Partially Integrated brake swap Partially Completed, ATTN: BRAKE EXPERTS

[swilson143]

Overall I'm really pleased with the 2002 R1150RT I bought a few weeks ago. While the brakes are excellent... having the front calipers activate while depressing the rear brake lever is TERRIBLE. I'd probably just let myself adjust to it if it weren't for the fact that I ride a R1150GS-P 40-hours a week at work, and it has Partially integrated brakes.

With partially integrated brakes, when you pull the front brake lever, both front and rear brakes are activated. However, when you press the rear brake lever all you get is rear brake. IMHO, this is the best of both worlds. You get the exceptional integrated braking when combo braking (or cheating and only using the hand lever). But you maintain the ability to use the rear brake for really right turning manuevers or parking manuevers and can also use it to slow yourself a bit if you've set yourself into a turn too fast and need to drag off some speed.

So, I set out on my quest for Partially Integrated brakes for my RT. Unfortunately I didn't find any info on this online. I went to the two nearest BMW motor dealers and spoke with the techs, but they were no help either. My agency had sent me to CHP for their 80 hours school for certification, so I've spent about 40 hours on one of their R1150RT-P models and knew they had the Partial integral brakes, not the fully integrated brakes.

I started calling bike recyclers all over the place, but couldn't find any with an ABS modulator from in RT-P in stock. I located an RT-P ABS modulator on Ebay and won the auction, but the seller admitted it came from a wrecked police bike and it was unknown if the unit had been damaged in the wreck. Anyway, I installed it today.

I had no surprises during the installation, though I had never had the misfortune of going through the factory brake bleeding process before... sheesh! Nine bleed screws? What were they thinking?!

The RT-P modulator swap has done the trick. I now have integrated brakes when I pull the front brake lever, but only rear brake when I press the rear brake lever. Its heavenly. But, I have one abnormality... and its gotta get solved.

BRAKE GURUS... HERE'S WHERE I NEED YOUR HELP!
If I slightly pull the front brake lever and leave the lever there about 1 second or more, the upper Red brake warning light blinks rapidly and the rear brake pump (or servo) stays on. The only way to correct this is to turn the ignition off and on at the key and reboot the brake system. I can also get the error if I've activated the brakes at a normal pace, but then release the front brake lever slowly and hold it for more than a second where its just short of entirely released.

I took the bike out for over an hour tonight and FLOGGED the brakes. They're working absolutely great except for this weird thing I described above. I even tested the ABS... rear only and then front and rear together. Worked as it should.

Anyone know the solution? I'll be thrilled if the answer is I didn't bleed the brakes well enough or something like that.

Scott

 

[swilson143]

Ok, maybe this forum doesn't have brake gurus to reply. But! I found the solution!

While riding the bike today noticed another oddity about the way the new brake setup was working. When using the front brake lever the brakes were extremely 'grabby', especially the front calipers. One of the things I noticed when I did the swap was the increased size of the reseviors on the modulator housing. Made me wonder if the internals were also larger. See photo...



So I decided to tear the thing down again. This time I opted to separate the controllers from the hydro pumps and swap them. So now I'm running the RT-P controller, mounted to my original RT hydro pump. I put it back together and its MONEY! The bike has the partially integrated brakes I had to have, and I got rid of the grabbiness that the other hydro pump was causing, and went back to the comfortable feeling brakes it originally had.

As for the weird brake error I was getting? I didn't get it put back together till about 2:30am, so I only put a mile or so on the bike so far. No brake warning lights on my short test ride or during the brake bleeding process. Looks like I've got it licked. I'll take it for a ride tomorrow morning and see if any weirdness pops up.

Scott

 

[Troutluck]

Brakes, eh? Never use 'em myself. They'll throw you right over the bars.

 

[jimvonbaden]

Nice detective work, especially for anyone in your shoes!

Jim

 

[swilson143]

Nice detective work, especially for anyone in your shoes!

LOL.

