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Slow Brakes


RonB001

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Hi, All

 

Newbie here (new to BMW and 2-cylinder motorcycles)

 

My new-to-me R1150RT has a really weird braking behavior. The brakes are s_l_o_w.

 

When I squeeze the front brake lever, I can feel the brakes slowly start to apply over a 3-5 second time lapse. Of course, by the time I back off, I am getting a lot more brake than I intended. Then, when I release the brake lever, it takes about the same amount of time (3-5 seconds) for the calipers to release braking and the bike to start rolling again. This makes slow speed corners kind of tricky.

 

The ABS lights sequence normally, and go out when I start rolling.

 

Is this something that has been seen before, and has a known cause? I looked through all 60 pages of results for "brakes", and all 20 pages of Oilhead threads, without finding anything similar.

 

The previous (2nd) owner rode about 2,000 miles a year. The bike has about 40,000 miles. It looks to have been ridden gently. I haven't yet done any maintenance on the bike. This was my first ride, about 25 miles just to start getting used to the bike.

 

Could this be a "low voltage" issue? Or, is it more likely to be a brake bleeding issue?

 

Regards,

RonB

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A total brake and clutch bleed is just the beginning, if your lucky that's all it needs. Does it still have the rubber brake lines?

(Mine still does)

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It probably does still have the original lines. The previous owners were of the "take it to the dealer" type.

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It probably does still have the original lines. The previous owners were of the "take it to the dealer" type.

Several possibilities. While I agree the hoses are most likely, could also be nearly-stuck caliper piston(s) and/or a couple other things.

 

You didn't state what year 1150, but it is more than a decade at least -- I would suggest replacing the lines with stainless steel hoses (my preference is Spieglers, others like Galfers, etc.). While the hoses are off you could check how smoothly the pistons move and decide whether caliper rebuilding is in order to clean out accumulated crud (hopefully not corroded pistons and/or bores in the calipers!).

 

If you can get up to Northern Virginia sometime, I would be happy to lend a hand/garage.

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Thanks to both of you for the quick replies.

 

I have speed bleeders on order.

 

More rides will help determine whether this is a "one off" or a consistent occurrence.

 

Garage space I have. Competence with this bike I lack. Oh, and not a lot of time to spare, either. :-)

 

Let's see what happens with all fresh fluid.

 

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Morning Ron

 

It could indicate air in the wheel circuits that allows the pumps to take longer than necessary to pressurize the calipers, or as Mark mentioned, sticky calipers (are the brakes also slow to release?)

 

In any case it indicates something seriously wrong with the brakes so--

 

As Pas mentioned start with a full ABS system bleed (both control circuits & wheel circuits) then see if they feel & work better.

 

If not then get the brakes checked out by knowledgeable BMW technician.

 

You don't need speed bleeders to bleed the power assisted BMW I-ABS system & in fact, unless very careful, they can damage the ABS controller valve body.

 

 

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You don't need speed bleeders to bleed the power assisted BMW I-ABS system & in fact, unless very careful, they can damage the ABS controller valve body.

 

Thanks for the heads up. That would be a very expensive mistake.

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greiffster

 

You don't need speed bleeders to bleed the power assisted BMW I-ABS system & in fact, unless very careful, they can damage the ABS controller valve body.

 

 

DR, I have not heard this before. Can you explain?

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Morning greiffster

 

I've seen 2 myself & there have a been a few others reporting issues.

 

On the BMW I-ABS controller valve body the alloy that the valve body is made out of is somewhat brittle & a couple of the bleeder nipples are near the corner so screwing in a speed bleeders with the encapsulated sealer on the threads can expand the bleeder nipple hole enough to crack the valve body.

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So using speed bleeders on the calipers is not a problem then? Your warning is only to avoid using them on the controller body itself?

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Afternoon Rex

 

Yes, they won't do any harm to the calipers, but on the other hand you bleed the wheel circuits (calipers) using the powered-up I-ABS controller servo pumps so I guess I don't see the need for speed bleeders on the calipers.

