Botched brake bleeding job.

[Taarne]

Hello there

 

A little background information. I'm a proud owner of a '99 R1100S with 30k km (20k miles) on the clock. This is my second bike, just bought it last year, had a brief run with a honda 500 before that. While putting the bike to the garage last fall, I noticed the rear brake was quite sticky, it would hardly turn at all when I'd try to spin the wheel with the bike on the center stand. I decided to wait until the spring.

 

Today, it was sunny and a little above freezing, so I deemed it to be spring and thus time for a fluid change, to see if it would help. So, I hop and skip to get some dot 4 brakefluid, strip down a bit of plastic and get to it. I've never done it before, but I read all kinds of guides on it over the winter.

 

I open the back reservoir, top it up a little with fresh brake fluid, attach a tube to the bleed nipple, pump the rear brake for a while, then compress it a little, opening the bleedingthingy at the same time. Lo and behold, some rather brown liquid pops in the tube. I compress the brake a little further, being careful to not bottom out the brake. I repeat this a few times, but..there's not really that much liquid coming out before I feel the brake starting to bottom out and me having to close the valve.

 

About 45 minutes after that, I go back to the house grumblin, very much aware of the fact that I just [censored]ed up the whole thing. Great, the brake is no longer sticky, but it doesn't do anything, either. Push the brake as far as one can, nothing happens. Clickety-click, it makes a wondeful sound, but..nothing happens. On further attempts to drain out the system, nothing comes out of the system with the brake level pressed down. The reservoir is still topped off.

 

Why didn't I take it to a dealer? I'm living in Norway, the land of crazy prices, my norwegian is very rusty (I'm finnish) and the nearest place is some 150-200km away. Plus it sounded really easy .

 

I was careful to close the valve with the brake compressed, yet not bottomed out. I didn't flip the lever up and down with the valve open. What did I do wrong?

 

Once I cooled off a bit, I went for the first ride of the spring, though. Who needs the rear brake, anyways 20km, and a big smile on my face, despite my mechanical retardness =)

 

Any help would be much appreciated =)

 

-Taarne

[Wooster]

Say Taarne,

Rear brakes are an important control; air in your system's affecting yours. So get another can o'dot 4 and try again. Some people use speed bleeders in place of stock nipples; me, I use a plastic vacume pump. Whatever, don't give up on those brakes !

 

Wooster

[Green RT]

If you pump the brake pedal, will it eventually build up pressure? Wooster is right. It sounds like you have air in the system. The rear brake is pretty easy to bleed without any special tools (Mity-Vac or Speedbleeders), since the pedal and the bleed screw are pretty easy to reach at the same time. Sounds like you have the procedure down pat.

 

Personal confession... I once drove an old car around for several weeks with brakes that required pumping two or three times before anything happened. I just planned ahead when I wanted to stop. I finally cured it when I realized they were just way out of adjustment. These were old drum brakes. That can't happen with disc brakes. It is amazing the things we survive.

[AviP]

Who needs the rear brake, anyways

I had a ZX11 without a rear brake for a long time and I hardly missed it. It is arguably more useful on the track.

 

As to your problem, I'm thinking air too.

[russell_bynum]

Just to clarify...are you sure you've topped off the rear brake fluid reservoir?

 

[russell_bynum]

It is arguably more useful on the track.

 

FWIW, I can't say I've ever used the rear brake on the track, but I use it on the street quite a bit.

[Steve W.]

I think because of your original problem with the sticking brakes, which are now fine. The sticking was caused by the master cylinder not releasing the pressure in the system. Be sure you have some "free play" between the master cylinder piston and the actuator. If the piston does not return to rest the fluid can not flow from the reservoir to the master cylinder. Sounds like your bleeding procedure is OK. If the free play is there and still no brake action, the master cylinder is probably bad. The cup seal on the piston is "gone". A rebuild kit may be available at the stealers.

Cheers

Steve

[Taarne]

If you pump the brake pedal, will it eventually build up pressure?

 

Thing is, I don't seem to have any pressure anymore. It seems I ended up with totally dead brakes, and I can't quite comprehend just what it is that I did wrong. When I fully depress the rear brake lever, pretty much nothing happens. The wheel spins as freely as it did when the brake is pressed, if the bleeding valve is open, no fluid comes out, a couple of air bubbles *at best*.

 

I don't think there was any air in the system when I started, the fluid was just quite old and dirty. Am I supposed to hold the brake lever as far down as I'm able, or to strictly keep it from bottoming out?

