Compressor bracket... 1980 300SD - Page 5 - PeachParts Mercedes-Benz Forum

1980sd · #61 10-04-2011, 11:18 AM

Quote:

Originally Posted by leathermang

I don't even know what to say....

You always have something to say. Just nothing to do

The shop is less than a half mile from my house and they loan me tools, give me good deals on parts, let me use their brake lathe, etc. I haven't done any work on their lift but if they're not busy they will throw it on on the lift for inspection. Nice guys who are within walking distance from my house. They vacuumed and charged for $60 including 2 lbs of 134a. This included vacuuming the system TWICE so I could drive it home and fix some leaks.

I asked them about vacuuming it down for an hour and they poo-pooed the idea saying it isn't really necessary until I was 100% sure there were no leaks

I suppose I should have jumped on my car at that moment and began quoting from "The Consolidated North American Guide to AC Repair" and yelling about how the internet says they're wrong... I guarantee that would have raised future prices...

Remember, I still had mechanical testing to do at that time which could have required another evacuation so this was cheap plus I got to watch how it was done.

It's still in beta testing. I always planned on vacuuming it down to change the accumulator and OT.

Hopefully I'll get a vacuum pump next week...

But yea, I now know full well what moisture can do to your system other than obvious performance issues:

Bushehr reactor #6 inlet - YouTube

I think that after 3000 miles of running I can call mechanical OK thanks to Jims help.

leathermang · #62 10-04-2011, 11:31 AM

What worries me is that there is still no mention of R22 and nitrogen for pressure testing.... vacuuming only.... pulls the seals the wrong way.. particularly the compressor shaft seal.... so you can not tell if you have a sealed system with vacuum... AND you can not tell where the leak is... as compared to pressure/sniffer...

leathermang · #63 10-04-2011, 11:34 AM

Do you know how much the Harbor Freight 2 STAGE vacuum costs on sale? capacity does not make any difference....you are going to leave it on there a long time.... not like a pro doing house ac who needs to get to the next house sweltering in the heat....

1980sd · #64 10-04-2011, 11:58 AM

Quote:

Originally Posted by leathermang

What worries me is that there is still no mention of R22 and nitrogen for pressure testing.... vacuuming only.... pulls the seals the wrong way.. particularly the compressor shaft seal.... so you can not tell if you have a sealed system with vacuum... AND you can not tell where the leak is... as compared to pressure/sniffer...

Meh... Not everyone can get R22 and not everyone has a tank of nitrogen around. True, that would be ideal. Especially for a pro AC shop that's worried about comebacks.

I'm trying to keep this as DIY as possible with COMMON AC servicing tools/gas that folks can get at a parts store.

I agree that pulling a vacuum is a piss poor leak check. I saw it with my own eyes. It shifts the seals in the OPPOSITE direction from normal operational positions. I'm amazed that those O rings work at all...

Just rely on vacuuming for moisture removal.

Leak checking? Run the ***** out of it with gas of choice and sniff it. Check it cold and hot. If you lose gas you have a leak. Find it and fix it...

Legalities of oozing a little gas into the atmosphere. Moot point for me...

I looked at the single stage and 2 stage when I got my gauges. I didn't see a sniffer.

leathermang · #65 10-04-2011, 02:53 PM

John, don't you do some tig welding ? If not ,with your projects you need one..... you will then have argon....and you can use that just fine instead of the nitrogen...
Have you even checked the local welding house for how much a nitrogen bottle costs ? OR if you can rent one for a month ? ( the normal minimum time -- called demurrage) ....is one month..

Demurrage - Wikipedia, the free encyclopedia

lots of ways to have total control over your whole AC project and not put out a bundle ....
But , for the record, how much would a small nitrogen bottle cost locally ? Do you even know.. or did you assume ' too much' ....

R22 is easily available on Ebay.... a 15 oz can typically.... technically three pressure checks....

1980sd · #66 10-04-2011, 04:02 PM

Quote:

Originally Posted by leathermang

John, don't you do some tig welding ? If not ,with your projects you need one..... you will then have argon....and you can use that just fine instead of the nitrogen...
Have you even checked the local welding house for how much a nitrogen bottle costs ? OR if you can rent one for a month ? ( the normal minimum time -- called demurrage) ....is one month..

Demurrage - Wikipedia, the free encyclopedia

lots of ways to have total control over your whole AC project and not put out a bundle ....
But , for the record, how much would a small nitrogen bottle cost locally ? Do you even know.. or did you assume ' too much' ....

R22 is easily available on Ebay.... a 15 oz can typically.... technically three pressure checks....

