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2000 320Ci 2.2 vert MT
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Discussion Starter · #1 · (Edited)
After i changed my soft top canvas some weeks ago I topped my pump reservoir.
Was quite low but already on the "spot", an acceptable leak/loss after 4 years.

When I changed the top I inspected for what was in my little knowledge of there were stains/marks of oil around the soft top asembly. No visible signs, no stains or similar. I always had the insulating sponge wrapping the pump "oily", but not more than my ex z3 for example: something that seems trasudation.

After soft top was correctly reinstalled, I enjoyed it and opened/closed 10/12 times approximately: I retested today the level 'cause I felt the soft top a little "sluggish" on closing with car on a downhill and was quite low again. Again near the lower part of the "spot" on the reservoir.

  • True I moved the top for 2 weeks by hand when I changed the soft top
  • true the pump has surely some trasudation: is always a little "oily", but there are no visible signs of stains or losses in a particular point.
  • The system itself has "pressure": if I leave the soft top open half way, there's no way to move it by hand before some minutes necessary for the system to "unpressurize" leaving it there
  • while opening/closing the soft top several times changing the canvas, I left the soft top halfway witht the system pressurized. When it de-pressurized I heard a loud "sound", a "whistle" of the system losing pressure after some minutes. Never heard it before, and was not the first time I left the soft top halfway
There is a common leak points to check or a guidance to find a leak somewhere?
I've searched the sticky link but are (obviously) for repairs, can someone suggest me where to start finding a leak, weakest points ecc? Some suggestion to find very slow leaks/methods?

Due to the fact that the pump assembly is a little "oily" I was wondering if cleaning it with breake cleaner or similar maybe I will notice on next weeks some specific points of leak. Is it safe to clean with that kind of aggressive cleaners? I don't know honestly if it'll help, cause I think the leak will be microscopic to see at every lift/storage of the soft top.

Advices on your experiences? On post #5 I've found the pump may be leaking somewhere.
 

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2000 320Ci 2.2 vert MT
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Discussion Starter · #2 ·
I updated and detailed the first post :)
Hope someone can give me some hints! :p
 

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Discussion Starter · #4 · (Edited)
Here's all the hyd's on the E46. The cylinders would most likely leak 1st, IMO. Look for oil spots from them first, then all the connections would be next, again, IMO. Check the (6) hyd cylinders Good luck
View attachment 963590
Thanks. As said visually I found no leaks on lines and cylinder, what I could see with canvas off seemed "dry". But I'll obviously re-check it, obviously.
Check the (6) hyd cylinders
you're talking about the other lines, I assume. Are the connections all visible?

The fact that the pump is quite oily: may I should start from here? What are the parts that may leak on the pump itself? Only the connections of lines or there are other weak points?
Can I clean it with brake cleaner or it can harm plastic/rubber?
 

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Discussion Starter · #5 ·
I checked all lines.
They are dry, so are pistons.

I instead found the insulation was oily. This made hard to diagnose a leak, cause it is impregnated and diets all the pump.
In this pic I removed it and main oil stains was obviously on the bottom(top is up, so il level is low for this reason)


Electrical wiring Gas Cable Machine Auto part


And in the rear in that point
Automotive tire Tread Electrical wiring Gas Automotive fuel system


Surely cause is the point where pump sits on chassis.

IHow can I diagnose leaks there? There are parts that commonly fail?
I now cleaned it all with brake cleaner and when the weather is better (total rain these days) I will try to open the top so maybe there will be some drops.
Hard honestly, cause leak is very little.
I bought a second hand pump to investigate and dismantle it, in case is useful.

Ideas?
 

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I had a similar problem. It was hard to find exactly where the leak was coming from so I changed all of the hose seals. Problem immediately went away. I used X rings as the installed square section O rings are hard to come by and won't work as well. Haven't had a problem since.

Replacing the seals is a bit tedious, but can be done. Video below on how I did it. Same seals for all connections. I replaced those on the main jacks as well to fix the small leaks there.

 

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Discussion Starter · #7 ·
I had a similar problem. It was hard to find exactly where the leak was coming from so I changed all of the hose seals. Problem immediately went away. I used X rings as the installed square section O rings are hard to come by and won't work as well. Haven't had a problem since.

Replacing the seals is a bit tedious, but can be done. Video below on how I did it. Same seals for all connections. I replaced those on the main jacks as well to fix the small leaks there.

Thanks, I've already saw your video 3 times on the last days.
What kind of o rings did you use, as material? What does it means X rings?
 

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Thanks, I've already saw your video 3 times on the last days.
What kind of o rings did you use, as material? What does it means X rings?
Nitrile 70 is the material, which is cheap and readily available. The X is the cross section shape. A standard O ring has an O shaped cross section. X rings are a newer design and are generally considered better because they have two sealing surfaces instead of one with a normal O ring.
 

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Discussion Starter · #11 · (Edited)
Nitrile 70 is the material, which is cheap and readily available. The X is the cross section shape. A standard O ring has an O shaped cross section. X rings are a newer design and are generally considered better because they have two sealing surfaces instead of one with a normal O ring.
do you think it's the first thing to investigate? Maybe you have a list of all the o-rings in the pump to change, apart from these little ones.

