Disconnecting Fuel Bleed Valve

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devontas
Posts: 2
Joined: Sun 29 Jan, 2017 5:34 pm
Model you own: I own multiple different models

Disconnecting Fuel Bleed Valve

Post by devontas » Sun 29 Jan, 2017 7:05 pm

Newbie question on how to disconnect an ML270 W164 fuel bleed valve plunger.

First, I had a problem with the glow plug light not going out after the engine started. Some months later, the car would start at first crank and a few seconds later it would cut out, and 20 seconds or so of cranking before it would start up.

The local repair places told me horror stories of glow plugs breaking off and that it could be very expensive. I bit the bullet, bought new plugs and a new fuel relay, and decided to do it myself! I took my time with RP7 and carefully loosening the offending plugs (which I found from testing the resistances at the fuel relay plug). I cleant the plug holes and fitted the new plugs. The glow light went off at the second start but the engine still took a long time to start up.

This time I figured the fuel line o-ring seals had gone. The ones on the low pressure fuel pump were brittle. I replaced those along with the one on the fuel filter and the one at the back of the fuel rail. The car started much better – still not perfect. I figured that the offending seal was on the “plunger” out of that T-piece with the white cap on the top and front of the engine – see picture https://i.ytimg.com/vi/Rz1KVf1IfTQ/maxresdefault.jpg. It looks like the white cap must be screwed to the left (or right) to release the plunger? I tried pushing, pulling and twisting the cap but was too afraid to use a lot of force. Please, tell me how this contraption works! And, whether or not it takes the same seal as the fuel lines. After pushing the plunger in a bit, there appears to be no more air leak and the engine starts just fine first crank! So, I’m keen to finish off the job properly and replace the seal. Much appreciate any help you can give on how to get the plunger out without damage!

Cheers

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devontas
Posts: 2
Joined: Sun 29 Jan, 2017 5:34 pm
Model you own: I own multiple different models

Re: Disconnecting Fuel Bleed Valve

Post by devontas » Sat 08 Jul, 2017 2:29 pm

Ok, managed to figure out how to pull the plunger out from the fuel bleed valve! Hold the outer white/gray sleeve whilst pulling on the plunger. Pull it straight and twist a bit if necessary. If you peer into the hole you’ll see the shiny ball which acts as a one-way valve. And, if you look closely on top of the barrel you’ll see a small hole which is for the expulsion of air/fuel. There is an o-ring in there but it’s harder to get at than the fuel pipe o-rings. For reference, the part number of the bleed valve body is 6110780349 (visible on top of the body), and I think it’s the same part as on the Jeep 2.7 CRD engines. Putting the plunger back is simply a matter of pushing it back in!

So, the next time you need to bleed the fuel system, operate the plunger and it will draw the fuel up through the one-way valve action. No need to labour the engine, fuel pump and battery cranking away for 20 seconds or more! Seems so easy and obvious now! But hey, live and learn.

Cheers

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