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Discussion Starter #1
Having had both front and rears fail in Steamboat on the way home from CCR, I've rhetorically asked myself a few questions that might be answered in a FAQ, but I've not seen it addressed.

For quite a few years (pioneered by Volvo or Mercedes), automotive brake systems have been dual-redundant (insomuch as I understand the concept) --
There appear to be two chambers in the master cylinder, each one supplying brake fluid/pressure to a separate set of brake lines, usually covering three of the four-wheel brake systems.

In this case, a failure of the brake lines in one system will not stop the other system from functioning, albeit maybe at a reduced effectiveness compared to both systems working.

I was told by the dealer, (and borne out by my experience), that for all the advanced brake technology on the LT, the system is essentially only one closed system. The failure of the brake line at the fitting on the right front caliper managed to take out all braking function on my '02 LT.

Is this a conscious design choice/criteria, or did my system not work as designed?
I have had Lonestar fit the Spiegler's, so as I have understood some, this should remove the concern of this same problem reoccurring.

With the dual-reservoir rear and handlebar-mounted front reservoir, the ABS pump and all the other kit associated with the ABS system, it does not appear that weight-saving or simplicity would be the overriding reason to not have some redundancy - at the very least, one front side caliper system could be independent of the other.

I must be missing something elementary here ...

Paul -- '02 K1200 LT - Toscana 'Olive'
 

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Something is not making sense here, but I may have an answer.

The '02 LTs have two separate wheel circuits (4 circuits total - front control from front lever master cylinder to ABS pump, rear control from rear pedal master cylinder to ABS pump, front wheel circuit from ABS pump to both front calipers, and rear wheel circuit from ABS pump to rear caliper).

The front and rear circuits are independent (with the exception of a small cross-passage arrangement which allows pressure applied in one control circuit to be partially applied in the other control circuit -- not a feature involved in this problem).

When you lost the front wheel circuit, I suspect that you did *not* actually lose the rear wheel circuit at the same time -- it only seemed like it! How can that be?? :confused:

What I suspect happened is the rear wheel circuit was intact, but you lost the "power boost" -- i.e., when the Integral system detected a system fault (the front wheel circuit pressure loss), it turned off the pump assist for both front and rear brakes. The lack of power assist, combined with the generally pretty anemic power of the LT's rear brake probably felt to you like "no brakes" (you *REALLY* have to mash the lever to get much out of the rear brake when the pump is off).

Now that you are aware of how the system works, I suspect that if there ever is a next time, you'll know to really lay on the rear brake pedal to get more out of the system.
 

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Discussion Starter #3
Hello Mark,

re-read your brake-bleed document again this morning - thanks for putting that together, it is a very good explanation of the system.

I don't know about mashing on the rear lever harder -- thought it was all the way to the 'floor' -- of course a bit harder to do if you are trying to drag both riding boots at the same time -- (;^o --

Think we missed you at CCR this year?

Paul --
 

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N5PN said:
I don't know about mashing on the rear lever harder -- thought it was all the way to the 'floor' -- of course a bit harder to do if you are trying to drag both riding boots at the same time -- (;^o --
Understand! Now, if we could find a way to convert pucker power into stopping force, you probably could have stopped in about 10 feet!

N5PN said:
Think we missed you at CCR this year?
Afraid so -- between dropping my son off at UNC for his freshman year (gotta have your priorities!) and not actually having a bike (my K16 was in the shop from July 30 to September 10!), CCR was not in the mix this year.

I'd really like to get back to see folks. Where is CCR next year?
 

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Toad Suck of course! :)

Actually, it is in Duluth, MN Mark. You should be able to make that one, eh?

John
mneblett said:
--(SNIP)--
I'd really like to get back to see folks. Where is CCR next year?
 

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AlaskaFish said:
Toad Suck of course! :)

Actually, it is in Duluth, MN Mark. You should be able to make that one, eh?

John
Toad Suck! Of course! I remember it well ;)

Duluth is a definite possibility. The year we were at Gatlinburg I attended one of the BoD's pre-meetings at the hotel -- via Duluth (i.e., Fairfax, VA to near Duluth the first day, after a custom Roadcrafter fitting the next morning, heading to Gatlinburg for the meeting, then back home to Fairfax). While I'm getting older, I believe a run to Duluth is still within my feeble grasp. :D :thumb:
 
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