Fuel Filter Replacement R107
 

Hi--

I'm going to be replacing the external cannister fuel filter in my 1981 380SL.

Is there anything that I should know before I start? For example:
Will I get a gush of fuel when I break open the lines? If so, how much?

I presently have a full tank of gas. Should I run it down first, or is OK to replace the filter with a full tank?

Any other tips or warnings?

Thanks in advance for your help.

Joe

Yes you will get a gush of fuel. First you will get a high pressure gush as the accumulator discharges. Followed by the tank just draining. Best to use hose pinch pliers.

John Roncallo

I just did a filter AND a fuel pump. If you are planning on doing it on the ground laying under the car let me make a few suggestions: Get a old large towel...do not attemp this where other people are smoking or will complain about the enviroment; you will lose some gas. Before you attemp to undo any lines, make sure that you are able to remove the support bracket from the undercarriage. Sometimes the screw that loosens this bracket (So you can slide the canister out) is rusted or hard to hold in the rear (There is a phillips head on one side-then it is secures by a bolt that if corroded will turn over and over while you think you are unloosing it. As previously mentioned, get clamps to clamp the fuel line. Mine gushed gas all over me, and the driveway...Oh, Be SURE to disconnect your negative battery ground - just in case ...after you remove that old cannister make sure you remember the right way it goes and slide in the new one. Attach all your hoses tight, remount the unit and then go wash up and the car will start in less that 10 seconds...if you have success, after driving the car go and look anderneath it to make sure there isnt any leaks. I did the first day, and on the second day it was leacking so it got fixed pronto. Good luck! FYI wear an old baseball hat if you are laying on the ground it helps! :0)

Since this is such a fresh topic, would you mind looking at a post I just made about what should be replaced while I'm in the fuel filter/fuel pump area? See http://www.peachparts.com/shopforum/tech-help/213275-560-fuel-pump-filter-reseal.html

Thanks.

fuel filter replacement
 

Dont forget to get new copper washers for fittings when replacing filter. I used old ones, but now that I am aware they need replacement to insure proper sealing. good luck Abe G

If you buy an MB filter...you get the new washers.

I just checked the Mercedes filter I recently bought and it doesn't have any copper washers with it.

I guess my MB parts guy likes me more then your parts guy likes you.
Try the gift of wine at Christmas. It has saved me $$ and he takes care of the little things...like washers.

* Here's a quick comment about safety.
* If you need additional light under the car when you're changing that fuel filter, USE A FLASHLIGHT! One of those little 2-AAA Mini-Mag lights betwen your teeth leaves your hand free and puts the light right where you need it. Do not use a standard incandescent-bulb drop light. You've probably seen what happens to a hot light bulb when it gets a few drops of cold water on it. Imagine that the cold drops are gasoline. And that it's right next to your face. Not only will you have the mother of all fires, you will be toast, literally.

So I will be doing this on my back laying on my garage floor. I expect to get some gas spill, but are there any tips for limiting the amount that will spill? My plan right now is to not only replace the filter but to replace all the copper seals and old rubber hoses on the pumps and the filter. I have heard the suggestion to use fuel line clamps and/or vise grips over some wood. Do I need to relieve some pressure in the system first? How much fuel can I expect to spill on a good day?

Thanks.

* You know by now that you need to crimp the hose (outlet) from the tank which feeds into the fuel pump. If you're planning to replace this hose too, then just take the hose off the pump and drain the tank into a clean pan. If it's an option, it helps if you wait until the tank is nearly empty before doing the job.
* Since you plan to replace more than just a filter, it might be easier to remove the carrier that holds everything in the car, and then do the job on the bench. Rubber buffers (mounts) w/ 5mm nuts hold the carrier in the car. It can save time to have a reference picture (or a quick photo or two) of the whole assembly, on the bench, before you take it apart.
* All the hardware is available at most Lowes. I like to replace the 5mm philips machine screws with 5mm hex bolts (same thread pitch). Will make subsequent filter replacement easier.
* You probably know that you'll need to counterhold all couplings; i.e., use one wrench to hold, and another wrench to tighten. What you're planning to do isn't particularly complicated, yet there are a variety of ways to break things or leave leaks.

Len, you can get a proper hose crimp for the main hose or get by with the vise grip / wood method. I installed a ball valve in the hose after disconnecting it so that I could drain my tank directly into 5 gallon cans at my leisure. NO spillage at all.

fuel filter replacemant
 

IRF depressurization. Loosen/remove your gas cap to depressurize the fuel tank.

Thanks guys. I think I'm leaning to doing the method Robert suggests, i.e. run the tank to near empty and then just drain it all, move the whole unit to the work bench and do things standing up rather than on my back. And if I'm going to go to all that trouble, I may as well replace all the rubber hoses I can get to. After 20 years, they ought to be about due.

no need - a socket extension worked for me pretty good