#991019 - 07/01/17 05:00 AM
Lower front brake hose burst - R1100RT
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Joined: Jun 2007
Posts: 131
Reecehk
Member
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Member

Joined: Jun 2007
Posts: 131
South Australia
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I just got all the new rotors and pads installed, I pulled the brake lever and it went all the way down to the hand grip!! I pumped it up but with steady pressure just kept moving down to the grip. I then discovered that the wheel was jammed tight, I could barely move it then suddenly the LH lower brake hose swelled and burst!! Now I am in a fix, I assume I'll now have to replace the lower 2 hoses (minimum) and bleed the brakes. But what caused the pressure build up and the wheel to lock up? If I repair it what's to stop it from happening again? Where did I go wrong? Please Help! I just had a horrible thought, it's ABS, I probably should have had the bike running, the manual never mentioned anything. Could there be any damage to the, I assume, power assistance??
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#991025 - 07/01/17 10:30 AM
Re: Lower front brake hose burst - R1100RT
[Re: Reecehk]
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Joined: Jun 2010
Posts: 13,708
dirtrider
The Oracle
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The Oracle
Member

Joined: Jun 2010
Posts: 13,708
Ohio
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I just got all the new rotors and pads installed, I pulled the brake lever and it went all the way down to the hand grip!! I pumped it up but with steady pressure just kept moving down to the grip. I then discovered that the wheel was jammed tight, I could barely move it then suddenly the LH lower brake hose swelled and burst!! Now I am in a fix, I assume I'll now have to replace the lower 2 hoses (minimum) and bleed the brakes. But what caused the pressure build up and the wheel to lock up? If I repair it what's to stop it from happening again? Where did I go wrong? Please Help! I just had a horrible thought, it's ABS, I probably should have had the bike running, the manual never mentioned anything. Could there be any damage to the, I assume, power assistance?? Morning Reecehk Difficult to tell what happened from here but it might be as simple as the hose that burst had the inner liner break or split then act like a check valve as the hydraulic pressure got behind the lining & ballooned it into the fluid passageway. It doesn't sound an ABS controller problem but nothing is assured. Did the front wheel unlock after the hose burst? If so then it was more that likely that hose inner liner causing the lock-up or possibly the master cylinder take-up port plugged then trapped pressure in the line. (small hole in bottom of master cylinder reservoir)-- If this hole is plugged, or the master cylinder piston isn't returning far enough to uncover that hole, then you probably won't be able to bleed the front brakes. If you get good fresh brake hoses on that bike (all the hoses as they are probably all in the same condition) then you shouldn't be able to break or fail a hose just by pulling on the brake lever.
D.R. ___ Sent from my rotory dial wall phone!
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#991026 - 07/01/17 10:31 AM
Re: Lower front brake hose burst - R1100RT
[Re: Reecehk]
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Joined: Jun 2006
Posts: 2,329
szurszewski
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Member

Joined: Jun 2006
Posts: 2,329
Portland, OR
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Sorry to hear that, but very glad it happened in the garage, so to speak, and not out on the road. Are these the original brake lines? If so, it's not a surprise that it burst - more of a surprise that it lasted this long. It's possible that the lines were coming apart internally and you had a piece of line lodge somewhere preventing fluid from moving back away from the caliper, and then you pushed more down and it was too much for the lines. Having installed new pads/rotors means you must have pushed the caliper pistons well back into the calipers, so it's normal that your lever was able to go all the way to the bar. That said, I'm always careful in that situation to gently work the lever less than the full travel - I'm no expert but I've been told that pulling it all the way will move the piston in the master cylinder further than it normally goes, which puts into territory that could have crystallized fluid/crud build up that might damage the seals up there. When you did the pads/rotors, did you also bleed the brake circuits? When you say you should have had the bike running, are we talking about an 1100? I am maybe mixing years up, but I thought that meant you would have non-servo brakes so it would not matter if the bike was running. I'm sure you'll get better answers soon - good luck! josh EDIT: I type slowly - you ALREADY have better answers 
Last edited by szurszewski; 07/01/17 10:32 AM.
*insert witty remark here*
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#991027 - 07/01/17 11:26 AM
Re: Lower front brake hose burst - R1100RT
[Re: szurszewski]
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Joined: Jun 2007
Posts: 131
Reecehk
Member
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Member

Joined: Jun 2007
Posts: 131
South Australia
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The bike is a 1998 R1100RT, All I did was to install the rotors and new pads, I was avoiding having to bleed it, was going to take it to a BMW mechanic. The brake lines are likely the originals. Problem is the mechanic is over 200Kms away, I don't have much choice other than doing the job myself. Once I get the tupperware off is it easy enough to get the hoses off without taking the petrol tank off? I assume I am to replace the 4 hoses, anything else? What's the easiest way to drain the existing fluid? Is there a simple method of bleeding the brakes? I don't have any bleeding tools other than normal spanners etc. Sorry about all the questions but I have never done this before only on an old car with drum brakes!! 
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#991035 - 07/01/17 01:34 PM
Re: Lower front brake hose burst - R1100RT
[Re: Reecehk]
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Joined: Jun 2006
Posts: 2,329
szurszewski
Member
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Member

Joined: Jun 2006
Posts: 2,329
Portland, OR
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I would suggest as above that you purchase a kit of stainless brake lines - here in the US that is generally cheaper than buying the factory lines and they should last longer. In any case, you're going to need to replace the burst line (and if that one burst...well, the others are probably in the same shape - you really don't want one to rupture while you're on the road!). If you are ok removing the body work, removing the tank is really not any harder - you will need to disconnect the fuel lines (mark them so you can put them back together the same way) and the electrical plugs, but it's really way less work than removing all the body screws was - not complicated. You *can* actually get to the abs bleed ports by just lifting the rear portion of the tank (once the body work is removed) and blocking it up a few inches, but as you said you might as well replace the fuel filter while you're in there if it's due, or if you don't know when it was last done. Here's a vid for you - I confess that I haven't watched it as our motel internet is very slow, but check it out. I did the lines on our K1200LT at the beginning of this trip in a friend's garage with only the instructions in the brake line kit package (and they really just said, remove this line, replace it with this one... and repeated that for each line). It took me a handful of hours, but mosty that was removing and replacing a lot of body work. https://www.youtube.com/watch?v=3qDYjAfwow8You can do it - good luck! Oh - you can manually bleed the brakes by hand. Just make a container from an old water bottle, put a hole in the lid to fit in some tubing that is sized to fit the bleeder. Helps to have someone to open/close the bleed valve, but if you put enough fluid in the container so you can't suck air back into the caliper you can use it as a one man bleeder. Just remember that after you have it bled and closed off, gently pump the brake lever (not full travel!) to get the pistons moved back into place before you try to ride the thing. josh edit: here's a DIY brake bleeder on youtube https://www.youtube.com/watch?v=1wwq1Vlk4Wg
Last edited by szurszewski; 07/01/17 01:38 PM.
*insert witty remark here*
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