• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Bleeding Brakes 1999 R1100RT

EMSimon

No longer a member here
I installed new front brake lines and I am ready to bleed the brakes. What, if I may ask, is the strange looking plug in the right front caliper where the bleed screw is on the left one? That being said, is bleeding done through the left caliper only?
 
I installed new front brake lines and I am ready to bleed the brakes. What, if I may ask, is the strange looking plug in the right front caliper where the bleed screw is on the left one? That being said, is bleeding done through the left caliper only?

That should be a bleeder in the right front caliper as well.
If it was replaced with a bolt at some point in history? ick.
Mine (still) has little rubber caps that keep the grime out of the bleeders.
Might wanna pick those up as well when you go get a replacement bleeder.

In your case you are chasing air out today.
But once a year or so you also want to bleed out the older fluid sitting in the caliper where it gets hot.
The fluid absorbs punishment (heat and moisture) by turning brown.

Did you replace the line from the master cylinder?
If so it may occur to you that that air has to go through the ABS towers to bleed out.
It has been my experience that this air will come all the way out through the bleeders at the calipers, you don't need access to the bleeders on top of the towers (which are under the fuel tank).
Of course you will waste about a quart of brake fluid doing it.
 
Thanks, Scott. I am familiar with the maintenance requirements of brake systems and I also had the same experience on other bikes as you had as far as bleeding the ABS system is concerned. This strange plug has me stomped, however. It is not just a bolt. I have to take a picture and see if anybdy knows what it is.
 
It seems like all the Oilhead experts are still on the road back from the National.
Thinking someone may have messed up the caliper and I may need a new one, I looked at some at ebay and all of the ones from the same time-frame (98-02) have this plug. So it is definitely an OE BMW part

Have you guys who responded, looked at your 2000RT, whether it has the same plug?
 
I looked at some at ebay and all of the ones from the same time-frame (98-02) have this plug. So it is definitely an OE BMW part Have you guys who responded, looked at your 2000RT, whether it has the same plug?

Just checked my '98 and it doesn't have that part. :scratch
 
It seems like all the Oilhead experts are still on the road back from the National.
Thinking someone may have messed up the caliper and I may need a new one, I looked at some at ebay and all of the ones from the same time-frame (98-02) have this plug. So it is definitely an OE BMW part

Have you guys who responded, looked at your 2000RT, whether it has the same plug?

My 98 RT does not have that.
I have no idea what it is.
Did you try giving it a yank to see if isn't just a dust cap?
 
Here is a picture of the "thing"

The earlier 1100RT bikes had a bleed valve on both sides. The later 1100RT bikes only had a bleed valve on the left caliper. I don't recall the exact name of the part, but what you see on the right side caliper is a "fill plug." It was used at assembly to fill the brake system with fluid from the bottom. You can do several things with this:

. You can ignore it and just bleed the system at the left side.
. There's a grub screw on the top of the plug; you can remove it and screw in a bleed valve at that spot. This can be either temporary, just for bleeding - or you can leave it there permanently. It will sit kind of high up, but it will stay there.
. You can remove the entire fill plug and replace it with a bleed valve in it's place. Note that the fill plug is usually installed with Loctite and will require some heat to loosen the Loctite when you go to remove the fill plug. Once the fill plug is out, screw in the bleed valve and your brakes will be just like the earlier brake calipers.
 
Thank you all for shedding some light on this. It seems it is a 1999-forward change.
The service bulletin describes the bleeding procedure, which I interpret as needing to bleed the right caliper, not only the left.
There is still some confusion in the description as to when the fluid will come out of the caliper. First it says: Tighten the bleed screw by hand...so that the check valve is closed....Open bleeding screw again by ? turn (check valve open)But then it say in a "Caution" box: As the bleed screw is tightened, the valve opens and brake fluid flows out immediately

Well, I guess I will see...

Again, thanks to all for chiming in!
 
When you first install a bleed valve on the right side, there will be a little seepage. Just have a wet towel handy to wipe it away. Keep the cover on the MC closed until you are ready to bleed the lines. When you are ready to bleed the lines, place a bleed hose on the tip of the bleed valve before you crack open the valve. When the valve starts releasing the old fluid it will flow into the hose.
 
Here is a picture of the "thing"

You've probably got this sorted by now but the part you are looking at is called a grub screw and is used by the factory to fill your brake system with fluid from the bottom up. Most people remove it and replace it with a standard bleeder screw identical to the one on the left front caliper. This allows you to bleed both sides and get old fluid out of all those nooks and crannies. If you plan to do this make sure you heat that grub screw good and hot before you spin it out or you WILL damage the threads in your caliper. They are loctite coated at the factory and it is the tough grey stuff.

Some folks also replace all three bleed screws with Speed Bleeders which have a spring loaded one way valve in them. This eliminates the need to keep opening and closing the bleeder. You just open it once and pump the old fluid out.

I use a large syringe and the standard bleeders and refill my brakes from the bottom up like the factory does. Bubbles are easier to push up than down. :whistle
 
You've probably got this sorted by now but the part you are looking at is called a grub screw and is used by the factory to fill your brake system with fluid from the bottom up. Most people remove it and replace it with a standard bleeder screw identical to the one on the left front caliper. This allows you to bleed both sides and get old fluid out of all those nooks and crannies. If you plan to do this make sure you heat that grub screw good and hot before you spin it out or you WILL damage the threads in your caliper. They are loctite coated at the factory and it is the tough grey stuff.

Some folks also replace all three bleed screws with Speed Bleeders which have a spring loaded one way valve in them. This eliminates the need to keep opening and closing the bleeder. You just open it once and pump the old fluid out. :whistle

Be sure to get the grub REALLY HOT with a heat gun or similar (using caution not to melt the brake line or burn the finish on the caliper) before extracting it.
I am a big fan of Speed Bleeders. They make the bleeding job a 10 minute one. They also manufacture a replacement bushing for the rear caliper. BMW uses a tiny bleed nipple that shears off very easily...it screws into a bushing that is not readily available from BMW...DAMHIK.

Good luck.
 
I left the "fill plug" in the caliper and put the bleed screw in the top hole after removing the small allen plug (all as described in the service bulletin). Within 25 minutes I had bled the brakes and had everything back together incl re-installing the right fairing. Absolutely smooth job. No need to bleed the ABS unit. Good lever feel. 250 mile ride yesterday.

Thanks all for your help and educating me on this!

BTW: I looked at a bunch of Rs, RTs and other models during a club get-together yesterday and my bike was the only one that had this "thing". Wonder if the dealers take it off during a service job?
 
Back
Top