dissembling R4 compressor - Page 6 - PeachParts Mercedes-Benz Forum

Doktor Bert · #76 05-09-2011, 02:46 PM

First of all,

Do not be afraid of the R-4. People will try to frighten you from working on them to maintain a self-perceived level of superiority. In reality, if you follow the steps outlined in the manual and you keep things clean, anyone who can change an alternator can reseal this unit.

Hint: Any GM FSM from 1975 though 1995 will have a much easier to understand service procedure for the R-4 than the MBZ FSM, with the 1975 Pontiac FSM being one of the best, as it has photos instead of sketches, like the later FSM's do.

Don't worry about the bolt-together clutch and hub on the R-4. I have taken many of them apart. All you need to do is Loctite the bolts and bend the integral washers over.

Here are a couple of photos of the tool I made from an old R-4 compressor band.

Cut through the band with a chop saw until it pops off. Then, grind notches as shown in the photo, to clear the bolt bosses on the compressor body.

Put the band back on the junk compressor and put a large hose clamp or zip tie around it until it will just slip past the old ‘O’ rings with no resistance.

Then, weld the band back together.

Place you ‘good’ R-4 in a hydraulic press, with the front hub facing downward into a 2 pound metal coffee can.

Bend the locking tab outward on your ‘good’ compressor and place the ‘tool’ on top of it. Align the notches to clear the bolt bosses and locking tab and lay a short section of wood or metal across the top of the tool.

Press down on the tool and the band will fall off.

Replace both the large ‘O’ rings on the compressor body and coat them with the correct type of refrigerant oil that you will be using in your system.

Place the band in place and make sure it is ‘clocked’ as it was when you removed it. Place the ‘tool’ on top your ban and gently press it back into place. Bend your locking tab back into place and this operation is complete.

funola · #77 05-09-2011, 03:43 PM

Doktor Bert, Thanks for reviving this thread. He who put so much negative energy into this thread never dissuaded me one bit.

That band clamp is a brilliant idea! I have a junk R4 from which I will make one, even though I have no immediate need for it.

I have not finished the project of having working AC in my 300D. I do think I have a good R4 (the one I been working on in this thread). I pressure tested it (end of last summer) and it went up to 300 psi as I recall and I hope that is an indication that it is good. I need to install the R4 and a few hoses, flush, evacuate, test for leaks and charge.

Doktor Bert · #78 05-09-2011, 06:27 PM

There never sems to be a shortage of junk R4 compressors laying around. In my opinion, based on many years working on GM and MBZ cars with the R4, I believe the most common cause of failure are leaks that depleat the compressor's oil supply and failure of the low pressure switch to deactivate the clutch when the refrigerant level is too low.

Some of the older MBZ's used the GM A6, which has an oil sump and an oil pump for lubrication. The R4 is more like a two-stroke engine in that it is lubricated only by virtue of the oil that travels along with the refrigerant charge. I always reseal them (both body 'O' tings and a new front seal) every time I install one. I have had a few of them leak and it just isn't worth the hassle when the seals are so easy to replace, especially with the rising costs of R-12.

The front seal will come with a white plastic cone that serves as a seal protector during assembly. Again, I just remove the 4 bolt front hub and change the seal on the workbench, so there is no chance of gouging the sealing surface with a sharp instrument.

NOTE: There is a cone-shaped washer (its called a Bellville washer IIRC) under the front housing. Pay attention to which direction the cone faces on disassembly.

I once worked for a BMW/MBZ shop who threatened me for giving customers DIY advice.

The shop owner was obsessed with profiteering at any cost.

The shop owner once re-installed a USED oil filter on a customer's 5 series BMW, with the customer standing under the car with him, to keep from buying one from a local competitor, and then joked with his staff about his 'slight of hands' expertise.

This is the same shop that also sold a woman a used differential on a 325i in 2004 when the tech told the shop owner, repeatedly, that the noise was a bad axle bearing. After replacing the differential, the owner called the customer and told her that "now that the rear end is quiet, we can hear a abd axle bearing that we couldn't hear before."

She authorized the reapir and the onwer asked me to mark the differential that came out of her car 'good' so it could be sold to another, unsuspecting customer.

I fought with this fellow quite a bit over his unethical practices.

