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Problem w/ clutch

clmanaa on Fri July 03, 2009 8:34 PM User is offlineView users profile

Year: 2000
Make: Jeep
Model: Cherokee ( plain )
Engine Size: 6 cyl.
Refrigerant Type: 134A
Ambient Temp: 95
Pressure Low: 35
Pressure High: 225

Someone please take look over this discussion with a supplier and give me an opinion.

Supplier:
More often then not there is an internal problem with the compressor that makes the clutch go bad in the first place. You need to check your compressor shaft to make sure that it turns freely (no binding or restricted). You will need to make sure that the compressor front nose cone is not scored, grooved, or out of round ( distorted) due to excessive heat.

Installing a new clutch under any of the above circumstances will only cause your new replacement clutch to fail in a very short period of time.

Information we would need from you:
We would need you to take a look at your compressor and give us the number that is on the label, part numbers such as U4650 / 4691 /4703 / 4770 / 4784 / 4798, etc.

If the label is missing, we would ask you to take a look at the front face of the clutch plate. There should be three holes in a triangular configuration on the outer perimeter of the clutch shaft hole. We would need to know if these holes are threaded are not.

Reply:
M#: U4784
S/N: 0864790870
MFG. DATE: 4/22/1999
UNIDENTIFIED#: (P) 55037205AH REV. A
Symptoms:
Compressor sounds normal. Cooling is normal. Pressures are normal ( for this ambient ). Clutch voltage is 13.5v dc. Clutch kicks out when supply temp. bring pressure to 18 - 20 psig then kicks out on low pressure and, with voltage present, sometimes kicks back in sometimes does not. Clutch will also kick out, with voltage present, when pressure is between the pressure switch pressure cut out points. This begins to happen after the engine / clutch operates at high RPM for approx. ( and variable ) 10 - 15 min. Assumingly after it heats up. Running cool water on the clutch greatly reduces the cycling. This is the original compressor. The evaporator was recently changed.

That should cover everything.

Supplier:
Here is some information for you and try to answer the questions I have and let me know as soon as you can:

How soon does this start to act up after the ac is turned on?

It sounds more like the ac system (compressor) may be building a high head pressure. The higher the head pressure, the more difficult it becomes for the clutch to do it's job (turn the compressor shaft).

Did you take pressure gauge readings? If so, can you let me know what the low and high side gauge readings are?
When the evaporator was changed. Was the system evacuated (45-60 minutes) before recharging, and was the system recharged with the right amount of Freon?

Have you checked the clutch air cap. It should be between .016 - .031

Is the ac working okay (blowing cold) when driving? Then starts to act up (blowing warm) and cutting out when standing still or at idle speeds? If so, this is an indication of an air flow problem.

Do you know if the vehicle has a separate condenser cooling fan. If so, is it working properly, or at all?
See what you can find out and let me know.

Reply:
10 to 15min. after accelerated to approx.. 2000 rpm's while in park and 15-20 min. while driving. More frequently during high ambient conditions I.E. day vs. night.

The electric cooling fan is cycling when the head goes above approx. 275 psig. and immediately reduces the head to 225 psig or less.

The suction pressure at the beginning of the cycle is approx. 40 psig at idle and 30 - 25 at 2000 rpm. The suction goes down as the indoor temp falls till it reaches 20 - 18 psig at which time the low pressure sw. cuts out the voltage to the clutch. The voltage to the clutch comes back at approx. 50 psig. However, the clutch intermittently draws in and out. Again while voltage is present.

The centrifugal fan clutch is engaging properly and the fan is moving the correct amount of air. There is no overheating problem. The coolant takes a normal amount of time to get to 210 on the gauge and stays there.

I have never witnessed high than expected head pressures. The a/c cooling when the clutch is engaged is good.

The evap. was evacuated for an hour, shut off for an hour, evacuated again for an hour, let sit for another hour and finally weight charged to OEM specs. There was no rise on the gauge to indicate moisture boiling off on either sitting.

I have not checked the clutch air gap because it looked normal to me and it grabs without slipping every time it kicks in.

Supplier:
Are low side pressure pipes hot to the touch?