It's hard for me to understand how I could do such a crap job of a seemingly simple operation - hold down brake lever, open valve, wait a bit, close valve, pump brakes and repeat, while monitoring the fluid level.

 

Also, in all guides I've read, in case you happen to run the fluid reservoir dry, you have to just start over. I'm completly ok with starting over. It's just an extra 30 mins and a bottle of dot4 at most - it just..doesn't seem possible. Zero pressure at all. I've tried pumping the brake for a few minutes, opening the valve with the lever down, and shutting it again. Doesn't seem to help

 

I also checked out the Speed Bleeder website for an alternative option. Here follows some utter newbie questions, I hope you can bear with me =)

"Remove the old bleeder screw and discard." when doing this, I assume the whole system should be clean of fluid? Does the whole bleeder screw come loose by just unscrewing the valve screw further?

Also, for R1100S, it's SB1010S for the front and SB6100 for the rear? Do I need the BMW "adapter kit"?

 

I'm a little embarrassed asking all the questions, but I feel a second failure in areas directly related to my well-being is definately not a good thing, so please bear with me

 

-Taarne

[philbytx]

I would do the bleed but remove your rear caliper, push the piston fully back (watching to make sure you have sufficient room in your fluid reservoir for it whe you do!!) and then put blocks/shims in the caliper. THEN do your bleed using the tube/container method watching the flow. Hopefully, its not a shot master cylinder.

[Ken H.]

If you observe the master cylinder carefully, is the piston returning, or just the linkage? Everything you are saying is pointing to a stuck master cylinder.

 

Another check, as mentioned, take the caliper off and push the pistons back. Now, before blocking them, carefully push the pedal. Will it move the pistons out at all? With nothing to push against, even with a bit of air in the system if the master cylinder is working the pistons should move a bit.

 

Is this an ABS bike? If so, there is a secondary bleed point on the ABS unit under the tank. You may have to go there and try a bleed to help figure out what is going on.

[A-Red Bill]

It is probably going to take about 20-30 minutes of non-stop pumping and bleeding. I changed my brake hoses a while ago and it took quite a while to get things going again.

[Taarne]

Thanks for all the replies =)

 

No, it's not an ABS bike, and I definately topped off the rear brake fluid reservoir

 

I'll try the pumping some more. I'm not totally comfortable with taking apart the brakes, but.. It's not rocket surgery, can it? Could I possibly get a small walkthrough, please? Any special tools I'll be needing for it? Thanks

 

-Taarne

[SWB]

Thanks for all the replies =)

 

No, it's not an ABS bike, and I definately topped off the rear brake fluid reservoir

 

I'll try the pumping some more. I'm not totally comfortable with taking apart the brakes, but.. It's not rocket surgery, can it?

 

Not hard at all. Pull a few bolts to remove the calipher, as I recall, press the piston's back into the calpher (to clear the rotor as you remove it, and also to block open with wood shims while your performing the bleeding, so you get all the old fluid out of the calpher). Use a rope or plastic tie to support the calpher while it's detached from the bike. Also, before you press the calpher pistons back in, clean them throughly with brake cleaner (so the dirt doesn't get pushed into the rubber seals around the pistons, damaging them and causing a leak.) In addition to checking for leaks, and checking your brake pad wear, removing the calipher enables you to clean up the pin upon which the pads hang, and then lubricate it. A dirty, corroded, and/or rusty pin could cause your brakes to stick and the pads to wear prematurely.

 

From personal experience, I'd skip the speed bleeders. No, they don't let air in, or at least not much, when you pull the OEM bleeders out to replace them with speedbleeders. But the speedbleeders let allow trace amounts of air in around the fittings, which cycles back into the outbound drain line. I can't tell whether the air is coming from the brake lines or from around the fitting of the speedbleeder (i.e. which is harmless, but annoying).

 

Also, the first "new guy" mistake I made was being a bit too cautious about opening up the bleeder. I was so afraid that the fluid would drain out in 3 seconds allowing a brake line full of air, that I didn't open the bleeders enough to allow the fluid to exit. Open the (conventional OEM) bleeder up half to a full turn, and when you get fluid moving, meter it back a bit more towards closed. Just make certain you close the bleeder as your in the last half of your compression stroke on the hand brake of foot pedal. That'll keep positive pressure through the line, keeping air out. And of course, as you know, keep the reservoir topped off. It's 3-4 strokes on the brake pedal, close bleeder, top off reservoir, then press the pedal again, open bleeder, 3-4 strokes, close bleeder 1/2 through the last stroke, top off reservoir, repeat, repeat, repeat.