In 2003, while he was away at the coast, I was put in charge of managing the shop.

During this period, we put a new radiator, thermostat and belts in a chiropractor's 750iL. At that time, we bought our parts from IMC and SSF. We got a Continetal belt that was marked incorrectly and the technician didn't catch it. It allowed the tensioner to travel past center. The car threw the belt a few miles from the shop, destroying the fan and radiator in the process. The customer called understandably upset.

I arranged for a tow truck to pick up the car, gave them a loaner 540i off the lot and ordered replacement parts.

I repaired the car at no charge, that included the towing fees, all the parts and the labor. The customer was quite pleased.

When the owner returned, he chastised me for wasting so much of the shop's money on the reapirs. He felt as though we could "blame the failure on something else and made money fixing it."

I protested citing that ethical business practices dictated otherwise.

I was 'laid off for lack of work' a few days later...Robert

vstech · #79 05-10-2011, 11:39 AM

Woof!
that kind of shop, while certainly profitable, really gets the rest of the industry a bad name.
my old shop boss was almost exact opposite.
price covered parts and markup, and exact amount of labor required for job.
all parts marked as removed, and given to the customer. ANYTHING done wrong by one of the techs (never me of course) was handled by a DIFFERENT tech, and remedied at no cost to the customer.
and ONLY the parts quoted are charged to the customer. never a charge for wd-40/loctite/or any cleaning materials... sandpaper/crocus cloth/scotchbrite etc...
I always tried to get him to put that stuff on the bill, but nope. only parts and labor.
he was a great boss. I miss him.

Quote:

Originally Posted by Doktor Bert

There never sems to be a shortage of junk R4 compressors laying around. In my opinion, based on many years working on GM and MBZ cars with the R4, I believe the most common cause of failure are leaks that depleat the compressor's oil supply and failure of the low pressure switch to deactivate the clutch when the refrigerant level is too low.

Some of the older MBZ's used the GM A6, which has an oil sump and an oil pump for lubrication. The R4 is more like a two-stroke engine in that it is lubricated only by virtue of the oil that travels along with the refrigerant charge. I always reseal them (both body 'O' tings and a new front seal) every time I install one. I have had a few of them leak and it just isn't worth the hassle when the seals are so easy to replace, especially with the rising costs of R-12.

The front seal will come with a white plastic cone that serves as a seal protector during assembly. Again, I just remove the 4 bolt front hub and change the seal on the workbench, so there is no chance of gouging the sealing surface with a sharp instrument.

NOTE: There is a cone-shaped washer (its called a Bellville washer IIRC) under the front housing. Pay attention to which direction the cone faces on disassembly.

I once worked for a BMW/MBZ shop who threatened me for giving customers DIY advice.

The shop owner was obsessed with profiteering at any cost.

The shop owner once re-installed a USED oil filter on a customer's 5 series BMW, with the customer standing under the car with him, to keep from buying one from a local competitor, and then joked with his staff about his 'slight of hands' expertise.

This is the same shop that also sold a woman a used differential on a 325i in 2004 when the tech told the shop owner, repeatedly, that the noise was a bad axle bearing. After replacing the differential, the owner called the customer and told her that "now that the rear end is quiet, we can hear a abd axle bearing that we couldn't hear before."

She authorized the reapir and the onwer asked me to mark the differential that came out of her car 'good' so it could be sold to another, unsuspecting customer.

I fought with this fellow quite a bit over his unethical practices.

In 2003, while he was away at the coast, I was put in charge of managing the shop.

During this period, we put a new radiator, thermostat and belts in a chiropractor's 750iL. At that time, we bought our parts from IMC and SSF. We got a Continetal belt that was marked incorrectly and the technician didn't catch it. It allowed the tensioner to travel past center. The car threw the belt a few miles from the shop, destroying the fan and radiator in the process. The customer called understandably upset.

I arranged for a tow truck to pick up the car, gave them a loaner 540i off the lot and ordered replacement parts.

I repaired the car at no charge, that included the towing fees, all the parts and the labor. The customer was quite pleased.

When the owner returned, he chastised me for wasting so much of the shop's money on the reapirs. He felt as though we could "blame the failure on something else and made money fixing it."

I protested citing that ethical business practices dictated otherwise.

