Compressor clutch broken, how to go on?

Hi Guys,
greetings from 5000 miles over here in Germany. On my BRM there was some days ago a burned smell, shortly after then horrible noise from the compressor. When I checked it out, I found the middle steel ring of the clutch was detached and was slinging around with the pulley. I removed the cpl. compressor out of the car and tried today to remove the clutch, stupidly I broke the housing cause I have not the correct tool and didn´t realise the circlip underneath when I pulled off the pulley. Not the biggest problem, an complete compressor is hardly more expensive than the clutch itself. What I was confused about was that there was no oil draining out of the rear side of the compressor, not even when I turned the pulley. An AC specialist over here told me that I have to remove the oil out of the comp and have exactly to measure the amount what was in. Furthermore he told that it might be possible that the whole AC system might be polluted with chips in case the comp has been scuffing. But I don´t see anything what points to any scuffing. The comp shaft can be turned smooth with some restistance what I would indicate as absolutly ok. Furthermore, the AC worked fine the day before and when I removed the connections the gas escaped with an considerable amount of pressure. This tells me that there was no pressure loss and supposedly no other problem as the broken clutch what has to be replaced however. Or are there any hidden symptoms which I didn´t have noticed? What also confirms my assumption with the clutch, I remembered a clunking noise whenever the clutch switched, more than it might be normal...

What would you guys now advice to me, first I will order a brand new comp from Rockauto, as well all minor sealing parts, new belt etc... Furthermore: Have I to flush the complete system and can i do this by myself? The guy told me that the system has to be flushed with some special devices as well as it has to be filled by the specialists, maybe pressure loss checks and sealing tests? What special parts should I replace in order to prevent any risks? Once the car is completed by me and the system is yet empty, how can I move the car to the AC specialist to make sure that the comp doesn´t move without oiling? The amount of oil seems to be very important, how can I find out how much I have to refill ( or the AC guy?)

You see, AC is not my core competence…..so I hope for some advices, thanks a lot

You did not tell us what year the car is.

If it is a 91-93, and no oil comes out of the compressor, you need to add 60ml/cc. I do not know the quantity for the 94-96, but I would think it is similar.

Check the orifice tube for debris, and if there are none, your system is probably fine. Also check for any black fluid from the system, commonly known as "the black death". If you find black fluid, you need to replace the accumulator, and clean/flush everything else. I would also replace all o-rings on any part that you disconnect.

If you mount the compressor and do not hook up the electrical connectors, the compressor will not turn, because the clutch will not be able to engage. You can drive it to the AC shop like that.

If you are inclined to refill it yourself, you need a vacuum pump, and a set of gauges. It may take about to 60 oz. of refrigerant, but the gauges will tell you the proper amount by the pressures. I do not know if you are using R12 or R134a, and the pressures may be different for them. You can vacuum the system, and let it sit with vacuum for at least 1/2 hour to check for leaks. It should hold vacuum. Unless you need a belt, yours is probably OK. If it looks worn, then replace it.

The oil amount can be found in the Factory Service Manual for your year.

Hi Fred,

Thanks  a lot for you helful advices as already established in the past The car ist 94, maybe there´s a hint about the oil quantity in the box of the new compressor or I´ll find it in the manual. I will go on how you adviced but move the car to the AC specialist for refilling. Make no sense to do this myself.

As I understood, the compressor has to be filled with oil before it is installed. Doesn´t the oil run out of the comp whilst installing it in the car? It´s a bit tricky to get it in place, I didn´t remove the water cooler, just removed the idler lever of the steering, then it worked. Or should i turn the comp shaft to suck the oil in (and it remains there)? What hole is the entrance, do I find it out whilst turning the shaft in rotating direction and it sucks ?

Last questions: The accumulator (not definitly to translate in german) is it the aluminium pot upon the RH Wheel, also refered as "dryer"? And where is the orifice tube located ?


Thanks in Advance

The orifice tube is in the line with the bulge in it at where it attached to the condenser. It is a little bit difficult to remove. It is a good idea to replace it when repairing the AC, even if it looks good.

