Bleedin abs rear brakes!!

[Chris G]

Hi All

just started bleeding the rear caliper on the gs, got about 15ml out of the bleed nipple [with resevoir full and being topped up] pumping through via brake pedal, when it all goes wrong and the fluid stops coming out of the caliper and the pedal starts to feel like it is just pumping air anyone get any ideas, or do I have to whip the tank off and do the first bleed from the pedal to the abs unit nipple [which i'm not to keen on 'cos thats bound to go wrong]


Heeelp

 

[PeterNicholson]

Aha - BTDT!

Leave for 1/2 hour or so, then go back an bleed it again the same way.
If you have a vacuum pump, this does make it much easier. Can't vouch for the SpeedBleeders as I don't have them.

Leaving it seems to allow the air to collect towards the top of the system, where you then have more chance of removing it, as it is in one big lump.

It may take several goes to get all the air out, but it did work for me.

Where are you? There may be someone close by who can help.

Good luck!

P

 

[Dave Hall]

I have a Mityvac (US) vacuum bleeder which makes it a doddle.
Performance Parts 0114 258 1151 have them.

 

[Chris G]

Cheers for the replies,
the problem was that i'd lost some fluid from the rear caliper when I took the nipple off, this had dragged some air to the abs pump and this has taken me about 7 hours to completely purge and get an air free rear system

 

[(RIP) maverick]

Tried to bleed my back brakes yesterday and they are now even worse. Had a pipe over the nipple and the moment I opened the nipple about a 1/4 turn the brake fluid pissed out at the bottom and not through the pipe. There is a large nut holding the nipple in place but that did not move WTF am I doing wrong?? Gave up after an hour and now have no back brakes.


Feckin bike is doing my head in

 

[Chris G]

Tried to bleed my back brakes yesterday and they are now even worse. Had a pipe over the nipple and the moment I opened the nipple about a 1/4 turn the brake fluid pissed out at the bottom and not through the pipe. There is a large nut holding the nipple in place but that did not move WTF am I doing wrong?? Gave up after an hour and now have no back brakes.


Feckin bike is doing my head in

sounds a bit like wot mine did, has the nipple snapped off where it comes out of the "large nut" ,cos if it has you now have loadsof air in the rear system and if it's an ABS bike the near horizontal rigid brake pipes really don't help the bleed [cos they seem to trap the air] only thing is to persevere mine took a couple of hour the first time due to the nipple snapping off, since then takes about 10mins tops - good luck

 

[(RIP) maverick]

sounds a bit like wot mine did, has the nipple snapped off where it comes out of the "large nut"

Chris I don't think the nipple snapped off as it is still there and not leaking brake fluid. But it seems when I bleed it the fluid escapes around the nut section and not through the nipple. So how many hours are we talking about pumping the brake lever before I get some pressure back again?

Ohh boy and it is not like I won't need it next week going to the Elephant rally.

 

[Chris G]

the nut bit is sealed into the caliper with an O ring, that may have been distrubed?? and damaged?

if needed the nut and bleed nipple are a bmw part [c34.21.2.314.017] and cost about £4

I eventualy bled mine in 2 stages
1 resevoir to the abs unit
2 abs unit to caliper

whole job took friggin ages

it can help i belive to lightly tap the metal brake pipes to the abs [to help move the air bubbles]


I am now running out of ideas, where's "the Mechanic" or "boxertools" when you need 'em

Again good luck

 

[Guzzler]

Bleeding brakes are a pain, no matter what (IMHO).

On the 1150GS with ABS you have to do it in two steps. First at the ABS unit, then at the caliper.

Make sure the reservoir is topped off.
Make sure you know which nipple on the ABS unit is front/rear.
Put a clear hose on the nipple into a jar of brake fluid (to watch bubbles and color of fluid)
Pump the brake three times slowly.
Pump and HOLD the brake.
While holding the brake fully compressed, loosen the nipple (brake lever will move, DON'T release the brake lever)
Tighten the nipple
Repeat the pump and hold, lossen/tighten nipple, pump, etc process.

Alot of people tend to try to lossen the bleeder nipple and just pump the lever acouple of times, then tighten the nipple. That doesn't work.

I have tried several alternative methods, MityVac, pump fluid from the caliper to the reservoir, etc. I always come back to the old tried and true method above.

One final trick that sometimes works. When all done, tie the lever to full compressed and let it sit overnight. The remaining microscopic air bubbles will coalesce, and ride the line to the highest point. The reservoir for the clutch and front brake. The rear brake tends to send bubbles to the ABS unit (so you have to bleed again at the ABS nipple)

Two BIG details to keep in mind when using the above method.
1. Keep any eye on the reservoir. Don't let it get low and suck air.
2. Pump SLOWLY and EVENLY. Short rapid pumping induces bubbles.

 

[bmwrich58]

Bleedin the brakes can be a night mare if you've never done it before.
And, if you have the newer generation EVO brake system, ie: power brakes, the fluid replacement is done totally different.

I personally don't like using the "Mity Vac" system. And especially don't use it on the "New EVO power brakes". The pump on the EVO will push the fluid for you at an alarming rate. So be careful, and if it's your first time doing this procedure, get help from someone who's done it before.

This is one service that you don't want to "screw up"!!!

You gotta be able to "stop"...Right...???...

Signup at www.BMWST.com that's where I hang out at.
Do a search on "brake bleeding". There you'll find step by step instructions for both generations of "Brake Service" and wonderful informative pictures. Goodluck ! Rich

 

[iletts]

Chris,

Have never done the job, I've only had my GS for a few weeks, but have just downloaded a maintenance manual from the states. They warn that pushing the lever right down (or to the bars for front brakes) may cause the master cylinder piston to leave the bore and damage the seal. As an established engineer I found this difficult to believe, but your initial symptoms would bear this out. The BMW manual states the use of a vacuum bleeder, which would tend to support this also. Its not a difficult recovery, strip down and replace master cylinder seal, and start again - with a vacuum bleeder!

 

[richie]

Bled my brakes a year ago at a mates. He had the kit to do it and it took only a few minutes. With the ABS system I think you'd be asking for trouble to bleed the bleeding brakes without the proper vacuum kit.

Good Luck