I was 'laid off for lack of work' a few days later...Robert

Doktor Bert · #80 05-10-2011, 12:56 PM

And that shop has expanded, moved to a larger location and is thriving. Corruption and dishonesty at its finest, all cleverly disguised.

If this shop were in a larger metropolitan area, it simply wouldn't make it. It has survived (and prospered) because it has no real competition.

Customers used to tell me they didn't like the owner's condescending attitude and business practice, but they didn’t have any real options in town.

libbybapa · #81 09-12-2011, 09:30 PM

Quote:

Originally Posted by funola

This is the first R4 clutch that I tried to pull with the wrong puller. Instead of using the puller to the left of the red box to pull the clutch plate, I used the puller below the red box to pull the entire clutch assembly. I said it didn't budge but I was wrong. See the 2 circular items in the center? There should only be one (a snap ring). The other circular item is the broken collar where the snap ring fits into. No big deal since this compressor is no good (no pressure or suction) to start with and is perfect to practice disassembly on. This is the one I will disassemble to look inside, not trying to rebuild it.

The puller for the clutch plate is Autozone 27002, it is not listed on their AC loaner tools (the ones listed 27005 and 27007 do not fit the R4). I'll post more pics later

edit: want to add that the Autozone puller 27002 is not the best quality. The compressor center bolt is pointy, so is the puller bolt. After use, the puller bolt mushroomed put! Either it is not properly hardened or not hardened in the first place.

I just pulled the compressor clutch with the compressor still in the car and figured I'd post some info I would have found useful.

The loaner tools I borrowed from Autozone were the 27002 to pull the outer hub, the 27001 puller that is pictured above ***and 27008*** which are the extended jaws that allow the 27001 puller to reach around the compressor. Apparently they have changed the 27001 kit and it now only contains the short black jaws that are in the puller case in the picture above and not the longer silver jaws that are shown installed on the puller and are needed to do the job. I would also whine here a little that it took THREE trips to Autozone and my own independent research online before I was able to get someone at Autozone to loan me the correct 27008 jaws... Even a manager said they didn't exist and yet in the end they found that they had three sets in stock.

I'm working on an '82 300TD and found that I had the necessary access to the clutch by pulling the three compressor mounting bolts, loosening the clamp on the A/C hose that goes UP, and loosening the bracket that holds the oil cooler metal lines in place. I was then able to angle the compressor down to gain the clearance needed.

Yak · #82 09-12-2011, 10:56 PM

I think O'Reilly's also has a deluxe clutch puller kit. IIRC, there may have been a specific unique tool in the O'Reilly kit needed to properly set the clutch gap on re-install. I may be mixing up repairs, though.

libbybapa · #83 09-13-2011, 12:32 AM

I checked out the O'reilly loaner tools. They did have a "Deluxe A/C Clutch Kit", but it didn't seem to have a puller that would work for removing the pulley. It seemed like it only had tools to remove the clutch plate.

Yak · #84 09-13-2011, 07:13 PM

Quote:

Originally Posted by libbybapa

I checked out the O'reilly loaner tools. They did have a "Deluxe A/C Clutch Kit", but it didn't seem to have a puller that would work for removing the pulley. It seemed like it only had tools to remove the clutch plate.

That may be correct. When I was looking at mine, I couldn't find a single source or kit that had what I needed. When re-installing the clutch plate you're supposed to set the gap. It needs a tool that tightens down onto the threaded central shaft in order to pull the plate the right depth (or distance, I guess, depending on perspective).

I don't recall exactly if that too was in the kit, maybe it was one of those reversible thingamajigs.

whunter · #85 09-13-2011, 09:08 PM

Quote:

Originally Posted by Yak

That may be correct. When I was looking at mine, I couldn't find a single source or kit that had what I needed. When re-installing the clutch plate you're supposed to set the gap. It needs a tool that tightens down onto the threaded central shaft in order to pull the plate the right depth (or distance, I guess, depending on perspective).

I don't recall exactly if that too was in the kit, maybe it was one of those reversible thingamajigs.