The accumulator is the same as the dryer. It is usually noted as accumulator/dryer. You only need to replace it, if the system shows symptoms of the "black death".

It does not matter which hole you put the oil in. The one that is less obscured is probably the better choice. If you put the compressor in without oil, you can use a funnel and hose to direct the oil where it needs to go. I measure my oil with a large syringe. The holes are usually at the top of the compressor when installed, so if it goes in with the end with the holes up, the oil will not run out. You might be able to find plugs for the holes before you install it. The new compressor may come with plugs in the holes.

Make sure you use the correct oil for the type of refrigerant you use.

Hi Fred,
in the meantime I pulled the orifice tube and I was really shocked. It´s full of chips and debris and - maybe - black death. No doubt that the system is completly dead. First I thought about flushing the evaporator and the condenser with the risk that it´s hardly impossible to get all debris out. Now I will order all parts new, compressor, dryer, evaporator and condenser, tubes if avalable, orifice, all seals, new belt…..about 450 $ seems to be a cheap invest for all these parts...To remove the evapurator was no pleasure, but worked in less than an hour. To remove the condenser is possible in an unbelievable 20 min. I´m just wondering that the A/C worked well so far the last years.
On the rockauto Website, they are offering the correct oil for the compressor, I will order it as well. Thanks a lot for your advices ! Cheers Udo

I would wash out the evaporator, and condenser. They will clean up well. There is a cleaner just for the AC system. I gave mine a final rinse of carburetor/intake/brake cleaner. Shoot it in until it runs out clear. The residue will evaporate in a couple of minutes, and the parts will be clean. The lines can also be cleaned the same way. It will save you a lot of money. You only need the dryer, orifice, and the compressor. I even used my dryer over, and have no ill effects, from my last compressor self destruct episode.

You may have to put some oil in the new dryer, and refill the condenser. You really need the Factory Service Manual to get the correct amounts for all components. Your AC guy will probably be able to correctly fill the system.

....too late now Fred, I just dropped the order to RA 1 min before I read your post You maybe right,
but it´s ok anyway. Please remember I´m German and if somethings doesn´t work as expected, it will be a mess because there are no guys 1000 miles around me, no scrapyard and no friends with cars like mine. So for me, 200 spent $ are well worth to make sure everything is ok. The evapurator was pretty dirty and I´m not sure to get it cleaned without damaging.

I will tell as soon as I go ahead with the repair !

Replacing the evaporator may be a good idea. You do not want to do that again for a long time, if ever.

Check with your AC guy. If memory serves, the EU has switched over to carbon based (read propane based) refrigerant. You may find that CFCs are no longer legal over there.

Propane is a safer and a more effective refrigerant, however, you are going to have to make sure your compressor oil is compatible. Bought a Mercedes that lived in your country that belonged to one of our diplomats. Decided to bring the car home and then promptly had a heart attack. Bought the car off his widow. That car used propane and was built in 1985 so at least Germany has used propane for a long time.

Bill

convert2diesel wrote:

Check with your AC guy.  If memory serves, the EU has switched over to carbon based (read propane based) refrigerant.  You may find that CFCs are no longer legal over there.

Propane is a safer and a more effective refrigerant, however, you are going to have to make sure your compressor oil is compatible.  Bought a Mercedes that lived in your country that belonged to one of our diplomats.  Decided to bring the car home and then promptly had a heart attack.  Bought the car off his widow. That car used propane and was built in 1985 so at least Germany has used propane for a long time.

Bill

I´m pretty suspicious about using another refrigerant as the producer intended to use. Maybe R134 isn´t actually permitted, most A/C shop can provide it anyway (and will do that for cars which are refered to) Nobody can guarantee that different refrigerants may work with the paticulary compressor oil without testing that and make a release for it. I´m not in the situation to play the testing guy for it. Is your car a W124 Mercedes?
I´m employée of them BTW....and anyway owning an Buick.....

