Pulleys used for adding A/C to W113's

[beachbear]

I've been trying to add A/C to my SL as I finish the engine rebuild. It has become a trial. Two years ago I purchased a kit from BudsBenz. This month my mechanic has attempted to install it. We didn't like the compressor bracket from Buds. I'm using a sedan bracket obtained from Classic Auto Air (CAA). The bracket is not as stiff out of the box as needed when applying tension to the belt, so we've made modifications. So the bracket works. I've installed a taller thermostat cover to compensate for the compressor position. But the pulley has us stumped. The CAA kit had a pulley included. But it didn't fit the dampner of my engine. That pulley is machined aluminum, so I shaved the collar to fit the hub of the dampner. The hub has a diameter of 4.18cm. The pulley collar that fits inside was 4.8cm. Sliding the machined pulley into the dampner revealed other problems. There was too much metal on the inside of the A/C pulley to mate with the balancer. I still had a 3mm air gap between surfaces. And removing 3mm to mate the two surfaces still results in a misalignment with the power steering pulley. So, I'm removing aluminum from from two more surfaces to mate with the dampner and come closer to the plane of the power steering pump. As this adventure unfolds the explanation escapes me. I bought a pulley from Buds thinking that CAA's pulley had the wrong dimensions. Buds stamped steel pulley has the same essential dimensions as CAA's. I'm stopped at bolting Buds pulley into my dampner because the collar is too large. The same size as CAA's. I have no other direct examples of dampness, but I'm fairly certain mine is original.  Does anyone have a clue to why I'm have to reinvent the wheel?

If your car had the factory /dealer AC, then the rubber/metal vibration dampner is also different on the sedans. If your car never had AC then the vibration dampner is correct.

[dpreston Virginia]

I am a little confused. I purchased the Buds Benz AC kit. Had it installed on my 280SL and it was very simple. No modifications just follow instructions and it works great. I did have the Pulley on my car that allowed for the AC compressor belt.
In hindsight should you if just used what Buds sent you? Or is there something different about your car?

[beachbear]

Sorry. I'll try to fill in some chronology. Two years ago, I purchased the kit from Buds. When I purchased the kit, I asked about the pulley. Their site states that W113's that never had A/C would likely need it. I asked rather after it thinking I would get knowledgable advice. Buds asked for a photo of my pulley. They never replied. The shop that was going to install it lost their lead mechanic. So, the kit sat until now. The opportunity to install the kit comes around when everything was coming to a halt over COVID19. My mechanic had questions about installing the bracket. Calls to Buds from my mechanic and me went unanswered and messages weren't returned. Wanting to keep momentum going forward, I located another kit (through Custom Auto Air) that uses a bracket we both like better and includes a pulley. The pulley from Custom doesn't fit for reasons I described earlier. Eventually, I talked to Buds, and bought a pulley. I tried to use Buds pulley, but it has the same critical dimensions as Custom Auto Air's. The major difference is the material: Buds is a Mercedes part. Custom's is machined from a block of aluminum. I am modifying the aluminum pulley. Tomorrow I'll find out if it will work.

I'd love to know why this set of parts isn't fitting though. From what I can find, the dampner is the right part. I believe Buds uses the pulley on shop installs and customers, like you DPreston, install Buds' pulley or Custom Auto Air's successfully.

Without the A/C kit in play, everything looks and works as it should. The stock pulleys line up with the water pump, alternator and P/S Pump. Everything's original. I've invested too much time, money and effort to pull it out. The issue seems like it should be solved by -some obvious, head slapping solution-. Making it work with a one off solution bugs the heck out of me. I'm still grateful for the opportunity to bounce the problem off the group though.

[ja17]

Here are two style pulley set-ups.  The one on the left is a stock W113 version with dealer/factory AC.  The one on the right is a sedan version of the era with AC which use only a single AC and belt.

[beachbear]

Thank you for the comparison, Joe. So, are you saying W113’s could be ordered with A/C, but Mercedes would send a car over with a pulley and maybe a compressor bracket to be completed at the dealer by mounting a blower, drier & compressor? I suppose the W113 A/C pulley is bolted onto the dampner/crankshaft like the sedan version. Have you ever seen that pulley listed as a part number? I’ve seen the sedan version, and the pulley I used from Classic Auto Air used the sedan’s dimensions.

[beachbear]

Also, I’ve attempted to compare the sedan and SL dampeners. By part number, those two are the same.

[ja17]

The stock W113 dampner with AC looks like the pulleys are built-in as part of the dampner. It has two grooves and does not seem to be removable from the dampner. The sedan dampner has only one groove pulley built onto the dampner. The sedan arrangement uses one alternator belt by itself first, then one wider belt for the AC by itself, and one power steering belt by itself (same belt same belt and  location on the outer-most groove as 113 version). In comparison the W113 "monster arrangement" uses two equal belts running together in two grooves for the AC compressor and water pump, the next and out-most pulley runs the power steering belt (same belt size and same location as the sedans). On this version the alternator (mounted above) is run by a single belt off of the outside groove of the water pump only.

[beachbear]

Aloha guys & gals, I wanted to follow up with a final post addressing the air conditioning installation performed last month. The installation is complete. Mysteries remain. Here is a snapshot of the installed compressor and the bracket that we used to attach it.

Notice the compressor is shorter than the typical ones I see. Also notice the tab anchoring the inner bracket to the intake manifold. This tab was not included but needed because the slightest tension from the belt was too much to keep the pulleys aligned. This is the bracket/compressor combination sold by Classic Auto Air (CCA). The design and kit came from another company, now defunct. The position of the compressor brought the original thermostat cover hose too close to other parts, so a W108 cover brought comfortable clearance.

The pulley mismatch is still a mystery. The stamped steel power steering pulley it had and the OEM part that included a pulley to drive the compressor still show a 3-4mm difference in depth for the power steering pulley and the collar diameter where the pulley fits into the vibration dampner. CCA’s pulley used the same essential dimensions as the OEM A/C pulley, but being turned from a billet of aluminum made it possible to reshape it to fit.

In finished condition, I used BudsBenz blower unit, drier and condenser and CCA’s bracket, compressor and hoses. As I’ve said already, I prefer the BudsBenz blower to the CCA’s even though neither style really fits the W113 interior. BudsBenz allowed me to cover the box to match the brown MB-Tex of my interior. The control knobs are a bit cheap so I’ll get some styled similar to the radio knobs.

Importantly, it blows cold air when I want it, and it's finished!

Oh, and the engine/injector pump rebuild is done too! I recommend Hawaii Vintage Workshop here on the Windward side of Oahu for quality vintage car service.

A Low Ha!