Update on 280C Progress, question regarding air pump... (W114 M110) - PeachParts Mercedes-Benz Forum

Rahulio1989300E · #1 03-13-2010, 01:28 AM

Hello Everyone,

Back at home for the weekend, got some progress made on the 280C this fine Friday afternoon.

I decided to pull the radiator and condenser to get a better look at the engine... this car is just interesting to me, so I don't mind tearing it down a bit to explore each part and clean it properly. It seems like there is a quarter inch on gunk caked on the entire lower half of the M110!

Three odd things that I found:

1. It appears the engine fan came loose at some point and got the blades notched a bit by the pulley above the fan clutch. The blade is tight and the clutch appears healthy, so it was repaired by the previous owner.

2. Maybe a victim of the fan failure, the fan shroud appears to have been cracked, but repaired using a bracket and a couple of rivets. It is holding fine, but I may want to replace it if I can find someone with the part.

3. The vacuum/air pump was loose and had only 1 long bolt holding it in. (As opposed to 2!) There was a hose plugging into it on the back, I have since removed this pump. It looks like I will have to take the one long bolt I have and match it up at Home Depot so that I can reinstall it properly.

Other findings:
When I got the car it was missing the A/C compressor belt, I assume the compressor has seized. I am planning on extracting the entire A/C system as I don't care to put any money into bringing that part of the car back. The A/C lines had no pressure so I removed them from the compressor and found one to be lined with a rust colored dust powder... I assume the compressor is dead... but I will pull it off the car tomorrow and take a closer look.

QUESTION:
What is the function of the vacuum/air pump? I assume it does what it says? generates vacuum for the engine and the accessories? Am I to assume it is non functional since even when I got the car in its poorly running state (Solex 4A1 with warped top cover) the door locks had to be unlocked one at a time? (Does this car even have a vacuum controlled door lock system??!?

)

I will update tomorrow with more pictures and progress! Thank You!

JeffreyNMemphis · #2 03-13-2010, 08:39 AM

I just bought a 1973 280C named "Goldie Locks".

The Solex carb was warped too. I was looking for the warp because so many others have written about it here. My friend Don fixed the warp by heating and cooling the carburetor several times. It is not warped anymore. He put a carburetor kit on the car and we ran it last night for the first time. It works perfectly now. When we got the car, the carburetor was in a bucket.

I believe the door system functions on vacuum. The vacuum pump can be rebuilt if it is not working correctly.

The A/C compressor can be rebuilt also. There are two bearings that fail on this model. Currently, I have the bearings in a box for my 1962 and I am about to go on a scavenger hunt to find them. Atlanta gets hot in the summer, I can't imagine enjoying a drive with sweat pouring our of me...

Mike D · #3 03-13-2010, 08:52 AM

That's just an emissions air pump. No vacuum involved.

The aux. vacuum pump would be mounted on the right front of the engine. The plate with the 4 bolts on the cam housing wouldn't be there and a big hog nasty looking pump would be in its place. The vacuum pump was last used in the '73 line-up. My '73 M110 has it but my '74 M110 doesn't have it and I've never seen it on any year later than the '73 production models.

If your state does not require visual emissions equipment testing then you can remove it and plug all engine-exhaust connections with no change to performance.

JeffreyNMemphis · #4 03-13-2010, 09:00 AM

Mike D,

Thank you for sharing your experience. My car is a 1973 280C, so it should be vacuum actuated door locks? Rahul's 1975 will be electric with no aux vacuum pump?

wolf_walker · #5 03-13-2010, 09:25 AM

Having the vacuum pump on the motor does not indicate for sure a car has vacuum door locks. My 73 sedan does not, which I thought was odd with power windows, but hey.

Mike D · #6 03-13-2010, 11:35 AM

Best way to check for door locks? See if there are large vacuum lines going into the door in the wiring bellows. No lines? No vacuum locks. If you have lines (I believe they are "yellow") then either the diaphragms are bad or the mechanisms are just gunked up. Many times a good cleaning and light lube will restore their operation. Do yourself a favor. Go out and spend $30 on a vacuum tester (Mitey-vac makes a fine one). It'll save you a ton of time diagnosing all the vacuum operated systems on your Benz.

The '75 would be vacuum operated also. No electric locks on the W114/115 chassis I have ever seen.