Reply:
Are you trying to determine the temp. of the compressor by means of the suction line temp. at the hose block mounted to the compressor ? The system is operating normally in all other regards. The suction lie is sweating ( therefore cool ) back towards the compressor as it should be. I guess be more specific as to the exact location of the temp. you want.

Supplier:
You have have the right line.

A normal functioning a/c system gauge readings are between 20-35 on the low side and 200-225 on the high side.. Your low side is reaching 50 and high side pressure is going up to 275.

This is usually an indication that there is either air present in the system, refrigerant overcharge, condenser cooling fins clogged with dirt, or cooling fans malfunctioning.

Reply:
The low side is reaching 50 psi when the pressure switch is cut out on low pressure. Not when cooling. The low side pressures, as I stated previously, and that are common, at an idle are " 40 psig at idle and 30 - 25 at 2000 rpm. The suction goes down as the indoor temp falls till it reaches 20 - 18 psig at which time the low pressure sw. cuts out the voltage to the clutch. The voltage to the clutch comes back ( when the pressure switch reaches the cut out - cut in differential, at approx. 50 psig. " The head pressure only reaches 250-275 momentarily until the electric cooling fan kicks on and then reduces it to 225 psig. I have seen many 134A systems operating with head pressure between 225 and 300. Especially the earlier 134A systems.

I appreciate you assistance in determining the need for the clutch but it appears that you have misread some of the info I provided. All of the above info is common and normal in a non TXV auto a/c system. The 40 psig is at initial start up with an interior temp. above 90 degs. At approx. 80 degs. the suction pressure is 30-35 psig.

I have 25 years of experience with a/c systems. Most in commercial and residential HVAC systems. Plenty with auto but not as much as someone that specializes in it. According to my experience all the symptoms indicate the pressures, temps. and heat removal are in line with what is to be expected.

The clutch's magnetic field is collapsing or is weak as the clutch temp. rises to normal operating temp. Of course the ambient temp. lately has been above 90 degs. so that makes it worse.

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Accurate A/C-Appliance & Htg.

Edited: Fri July 03, 2009 at 9:49 PM by clmanaa

TRB on Fri July 03, 2009 8:48 PM User is offlineView users profile

What exactly are you trying to achieve in this post? Do you want someone to confirm your clutch is bad? I'm not really sure how long I'll leave this post on the forum as this is a discussion between you and another company! Which is where this should be handled not an a forum which is a direct competitor.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

clmanaa on Fri July 03, 2009 9:21 PM User is offlineView users profile

After a lot of searching, "They" are the only mfg. that has the clutch. If I could get the clutch from you I would seeing as I bought a Ford E250 kit from you and it works well. I believe the clutch is at fault and want others imput since the doubt was raised. Furthermore I would think you would appreciate your members seeing the competition not backing up thier product and being incorrect. They don't have a fourm to help folks like you do.

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Accurate A/C-Appliance & Htg.

Edited: Fri July 03, 2009 at 9:29 PM by clmanaa

TRB on Fri July 03, 2009 9:37 PM User is offlineView users profile

I understand just need to be careful with these types of post but I'm sure the other party can respond if they want.

As for the clutch we can get anything anyone else can and usually offer it a a equal or lesser price. There is so many items we stock or have access too which are not listed on our site. It's all about time and getting them added.

As for the clutch itself, what is the gap set at?

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

clmanaa on Fri July 03, 2009 9:57 PM User is offlineView users profile

I edited the post and removed the mfg. info.

I will have to check the gap.

Come to think of it the system had been re-charged several times while looking for the leak that turned out to be in the evap. With all the time running in a low pressure state the clutch was kicking in and out a whole lot more than usual. That would wear it out and increase the gap. The gap being too wide would cause the clutch to have a difficult time pulling in and even more so when it heats up as magnetic fields are distorted by heat.

What do you think ?

If this is so the gap may not be able to be decreased if there are no shims in it from the fact.

Please quote me on a clutch.

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Accurate A/C-Appliance & Htg.

Edited: Fri July 03, 2009 at 10:00 PM by clmanaa

Chick on Fri July 03, 2009 10:17 PM User is offlineView users profile

when the compressor cuts out and does not come back on, tap the front of it, if it grabs and starts working, the gap is to wise, remove a shim... Tim can you a clutch assembly if you need one....hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

clmanaa on Fri July 03, 2009 10:20 PM User is offlineView users profile

I remember that trick. Thanks. I'll try it.