Yes it was a W124. Rust got the better of it but was an excellent car while it lasted.

Have been using propane derived refrigerant in all my GM vehicles and seeing as you have to do a total purge, this would be the time. Actually it is more efficient (read colder) then 134. Have experienced no AC failures associated with refrigerant as long as you use the correct lubricant. All of my Bs and Ds were converted as soon as I got them and had no issues.

Again, ask your AC guy. Don't know what is available on your side of the pond.

Bill

I will ask him , Bill, thanks a lot for the advice. I´m wondering how well the A/C performed even once the system was polluted, as the orifice looked like I couldn´t  imagine that the issue came up just now before I discovered the failed compressor. There wasn´t inside not one drop of oil....Supposedly the A/c will frozen my legs even when it works with normal performance
About the propane and efficency of the colder operation: I´m living in Germany   , not in Florida  

Anyway, in these days now the temperatures are raising up and we had almost 85°F...

I have now a specialist over here in Germany who can refill the system with R134a. But another question concerning the refilling of the special compressor oil. There is a confusing procedure descirbed in the Manual, how to drain the comp oil , measure the amount and refill  new oil depending of the amount of the old one. Now I have all parts brand new, and there was not one single droplet found out of the old compressor or dryer or whatever. I´m a bit unsure what quantities I should fill into the new parts. Yesterday, I filled 60 ml (2 oz) of PAG 150 (is compatible to R134) into the new compressor. As said before, there wasn´t any oil in the old one. Furthermore, the manual says that I´ve to fill 105 ml (3,5 oz) into the Evaporator (???) and 30 ml (1 oz) into the condenser and something ( don´t remember the amount) into the dryer. That seems all strange to me, could somebody confirm that? I don´t understand why the quantities are depending on the old drained quantities once I have replaced all the system parts? Thanks for help,

The FSM is a bit confusing even for me. The oil migrates through the system, and you should find some in each component. I do not know the total necessary to "fill" the system.

Hi Fred, what is FSM?

Apart from that , the missing oil matters actually nothing regarding my problem. Since I´m going to replace all parts of the system, I have the same situation as if the car leaves the production plant and the system has to be filled for the first time. I guess that they´ve had a quantity of oil in every component or at least there must be a reliable statement how much i have to fill.What I´m wondering about is the quantity they want to be determined by draining the old compressor. The condition of it maybe unknown as it is on mine. If I have an engine failure, I wouldn´t determine the remaining oil quantity as well to determine the oil amount what has to be filled into the new engine. Maybe I´ve no idea of the function of an A/C, yes, I´m aware

FSM...Factory Service Manual.

My truck has a very similar AC system. The FSM states:

REFRIGERANT OIL CAPACITIES

ACCUMULATOR REPLACEMENT
NOTE: Add 60 ml (2 ounces) of PAG oil, plus the equal amount of oil drained from the accumulator.

COMPRESSOR REPLACEMENT
60 ml (2.0 ounces)
NOTE: The Denso replacement compressor is precharged with 237 ml (8.0 ounces) of PAG oil.


CONDENSER REPLACEMENT
30 ml (1.0 ounces)

EVAPORATOR REPLACEMENT
90 ml (3.0 ounces)
NOTE: If more than the specified amount of PAG oil was drained from a component, add the equal amount drained.


TOTAL SYSTEM PAG OIL CAPACITY
210 ml (7.1 ounces)

The capacities would be very similar (less then 10%) difference.

Bill

Fred Kiehl wrote:

FSM...Factory Service Manual.

Thanks Fred.....some things are that simple

@Bill
Yes, the quantities seems to be very similar. The accumulator is refered at the Buick with 105 ml (3,5 oz) , evapurator and condenser are equal. The only thing what confuses me is that I didn´t drain one single droplet out of the compressor, even in all the system I didn´t find any oil. I didn´t check the condenser as yet, but no oil inside the comp., no in the evapurator and no inside the accu. Seems very strange.

