Honda 45530-MCA-006 - MASTER CYLINDER PISTON | Partzilla.comI replaced the part described in this thread. That did the trick.
So, just to be as crystal clear and succint as possible:The root cause was contaminated brake fluid which created a buildup and sludge like substance in the reservoir/valve and brake lines. It got to a point that the brake fluid was only flowing towards the caliper and due to the build up in the lines and valve system at the brake handle the fluid backed up creating pressure in the caliper where the brake pads remained on the rotor and overheated causing the the front brake seizure. Immediate remedy is to let it cool down 100% that will give you me 20 minutes depending how much you use the front brake. I decided to tow. I replaced the part described in this thread. That did the trick. Remember your rear brake is tied into your front brake so when you replace the brake fluid do front and back.
In my case and the little knowledge if have. The brake fluid change was scheduled but the seizure happened before we could change the fluid. In my case the seizure would have happened anyway. When it seized we thought just cleaning the front caliper replaced the fluid would do the trick. It didn't, we saw one of the ports in the reservoir leaking cloudy liquid. We knew then it was the valve. If the fluid is contaminated and if its been a long time before fluid change I would, knowing what I know now change the proportional valve, Its not a very expensive fix and would recommend changing it.So, just to be as crystal clear and succint as possible:
The proportional valve, PN 46400-MEC-016, was causing the front brake to lockup under normal operating conditions. The reason the proportional valve was locking up was due to contamination in and/or degredation of the brake fluid, due to lack of maintenance / regular replacement of the brake fluid.
Why is this important? If someone has neglected to replace the brake fluid regularly and/or it has become contaminated, they should probably also replace the proportional valve, or at least test it somehow to make sure it is ok.
Correct?
Again, thank you for posting the info.
So the PCV replacement was precautionary, and what actually caused the lockup was the valve / PN 45530-MCA-006, as Rune-Gearhead stated? So to summarize:We knew then it was the valve.
Rune brakes are 2 separate systems. There is no fluid flow between the systems. The front brake lever actuates 2 of the 3 pistons on each front caliper only. The rear brake pedal actuates the rear caliper and the centre pistons on the front calipers, through the proportioning valve.... Remember your rear brake is tied into your front brake so when you replace the brake fluid do front and back.
Rune brakes are 2 separate systems. There is no fluid flow between the systems. The front brake lever actuates 2 of the 3 pistons on each front caliper only. The rear brake pedal actuates the rear caliper and the centre pistons on the front calipers, through the proportioning valve.
Bleed accordingly.
Have I got that right Gearhead?
skip
Yeah, what Skip said. Except that the rear brake pedal actuates the rear caliper and the CENTER pistons on the front calipers, through the proportioning valve - on US models instead of the CENTRE pistons on the front calipers, through the proportioning valve on the Canadian models.
All true, however I talked Honda USA into sending me the book and the toolkit."His working Runes are probably US Runes and not Canadian? Like many folks north of the border they picked up Runes south of the border to save $$$, and they didn't want the tool kit vs chrome wheels or the plugs in the headlight bucket.???"
"You have a PM on the rest Skip."
Attached, are the parts that were replaced. Except the statue.So the PCV replacement was precautionary, and what actually caused the lockup was the valve / PN 45530-MCA-006, as Rune-Gearhead stated? So to summarize:
The master cylinder piston, PN 45530-MCA-006, was causing the front brake to lockup under normal operating conditions. The reason the master cylinder piston was locking up was due to contamination in and/or degredation of the brake fluid, due to lack of maintenance / regular replacement of the brake fluid.
Correct?
Not trying to be a PITA, just want to make sure I (and others) clearly understand the cause and resolution.
Found this post in another thread, from the late, great . . . RIP, buddy.First, in case there is any confusion: DOT 5.1 is glycol; DOT 5 is silicone. DOT 5.1 mixes with DOT 4 with no problem. It says so on the can, and I have done it with no problems. DOT 5 mixes with nothing but DOT 5.
Second, unless you have a vehicle that you almost never drive (e.g., a show car) or one where you change the fluid every six months or more often (e.g., a race car), do not use silicone fluid. That glycol absorbs water is a key reason it is the perfect brake fluid for a street vehicle. The last thing you want is a fluid that does not absorb water. You'll find out why when you apply the brakes and that unabsorbed water vapourizes.
Not sure what you mean? "Conversation when its words in type"???"There are other things that could be the cause or part of the problem, in the end, none of it matters if the bike is fixed and ready to go. The information provided/shared by Mitchell will be helpful to anyone that has a similar situation in the future as a possible solution to their problem-Thanks to Mitchell for the thread! At this point with it being limited to one Rune, it's an isolated problem/situation to one Rune and not a pattern."
"Mitchell you have a message/pm/conversation (how the F can it be a conversation when it's words in type)?."
If that was so the problem would have gone away when we flushed the brake system the first time. It didn't, we then rebuilt the valve assembly. That fixed the issue.Found this post in another thread, from the late, great . . . RIP, buddy.
He was almost always spot-on. Perhaps this is exactly what happened in the OP's case. Unabsorbed water in the system vaporized from the heat, causing increase in pressure, with caused the brake to lockup. May have had nothing whatsoever to do with the piston or the PCV. Simply unabsorbed moisture in the brake lines from lack of maintenance. Thanks, again, Al. Miss you!
ISo the question is are conversations only oral. Does a deaf person signing have a conversation??Not sure what you mean? "Conversation when its words in type"???
