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1982 300gd
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57 Posts
Discussion Starter #1
Just changed my fuel filter , pre-filter , and return lines with compatable non turbo 300cd parts from local auto parts. After filling the filter with diesel , pre-filter and lines I bleed the system or so I think. During the intial start there was some hesitation but it started and is running fine . The problem is air pocket in the pre-filter. I again tried bleedding the system,pump,pump,pump...pump,pump,pump ,opened the nut on the fuel filter ,and loosened the injection in cylinder one and still no luck. Took it for a 20 minute drive - no problems . Will this air pocket minimize and work itself out overtime or do I need to continue to pump the bleeder. All the fuel spilling is a pain. And could someone recommend other more preferable filter brands and / or experiences.
thanxs
scott
 

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85 300GD 83 300TD
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978 Posts
Hi Scott,

The little bit of air in the pre-filter is no problem. I like the clear pre-filters that have brass sleeves inside the hose barb areas. I don't like the milky white pre-filters because you can't inspect the filter media for build up of gack. I use Knecht or Mann main filters and fill with LubroMoly Diesel Purge when I change them. Don't panic about a little air bell in the pre-filter; it happens. If it's running fine you're OK.

-Dai
 

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1982 300gd
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57 Posts
Discussion Starter #4
DAI
Thank you for your reassurance about the air in the filter and I have had the MANN filter previously but was unable to locate a source nearby. Thomas can you explain which nut your referring to.
I know little about the Bosch fuel injections only that they perform well when they are maintained properly . I appreciate the assistance.
thanx
scott
 

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85 300GD 83 300TD
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978 Posts
Hi Thomas, I have never done that. I crack the banjo on the top of the filter housing for the returns and pump away until I see no air bubbles. You may be interested in the new style lift pump when you need to replace yours. Instead of a plastic wheel that needs to be loosened so the pump can be lifted up and down the new style has a top that you press down on and it returns with spring pressure. They are less prone to leakage and easier to use.

-Dai
 

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1985 300GD LWB 5 Speed
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1,079 Posts
Hi Scott,

I am referring to the banjo connection at the top of the large fuel filter, the one Dai refers to. He thinks I don't need to go through the loosen and tighten procedure and maybe I don't. Howerver, it seems to me that if I crack open, and leave open the banjo connection during this procedure, that I am sucking air into the system. So, I lightly tighten the banjo connection prior to pulling the pump knob up. On the other hand, air that would get into the system is at the far end of the fuel stream and likely not to be a problem. Old habits die hard.

Dai, Yes, I have on the primer pump replacement on my list of things to do. The new one sounds a lot better than the old version. Thanks for the reminder.

ts
 
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