When I removed the whole system, I simply opened all connectors and let flow the refrigerant outside ( with massive pressure   because it was sure that I would replace all parts ). Would it be possible that this evacuation did drag away all the oil in the system? Now it´s no longer possible to drain the old compressor to determine the left oil quantity and put in the additional amount into the new one.

Now I filled 60 ml (2 oz) of PAG 150 oil into the (brand new) compressor, it was refered to be completly empty from Rockauto. I hope with 60 ml it will work, together with all additional quantities in the other components. Is it right that the A/C balances the oil amounts in the components when operating for a longer time??

I was never that unsure when repairing whatever car components........

A method I have used over the years, though frowned upon, is flushing all the components separately with methanol. After flushing, use a dry air source (I admit I used to use a small shop vac on blow mode) to dry up any residual methanol. Even if there is some trace amounts present, that will be taken care of when the refill process pulls a vacuum. This assure that there is no oil left in the system and allows you to add oil to the various components individually for a fresh start.

Immediately put the system pack together, suck the system down to check for leaks and keep the vacuum on for at least 1/2 hour to assure the system is moisture free and to vaporize any residual methanol before adding any Freon. You should be then good to go.

Good luck.

Bill

BuickRM wrote:

Fred Kiehl wrote:

FSM...Factory Service Manual.

Thanks Fred.....some things are that simple

@Bill
Yes, the quantities seems to be very similar. The accumulator is refered at the Buick with 105 ml (3,5 oz) , evapurator and condenser are equal. The only thing what confuses me is that I didn´t drain one single droplet out of the compressor, even in all the system I didn´t find any oil. I didn´t check the condenser as yet, but no oil inside the comp., no in the evapurator and no inside the accu. Seems very strange.

When I removed the whole system, I simply opened all connectors and let flow the refrigerant outside ( with massive pressure   because it was sure that I would replace all parts ). Would it be possible that this evacuation did drag away all the oil in the system? Now it´s no longer possible to drain the old compressor to determine the left oil quantity and put in the additional amount into the new one.

Now I filled 60 ml (2 oz) of PAG 150 oil into the (brand new) compressor, it was refered to be completly empty from Rockauto. I hope with 60 ml it will work, together with all additional quantities in the other components. Is it right that the A/C balances the oil amounts in the components when operating for a longer time??

I was never that unsure when repairing whatever car components........

I just rebuilt the whole system in my 95. I added the quantities as advised in the FSM and above. Only difference is I didn't add any to the condenser (next to radiator) as the one I pulled out was clogged and the one I put in came out of a Caprice sedan I dismantled a few years ago. I did flush the lines with a cleaner, as I had black death in another wagon some years ago.

You should be fine. The automobile AC is alot simpler than a house, I've done about 6 or 7 now. The Rock Auto kit was pretty good and so far so good (about 4 months now).

I´m in progress with the rebuild, everything worked. The only ****ing mess is to get the evaporator in, 2 years ago I did it with the heater core what is in the same region
The worst is the lower plastic cover and the access to the tapping screws towards the bulkhead. Apart from that it´s not that problem. A little tricky is the routing of the A/C lines, it`s a bit a snakepit. A hint of mine for those who didn´t do it before: Remove the steering idler post from the frame to get the compressor out. Also the two M8 screws behind the compressor are tricky to access, to remove he coolant tank is also a good idea. I will report as soon as the system works again, still waiting for the condenser what should arrive today afternoon.

Other problem off topic: Does anyone know where I can source a belt tensioner for the additional HD cooling fan ( mechanical drive "Viscolüfter")? Rockauto doesn´t offer one, only for the main drive. The bearing inside make a bit noise, the belt wheel is plastic, not that robust design....I don´t think that I´m the only with HD Fan... supposedly you US-guys are digging happiliy in the scrapyards

The evap core is right next to the heater core.

There are no new tensioners. I just sold my last one, and do not have any leads for another. If just the bearing is bad, you can carefully press out the one in the pulley, and replace it. It is a standard bearing. You may be able to get a pulley from another model car, but the tensioner itself is not available.