I have an argon tank I swap between the tig and mig. I used a butt load of it on this project and need to swap it out

I don't really want to invest in a sniffer. I may change my mind after I get a vacuum pump though... But if I do I doubt I'll fool with R12. I know that nitrogen/R22 is supposed to be a really good way to check for leaks but since r134a is supposed to be more leak prone then why test with R12 other than compliance with the law

The system looks promising with 134a, near freezing vent temps with ambient in the 90's. Vent temps are vent temps right? As long as the system isn't under any strain it should be all good.

leathermang · #67 10-04-2011, 06:07 PM

Quote:

Originally Posted by 1980sd

I have an argon tank I swap between the tig and mig. I used a butt load of it on this project and need to swap it out

I know that nitrogen/R22 is supposed to be a really good way to check for leaks but since r134a is supposed to be more leak prone then why test with R12 other than compliance with the law

I assume that is a TYPO and you meant R22 as test medium.
Where did you get the idea that 134a is more prone to leaking?
Why do you think you are above complying with the law on venting refrigerants ?

1980sd · #68 10-04-2011, 08:15 PM

Yea, R22. It's my understanding that the R22 molecules are larger than 134a molecules so 134a can actually leak through the hoses if they aren't the right barrier type. I figured this also means it's more leak prone. Lotta stuff about beadlock and barbed fittings and crimps, hose types, etc. seems to address the change from 22 to 134 as well.

I think John mentioned that nitrogen and R22 will kind of "supercharge" your sniffer and make leaks easier to find. Maybe I got the "4 oz" rule tangled up in this...

Hopefully he will weigh in on some of this.

Laws, moot point... I'd be worried about that chemical plant that's burning over your way rather than worrying about some yahoo in Ga with an aerosol can he bought at Autozone

Marvelicious · #69 10-05-2011, 02:53 AM

Quote:

Originally Posted by leathermang

Why do you think you are above complying with the law on venting refrigerants ?

Pfffft, and I suppose I shouldn't heat my house by burning used tires either...

Joking aside, I do find it hard to worry about my occasional violation of the rules in light of the smell of hydrogen sulfide as I pass the paper mill down the road from my house.

leathermang · #70 10-05-2011, 09:52 AM

1. Some things in life we do not have control over.

2. Little things by lots of people can add up to big things... either good or bad.

3. One can often minimize the cost of doing things (following the law in this case ) if some logical thinking/searching is put to the situation.... as with using the Argon tank he already has or renting the nitrogen tank at the local welding supply.

4. Those tires, instead of burning them, can be used as an excellent road base when chipped up. With the added benefit of not getting so hot that your chimney catches on fire and burns your house down....like using pine for firewood... and letting creosote build up....

5. Plenty of laws need to be changed. Instead of substituting violating Other rules in protest of bad or non enforced laws....... work on changing those laws that need to be changed...

Yes, I know... sorta old fashioned ....

Air&Road · #71 10-05-2011, 09:58 AM

That looks like a nice bracket. The ones I have on my Euro cars require an idler pulley. The one shown fits the later 616/617 accessory arrangement similar to the R4 layout.

vstech · #72 10-05-2011, 11:02 AM

Quote:

Originally Posted by 1980sd

Yea, R22. It's my understanding that the R22 molecules are larger than 134a molecules so 134a can actually leak through the hoses if they aren't the right barrier type. I figured this also means it's more leak prone. Lotta stuff about beadlock and barbed fittings and crimps, hose types, etc. seems to address the change from 22 to 134 as well.

I think John mentioned that nitrogen and R22 will kind of "supercharge" your sniffer and make leaks easier to find. Maybe I got the "4 oz" rule tangled up in this...

Hopefully he will weigh in on some of this.

Laws, moot point... I'd be worried about that chemical plant that's burning over your way rather than worrying about some yahoo in Ga with an aerosol can he bought at Autozone

while 134 is not an ozone depleting chemical, it's still banned from venting due to the massive carbon footprint it has. (it's something like 1200 times more reactive than CO2 to the atmosphere...)

the EPA's rules are there due to laws and backing from pac leaders... weather or not they are right does not matter, what matters is they are law. change the law, and it's ok, otherwise, it makes you a rulebraker, and severe punishment is possible. I personally think it's all rubbish, and simply a way to charge us money, increase taxes, etc... but it's law, and I make a living following that law.

yes, it's allowed to mix 4oz of R22 into a nitrogen pressure test to get a reaction from the sniffer for leak testing. R22 is an HCFC and as such is far less reactive to the atmosphere than 12 or 134, so it's better to leak a little 22 than to have a system in place that actively leaks one of the more reactive gases.

1980sd · #73 10-05-2011, 11:08 AM

Quote:

Originally Posted by vstech

yes, it's allowed to mix 4oz of R22 into a nitrogen pressure test to get a reaction from the sniffer for leak testing.

Thanks John. So is the nitrogen/R22 mix sniffed easier than pure 134a (meaning that it's a better leak detection method) or is it just a regulatory thing.

vstech · #74 10-05-2011, 11:15 AM

R22 is SUPER reactive to the sniffers.

leathermang · #75 10-05-2011, 11:28 AM

VSTech, very nicely said. Thanks for your support ( remember the Bartle and James commercials ? )