R4 compressor:Clutch AIR gap measurement
R4 compressor:Clutch AIR gap measurement

.

my123ca · #86 09-30-2012, 07:44 PM

Quote:

Originally Posted by funola

If the orientation of the hole is wrong, you can re-orient it by removing the 4 bolts and pulling the cover. I used a 3/8 breaker bar to tap it off but there must be a special puller for it.

Has anyone done this yet on a new compressor? Is it necessary for longer compressor life? I have a NOS delphi R4 which when mounted, the X mark will be on the bottom.

Doktor Bert · #87 10-02-2012, 11:16 PM

I has to do with proper oiling and the position of the compressor on the engine. The GM manual shows the proper orientation...

my123ca · #88 10-05-2012, 12:50 PM

How hard is it to pull the cover? Do you need a special puller or does it come off after removing the 4 bolts?

funola · #89 09-23-2015, 10:15 PM

Quote:

Originally Posted by my123ca

How hard is it to pull the cover? Do you need a special puller or does it come off after removing the 4 bolts?

Sorry I'm 3 years late lol. Just dug up this old thread to get p/n's of the pullers in case I need to adjust pull the smoking clutch on my 85 300D. Turns out I didn't need to, just clean the grease off.

In anticipation of more serious work that may arise, I just found this exc video on resealing an R4. https://www.youtube.com/watch?v=vImsu-D_Qnk

An important message from the video is: If you have an old OE R4 that leaks due to old seals but otherwise ok, you are better off re-sealing it instead of buying a new one that is of lesser quality than the old R4's.

funola · #90 09-26-2015, 07:14 PM

Quote:

Originally Posted by Doktor Bert

First of all,

Do not be afraid of the R-4. People will try to frighten you from working on them to maintain a self-perceived level of superiority. In reality, if you follow the steps outlined in the manual and you keep things clean, anyone who can change an alternator can reseal this unit.

Hint: Any GM FSM from 1975 though 1995 will have a much easier to understand service procedure for the R-4 than the MBZ FSM, with the 1975 Pontiac FSM being one of the best, as it has photos instead of sketches, like the later FSM's do.

Don't worry about the bolt-together clutch and hub on the R-4. I have taken many of them apart. All you need to do is Loctite the bolts and bend the integral washers over.

Here are a couple of photos of the tool I made from an old R-4 compressor band.

Cut through the band with a chop saw until it pops off. Then, grind notches as shown in the photo, to clear the bolt bosses on the compressor body.

Put the band back on the junk compressor and put a large hose clamp or zip tie around it until it will just slip past the old ‘O’ rings with no resistance.

Then, weld the band back together.

Place you ‘good’ R-4 in a hydraulic press, with the front hub facing downward into a 2 pound metal coffee can.

Bend the locking tab outward on your ‘good’ compressor and place the ‘tool’ on top of it. Align the notches to clear the bolt bosses and locking tab and lay a short section of wood or metal across the top of the tool.

Press down on the tool and the band will fall off.

Replace both the large ‘O’ rings on the compressor body and coat them with the correct type of refrigerant oil that you will be using in your system.

Place the band in place and make sure it is ‘clocked’ as it was when you removed it. Place the ‘tool’ on top your ban and gently press it back into place. Bend your locking tab back into place and this operation is complete.

I never got around to making your tool until today. Since I do not have a press or a welding setup handy, I improvised and used some of your ideas and some from this video https://www.youtube.com/watch?v=vImsu-D_Qnk

Went over my collection of AC parts and found 2 GM Delco R4's (with the bolted together clutch). One of the Delco R4 is broken ( I broke the bearing hub by pulling it w/o removing the circlip). The other Delco I swapped in a good clutch , new front seal and bearing. I also have a new-ish looking Delphi R4 (with non bolted clutch) which has a nice smooth spinning bearing and good suction when I turn it so I think it is a good spare.

I took the broken R4, slit the band with a Sawzall, made the 2 cutouts with a grinder. The biggest hose clamp in my collection (to adjust the the diameter of the slit band) was just a hair too small so I used 3 zip ties for the test and it worked fine. I wanted to use a 1/8" aluminum plate for the puller but didn't have any. Looked for a piece of 3/4" ply wood, didn't have that either but found a piece of 3/4" pine board which worked fine. The puller bolts were used head bolts from a 1.6 VW engine which was perfect for the job. Now I have the tool to do the case re-seal if I ever need to.