Fred, I replaced the evapurator core last week already, just reported about    I just have to wait for the condenser.

Bad news about the fan tensioner. I already replaced the bearing about 2 years ago with a std. ball bearing with lateral sealings whilst keeping the pulley. Strangely, the bearing is again a bit noisy. I think about turning a new pulley out of steel with a better bearing. The tensioner itself shouldn´t cause a problem.

You may be able to get a better grade of bearing for the job. The tensioners are noted to break, but if it has tension, it should be good.

@Fred, yes, the tensioner looks pretty rachitic to my opinion. Two years ago, I removed the visco fan completly because i thought it wouldn´t cause a problem and the remaining electric fan would be good enough, even because I don´t have an trailer. I would save some power and consumption.... My wife used the car that evening and she´ve sent me the temperatur display from the dashbord via whatsapp. UUpppssss......next day I´ve quickly put it back in, the engine was about to boil off. It doesn´t work definitly with just one electric fan. To my knowledge, if you have no visco fan, the corresponding (main)electric fan is bigger than the added fan used with the visco. With what fan is your car equipped? What temps with two electric fans, no temp troubles ? Just in case my visco fan belt tensioner breaks down and I have to switch to a second electric fan...

I have a 92, and put the fans from a 93 FW on it. They work fine. 

It is easy to replace the viscous drive fan with the other electric one. You do need the correct harness. I believe it is a plug and play, but am not absolutely sure. I have a second temp sensor, and three relays to run my fans. The primary is set for 195, and the secondary is set for 210, or any time the AC is on. I probably use the fans improperly, but it works.

Guys,
I want to inform about my AC right now, finally I´ve got the condenser some weeks ago, it was the last part I´ve got brand new, the condenser was really a mess. I ordered from rockauto, the first what arrived was completely warped ( yes, really) ,but he package wasn´t damaged in any way. Strange. When I complained Rockauto was very customer -friendly and they didn´t want me to return the part as the pics showed the scope of damaging. Then it took again some weeks to get another new one (supposedly it comes from another RA store, usually I get my parts in some days over here to Germany). Now the condenser was not warped, but the connection tubes were kinked at the bends due to taken no care when packing. I was very close to collapse, but then I fixed the kinked areas by myself. Then I mounted the condenser, refilled the AC with gas and it worked fine since some weeks.


Now, yesterday my wife complains  about a clattering noise inside the engine bay, today I went to check it. It´s again the AC compressor clutch. It switches the compressor with a frequency of about 1 sec on and off, it´s clearly to see on the clutch when the engine is idling. The comp is brand new !!! I got into the car and switched off the AC, the noise disappears immediately (who knew?)

When I push the AC to a lower temp, I´ve a feeling that the clutch switching will be less, but anyway the noise is relativly hard clonk and worrying, particulary because I didn´t hear it the weeks before after I started the AC system to operate after replacing all parts brand new. But I couldn´t suggest that the comp will be the reason, why does the clutch switching like crazy? And why that suddenly when it worked some weeks ordinary?


What I´m be worry is that if the comp clutch breaks, the belt drive is involved and on a longer ride it´s prone to fail together with all devices ( water pump and power steering, alternator). I would expect from a brand new AC system and especially compressor to last longer that 6 weeks…..thanks for your advices.

if it's a 94 with the LT1 if the belt snaps you only have to worry about loosing your alternator, power steering, and primary mechanical fan. The water pump is a direct drive thru the timing cover similar to the opti spark.

Did you check for a pulsating voltage from the high and low pressure sensors?

Hi Fred,
I didn´t check any voltage at any sensors at all
I went to a mate who´s able to fill the AC with refrigerant after I had completed the system with the missing condenser. As long as the system was empty, I disabled the comp by leaving the plug off. The mate ( he owns a garage and uses to work on Mercedes) refilled the system with his professional device.. The AC worked perfect after, produced ice cold air, I noticed at least no strange noises at all even when I drove home that day, it´s about 20 miles.. My wife just tells me that the noise did occure straight after the AC was activated, maybe I didn´t hear it cause I use the car very rarely. So I hope the comp is not pre-damaged.......thanks a lot for your advice.
If the voltage is pulsing, whats the reason for this? ECU of the AC? Sort of this existing?

