ok - so how bad did I screw myself?

[Tom_Becker]

So, I did a brake job today. First up on the agenda was changing brake fluid. I had obtained the speedbleeder bag and was confident about doing the job.

First I did the handlebar level circuit followed by the footpedal. Everything went according to plan. The brake fluid needed changing and it was nice to do it myself. Next I did the rear foot pedal circuit and again no problem.

Switched over the front wheel cylinders. I compressed the brake calipers since I was putting new pads in. It took a bit to get the pistons to move but they did go in. And yes, I took some fluid out of the reservoir so it wouldn't overflow. I'm feeling good - front brakes done fluid changed. Life is good.

Finally, I head to the rear. I removed the pads and pushed the caliper cylinders back in. Now I get ready to change the rear wheel caliper fluid. Turn on the ignition and lightly squeeze. My helper reports fluid and I'm looking in the reservoir - it doesn't seem to be going down.

OH CRAP! I was looking in the rear reservoir not the front. I drained the front reservoir and my helper reports air bubbles coming in to the speed bleeder bag. Now I'm thinking what in hell did I do to myself?

Well the only thing to do is to start filling the right reservoir and pump a lot of fluid through to get the air out. Well I did that about 8 times. Helper reports no air coming through.

So what kind of mess did I make? Any advice?

Tom

[tbarstow]

Sounds like you recovered your error properly.

If the front brake lever doesn't feel spongy, you should be fine.

Make sure you change the fluid in the servo unit as well. It isn't hard to do and doesn't require the modified 7mm wrench to get to all of the bleeders.

[cfell]

Sounds like yo ugot it, Tom! Ride.. enjoy.. repeat.. if you notice erratic rear brake function then reflush.. riding it a while will allow bubbles to "congregate"..

[Tom_Becker]

Well I put everything back together. This was a major maintenance job. About the only thing I didn't do was flush the clutch line and check the valve clearance.

Anyway, the brakes actually feel better now than before. I did multiple emergency stops to check ABS function. Could not get it to go into typical ABS "chatter" mode but stopped as straight as an arrow. I did not have any fading or sponginess. In fact I had no evidence of any kind to suggest that I had to bleed the brake lines multiple times.

I think your advice about watching it and re-flushing might be the ticket. I'll just have to see how braking action is over the next couple of weeks.

Tom

[jzeiler]

If you have gone that far without a fault indicated, I would say you were successful. Another tip for recovering from a bad flush (letting air in) is to run the line from the caliper back to the reservoir. Let the pump cycle the fluid until the bubbles are gone.

[Tom_Becker]

Thanks for the tip about running the wheel cylinder output back to the reservoir. That's a real good way of clearing the trapped air.

Kind of makes me think of an aquarium pump except without the fish.

[cfell]

make sure you run a clean hose...

[Tom_Becker]

I rode about 35 miles through the mountains yesterday. No fault lights came on - nada... ran like its supposed to.

Tom

[BeemerRiderBoB]

I'd say you're good to go.

One last check we do after brake flushes is to hook up a GS-911 to clear the old error faults. If someone nearby has one might be worth a check to verify everything is ok and clear any old faults. Alternatively you can take it to the dealer but there's a growing number of members who have these diagnostic units and are willing to help.

Here's a link to the thread on list of GS-911 owners.

http://www.bmwlt.com/forums/showthread.php?t=24561