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Accurate A/C-Appliance & Htg.

TRB on Fri July 03, 2009 10:23 PM User is offlineView users profile

I got an email in to my main supplier. So email me Monday if I forget the post which I doubt I will. This way I cover my butt if I forget! If the clutch can't be fixed you might consider just swapping the compressor with a import version of the Sanden. Cost is not that much more than the clutch when I price them out in the past.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Fri July 03, 2009 at 10:24 PM by TRB

iceman2555 on Fri July 03, 2009 10:34 PM User is offlineView users profile

I think what the 'supplier' was attempted to discover was the true reason for the clutch replacement. For you it seems a very simple straight forward issue, for the 'supplier' it is a possible warranty return issue that he may have to 'eat'. All to often many clutches are replaced and then the true fault is discovered....a compressor that is not functioning to spec's...at this point the customer (you) more than likely would wish to return the clutch and perhaps purchase a replacement compressor. This clutch is being returned as a defect when in actually it is not defective....it simply did not complete the expected repair. Many warehouse/jobbers purchase products in lieu of warranty (better price) and in those cases, the jobber would be stuck with a 'warranty' (?) part with no recourse to recoup his money. When someone approaches me for a 'clutch job' I also want to know more about the system. This is to determine, if indeed, a simple clutch replacement will accomplish what the customer expects. This is most important when the clutch is inoperative. Of course,this is more easily accomplished when a tech can perform certain hands on test prior to the clutch replacement. This is not the case with the jobber.
A true question would be addressed to you..........What would you do if you installed the clutch and then discovered that the compressor was truly at fault for the failure and that the compressor would need to be replaced? Would you 'eat' the cost of the clutch or attempt to return it as a 'defective' part? Look at both sides of the coin.......he is in business to make money...not supply test parts !!!


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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

TRB on Fri July 03, 2009 11:00 PM User is offlineView users profile

Ice what you say is true, but we all have defective parts at times. Not saying one way or the other here! I cut open a P &F core yesterday to prove that the customer had either failed to flush properly or used a sealer. After cutting it open we found main tube supplying the passages was plugged from welding. Customer got a new core and was on their way. It is a very fine line between offering unlimited replacement parts and holding a customer accountable for their actions.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Fri July 03, 2009 at 11:02 PM by TRB

TRB on Mon July 06, 2009 10:19 AM User is offlineView users profile

As I thought it will be about the same for a clutch as it will for a Sanden knock off compressor. If you would like a quote on these 2 items feel free to email me.

Clutch # 22-11229

Sanden Import # 20-04691-AM

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

clmanaa on Mon July 06, 2009 4:24 PM User is offlineView users profile

At what e-mail address ? The price I got on the clutch is $156.00 + s&h. Which is not much less than a compressor - but; In order to do the job right and validate the warranty the oriface liquid line tube assmy. and accumulator/drier have to be changed as well now costing over $400.00 plus additional time.

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Accurate A/C-Appliance & Htg.

Edited: Mon July 06, 2009 at 4:25 PM by clmanaa

clmanaa on Mon July 06, 2009 4:38 PM User is offlineView users profile

Reply to iceman2555,

I know the supplier was trying to make sure the clutch was actually at fault and needed. That's o.k. I do the same thing with my customers. I posted for two reasons:

1) Because of his replies, I think he wasn't understanding, or paying attention to, the answers I gave him. And that I believe he is wrong about the determination he made at the end.
2) Their unwillingness to accept any returns.

I have been in the factory authorized repair business for many years. Factories and warehouses make mistakes. They put out defective parts ( they don't test EVERY part. They spot test. ), mis-box and mis-label parts, ship out the wrong parts and much more. Stuff happens. If you want to be competitive and fair you shouldn't have a no return policy - period. At least get the item back, verify the problem then either ship the correct one or a functional one back or issue a refund if you don't have the correct one.

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Accurate A/C-Appliance & Htg.

Edited: Mon July 06, 2009 at 4:41 PM by clmanaa

TRB on Mon July 06, 2009 4:45 PM User is offlineView users profile

[email protected], I also updated my sig to our contact page.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

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