Looking to buy System Pressure Regulator for 107

[DAVID LEE]

I have a 78 350 Euro SL and it has the mechanical "system pressure regulator" in the fuel distributor. I have determined that it is leaking pressure down to 0 when the engine is shut off and would like to purchase a new one, but can't seem to find one anywhere.

Does anyone know where these can be purchased, or have some tips on how to "repair". I've changed the o-rings but that hasn't seemed to help.

I would even consider buying a used one from someone if one could be found.

thanks for anyone's help.

[DAVID LEE]

This morning I tried a different size o-ring on the control piston, and the leakage seems to have been resolved. Oddly enough, I used a smaller o-ring.

I love it when you can go to Lowes and for 1.50 fix a problem that would have cost $450 for a fuel distributor rebuild.

Now, I hope this is going to be a somewhat long lasting solution.

[DAVID LEE]

This past week I found a place out in California that had a used System Pressure Regulator and sold it to me for a somewhat reasonable price. My intention is to determine the size of the o-rings and then to take the thing apart and determine what keeps the WUR return fuel from draining back through the regulator and subsequently into the fuel return line when the "schrader like" valve is supposed to be shut off (the engine is shut off). If it is only a "close tolerance" fit then I can see why the entire system won't hold pressure for an extended period of time. There is an o-ring on the "Control Piston" that keeps fuel from leaking back into the fuel return line once the engine is shut off, but I'm not sure about the WUR return line circuit.

This is on older style Fuel Distributors that does not have a "Compensating Valve" and newer style WURs that does not have a "Shut Off Valve". I believe this combo was in production from 72-74, but apparently was held over for a few years on the Euro model. But who knows what the prior owner did to the car - so perhaps the parts combo on my car is not what came from the factory. There is a company that has seemed to solve this problem using an electronic solution. They have attached a relay to the Fuel Pump shut off circuit and put this realy in series with the WUR return fuel line so that unless the Fuel Pump is energized, the return fuel line from the WUR is shut off. The purchase of their product (99.00) may be my eventual solution, but I enjoy figuring out how things work (sometimes breaking things in the process), so I'm gong to do some exploring before purchasing. Who knows, I may come up with another solution.

Anyway, I'll continue to post as I pursue solutions.

Regards

[ctaylor738]

You can get a "Regulator Repair Kit" from Mercedes. I believe that the part number is A000 584 19 07. You can also get a "Piston Parts Kit," A000 070 08 18.

[DAVID LEE]

Thanks, I will give that a try. When I called the dealer last week about getting the pressure regulator, they said the part was no longer available. I'm surmising that had I known to ask for a kit that perhaps they would have been able to locate the part accordingly. It's always a crap shoot when I call the dealer as to whether they will understand anything about what I'm talking about.

About 2 years ago, they got rid of anyone that knew anything about MBs in the parts dept. and replaced them all with "guys looking for a job of any kind".

Oh well - I guess they need to make a profit.

[ctaylor738]

If you have an older or euro car, the only way to do this is to get a free EPC subscription and find the PN yourself. At least at my dealer, the parts guys have to go to the paper books for older cars like my 230SL, I don't think they have easy access to the euro models. But if you give them a PN, they can key it in and tell you price and availability.

Go here: https://epc.startekinfo.com/epc/home.jsp to sign up.