JeffreyNMemphis · #7 03-13-2010, 11:40 AM

Wolf,

How do your door locks work? Are they manual or electric? Which car model is it?

wolf_walker · #8 03-13-2010, 04:26 PM

73 280 sedan, US car, just plain manual locks, no hint of ever having had vac locks. I looked all over. I thought it was odd.

mbbuff · #9 03-13-2010, 09:27 PM

My 73 280C does not have vacuum door locks. I don't know if it was even an option for the 280C in back in 73. The vacuum pump that goes on the front of the exhaust cam side of the housing (not installed on the pictures above) is strictly for the power brake booster. There is a vacuum storage tank in the back of the right front wheel well that is used for the vacuum accessories. Mine does have the vacuum seat back locks. If yours has this there will be a small vacuum button on each back seat side panel. This is used to release the front seat vacuum lock so you can get in and out of the vehicle. If the 280C above is truly a U.S. 73 model, I don't think it should have the "smog pump" that he is referring to above as the "air pump". Mine is originally a California vehicle (I am the second owner) and it does not have a smog pump. I am pretty sure that the later models did have it though. You asked about the air injection smog pump. It's purpose is solely for emissions. Don't know exactly how it works on the Benz, but in theory air from the pump would be somehow injected into the exhaust manifolds and supposedly burn any unburned fuel coming out of the combustion chambers. If you live in a smog inspection state, you'll need to repair and keep this system. It is fairly common for the fan blades to get "notched" if the water pump or fan clutch bearings starts failing. There is very little clearance between the blades and the air conditioning compressor. If you're going to remove the A/C that problem will go away. Do check the fan clutch (installed for worn bearings), and since you have the front of the engine apart, I'd just change the water pump. That way you won't have to do it again later. As you've no doubt already found out, some of that stuff is time consuming to take apart.....even more fun to put back together. It's also common for the fan shroud to break. I no longer use one since I changed everything over to thermostatically controlled electric fans. Works much better for me, but the stock setup shouldn't be a problem for you, again, since you're removing the A/C unit. Have fun working on your new toy. Keep us posted on your progress. I just (last spring/summer) went through everything on mine, replacing almost everything. Did this just because it hadn't been done in the 24 years I've owned the car. Now I shouldn't ever have to worry about anything failing (knock on wood) for as long as I have it.

wolf_walker · #10 03-14-2010, 11:15 AM

Did you use a particular brand/size of electric fan? I've been contemplating the same conversion.

mbbuff · #11 03-14-2010, 03:40 PM

Wolf, I just bought the thinnest fans I could find with the highest CFM capacity and the lowest current draw. The one in front of the radiator that replaces the tiny (and heavy) stock unit is a 16 inch unit. It is wired up so it will come on any time the A/C is on, and when the 100 C switch triggers it. The fan replacing the stock water pump driven fan is a 14 inch unit. It had to be mounted off center slightly for clearance reasons. It is controlled by an thermostat. I had a bung for the temp. sensor soldered into the radiator tank when I had it rebuilt. I have it set to about 185 F. Mac's Radiator (fortunately one of their shops is here in town): http://www.macsradiator.com/ did the radiator work and provided the thermostatic fan controller. I researched and bought the fans off the internet. Some people said it won't work because of the additional current draw required. I haven't had any problems in almost a year and if I do, I'll just put a bigger alternator on it. The way it is setup now, it works soooo much better than the stock setup, especially in stop and go traffic around town in the summertime with the A/C on. Total cost of the setup was a less than a new MB fan clutch unit, which is why I decided to try this in the first place. Here's a pix of the smaller fan and radiator temp. probe. It's kind of hard to see because of the clearance issue. Hope this helps.

wolf_walker · #12 03-14-2010, 07:33 PM

Very cool MBBUFF, thank you. How much did the radiator run if you don't mind my asking? Mine scares me, I keep hearing people say that shops cannot re-core them.

JMURiz · #13 03-15-2010, 09:56 AM

Good info MBBUFF, maybe your place should make a radiator/radiator fan kit. I'm sure lots of people here, including myself would like to replace the mechanical ones with a low-draw electric one. I think there was a thread a while back where another person on there found an electric unit that fit, maybe a truck one?

Either way, your car looks excellent!

Mike D · #14 03-15-2010, 10:05 AM

I run electric fans on my '72 250C and '73 280. I can't on my '74 280C due to changes in the body style. They have moved the radiator mount back about an inch or so and it doesn't allow enough safety clearance. Maybe with a thinner radiator?

No problem with cooling and that is here in Tucson where the summertime temperatures get a tad "warmish".

Takernz_30 · #15 03-15-2010, 10:27 AM

Quote:

Originally Posted by JeffreyNMemphis

I just bought a 1973 280C named "Goldie Locks".

The Solex carb was warped too. I was looking for the warp because so many others have written about it here. My friend Don fixed the warp by heating and cooling the carburetor several times. It is not warped anymore. He put a carburetor kit on the car and we ran it last night for the first time. It works perfectly now. When we got the car, the carburetor was in a bucket.

I believe the door system functions on vacuum. The vacuum pump can be rebuilt if it is not working correctly.

The A/C compressor can be rebuilt also. There are two bearings that fail on this model. Currently, I have the bearings in a box for my 1962 and I am about to go on a scavenger hunt to find them. Atlanta gets hot in the summer, I can't imagine enjoying a drive with sweat pouring our of me...

hello I'm asking, how did your friend Don heat the SOLEX? the carb in my 280S is also warp. Also the secondary linkage on top the carb is also free or not binding?