Help with bleeding ABS brakes

[Geoff Crowther]

Hi
Bit of a stranger on this page, cos I've got a 1200.
But ... a pal of mine (as the saying goes) has run into a problem with his 04 650GS.
To alleviate a dragging rear brake, he's stripped the rear caliper and ensured that's ok, found that his master cylinder wasn't moving freely, so replaced it with a new one.
Now he finds that the system won't bleed. When he presses the pedal there seems to be no movement of fluid or air.
Please bear in mind I've not seen this; it's only come via a phone discussion so far.
Looking at my 850R Haynes manual (used to own an 850R) I note that they seem to say that you can't bleed the brakes on an ABS bike without a "pressure bleeder". Never heard of one.
I used to do all the maintenace on my pre ABS K100RS and all previous bikes, but I've never worked on an ABS system.
Can anyone offer any help/advice or does my pal really have to (as Haynes imply) "take it to a BMW dealer"?
Bear in mind the rear brakes on the bike are now disabled.
Any practical advice would be welcomed.
Cheers
Geoff

 

[barrym]

Geoff

Suggest he takes a look here:

http://faq.f650.com/GSFAQs/TheABSFAQ.htm#ABS & Brake Bleeding. Can I still do it myself

No personal experience of bleeding ABS bikes either, but I think, from what I've read I'd leave it to a dealer. Even some of the BMW specialists won't touch the ABS versions of some models.

Not much help really

 

[Geoff Crowther]

Cheers Barry. That looks like as complete an answer as is possible.
Many thanks,
Geoff

 

[rc mad]

you won't actually bleed the abs section of the brakes, you need the computer to open the valves to do that. The only bit you'll do is from the master cylinder to the abs unit then to the rear brake.

I've not bled the rear brakes on mine but the front were easy. I filled the master res to the top, made sure the bleed nipple was closed then pressed the lever, then with the lever held in i undid the nipple to release the pressure, closed the nipple then released the lever. I repeated this procedure till the lever felt firm. topping up the master res as needed making sure it didn't fall below the minimum level.

last thing i did was hold the lever in with a cable tie overnight to allow any air bubbles to escape.

If he really wants to bleed out the fluid in the abs pump he'll need to activate the rear abs, which will mix the old and new fluid, then re blead the system with fresh fluid, sure it means the fluid in the abs unit is a mix of old and new but it's better than the old. Personally i wouldn't bother with this step, i'd just make sure to activate the rear abs a few times to mix the fluids properly.

 

[RadioActive]

I think rc mad has summed it up. I've replaced the front lines on my 650 ABS and 1100 ABS and just used a one-way bleed valve on the end of some rubber pipe in a jar of fluid. Good luck!

 

[Geoff Crowther]

Thanks guys. I've given this very useful info to my pal.
Cheers
Geoff

 

[ratrider]

I've bled my 02 650GS ABS just fine.

Bled as normal, then rode to a road behind an industrial estate, put my faith in BMW ABS, and slammed on both brakes a few times, and bled again. Brakes and ABS been fine

 

[the venturer]

Bled mine last week. I tried for half an hour for the rear, but 10 mins for the front.
The gist is that you should try not to let air inside. To avoid this, bleed through the nipple as you strongly push the pedal. It is as follows in short: PRESS THE PEDAL, UNSCREW NIPPLE NUT, LET SOME OLD FLUID SQUIRTING OUT, SCREW NIPPLE NUT, LEAVE PEDAL AND SEE ITS MOVING UP. And continue doing this several times till you are happy with the pedal's response. NEVER forget to fill in the fluid to the maximum right after every two bleedings, otherwise you may let some air bubbles in. Don't worry, the membrane inside the reserve will empty some fluid after putting it back.
After all, test-ride the bike carefully please, and bleed a few more times if necessary.
P.S. -Keep in mind that fluid may harm your paintwork.
-It is DOT 4, strongly recommended and change every year.
-Rear fluid reserve takes only very little fluid and therefore more prone to
let air in when empty. Watch this while the bleeding.
-Be careful with the membrane inside the rear fluid cap. You are not
going to fill inside the membrane, only the cap itself. Membrane
prevents the air from being sucked up in while compression.
-As for the front; may squirt outta each time you squeeze the brake
lever. To prevent this; close the reserve cap but don't screw the bolts.
Easier to open it back for each refill.
-Keep caps and around very clean.
-Always use a LOCTITE or RITE-LOK TL43 NUTLOCK for the rear cap nut
and bolt.