Primer pump....help - PeachParts Mercedes-Benz Forum

bravohotel · #1 03-15-2006, 08:37 PM

Guys,

I need to change my fuel filters, but I want to know how to use the primer pump first. From reading other posts (and seeing pics) I'm pretty sure that I have the "old" style pump...but I can't figure out how to use it. Do I turn the white knob?...I have tried but it doesn't seem to want to move...

Help me,
Thanks

Brian

Jimmy Joe · #2 03-15-2006, 08:44 PM

Turn the white handle counter-clockwise till it is all the way unscrewed, several turns. Pump many times, push all the way down, then screw back till tight, b4 starting car.

Jimmy Joe · #3 03-15-2006, 08:45 PM

They are often real tight when they have not been moved in awhile. Mine pees fuel all over the place when I pump, they make a better newer version you do not turn, just pump. Been playing with mine all day....

bravohotel · #4 03-16-2006, 12:44 AM

JJ,

Thanks for the help...I figured it out. Of course, when I pushed on the primer, fuel went spurting everywhere. So i guess its time to order a new primer pump.

Martin · #5 03-16-2006, 01:35 AM

Quote:

Originally Posted by bravohotel

JJ,

Thanks for the help...I figured it out. Of course, when I pushed on the primer, fuel went spurting everywhere. So i guess its time to order a new primer pump.

Buy the new style Bosch primer pump. I just bought one last weekend for $15.49 (compared to the original design pump for $5.99) and it was a breeze to install. Took about 15 minutes and it works way better/easier than the old style.

greasybenz · #6 03-16-2006, 02:45 AM

My friend has the new one on his SD i was loving it! if its only $15 and easy to install im going to get one! i hate the old style one.

Ralph69220d · #7 03-16-2006, 11:37 AM

I guess it's nice if there is a diesel model that doesn't require opening any bleeder screws. But, if there are bleeders it's best to use them; both on the fuel filter cannister and especially on the injection pump.

Stevo · #8 03-16-2006, 01:49 PM

Quote:

Originally Posted by Ralph69220d

I guess it's nice if there is a diesel model that doesn't require opening any bleeder screws. But, if there are bleeders it's best to use them; both on the fuel filter cannister and especially on the injection pump.

You dont need to open any bleeder screws, just pump like crazy untill the sound changes.

Ralph69220d · #9 03-30-2006, 06:32 PM

Quote:

Originally Posted by Stevo

You dont need to open any bleeder screws, just pump like crazy untill the sound changes.

It's a lot more pumping to try and pump air, occasionally uphill, without using the bleeder screws. I understand you can be successful without using the bleeders, but you're pumping air from the main filter through the IP, then the IP lines, then back to the tank through the braided hose return lines, then downhill to til you reach the tank. So, it is my opinion that bleeding the fuel system of air by using the instructions contained in the Factory Service Manual is best. Now, I do understand by not using the bleeders, one doesn't have to push the air all the way back to the tank; just enough sufficient to get fuel to IP/Injectors. But still the bleeders are physically located in the filter and IP trouble spots where air become's trapped.
Regarding reasons for fuel bleed back, failing braided line is sufficient in itself to cause bleedback in a 220D and I assume a 240D unless there is some radical difference in the two. Though, whatever differences in engines a leak in the supply or return line lends itself to bleedback, the degree only dependent on just how the whole system is physically constructed.