6.3

120+ psi works. I installed a shrader valve on the braided line from pump to the check valve. Way easier. If it’s going to be a long time you can always install shrader valves on the air tanks. It takes three.

jim

I did not want to clutter the board so posting my question here. My car has been parked in air lock mode for around 7 - 8 months as I have been working on the engine. I have noticed that, with my moving on and off the engine compartment, the car has lowered by about an inch. Considering I can not start the motor, how much air pressure do I need to put into the air tank to be able to raise the car back up again?

There cars and then there are BABIES!
1969 Euro Model
10901812000931

This is a great guide. Currently rebuilding a pump.

The bearing is not included in the kit. it was a FAG 6303A, but that is not available so a 6303 c3 is what you will find. I used a hot air gun and heated the bearing to @275 degrees F and it easily slipped onto the shaft. I had to remove the key from the shaft to get the bearing and seal on and then put it back in after the front cover was on.

I used a properly sized metal hose clamp to compress the piston rings while I pushed the head over the piston. I found trying to push the rings in by hand impossible to do.




rumb
68 250S, 77 450SEL 6.9, 91 300SE, 98 SL500, 14 CLS550

It's just an old fashioned air compressor with a hydraulic pump screwed on to it. The real complexity, as we all know, are all the components "south" of the compressor. We are fortunate to have Martin, who's remanufactured components are arguably better than the OEM's.

300SEL 6.3
E55 AMG
CLK63 AMG Gone
Ferrari 400GTC4
ML400CDI BiTurbo
ML350 CDI BT
9146GT

Thanks I will check mine when I get a change. I will also need to have my crankshaft repaired it is badly worn.

Here is another aspect to consider.
Testing the check valves

I have renovated various compressors. In my humble experience the tightness of the compressor determines the power of the compression and suction. This means if the check valves are not closing properly even the best renovated compressor is not pumping well.
New check valves sometimes are not tight enough and I developed my own testing protocol. I have not experienced how slightly leaking new check valves are improving or not over time. Whenever I renovate these compressors I am testing and work as long as it takes to have the valves working properly.
The tightness of the piston rings/cylinder is important too but the check valves come first.

Martin

I just read through the compressor repair. Nice. What I am missing is the bronze bushings that potentially need to be exchanged if worn.
This is for a higher mileage compressor or one that had problems with lubrication.
I have seem some of the compressors in not that great shape as the one here. Some have 2/10mm play in the bronze bushings.
Knorr was using 2 types of bushings.. High leaded Bronze (15% Pb) for the softer Crankshaft bushings and 'Rotguss'for the hard piston pin in the piston rod. These bronze bushings are not part of the MB kit.
These bushings need to be machined with 2/100 play for the rotating shaft and press seat for the seat itself (2/100).
Typically the cylinder requires some honing and piston with new rings for a higher mileage compressor.
Martin

Thanks. I Will maybe find some thing at my dealership or maybe aftermarket. And thanks again for the advice [:)] I appreciate

Pétur

Petur, earlier in the thread mention is made of the "double lipped seal." I may have bought the last one available from Tom Hanson at the Classic Center recently. Seems these are only used on the W109 cars with the two pumps linked. Perhaps Tom was successful in having a new batch produced. Good Luck.

Jack English
300SEL 6.3 #4768

Thanks for the quick answer I appreciated, I will find some experts here in Iceland to take a look at it for me thanks again.
Pétur

If you know anyone in Iceland who is good with motor bikes or works on engines in general, show them the crank shaft for advice. There is nothing fancy regarding this small "engine" as far as the crank is concerned. It would depend on whether the wear is through the hardening and the availability of undersize bearings if the bearing surfaces are not beyond repair. If the crank is beyond repair, then you would need to buy a second hand pump or check with the Classic Center if they can still supply a new pump and at what price. They were still available new in the 1990's but I have not enquired since.
Art

Used pumps are around. Do be careful with pulley on yours as been probably said three times already on this thread, but it bears repeating as a used pump may or may not have a good one.

Also, anybody shipping a pump should ensure that it is packed immobilized and such that if dropped, the pulley won't suffer a catastrophic shock and crack. A few cm of styrofoam packing is a good thing.

-CTH

Hi i have a 1970 300SEL 6.3 and I have taken the compressor out and apart and the crank is very worn because of the blocked lubrication lines, is there any thing I can do to repair it.
Regards Pétur

The pumps are different. 100 460 03 80 for the 600 and 189 460 06 80 for the 6.3. Without going down into the garage and lifting bonnets, I don't know what the external differences are, but I would not be surprised if the 600 pump were bigger and worked at a higher pressure. I don't have a part number for the 600 radial seal.
Art

The size was for the 6.3 pump - could the 600 one be a different pump ?.

Can anyone confirm these measurements are correct. I measured the seal on my 600 p/s pump and it seemed more like 36/26/7. Are there a range of pump sizes, could the previous post relate to a smaller pump ? The part doesn't seem to be listed as a stand alone item on EPC so if anyone had a part no. that would be great (if it exists)

Gar

Yes - the PS has a 22x35x7 seal

Thanks Paul.
I can see how it works in principle, but not in detail. Justin is not planning to pull one apart in the near future, so I'll have to remain ignorant for the time being. That set of O rings you listed does not seem to include the radial seal. I presume it is in addition to the O rings you list.
Art

Art

Your in luck - i remembered to take a picture of the PS pump when i overhauled it.





Hope this helps show how it works

I was talking to Justin yesterday about these air compressors. He has exactly the same thing on his trucks, just bigger. He showed me one disassembled from one of his trucks. He said the main problem with these air cooled pumps is that the bore and the piston become oval with time. He said that once they begin to pump oil, repairing them using the existing piston, even with new rings, results in only a short term fix before they start pumping oil again. He said that even though he measured the truck piston and bore and they were OK, his repair with new rings was short lived. His enquiries with his local expert revealed that the metal distorts as the pump gets hot and things become oval. Only solutions if that is the case are to buy a new pump or to bore the cylinder and put in an oversize piston. As these pumps are NLA new, once these is a lot of blow by, seems a rebore and replacement piston and rings will be the only answer.

So grab every one of these pumps from wrecks before they are crushed. I do not know if Knorr are able to supply oversize pistons or whether we will be forced to look elsewhere. I just post this for general advice. Overall, these little pumps are very durable with most still doing an adequate job after 40 years.
Art