AC compressor does line up; new compressor

[adamj]

I guess you could, but I wouldn't want to risk it. Plus, the orifice tube is cheap, so you might as well do that while you have the system open. The only heads up for the orifice tube is that sometimes they can get stuck in the evaporator inlet tube, but it's easy to check if you can remove it or not. Accumulator should definitely be replaced too when the system is open since it will draw moisture from the atmosphere once exposed. Moisture in the system/not being able to remove moisture will hurt cooling efficiency. Again, not an expensive item, and it's easy to swap out since there's plenty of access space. When you pull vacuum and ensure that it holds, then there's no need to replace the o-rings since that's usually the reason for replacing – leaking o-rings crack when the system is not operational for a while since the oil keeps those supple. If you have a leak, then start checking o-rings. If you replace the accumulator, remember to transfer the low side R134a adapter on the accum, and the high side adapter on the line to the condenser. That way you can hook up standard R134a manifold gauges to evacuate and charge the system.

Technically you should be flushing the condenser before replacing the compressor, but as long as you didn't have complete compressor failure (aka "Black Death") then you should be fine. However, only original condensers are technically flushable since the passages are larger. If the condenser has been replaced within the last 10 years or so, then it probably is too new of a design to be flushed properly, and will have to be replaced.

Check that the new compressor has oil in it already, you may need to add some, or if the oil already in it is not compatible with R134a, then you will have to empty and refill with the correct PAG oil. Also make sure you rotate the compressor drive by hand to circulate the oil and lubricate the internals.

I assume you are working on your 305 in the K10. If so, you don't have an expansion valve, that is only for the additional rear AC system on suburbans.

 

[maxtwms]

I. When you pull vacuum and ensure that it holds, then there's no need to replace the o-rings since that's usually the reason for replacing – leaking o-rings crack when the system is not operational for a while since the oil keeps those supple. If you have a leak, then start checking o-rings. If you replace the accumulator, remember to transfer the low side R134a adapter on the accum, and the high side adapter on the line to the condenser. That way you can hook up standard R134a manifold gauges to evacuate and charge the system.the K1

Man this would have taken so much research! I bought a new accumulator and orifice tube. Pretty sure the accumulator came with o-rings... I'm confused on what you meant by the edited quote above. Particularly if I replace the accumulator, the o-rings should be fine unless you mean the condenser.

Also I'm confused about the transfer of high and low adapters... What do you mean here? I'm sure I misread but I can't figure that out.

Doesn't all refrigerant escape once I remove the lines from the compressor.

Thanks for your experience

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[maxtwms]

I think I understand the o-rings now... It was never leaking so all other o-rings should be fine. I forget how many questions I ask. But still confused about the adapters. I imagine that's for convenience later?...

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[adamj]

Our trucks with the original R12 system used a different style port to interface with the manifold gauges. When retrofitted, adapters are used so that the R134-specific connectors on these gauges can be used. So your new accumulator (like your old one) should have the old-style R12 fitting on the low side access port, and then with an adapter screwed on. I was just noting that you should transfer this adapter since you plan on staying with R134.

I'm not sure if you've done this before, but here's a basic run down of AC work:
Two crucial tools you need when working on AC are 1) Manifold gauge and 2) Vacuum pump. The manifold gauge allows you to read the pressures of the system on the high side and low side, and also serves as a way "in" to the system. You hook up a vacuum gauge to pull vacuum on the system which removes moisture. You also use these gauges to add refrigerant to the system via the low side port.
When replacing any component of the AC system, the refrigerant that is in the system needs to be removed safely. Measure your system pressure with the aforementioned gauges, and if you still have a pressurized system, I would not simply disconnect the compressor lines, you could get a spray of refrigerant on your skin or face. You need to evacuate the system safely via the access ports.
Once the system is safe to work on, you can replace the parts, tighten everything up, and then pull vacuum to remove the air and moisture. Ensure the system holds this vacuum, and then you can charge with refrigerant.

 

[maxtwms]

Perfect explanation. Thank you! I'll report back tomorrow!

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[maxtwms]

FIXED THE ALIGNMENT!! Holy cow was this frustrating.

So the ToughOne didn't work. It had some extra protruding fasteners on the backside that wouldn't agree with the existing mount. I had a few issues that were hindering the line up.

1. My valve covers we're so tall that I could really rotate the compressor at all because of the bracket for the lines.
2. The bolt used to pivot the compressor was rigged but seemed to work. Only thing was, I required a shim between compressor and mount of about 3/8" which was the same size as a flange nut I had.
3. My belt was too long for me to know this.
I found if I lossened the compressor tension and added it to the ps pump everything clicked!

I'll take some pictures later but this was such a headache I think it could help others too. I really appreciate the help. Gonna have a vacuum pulled and charge tomorrow.

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[maxtwms]

One last question. My old compressor was a 9oclock harness and the new one is 12. Does this actually matter? And while we're at it, I imagine the polarity matters too? Couldn't tell what the new compressor prefered

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[adamj]

Polarity does not matter. Clocking does not matter either as long as the cable routing doesn't interfere with anything.

 

[hatzie]

Doesn't all refrigerant escape once I remove the lines from the compressor.

Yes but that's called venting refrigerant. Don't say another word about doing that if you don't want EPA goons knocking on your door. You got a buddy with a recycling machine to empty the system or it was already empty when you hooked up the manifold gauges... that's the end of the story.

 

[maxtwms]

That bottom bolt there has about a 3/8 thick flange nut as a spacer between the mount and compressor. I found this lined everything up even though it seemed counter productive in the application. Hope this helps someone. Try everything u can!

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