Tuesday, 3 June 2014

Front brake woes...

OK, I cannot put it off any longer; it is time to assemble the front brake system. For some reason, this has been one of those jobs that I kept putting off; preferring to polish or paint other bits, but it has to be done now. I started by honing out the master cylinder bore then cleaning it all up and re-assembling with a new piston/seal kit before mounting it back on the handlebar right lever assembly. I then cleaned and re-assembled the front brake calliper using the original seals as there didn’t look anything wrong with them and there was no corrosion or parts seized. The original problem of the front brake seizing on was just the brake lever pivot that had seized. As this had an aftermarket braided hose on it I looked carefully at both ends, the calliper end seemed fine with a convex ended male fitting to go into the calliper which had a concave female inlet, as expected. But upon checking the MC end of the brake hose, I noticed that the MC again had a concave female outlet but the end of the male fitting was also concaved. This just confused me as my previous experiences with brake hydraulics said that this was wrong. However, that is how it came off so that is how I will put it back together as it all worked OK before. I then filled the reservoir with brake fluid ready to bleed the front brake system. Unfortunately, whatever I tried, nothing was working, I couldn’t even bleed the master cylinder on its own using a bleed nipple in the end. So I took it all apart again and double checked everything, put it back together and it was still the same. Re-fitted the original piston/seal assembly in the MC but still could not bleed the brake. Could it be that brake hose issue that I was concerned about? After much Googling and checking with other ST owners, I was re-assured that this was the normal setup so I ruled that out. Time was running out now and this needed to be done within the next week to stand any chance of getting it ready for the HUBBUK event. So without further delay, I ordered a brand new, complete master cylinder which came within a couple of days and once it was installed the front brake system was bled without any problems. Go figure that!

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