Hello all,
I'm working on my dad's 2003 ST1300A, and today I replaced a front brake line because I noticed last fall that the rubber outer portion of the line had separated near the metal crimped portion of the line, leaving the nylon exposed for who knows how long. This hose was "Hose C Front" in the parts diagrams, and part number was: 45131-MCS-G01.
This line connects on one end to the front left caliper (it's the top of the two banjo bolts on that caliper), and other end to a junction box where a hard pipe line screws into on top of the front fender.
Well, when I installed the line, I attached the hard pipe end to the junction box, then left the banjo bolt end (where it connects to the caliper) open for a minute or two to try and gravity feed some brake fluid into the line before I started the bleeding process. It seemed to work as I saw fluid flowing through the line, and I then followed the exact procedures/tips
@jfheath wrote up, in addition to the pointers I received from
@Igofar when we spoke last summer when I was just bleeding the brakes at that point.
Every thing went seemingly normal during the bleeding procedure, except for the very last bleed nipple: the rear caliper outer pistons bleed nipple (the right side nipple on the rear caliper). While bleeding that nipple, there was a couple of times where my dad--who was helping me--had pumped the foot pedal, held it down, I opened the bleed nipple, and nothing happened... No fluid moved, no air, just nothing--while this was happening, I tried to pump the SMC and it was hard like the foot pedal was still putting fluid pressure on it like it normally does. So, I tried to close the bleed nipple, asked my dad to pump it a few more times and hold it, then tried again and all of a sudden it worked as normal where fluid came out of the nipple... So, we continued as normal, pumping the pedal and SMC, while working that bleed nipple appropriately, and it worked normally for a few cycles, but then it did the same thing again where nothing happened.... At this point I was perplexed, so we went through the whole bleed procedure again just to make sure no air was trapped. Every single bleed nipple was flowing clear, clean fluid with no air. We got to that last nipple again, and it did the same thing--worked as normal for the first couple of bleeds, then it randomly didn't do anything again one time when I opened it... So, we closed it, pumped a few more times, then opened it again and it bled as normal with no air--and I also pumped the SMC which also didn't not let out any air.
Keep in mind, for each step of the bleeding procedure, I tapped all of the appropriate lines/junction boxes/delay vales/tilted and pumped the SMC/etc all as necessary as advised in
@jfheath's brake bleeding PDF and the Honda manual. Also, I checked and refilled the appropriate reservoirs between each bleeding step. So, I know I didn't introduce any unintended air at any point during the bleeding process.
I'm a little confused, and am wondering if anyone has ever experienced this? Or, does anyone know what the cause of this happening might be?
Between all of the bleed nipples throughout the bike, and doing the whole process through twice, I flushed almost a whole quart bottle through the entire system. So, it's definitely clean, and I'd like to think free of air, but again this happening confuses me and I just want to check with all of you to get your input! What do you think could be causing this?
Thanks so much for your help,
Tanner
www.fowlersparts.co.uk
this should not even be done with "clamps designed for that use".
that video before somebody breaks something 
