I use this forum site all time but have never posted any of my DYI repairs, so here it is, my first post.

My washer fluid kept leaking out, but very slowly, so slow it didn't even hit the garage floor. But annoying none the less.

There are actually 3 issues with this design.
1) The hose going to the side of the pump can very easily pop off.
2) The grommet going to the lower nozzle of the pump into the bottle is very soft and develops a groove where it seals to the tank.
3) The washer pump raises up when you fill the bottle to the top due to a very weak clamp holding the pump to the bottle.

The first time I disassembled the fender lining to reveal the washer bottle and pump assembly, It appeared to be obvious, the hose had popped off of the side of the pump. I applied a small amount of rubber cement on the nozzle and popped the hose back on. Filled up the bottle, reassembled and went on my way, next day the bottle was EMPTY AGAIN!

So I purchased a new grommet (i read that the grommet leaks over time) I figured if I was going to take it all apart again, I might as well do it right. The grommet was only 3 bucks from the local dealer, I about fell over when he told me the price, must be the cheaper part in the parts department.

It's pretty easy to get to everything, here is how step by step:

1) Remove front left (drivers side)Tire
2) Remove inner lining
3) Remove Pump
4) Remove and replace Grommet
5) Wrap Gorilla tape or duct tape around pump
6) Apply rubber cement on side nozzle
7) reassemble

The whole job took me about an hour, only because I kept running into issues, so if you follow my instructions, it should take 30 to 45 minutes.

Once the tire is removed there are three 10mm screws and 3 push style plastic fasteners (there maybe more on yours, it appears I had empty holes under the bumper cover where there may have been one or two more).

Remove the fender lining and behind it is the bottle and pump assy.



Grab the top of the pump and pull toward you, it will pop off of the clamp, then pull up and the Bottom nozzle will pull out of the grommet.



Remove the old grommet and put the new one in, put the pump back in the nozzle. Read below before putting the pump back in the clamp.

Here you can see a grove in the old grommet and you can see the size of the grommet. There are two different sizes used on MB's mine is a W203 C320 and it uses the smaller one of the two.





I pulled the hose off of the side nozzle, applied a little rubber cement on the nozzle and popped the hose back on, and yes, it does pop when you put it back on. Then I filled the bottle all the way to the top and noticed that the pump backed out of the grommet on the lower nozzle about 2 to 3mm. This really pissed me off. The pic is upside down, sorry for that, i was trying to get up close and my camera phone flipped it around.



So I took it back out and wrapped the pump with gorilla tape before pushing it back on to the clamp, it was a much tighter fit after that, I even placed a small piece of gorilla tape across the clamp and pump just to be sure it never moves on it's own again.



Reassemble and you should be set. I hope this helps, please feel free to ask me any questions.

Tony

 

just did this yesterday, thanks!

 

Glad I could help, going to post the procedure for replacing the inside door handle next.

 

Ok. I'm about to give up!

My windshield washer started leaking when I apparently overfilled the reservoir one day. I followed the instructions in this DIY though I admit that I didn't start my repair using that method. I figured that silicone would probably do a better job sealing.

I got a new rubber grommet from MB. I glued it to the tank variously with GOOP glue, a few different types of silicone sealer, and finally rubber cement. I wrapped electrical tape around the snout of the pump so it would better seal the snout to the grommet and the grommet to the hole in the tank. I also tried it without the tape. I used the silicone sealers on the snout of the pump (and the tape) so that it would help seal the snout to the grommet and squish out the sides and mix with the silicone that had squished out from under the grommet and left it to cure overnight.

Finally, I used rubber cement. I was hopeful/desperate but didn't expect it to work because I thought it was too thin and wouldn't work as well mechanically as silicone. It turns out I was right at least about it being no better than silicone.

None of that has worked. When I fill the tank with a gallon of washer fluid, it will start to drip from under the pump in a few minutes. My pump does not push up from the grommet when I fill the tank with fluid.

Does anybody have any ideas?

 

I truly understand your frustration, I had to do mine twice before i got it to stop leaking. Although it appears you may have over killed it on the silicone, you shouldn't be leaking.

Are you sure you don't have a crack in your bottle? I only ask because another one of MB's bottle had a hair line crack on the bottom of the bottle, it only leaked when it was more than half full (enough pressure to spread the bottle apart) I would put blue washer solvent or water with Blue dye in it and then look at the bottle real good and see if the blue shows up on the outside of the bottle. IF it does, then there's the problem now. Not saying the grommet replacement was a total waste, if it wasn't leaking it was going to.

Let us know what happens.

TI

 

That is something that has occurred to me. I didn't see any cracks but if there is one it would have to be around the hole for the grommet and more likely a split at the hole. Your idea of dyed fluid is good. As it turns out, I've been using Rain-X fluid which is orange which wouldn't show.

That will be the next thing I try after the tank empties. I'll try a few tank fulls of dyed fluid to see if I can find a crack. That tank is such a slippery plastic that I bet it would be difficult to repair.

I will post what I find out.