1st time fuel filter change
 

So I changed my fuel filters this afternoon. It went something like this: changed the prefilter, unscrewed the main filter, emtied it into a gas can, put new filter on, took new filter off cause I forgot to fill it w ATF, put new filter w ATF on, primed the system, and started the car. She fired right up.

Shut the engine off, and looked for leaks. Found one from the big hex bolt. tightened. restarted. still leaking. I repeated that a couple of times.

The car wouldn't start after the second "leak check". Still won't. So, what'd I do wrong?

It was my first time changing a fuel filter that wasn't attached to a lawn mower.

There's a chance that I had the wrong main filter. It was a made in spain Bosch. The filter that came off the car was a Hengst made in germany. The seals on the filter looked a little different, but generally similar.

did you replace the rubber washers on the shaft (i think there is one) and the crush washer between the big bolt and the filter housing?

I changed my filter thinking that I would not need to change the O-rins on the big 24mm filter bolt I was wrong and it leaked. I lucky I was able to find some that worked from a bunch of American size ones that I have. I learned that before I start the job have the O-rings in hand (or if yours has only 1 O-ring that 1 o-ring and the crush washer that goes under the head of the bolt).
After you filled the filter with ATF it is still a good idea to do some pumping with the hand primer (if there is one) to get rid of the air. If not it is best to run the car longer and make sure all the air is out.
If a lot of air is in the system sometimes it is easier on the battery and sarter if you loosen some of the fuel injection lines up by the Injectors and crank the engine until fuel spurts out and retighten them.

diesel911,

i could not remember how many there were but i think there are two just like yours in your post.

I used to crack injector lines, but now just crack the out-going banjo bolt on the main filter. Then prime till fuel flows. I don't even bother filling the filter anymore, this works so good.

If your seals are sealing, chances are you just still have air in there. Crack that center out-going banjo bolt, prime like crazy till you have solid fuel, and I bet she starts fine.

There was no rubber washer on the shaft. I reused the crush washer.

I'll consider this option. Though I primed like crazy already. I pumped until fuel was coming out of the hand pump.

I figure the leak is a separate issue from the no start. Am I wrong?

If the leak in the primer pump was bad enough I would think you could draw more air into the system.Did you put the two filter seals up to each other?Make sure the rubber seal on the old screw on filter matches the new one.Different brand filters can have slightly different diameter cans but as long as the ports match up and the seal on the bottom it should be good.When I changed my fuel filters last the big bolt on the top of the can leaked for a little while tightened it up and i was good to go.

In my case (i had a poor primer pump that i put up with for ages, then finally swapped out; and I primed A LOT as I installed a veg oil system)- priming has worked for me only when I had a line or that banjo bolt cracked to allow air to escape. Just pumping, with no outlet for the air, never worked for me. My old pump would leak like a sieve, and require lots of pumps, but still did the job. My new pump does not leak, requires substantially less pumping, and works- but I always crack that bolt to allow the air somewhere to go.

Could be you have a poor pump. Probably needs tons of pumping, more than one would think necessary. Likely you still have air in the system; hopefully you are not still drawing it in somewhere. But imho you absolutely must crack an injector lone or that banjo bolt and pump till no more air remains.

I changed my fuel filters for the first time around Xmas time. Had the same issue with the bolt, temporarily fixed with some sealer, later did the job right.

You will need a new crush washer. They are a one time use item. Not all engines have them, tho.
On the bolt there should be a machined slot for a rubber "O" ring to fit in, if you don't have one, find one.
Replace the primer also, or at least replace the fuel lines going to it.

those new style pumps are soooo much nicer :) i just got one for my 240d after two years of the old squirting one. i dont even have to pull it up!

I have an O ring in the garage, but since an O ring wasn't on the bolt or anywhere else, I didn't use the new O ring. There was a black band around the mid-section of the bolt. It wasn't a ring though as it was flush with the bolt; had flat sides. Didn't look like it was meant to come off or replace, so I left it.

Regarding the primer, I pumped until fuel spilled out of it. Should I keep pumping? that seem's unnecessary to me...but what do I know.

What are the spec's of the copper crush washer? And can I do/replace anything now that will allow me to never have to use a copper crush washer again? they're too hard to find.

If you previously filled the fuel filter I ment use the priming pump before you start the car. It is hard to describe it but when you pump with the primer pump and the are starts leaving the IP you well he a buzzing, deep squeeling sound and keep pumping some more and at that point the air is out of the IP housing.
If air gets up into the Fuel injection lines between the IP and The Fuel Injectors it takes too much cranking with the engine to purge it. As I said if you loosen some of the Fuel Injectio Line nuts up by the Fuel Injectors ie bleed out fast.
Check this PDF below to see the factory method of bleeding the air out after a filter change:
http://www.pauldrayton.com/uploadfiles/merc/Service/W123/w123CD2/Program/Engine/617/07_1-140.pdf

Great, thanks. I'll do this tonight. I pumped before starting the car, a lot. The prefilter filled with fuel and the pump became hard to move, so I thought that was sufficient.