 

Also, take a close look at all your fittings. Through age, rot, or the work you're doing, those fittings could open up and let air in. If you see any moisture around any of the fittings, calipher pistons, or master cylinder, you need to replace some parts until you have a sealed system, and then rebleed the whole system again to get rid of the air.

 

Good luck..

[Eckhard Grohe]

Brown fluid. Could it be that the fluid change has been neglected for so long that the master cylinder is badly corroded?

 

The people on this board a very helpful. If we knew where you lived someone might offer to come over and give you a hand. Please fill in some of you personal info.

[Joe Frickin' Friday]

Brown fluid. Could it be that the fluid change has been neglected for so long that the master cylinder is badly corroded?

 

The people on this board a very helpful. If we knew where you lived someone might offer to come over and give you a hand. Please fill in some of you personal info.

 

OP mentioned he lived in Norway; if you book a flight now you might be able to get there by tomorrow morning.

[bmwmick]

Thanks for all the replies =)

 

No, it's not an ABS bike, and I definately topped off the rear brake fluid reservoir

 

I'll try the pumping some more. I'm not totally comfortable with taking apart the brakes, but.. It's not rocket surgery, can it? Could I possibly get a small walkthrough, please? Any special tools I'll be needing for it? Thanks

 

-Taarne

 

Taarne,

I believe Ken is correct. Your rear master cylinder piston is not returning. If your brake fluid was brown and 'gunky' (technical term) the piston has probably frozen in the cylinder. Best thing to do is just order a new one and install it. You 'could' remove it and attempt to clean it out but once the interior is etched, it is usually not worth the expense of rebulding. Do you feel 'any' resistance when you push down on the rear pedal? If not, time for that new M/C.

P/N 34312335717 $130 USD at http://chicagobmwmotorcycles.com/

 

Mick

[Eckhard Grohe]

OOPS!!!! I must have missed that in my reading of the correspondance. No offense was intended.

 

Have a great day!!

 

Motobins in England is closer. And they might have a rebuild kit.

[Taarne]

Alright, more troubles follow

 

Tried bleeding it some more, seemed dead. I removed the caliper from the wheel, removed the pin keeperthingy and the pin. It was dirty, but came out without big troubles. Both pads dropped, and with them what I assume to be.. an anti-rattle spring? Which I assume is important? Because I can't seem to figure out how it will fit back in there.

 

It looks like the only way to clean the cylinders is to pop out the pistons - I tried carefully pushing the brake lever down, to see if they would move at all. Nothing Even if I would completely remove the caliper, I don't have an air source to help pop out the piston, so I'm afraid my DIY-brakedisaster might end here Except that I don't know how to get the antirattlething to fit in with the pads.

 

At age 20, my knowledge of all things mechanical is pretty feeble, but I feel I should be able to do at least some sort of work on the motorcycle I ride. I read as much as I could on the subject, but.. I suppose it was a little more complicated than I thought I have to thank the folks on this board though, you are a very helpful and friendly bunch, cheers

 

-Taarne

[Wooster]

Taarne,

 

The cylinder that some board members are suspecting as the chief problem is not the slave cylinders (they're the ones that you're alluding to); rather the master cylinder is what your brake pedal activates when pressed. This then creates hydraulic pressure which activates the slave or wheel cylinders. Many years ago an excellent mechanic convinced me that slave or wheel cylinders are less likely to cause problems; the master cylinder is more likely to fail. And, assuming your brake pedal isn't returning to it's horizonatal postion, I, too, suspect the rear brake's master cylinder.

Now, in regards to where the anti-rattle spring goes, I suggest that you log onto to www.maxbmwmotorcycles.com and go to their parts page: rather detailed drawings are there to help locate where specific parts go. My bike and Haynes manual are both in another state so I'm unable to offer detailed location of anti-rattle spring.

 

Wooster

[Taarne]

Oh!

 

I was kind of wondering about the master cylinder, but just assumed it was in the caliper. Or something similar.

 

I'm going to take the thing apart tomorrow, see if there's anything I could do about it, and order a new one if there isn't. I'm having nightmarish visions about the brake fluid spraying overall, but I'm prepared

 

Once again, I really appreciate the help =) It's certainly teaching me lots about motorcycles, and keep me humble as well

 

-Taarne