I'm now thinking mainly about the big o-ring on the "plastic cap".
I've found that the "plastic cap" (reservoir?) on my pump has a little "gap" from the top squared part, confronting to pics I see online.
Maybe the metal tie has been removed for some maintenance and that "cup" was not completely put back on?
The rear of the pump is effectively quite oily. I cleaned with brake cleaner and if I rotate the pump (as I did to make that pic) I find always it some "oily".
Do you have a reference about it?
Now I'll put all back without the sound insulation (broken and very oily...on the way to fix)and put some pieces of paper cloth on the pump itself and see where it "stains".

Gas Nickel Machine Household hardware Engineering


Fixture Wood Gas Fluid Metal



Gas Nickel Auto part Metal Machine



..and @jjrichar that's yours:

Hand Finger Circuit component Engineering Gas
 

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do you think it's the first thing to investigate? Maybe you have a list of all the o-rings in the pump to change, apart from these little ones.

I'm now thinking mainly about the big o-ring on the "plastic cap".
If the reservoir isn't seated correctly then this would be high on my list of problems to correct before going further.

Regarding the small O rings (x rings), these are really the only O rings I replaced. Any O ring that needs flexibility to effectively seal, which is what these are, will need replacing over time as they harden.

There are two small O rings between the valve block and the pump that you might think to replace, but I don't think you would get a leak here as they are compressed hard between the two aluminium pieces.

Nothing else is a seal under pressure, so unless you can see damage (or it's not fitted correctly:)) then it shouldn't need replacement in my opinion.
 

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Discussion Starter · #14 · (Edited)
If the reservoir isn't seated correctly then this would be high on my list of problems to correct before going further.
Yeah, I think so. It is the fastest (and cheapest) way to move. I didn't notice it was badly fitted till I investigated that leak.
I think I'll simply start to remove lines from the pump, put it on a bench, clear it very well and re-fit correctly the reservoir.

Regarding the small O rings (x rings), these are really the only O rings I replaced. Any O ring that needs flexibility to effectively seal, which is what these are, will need replacing over time as they harden.
My concern is that if I might "disturb" them removing the small pressurized hoses.
Do you suggest re-fit them with some lube/oil/RTV on the terminal part/pray to the Lord of the (O)Ring?

There are two small O rings between the valve block and the pump that you might think to replace, but I don't think you would get a leak here as they are compressed hard between the two aluminium pieces.
I saw the o-rings in the aluminium block but I won't remove them if I have no need to. My main concern now is that the o-rings in the reservoir may need to be replaced or there are other "easy fix" I could do with no much effort with pump on bench

Nothing else is a seal under pressure, so unless you can see damage (or it's not fitted correctly:)) then it shouldn't need replacement in my opinion.
so the o-ring on the reservoir are not pressurized? sorry for my ignorance 😅

Yea, if you look at how close the little cut outs sit to the large O ring then your reservoir is probably quite close to those slots and causing a wicking effect of the fluid.
yep. I never noticed it before seeing other pumps closely as did these days.
 

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Discussion Starter · #15 ·
...and I bought a spare pump. On the refill hole has a copper oring, tha mine doesn't have. May be another culprit for the leak.
Wood Gas Rim Auto part Metal
 

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My concern is that if I might "disturb" them removing the small pressurized hoses.
Do you suggest re-fit them with some lube/oil/RTV on the terminal part/pray to the Lord of the (O)Ring?




so the o-ring on the reservoir are not pressurized? sorry for my ignorance 😅
...and I bought a spare pump. On the refill hole has a copper oring, tha mine doesn't have. May be another culprit for the leak.
Definitely don't fit O rings with any sort of sealant. It's important they can move in the groove, as this is what does the sealing when pressure is applied. You just need to fit with some sort of lube so it slides in there and doesn't get deformed/damaged. I just use the standard convertible hyd oil.

Disturbing the O rings isn't an issue. Like I said above, they need to move. Flexibility of the O ring is important, and if old this is what is going to cause leaks. Watch a video on 'how an O ring works' and you will see what I mean.

There isn't any pressure other than atmospheric on the large reservoir O rings. All the pressure in the pump is internal to this. It's just the squeezing of these large O rings between the plastic reservoir and the pump that is creating the seal. Unless these are damaged or hard you normally wouldn't get leaks here.

Weird there isn't a copper sealing ring. I'd be fitting one if everything else looks the same.
 

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Discussion Starter · #17 ·
Weird there isn't a copper sealing ring. I'd be fitting one if everything else looks the same.
searched around for a copper ring to fit,instead of using that old one from the spare parts pump. No success. Using that one will be safe? This part I think is under pressure, reading your post
 

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searched around for a copper ring to fit,instead of using that old one from the spare parts pump. No success. Using that one will be safe? This part I think is under pressure, reading your post
It's not under pressure as it's just sealing the reservoir. Also there is very little fluid contact because it's right up the top and away from where the fluid is held. I've never replaced or annealed this one for this reason and never had an issue.
 
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