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Advice requested on hard tubing replacement or flush

DonRuslo on Sat August 22, 2015 1:43 PM User is offline

Year: 1987
Make: Chevy
Model: R10
Engine Size: 5.7
Refrigerant Type: R-12 to R-134a

Hello Everyone!

I have been a long time reader, but am just now far enough along into one of my projects to need some assistance!

I have a 1987 Chevy R10 Pickup that I am replacing all of the components with new parts (Evaporator, Condenser, Barrier Hose Set, Accumulator/Drier, Orifice Tube, and a new R4 Compressor).
The old system had R-12. The new one I plan to run R-134a with PAG 150 oil.

Unfortunately I have found that there is a small ~2 foot piece of hard tubing that goes from the Condenser to the Evaporator that I cannot find a new replacement for. It also contains the high side service port connection.
For reference, the AC Delco part number is 15-33071.
Correct 15-33071 on Amazon (no stock)
The only replacement I can find is the tube version for a "rear air" application (?) that has a third and unneeded connection (AC Delco 15-33072).
Incorrect 15-33072 on Amazon


I see that I have potentially two options:

1) "Flush" and clean the old part and replace the O-Rings so that it can be reused. The issue is that the old system was filled with "Black Death".
I have flushed the tube with Paint Thinner and Aerosol AC Flush, but I am still hesitant to use it because I don't want ANY contaminants in the new system starting out.
However, it does seem like a "simple" part that aught to be easier to flush than say a...condenser?

2) Use the new tube and find a plug or screw of some sort to block off the unneeded connection. The issue here is that the unneeded connection is on the high side and could easily be a point of weakness for a leak to occur.



Any advice or discussion is greatly appreciated!

DonRuslo on Sat August 22, 2015 5:09 PM User is offline



The old tube is on the top.
The new tube with the unneeded "rear air" connection is on the bottom.
My new Drier is shown for size comparison

HECAT on Sat August 22, 2015 7:45 PM User is offline

I would not consider than line as complex as a heat exchanger needing to be flushed. If you have blown solvent thru it and blown it well and completely dry, you should be fine. You can always swab in a deep as you can with a q-tip to see if residues remain.

-------------------------



HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

DonRuslo on Sat August 22, 2015 8:50 PM User is offline

Thanks for your reply!
I just did a Q-Tip swab test and there is definitely still some black residue in the tube that is visible on the Q-Tip.
More flushing must be needed.

However, I wonder what the effect on the total system a relatively small amount of black death residue would be?
Surely it can't be as bad as coated components with larger surface areas (i.e. condensers)...

emsvitil on Sat August 22, 2015 11:35 PM User is offlineView users profile

Blow a string thru the tube.

Tie a small lint free wad on the end of the string.

Dip wad in solvent.

Pull thru until it comes out clean. (changing wad as needed)

-------------------------
Ed
SoCal

HECAT on Sun August 23, 2015 5:36 PM User is offline

Quote
Originally posted by: DonRuslo
Thanks for your reply!

I just did a Q-Tip swab test and there is definitely still some black residue in the tube that is visible on the Q-Tip.

More flushing must be needed. However, I wonder what the effect on the total system a relatively small amount of black death residue would be?

Surely it can't be as bad as coated components with larger surface areas (i.e. condensers)...

Its not Black Death as that was related to an old Ford pattern failure, but it is black. It is usually just carbonized (burnt, but not technically burnt, more like cooked) oil. It does like to "cling" to aluminum surfaces; and we have even documented a anodizing (metal surface penetrating) type effect. This is why I recommended a quick swap test; as when it is actually clean, the interior surface may still appear black.

Unfortunately, the longer contaminated A/C pieces are left open, the oils and residues dry out, harden, cure, and become even more difficult to dissolve and remove. But I think the chemicals you have chosen so far are just not cutting it, literally. Yes, it is a minimal issue, but something is telling you to do your best.

-------------------------


HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

DonRuslo on Sun August 23, 2015 9:27 PM User is offline

Thanks for all the replies everyone!
I am going to find a way to pull a swab of some sort through the tube to remove as much as I can.
Then just not worry about any residual after that.

Thanks everyone!

mk378 on Sun August 23, 2015 9:55 PM User is offline

Make sure to take the shrader valve out of the port and clean that little stub section too.

DonRuslo on Sat August 29, 2015 3:01 PM User is offline

I cleaned and assembled the tube as part of the whole system.
They system took a good charge and is cooling the cab nicely. With a little tweaking/topping off with refrigerant I aught to be even better off.

I bought some "black goop" thermal wrap with hopes to wrap low side sections to retain a little cool. Is this advisable?
Should I also wrap or insulate the accumulator?

Thanks!

Dougflas on Sat August 29, 2015 4:05 PM User is offline

I would only wrap aluminum parts. Steel parts could rust out.

DonRuslo on Sat August 29, 2015 4:40 PM User is offline

Thanks! Looking at the descriptions of my barrier hose ends and accumulator...they are supposedly aluminum.

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