Help! How do I get the vacuum pump out! - PeachParts Mercedes-Benz Forum

matthewdear · #1 10-12-2012, 07:43 PM

So I couldn't get to all the flat head screws on the pump to replace the diaphragm, so I figured I'd just remove the whole pump. Got all the screws out (just six, yay) but can't get the darn pump out of the car! Do I need to remove a belt or the fan shroud? The fan shroud is held back by the fan blades, and I am just stumped. It is almost 7 on friday, I have to be back to work by monday 7 am. Hoping you all can give me a tip on how to make it by then. I did play with the idea of just turning the pump to get at all the flat head screws, would be a pita but would work. I did get a glimpse of the bearings and race and the part seems intact so I'm getting excited to complete this and have a better working car. Tomorrow I get a new vacuum control valve, and that job seems to have loads more room to work.
Please, anyone, have you had this problem and how did you solve it? If I need to remove a fan belt, how do I go about doing that? This is for a '80 240d if that helps.

Stevo · #2 10-12-2012, 08:59 PM

Remove the power steering belt, then you should have room. Be careful when undoing the bottom allen, its easy to strip out.

vstech · #3 10-12-2012, 10:12 PM

the power steering belt is held in position by three 13mm bolts that pass from the rear of the pump to the front of the mount. nuts are in front, bolts are in rear, hold front nuts with an open end wrench, and get a 6" 3/8-drive extension with either a universal jointed 13mm socket, or a universal joint on the end of the extension and the socket. be careful around the fuel lines with the ratchet, ya don't wanna break it.
after you get all three bolts loose, there is a bolt head that is on the flat face of the pump mount right between the two hose connections. that is the adjuster bolt, and you loosen that until you have clearance to remove the belt. a 13mm gearwrench is best for this task, but it can be done with the socket/universal... it's just tight between the lines, and as the pump is loosened, the hoses move into/out of your way...

I don't recommend removing engine parts on a dirty engine, I would STRONGLY recommend cleaning it before beginning work, but in your case, I'd at least stuff a clean rag in the timing area, and scrape the goo off the engine, and clean around the pump opening well, remember to take the rag out before you put the vacuum pump back.

JustPassinThru · #4 10-13-2012, 01:23 AM

(Edited: this advice is based on experience with my 300D, YMMV)

Alternatively, undo the cooling fan (four 10 mm screws) from the water pump pulley (crank the engine over to get the screws up into position where you can get at them), pry off the two clips which hold the shroud to the radiator, and if careful you can get the cooling fan and shroud out without having to disconnect the top radiator hose. With the fan and shroud out, I found I had enough room to get at the Allen bolts which hold the pump on, and it is possible to wiggle the pump out through the PS belt without loosening it. A couple of the Allen bolts were on sufficiently tight that I had to use vise-grips on the bolt-head, and then vise-grips-on-the-vise-grips, to break them loose. There is a T-handle 5-mm ball-head Allen key, commonly used in bicycle shops, which I found to be highly useful in getting the Allen bolts off and on.

Those four cooling fan screws can be tough though. I suggest you break them loose with 6" needlenose vise-grips, before putting a 10 mm open-end wrench on them. Otherwise, unless you have a very high-quality open-end/box-end wrench such as a Thorsens, there is a high probability of rounding them. You need to pry the cooling fan forward a little, to get it off its shaft. A knife blade between the fan's flange (through which the screws go) and the pulley, works, but be careful not to puncture the radiator. Spray a little Liquid Wrench or WD-40 in between the flange and the pulley first, to lubricate the shaft.

Completely agree with the advice, to first use Gunk Engine Brite and then hose off, or else use a pressure washer, to clean the grease off the area around the vacuum pump first. Just don't let water remain very long on the water pump body, it will rust. Blow it off with a leaf blower.

Don't forget, when you reinstall the vacuum pump it takes a gasket. The overhaul kit which MB dealers sell, does not include the gasket, you must buy it separately. I put a thin, even coat of Permatex Hylomar on both sides of the gasket before reinstalling my vacuum pump in April, 2011, and used fresh high-strength Allen bolts from Tacoma Screw, and it has sealed perfectly ever since. But these bolts have rusted. Next time I'll use stainless.

The pump cover's original flathead screws are of poor quality, easily deformed by even a good screwdriver, so I suggest you replace these with stainless as well. I replaced mine with 5 mm high-strength Allen bolts, so next time the same tool works on all the bolts.

If the 240D's pump cover, like the 300D's, has its own gasket, I suggest you do like I did, use toothpicks to seal it with Permatex Hylomar too. You don't need to wait for Hylomar to dry, it's ready instantly, stays flexible, doesn't creep. Really good stuff. Originally developed by Rolls-Royce. My own pump, after I overhauled it, delivered (and still delivers) one full inch of Hg better vacuum than the FSM spec.

Doktor Bert · #5 10-13-2012, 09:43 AM

Quote:

Originally Posted by vstech

I don't recommend removing engine parts on a dirty engine, I would STRONGLY recommend cleaning it before beginning work, but in your case, I'd at least stuff a clean rag in the timing area, and scrape the goo off the engine, and clean around the pump opening well, remember to take the rag out before you put the vacuum pump back.

Good advice. I have seen washers and the like laying about on the engine which can easily fall into the mechanical abyss and spoil the pudding....

cho · #6 10-13-2012, 12:08 PM

Quote:

Originally Posted by JustPassinThru

Next time I'll use stainless.

stainless and aluminum body of the pump are not so great friends
zinc coated might be better solution ...

.

matthewdear · #7 10-13-2012, 12:20 PM

thanks for all the advice!! I tried the steering belt pump, couldn't get two screw's out, so ended up just taking the fan shroud and radiator out. Shoulda done that from the getgo, as I had to spend an hour just getting the pump back on. Five of the six screws went back on fine, but that pesky one down below is a royal pita. Still tryin to get that one in, but glad that I am now able to get to all eight of the flat head screws out front. Mine did have a gasket (the pump), that I cleaned off and applied a tiny bead of gasket gunk to the outer edges of the pump, in case the pump doesn't seat perfectly again. I will have to order that gasket and put it on another day. Well, out to get that last allen head screw in the pump, and then for the replacing of the diaphragm. It's rainy and cold out, so I have a tarp up over the hood. Makes for hard work, but 3 flash lights have been helpful. So would a garage, eh?

matthewdear · #8 10-13-2012, 01:45 PM

OH! how do I know that diaphragm is at it's further push, that is, do I turn the powersteering belt bolt to move the crankshaft? I was told elsewhere to make sure when I reinstall the diaphragm that (it sounds like) the bolt part is pushed out (further away from the car) the farthest it can go. When I took out the diaphragm it was fairly flat, that is, not sucked in looking or pushed out looking. Thanks,
Matthew

petecooke · #9 11-15-2012, 11:03 AM

Clean the heads of the allen bolts and scrape out any grease/dirt so the allen wrench seats all the way into the heads.

Loosening the power steering belt is probably a good idea if you can't get your allen wrench in properly. I used a 5mm allen wrench socket with an extension on my 3/8 socket wrench.
Make sure it is seated all the way and the tool is straight.

I stripped the bottom bolts on 2 different cars. I have now learned my lesson. I was not a happy camper.

I had to pull the ac compressor on both cars to get vice grips on the round bolts heads.

pete