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biometrics

+1 on changing the rubber brake lines before they FAIL. I was fortunate that the rear brake line failed in my driveway and not on the highway. The rear line split while I was checking brakes before departure on a trip of a couple hundred miles... brake fluid squirted clear across my driveway. When I change the front lines, it was apparent they were in just as bad a shape.

 

Your life is well worth the investment. No matter how well you think your old bike stops now, the stainless braided lines will be an unbelievable improvement.

 

-John

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roger 04 rt

Finally changed my rubber brake lines for Spieglers. The lever and pedal are now solid, in a good way, after the levers have bottomed. I do wonder if the abs was designed to take the compliance of the rubber line into account and if that means abs performance will now be different--unknown.

 

On another note, I couldn't make a living bleeding brakes. I must be the slowest in the world. I find it takes me an hour per control circuit to reload with fluid, get the air out via the 3+1 bleed screws, and continuously clean up my spills. Those control circuit bleeders are a PIA to get at and keep a hose on.

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On another note, I couldn't make a living bleeding brakes. I must be the slowest in the world. I find it takes me an hour per control circuit to reload with fluid, get the air out via the 3+1 bleed screws, and continuously clean up my spills. Those control circuit bleeders are a PIA to get at and keep a hose on.

 

Roger that.....uh, Roger. If you're the slowest, then I'm the second slowest. Good feeling when I'm done, though.

 

One small thing that improved my experience was getting an offset box wrench for those control circuit bleeders. It wasn't the easiest thing to find. I ended up rolling the dice on a set from Harbor Freight. As always, their stuff is a crap shoot and these were marginal quality, but the 7mm wrench works well for getting at those bleeders on the ABS unit.

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roger 04 rt

Thanks Wayne, I needed something like that. Had to remove the abs connector without having them. Then have to tape the abs sockets to protect from fluid. Then bleed hose pops off. Then wipe up and wash. Then move to next bleeder. What a klutz on this one ...

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Hi, DR

 

Yes, the brakes are slow to release.

 

I gave it another try yesterday, and the brakes were smoking by the time I got to the end of my street (1/2 mile).

 

So, I need to take a look at the calipers as well when I get my brake bleeding stuff.

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Hi Ron

Can I reiterate that your problem sounds like time for new hoses.

Of course you will find out when you get the calipers off. But the pistons will probably feel stiff anyway.

So it looks like you should do a very careful full brake service and replace the hoses.

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Hi, Andy

I hate it when somebody else is right :-(

I was going to try to just flush the fluid so I could get some riding while waiting on hoses.

Nothing was coming out! So, I squeezed a little harder, and the upper line let go squirting me almost in the face.

 

So, lines will be on order shortly.

 

Best Regards,

RonB

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  • 2 weeks later...

All better.

 

Got lines and new pads from Speigler.

 

Pistons pushed back nice and smooth.

Followed the procedure for bleeding, and got a nice, solid pedal and grip.

 

Now, brakes work very well. I have only ridden it to work twice so far, but it is very comfortable.

 

Many thanks to the forum contributors who helped :-)

 

I need to set aside some time soon to get comfortable with the low-speed handling.

 

I also need to empty the tank to replace the internal fuel hoses. If the POs didn't do the brakes, I can't imagine them doing that either.

 

The fuel pump stuff is on the bottom of the tank, right?

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The fuel pump stuff is on the bottom of the tank, right?

The tank is somewhat saddle-shaped. The fuel pump/filter/low fuel level float arm are mounted on the round metal plate that is on the lower portion of the inner side of the right "lobe" of the tank.

 

Check Chris Harris' oilhead fuel filter replacement videos to get a sense of what's inside and how you have to maneuver the assembly to get it out of the tank.

 

Also, check your external fuel line quick-disconnects -- if they are plastic, replace them with metal ones for somewhere like beemerboneyard. BMW had a formal NHTSA recall to replace the male halves with metal male parts because the plastic ones are *quite* prone to break. Better to replace both halves with metal to eliminate the issue. And use proper fuel injection hose clamps.

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