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How do I add brake fluid to front reservoir ?

14K views 21 replies 15 participants last post by  Roy Barnes 
#1 ·
I need to add brake fluid to my front brake fluid reservoir. (it's a long story...)

I've tried pushing in the 2 tabs and gently lifting and or rotating the cap, but it did not open.

Before I lift or rotate with any more force, can anyone tell me how to get the cap off?

Thanks, -Jeff
 
#5 ·
Jesus - we need tools to take the master cylinder reservoir cap off?

This boggles my mind. Why?

Hmmm, probably time to start thumbing through the Brembo cattledog for a proper master cylinder, with a reservoir that's tucked neatly out of harm's way - and with a cap that can be removed by hand.
 
#6 ·
Jesus - we need tools to take the master cylinder reservoir cap off?

This boggles my mind. Why?

Hmmm, probably time to start thumbing through the Brembo cattledog for a proper master cylinder, with a reservoir that's tucked neatly out of harm's way - and with a cap that can be removed by hand.
Just remember "out of sight, out of mind"... I've not had to top up my brake fluid in 200,000 miles of riding outside of normal services & never had brake failure, but back when the res had a little sight glass I very rarely checked it & there will be people looking down from the heavens above nodding & wishing they had... believe it or not it was designed this way, & as it is now it's patently obvious, which is why all new bikes have this... think about it before you try to improve the design for the sake of aesthetics.
 
#7 ·
If I could offer a couple points.

The 'bobblehead' reservoir, as it has come to be affectionately known, was designed this way for a reason. Based on spending too much time on these forums, it would appear that this design makes breaking off your reservoir much harder, which is handy when you bail in the middle of nowhere, and so that vibration from the bike and surfaces travelled does not agitate the fluid to the point of producing air bubbles in the reservoir which could move down the line to the master cylinder.

When it comes to removing the top, you don't need any special tools. I have done it by hand several times already. My technique involved appropriate preparation with a hopped beverage of your choice, followed with a gentle but determined counterclockwise rotation of the top until you feel definite resistance. At this point, press each of the little tabs in as far as you can with your fingers. Friction will keep them pressed in or you can continue to press both with your fingers like a ninja while rotating the cap one notch counterclockwise. You should feel the cap move one 'click' towards opening. At this point repeat the process. It is only challenging for the first few clicks, then you get past the safety clicks and it comes off like any jar lid.

As a precaution, I always wrap a towel around the reservoir to prevent splashing the brake fluid on the bike. Depending on who you ask, this stuff can eat through plastics, paint and concrete. Also, if turning the bars, the level in the reservoir changes and can cause you to spill some so be cautious if play-riding without your safety cap.

The max fill line is there, in one of the safety clip grooves but can be hard to see.

Enjoy.
 
#8 ·
As a precaution, I always wrap a towel around the reservoir to prevent splashing the brake fluid on the bike. Depending on who you ask, this stuff can eat through plastics, paint and concrete.
I heard it was a bit like that Alien blood & will breach the hull of your mothership... unless you use a towel of course.
 
#10 ·
I have no idea what BMW would sell that fancy wrench for, but probably lots. I made my own today in less than 20 minutes from a piece of 1/16" aluminum. Cut the rough opening with a 2" hole saw, then used tin snips to open it up, from that point, just a bit of file work to perfect the fit. Tested and fully functional all for a few minutes work and no cost.

Now I can get after the spring fluid flushes on our two F800s
 
#22 ·
I have no idea what BMW would sell that fancy wrench for, but probably lots. I made my own today in less than 20 minutes from a piece of 1/16" aluminum. Cut the rough opening with a 2" hole saw, then used tin snips to open it up, from that point, just a bit of file work to perfect the fit. Tested and fully functional all for a few minutes work and no cost.

Now I can get after the spring fluid flushes on our two F800s
I have used a piece of chalk line and rap around about twice and tighten and it will compress the little tabs and then unscrew.
 
#14 ·
Well, FWIW, it's simple enough... The bobblehead is replaced with a R12GS reservoir, BMW part number 32 72 7 666 151 (~$60 CAD, IIRC). The fluid is drained to the point where the bobblehead, bracket, hose and master cylinder flange can be removed, then replaced with 12GS reservoir. If done carefully, you don't even need to bleed the brakes. I used the bleed nipple on the 800's master cylinder to drain the fluid down. Total time... about 20 minutes for the mod.

Please note, this mod may not work with all types of hand guards. I use the 12GS hand guards on mine, and they work fine. Good luck with whatever you choose.
 
#17 ·
Both good responses...

LOL... however if one were to require washer fluid or a sample of their finest vintage with them, I doubt that anyone would independently come up with anything approaching the stock setup. [lol]

Anyway, the mod has been done, and if ever required for whatever reason, I still have the stock parts, and another 20 minutes to restore it. As to the question of crashworthiness, I'm not sure which setup would be more/less prone to damage. Also, given that there seem to be no ill effects from the mod in operation, I'm curious why BMW felt the bobblehead was required. [:D]

Cheers
 
#19 ·
I have the special BMW factory tool. I think calipers would work better. :rolleyes:
 
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