearing into it, you should drop in a VOV. AC Source should have it for any application.

 

[crashfirepm53]

Well I'm in Fl and it's hotter than hell so no time to wait.apparently there is no rear orifice tube anywhere that I can find.I went to the junkyard to replace the high pressure line and of course they were all cut.I paid $10.00 for one that will give me plenty of straight area to couple them together.Can I use brass couplers with the compression fittings?No one has anything else.

 

[azblazor]

As far as I can tell, the rear AC works off of an expansion valve right at the rear evaporator (in the overhead). We own a 77, 78 and an 84 and all those subs are the same.

 

[crashfirepm53]

I used a compression coupler no leaks.Looks good.Weird tho.At 2 parts stores the list the expansion valve as a orifice tube.The rear system does have a expansion valve not an orifice tube.