So I took it out for a 40 mile ride through the twisties this morning. Its about 99%. I got one brake error as I was turning around at the end of a dead end road. Same as before, lower red light ON, upper red light rapid blicking, which is supposed to mean one of the brake circuits is in residual mode. Couldn't repeat it though.

The brakes felt really comfortable during the whole ride.

I'll ride it as is for a few days and see how it behaves. I'll post an update when I know more. So far I'm very happy!

Scott

 

[Rinty]

brakes

Scott:

Seems to me you're in the wrong job; you should be with NASA.

Rinty

 

[swilson143]

Scott:

Seems to me you're in the wrong job; you should be with NASA.

Rinty

Thanks. I started out as an electrical engineer... I would have ended up dying young had I stayed in that career. I'm much happier chasing down bad guys.

I've been wrenching on my own cars since I started driving, so by now not too much intimidates me on vehicles. If you've got too much time on your hands, check you the 1966 Toyota Land Cruiser I'm building. 5 years in the making... should finally finish it this summer. http://pirate4x4.com/forum/showthread.php?t=476229


OK... back on topic. I put another 100 miles on the bike this afternoon. Still get an occasional brake warning light... however it is FAR FAR less often than I was with the other pump. (twice in 100 miles, and the second one happened when I was pulling into my garage).

Can anyone tell me how the ABS III controller reacts when it has an air bubble in the line? I'm really wondering if I just didn't bleed the system well enough. Come on, someone has had to seen this before!

If I can't solve this occasional brake error, I'll still keep the partially integrated brakes. The occasional warning light is a small price to pay for having this sweet brake setup.

Scott

 

[jimvonbaden]

I know on the latest generation of servo-ABS brakes having low fluid levels, or too much air simulating low fluid levels, will throw a fault. So it is worth rebleeding the system.

Or, put up with it for a while and it will eventually lett eh air out unless it is trapped in an odd spot.

Jim

 

[Bud]

Scott, I know nothing about brakes. But I admire your courage and willingness to try to make your bike better suited to you.

Congrats and good luck.

 

[ANDYVH]

I replaced the ABS controller in my 94 R1100RS last spring. One of my concerns was getting the brake system bled to be sure it operated normally. A few years previously I had installed SpeedBleeders brake caliper bleed screws on both front and rear caliper. I think the total was maybe $28.

I had no trouble getting the brake system bled. But before I attempted to bleed the system I had filled the ports in the ABS controller with brake fluid before I attached the steel brake lines.

After that I only took me maybe 1/2 hour to get the brake system bled and it has been fine since. I never got a low fluid fault code either.

 

[mrich12000]

Sherlock Holmes

Nice detective work, especially for anyone in your shoes!

Jim

Just use your gumshoes for brakes,till they become a flatfoot

 

[swilson143]

Just use your gumshoes for brakes,till they become a flatfoot

mrich1200 gets a gold start for the most Smilies in his reply.

Well, I'm hoping Jim is right and IF there is air in the system, the system can work it out on its own. I'm not eager to tear the bike apart again. Twice in one weekend was enough for me.

 

[swilson143]

Here's a minor update...

Well I finally figured out what is causing... well, maybe not what is causing... but how to consistantly create the fault condition in the brake system now that I'm using the '03 RT-P controller with my original '02 ABS modulator. If I give the brakes a HEAVY dose of rear brake, and then apply the front, it'll consistantly cause the the warning lights to activate, indicating one of the lines is in failsafe mode.

Now that I know what is causing it, its easy to avoid doing that. It wasn't a good habit anyway... I found myself doing it occasionally when coming to a stop, when I should have been combo braking anway.

I'm VERY happy with the partially integrated brakes... happy enough that I'll gladly put up with this one goofy error I can cause. However... I will keep my eyes peeled for a ABS modualtor from an 2002 model RT-P. Just in case its a change BMW made between 2002 and 2003 models that is causing the error for me.

I'll be sure to update the thread if I find a way to cure the brake error entirely. Anyway, hope this info is helpful to someone... getting partially integrated brakes was A HUGE improvement and I'm glad I invested the time and effort.