brake fluid ovrflow

[Bampa]

After I have returned the bike to the shed and after a few minutes of sitting on the side stand I find some brake fluid leaking from the resevior overflow tube under the bike. any ideas as to why? The problem showed up not long after the brakes were bleed but neither of the tanks are overfilled. I just checked the reseviors & the forward res. is at the full point and the back tank is slightly below the top mark (but may have been higher before the leakage?). The brakes work as they should and no other problem seems to have shown up. Any ideas would be appreciated.

[boxermania]

Bampa

Not to insult your intelligence but there are no brake fluid overflow tubes in our bikes, however, there are for gas tank spills outside the area of the cap, the carbon canister, both on the right side of the bike by the center stand and one out of the airbox, normally capped to remove any blowby oil from the engine that finds it's way into the airbox, this one is found on the left of the bike, also by the centerstand.

[riceburner]

As said - it's not brake fluid.

It's more likely to be fuel - had you just filled up?

[Bampa]

Oh no insult taken but there is an overflow that comes from the ABS brake res. which is located under the fuel tank. The drain line tees from the top of the filler caps and is routed down to the same location as the battery and fuel drain lines. This is the source of leakage.

[iowabeakster]

Yeah,
Don't listen to those guys.

Just kidding. Both Boxermania and Rice burner are both very helpful and informative. Some of our best regular posters!!!They must be having an off day.

Why is it overflowing? You stumped this chump.



All I can guess (wild stab in the dark)...is that it must have been overfilled when it was bled...when the calipers were put back on the rotors...the caliper pistons were pressed in and pushed some fluid out the top...and it took some time for the excess to work it's way past the Y connection and down the tube.

[Bampa]

Iowabeakster, Thanks-I hope you are right as that is the thought I came to. Time will tell. The book shows that the level in the res. is normal between the full points and the top of the pump. Do you (or anyone else) know how low it can go without worry. I can then just watch and see. I sure do not want to run out of fluid. B

[boxermania]

iowabeakster

Thanks for your kind words as no one is perfect, however, Bampa, in his description left it up to the reader to realize that the bike had ABS. I my case, I never read so between the lines and since I didn't have ABS on mine, more so.

However, if he had the brakes serviced recenly and I presume, one again as it doesn't mention who did the work, that this was done at the dealer, I would take it back and let them figure it out and fix it if it needs fixing.......

[Bampa]

Thanks to all of you,
Thanks for the imput and I am sorry to have been so vague. This is the first experience with a BMW in 45 years or so and I did not know that the non-ABS bikes did not have boosted brakes. I do most of the work on my bike myself (help from local non specific mech when needed) as I
1. am retired and on fixed income
2. have autimotive mech exp mostly with two seat cages and small cars
3. have primarly had british made bikes before this one
4. find it enjoyable to do stuff myself
5. the dealer is many miles away and the local BMW spec. shop is known to be less than upfront in operation and expensive
We did the brake bleeding with information from this board. I did not pay attention to the level when the job was started so I hope that it is a simple case of the max line is too much. We will see.

This site has been a major source of help and I thank all of you for this, past , and future information.
Again-thanks
Bampa

[Boxer]

Have you checked underneath the bike up behind the rear shock to see if the clutch slave is leaking fluid? Do a check at the reservoir also with the bike on the proper stand per the manual. I can't remember if it should be on the side or center stand for clutch fluid level check. If you see none, BEWARE. The fluid may be getting out around that slave cylinder...Or worse, leaking out and down along the push rod onto the clutch plates themselves. The hydraulic clutch uses the same DOT 4 fluid as the brakes.

Edit: Sorry, I misread your original post. I did not see that you found it coming from a tube.

[torquerulesok]

I had the same problem on my bike for about two months after my friendly BMW dealer changed the brake fluid. The seepage from the overflow pipe recently stopped. I reckon the dealer overfilled the ABS modulator unit reservoir.

Make sure the stuff doesn't leak onto the rear tyre and just keep an eye on it.

Achim

[riceburner]

I honestly didn't know the ABS reservoirs had a breather. I've NEVER seen a brake system that would allow the fluid to have access to atmosphere.

Remember brake fluid is hygroscopic (it'll absorb water from the atmosphere). Every system I've ever seen has sealed reservoirs. Quite frankly - I'm a bit confused......