Final Drive Fluid Continues to Have Water In It

[Steve Kolenda]

When I changed my final drive fluid last fall on my 2011 R1200RT I noted that the fluid looked milky and suspected that there was some amount of water in it. Today I am getting ready for a couple of weeks on the road and decided to change the fluid to see if there was any difference from the last change. If anything the fluid looks worse to me (looks like a strawberry milkshake)than the change last fall. This time I was very careful to have a clean container and to measure the exact amount that came out. As bad as it looks there appears to be very little if any increase in volume. 180 ml in 180 ml out. I have ridden very little in the rain and not heavy rain at that although the bike gets washed frequently but not with high pressure. I have no oil seepage anywhere that I can find. I am beginning to suspect the vent. I have removed the vent and the aluminum under the rubber was a little white looking like maybe water had set on it. I am thinking about removing the vent and placing some grease between the rubber and the aluminum to try and create a seal. Any suggestions?

Also, I am trying to figure out why not fill the unit through the vent hole which is so much more convenient to access than the filler which you have to remove the rear wheel?

[dirtrider]

Afternoon Steve

 

That is strange that you have a milky looking gear oil. What brand/type of gear oil are you running?

 

I have a couple of hexheads without the external final drive vents & the gear oil always comes out looking like new (I change gear oil at every rear tire change).

 

You might have a moisture issue or the gear oil might be getting contaminated from the crown bearing grease bleeding into the main cavity.

 

In any case (personally) I would send a gear oil sample to BlackStone labs for their report on EXACTLY what (if anything) is in your gear oil.

 

If it is a moisture problem then I would rework the vent to take a long hose & remotely vent the final drive up under the seat or into the air cleaner box. (I used to vent my 1100's & 1150's into the air box as those are noted to take in water & sand if pushed hard in heavy rain, deep water, & sand covered roads).

 

[Steve Kolenda]

D.R.

 

The last fluid was 75 90 BMW oil color is red. The last time I bought fluid the dealer didn't have the BMW brand so they sold me the Castrol brand which is more of a clear color and is what is in there now. After the fluid has set for a day or so I can see what appears to be a slight ring of water around the very top of the container. If you PM me with your email address I will send you a photo of the fluid I just took out.

[racer7]

I'm with DR- get an analysis and don't guess what you're seeing.

Heck, I'd have done a couple quick back to back changes to ensure getting all of whatever it is out the first time I saw it rather than ride it a bunch..

In the old day, some but not all bikes had wads of some kind of nasty assemby grease in the gears that turned FD lube blackish gray for up to 3 changes. Haven't played with any new ones so don't know what they look like these days.

Re the vent- before messing with it first check whether BMW incorporated a membrane in it. Gas permeable but liquid impeerable membranes are now cheap and incorporated in vents of much industrial stuff so might have made their way to BMW FD vent (the old style ones didn't have membranes- don't know about the new ones)

[David R]

Thanks for the info.

 

My 2012 R1200R had a grey looking fluid first change at 6,000 miles along with a new tire. It looked to me like it had a bunch of moly in it.

 

Second final drive oil change at 12,000 miles and another tire the oil had water in it. It was white or milky looking.

 

I use synthetic 75w90. Its gear oil color when I pour it in. A quart is cheap and good for 5 changes, so I don't mind changing it frequently.

 

 

I never thought to fil through the vent.

Thanks for the Idea. I didn't want to wait till this tire wore out to change it again. I am guilty of power washing my bike. Since I saw water in the FD, I stay away from the area when washing.

 

After riding with a fella I I met near Detroit, we did 46 miles in 30 minutes, the FD was not hot, but only warm to my hands just like the tires.

 

I am used to the oil coming out looking exactly like I poured it in. So far not true with this new bike.

 

I do ride in the rain, I do not have a car for the summer.

 

Going to change it tomorrow. Its been 2,000 miles (just over a week) since I changed it last. I am going to try to fill it with 180cc (6 ounces) of the same oil I put in last time.

 

I will report back.

 

David

[Steve Kolenda]

David,

 

Anxious to hear what the fluid looks like. My 2000 RT did not have a vent on the final drive and the fluid always looked the same coming out as going in. I suspect that vent is not real good at keeping water out and that possibly during my frequent washings some goes in. I found a little plastic piece to cove the vent during washings which will hopefully make a difference.

[David R]

EeeeHhaaa!

 

The oil came out looking like it went in!

 

I then poured a little in the vent with the drain still out. It came out the bottom. Reinstall plug properly torqued, Added 180cc, install vent and away I went with the biggest smile.

 

I used a good fitting hose in the vent hole because I did not want to get oil on the brakes. It went quite well. I added about one oune at a time allowing the air to come back out (up the hose and back into the oil bottle)

 

 

Thank you. I did not want to wait till the tire was worn out to change the fluid.

 

I have refrained power washing the bike in that area.

 

Thanks to Steve Kolenda for the fill it through the vent idea.

Since we don't fill to the plug, it makes total sense. I owe you a beer!

 

David

[dirtrider]

David,

 

Anxious to hear what the fluid looks like. My 2000 RT did not have a vent on the final drive and the fluid always looked the same coming out as going in. -- clip

 

Evening Steve

 

Your 2000 RT final drive did have a vent as all BMW 1100/1150's had final drive vents.

 

[Steve Kolenda]

D.R.

 

Thanks for correcting me. I don't recall a honking rubber thingy sticking up on the top of the drive on the 2000 but looking at the parts fiche there appears to be a number of items on the very top of the drive. None of which are labeled a vent. I'm assuming they are the venting mechanism? Possibly a more robust design? The vent on my 2011 just looks like a place begging for moisture to enter.

 

[dirtrider]

Morning Steve

 

The vent on the 1100/1150 is a conventional hooded vent (automotive like). They leaked water as well as road sand/dirt under some riding conditions or power washing.

 

I have had quite a few apart, on many was found a trail of dirt/sand on the baffle under the vent.

 

[racer7]

If the current BMW vent lacks a membrane this is an obvious place for anyone who want to make an aftermarket cap with one to make some $. Membranes that keep out liquids and grit but allow gas (pressure) exchange are commonly available and cheap and would prevent water pentration.

 

Probably the most common industrial use is in liquid storage tanks.

 

I'd prefer my FDs vented but not at the expense of getting crap into it. I can buy a truckload of cars FDs from a recycler for what one new BMW FD costs...

[Steve Kolenda]

Just an update,

Just returned from a 6,000 mile vacation which was the first ride after the above stated fluid change. Bike was washed after the fluid change and I placed a cover over the vent area prior to washing. During our vacation we had a total of about 8 hrs of steady rain. Upon returning home I immediately drained the fluid and am pleased to say no signs of water. No milkiness to the fluid. I suspect water was getting in during the washing process.

 

Also I had asked the question of why not use the vent hole to fill rather than removing the rear wheel and this appears no to be such a good idea. I wasn't able to get fluid to flow fast enough to make this practical. I suspect that there is a very small hole at the end of the lager hole that holds the vent.