It could be a bad switch, or a bad signal from the head unit, but beyond that I do not know. There is a low pressure switch on the accumulator, and if it is 92 or later, a high pressure switch on the compressor. The signal from the head unit should be steady (request signal), and the high and low pressure switches make sure the system has enough refrigerant, but also makes sure the high pressure is not damaging the system. The switches open an close, but are mostly closed. If one should have bad contacts, it could cause the signal to the compressor clutch to turn on and off frequently. A voltage check to the clutch would determine that. If the compressor has a constant voltage applied to it, it should run. If the voltage does not vary at head side of the low switch, and only when the pressures trip the switches, and the clutch disengages repeatedly at random, then the issue is with the clutch.

Quote :

It switches the compressor with a frequency of about 1 sec on and off,

Classic symptom of an underfilled (or leaking) system. You need to check pressures, but I can tell you it is probably low.

Hi all,
first time when we filled the system it worked well, Maybe we filled a bit much, the manual says 790 gr of refrigerant. The mate put in a bit more, let say 830 gr, due to his experiences. After the issues I talked about (frequently switching of the clutch) I went back to him and last Friday we evacuated the system again and refilled it with the correct amount of 790 gr. When he evacuated the system he made a leak test after, and he stated that the system is perfectly sealed. When we ran the engine afterwards, there were no issues, the performance was perfect, the air icecould. Then I went home and had to use the heating cause it got cold. Yesterday I used the car for a short time and heard again the frequently switching, and rechecked it today, again the same ****: frequently switching all the time. The system loses definitly no pressure. I´m now thinking about providing a new pressure switch and a comp. relay from rockauto, the only two parts which are available yet from this store. I´m not able to make any pressure measurements, and when I remove the sensor the system will be evacuated and I have to visit the A/C mate again anyway. I try to attach a short film of the running comp to show you the issue.

Apart from that, he was wondering about the big oil amounts what has to be filled into the components: 30 ml ( 1 oz) into the condenser, 90 ( 3 oz) into the evaporator, and 105 ml (3.5 oz) into the accumulator seemed very strange to him. He uses to service Mercedes Benz cars and he told that there are way less quantities of oil into the components, particulary just the compressor needs lubrication. Also the draining of the old compressor seems strange to determine the oil amount what has to be refilled into the new one. On my old compressor, I didn´t get out one droplet of oil thou it wasn´t fretted at all. We refilled 2 oz into the new comp hoping it will work. If there´s too much of oil, the mate thought that in worst case the performance of the A/C isn´t that great, but there might not be any issues from too much oil. And the system provides deathly cold air so too much oil shouldn´t be any issue. Only issue is the crazed switching clutch.


I just checked the size of the file, ist almost 30 mb. Doesn´t work….

Did you check for refrigerant when the clutch cycles? I am having a similar issue...it holds vacuum, then I fill it, and the next day is is empty. I put florescent dye in the system, and I can not find a leak. The only place it can come out without showing up with a uv light is the evaporator core. It should come out of the drain on the firewall, but I have not seen it to date.

Hi Fred, if leakage would be the issue, the AC wouldn´t work at all at least after a longer time. But it works, since weeks. The function was never an issue, only the switching of the clutch. I will check the relay next time, maybe the pressure sensor whats located at the accumulator.

>Guys, I want to clarify what reason my issues was, with the frequently switching clutch. It was sooo easy....the pressure switch whats located at the accumulator was failed. We unplugged the connector and shorted it with a jumper, then the clutch stopped immediately with switching. I ordered a new one from RA, unfortunately we had to evacuate the system completly, replaced the sensor and refilled it. The clutch just switched once or twice and then never heard at least not aware. Works now since 2 weeks without issues. Thank god….and thanks to all you guys….!