diesel leaking at/under fuel filter? - PeachParts Mercedes-Benz Forum

edge · #1 11-07-2003, 07:54 PM

I just got in after inspecting my 85 300SD. My son told me there was an oil spot under the car. I popped the hood started the car and notice diesel fuel squirting (like a blood artery) underneathed the spin-on fuel filter. I tightened the spin fuel filter, wrenched tightened the top bolt and bleed it with the hand pump. I then started the car and saw that my efforts did not stop the fuel squirting. It was getting dark so I 'll have to look at in the daylight. Is there anything else underneath there, lines etc. that's squirting other than the fuel filter? Thanks, guys.

lrg · #2 11-07-2003, 08:49 PM

Possibilities:

There is a O ring on the bolt that holds the spin on filter in place but that should cause it to leak from the top. If you remove the filter and bolt the O ring is obvious.

It's not unheard of that the filters themselves spring a leak. Did you check the filter before you tightened it?

One other possibility is the cloth covered injector overflow return line. It's a continuation of the series of small hoses that run from injector to injector and although I don't think it's under much pressure the return line that runs from the #1 injector back to the fuel return line could be cracked.

Let us know what you find.

Palangi · #3 11-07-2003, 11:02 PM

I second what lrg said. I had a filter develop a small crack once. Sprayed fuel all over the place.

nhodges · #4 11-08-2003, 03:08 AM

A fuel spray is really dangerous!!

Toblin · #5 11-08-2003, 09:43 PM

One word. Tourque. These things take a bit more than you might expect. You’ll need a wrench. Check the rubber seal on the filter, if cracked, buy a new filter. And remember to apply a thin coat of oil on the seal before tightening.

rickjordan · #6 11-09-2003, 12:44 AM

You tighten the main bolt more, but don't go too far, you could crack the filter mount. I had a leak form the bolt it'self that tightening would not fix. My indy. said that overtightening could crack the aluminum mount. The fix for my problem was a new bolt.

thebern · #7 11-09-2003, 03:36 PM

I replaced the fuel filters two days ago and the secondary filter leaked at the bolt; tightened some more and still leaked. Before I ruined something expensive I replaced the copper washer with a nylon one. Only had to apply about 25 foot pounds to seat and seal; no more leaks!

thebern

edge · #8 11-13-2003, 07:01 PM

Ok I removed the old filter. The seal looked a little raised and probably wasn't sealing. I think I neglected to tighten the bolt when I changed the filter last time. I only spin tighten it. New filter installed, no leaks. Thanks guys.

#9 11-13-2003, 08:20 PM

I was 800 miles from home pulled into WalMart. Went in and came out and found a three foot puddle under car. It was deisel.
When I cranged the car up it sprayed like a vain. No apperant source. Tried to tighten filter still leaked. Change filter with new one and no leak.
Moral to this story alway carry spare fuel filters.
Charles

bbergman · #10 11-30-2003, 04:31 PM

I just changed my filters, now I got leaks from around the bolt at the top. I changed the O ring, got better but still leaks. The washer under the bolt seems to be steel, not copper, is this right? The bleeder pump now leaks too, I guess we're replacing that one.

Brad

300sd 1983

edge · #11 12-01-2003, 01:40 AM

I don't think there's a washer under the bolt. The O ring on top of the filter is rubber.

bbergman · #12 12-01-2003, 08:41 AM

There was a washer on top of the filter housing under the head of the bolt, I beleive thebern said he changed it to a nylon washer. I am checking around town to find a nylon replacement but have not been able to source one. I have cranked this thing down as much as I dare. Any other suggestions or should I go buy another filter.

Brad

thebern · #13 12-01-2003, 09:11 AM

has them. if the I.D.is too small use a dremel to enlarge it .

thebern

84300DT · #14 12-01-2003, 07:40 PM

Quote:

Originally posted by edge
I don't think there's a washer under the bolt. The O ring on top of the filter is rubber.

agree. hope the new filter is stopping the leak.
btw how's the offers going on your mint SD edge, if it was a little older and a lot less money i might be interested!!

edge · #15 12-01-2003, 09:31 PM

Hi Bob, I had a guy in Missouri very interested but he topped out at $5k then I hadn't heard from him. Then again, I fixed the driver's seat spring and tuned the AT to shift earlier and if feels like a different car! It was a great car anyways but with the new seat spring installed, it's even better. I bought a set of alloys of Ebay for $60 so I'm am going by way of the set of snows (Kumho) rather than the Honda Element route. I kinda glad no one snapped it up as it's going to last a very, very long time. My next project is to add an Alpine MP3 player and new speakers in the rear.