My rear brake doesn't grip any more, unless I "pumped it up" during the ride?

[Afan]

Brake fluid is hygroscopic, and you cannot tell by looking at it if it is good or bad. Brake fluid is cheap, you are saving pennies but might have to pay dollars later to repair corroded parts. I believe there are testers that measure the resistance or current flow, get one of those instead of depending on its clarity.

All that said, if you live in a very dry area, you might be able to stretch the service intervals.

It's not about 'saving pennies' but rather avoiding unnecessary actions that won't fix my current problem. If there were bubbles in the brake line and I fixed the brake, I would probably replace the fluid because, as you said, once I've opened the canister, I can't keep the fluid for later due to its hygroscopic nature.
Additionally, any service performed to fix the problem, such as replacing the brake line or master cylinder, would require replacing the fluid again anyway, right?

 

[Rydinon]

It's not about 'saving pennies' but rather avoiding unnecessary actions that won't fix my current problem. If there were bubbles in the brake line and I fixed the brake, I would probably replace the fluid because, as you said, once I've opened the canister, I can't keep the fluid for later due to its hygroscopic nature.
Additionally, any service performed to fix the problem, such as replacing the brake line or master cylinder, would require replacing the fluid again anyway, right?

I was reacting to your comment that since the fluid appeared to be clear, it is good. Were I servicing a brake problem, and I had to bleed the brakes, with 2 year old fluid in the system I would do a full flush.

Since you are taking the bike to a dealer (or other mechanic) they will likely finish the job by doing a full flush, but I would verify that.

Having to pump the brakes usually means a seal in the master cylinder is weak, and not necessarily air in the system (the latter is manifested by sponginess).

 

[Afan]

I was reacting to your comment that since the fluid appeared to be clear, it is good.

Yeah, I should've say "good enough for my problem", I agree.

Having to pump the brakes usually means a seal in the master cylinder is weak, and not necessarily air in the system (the latter is manifested by sponginess).

That's my thought too. After several hours of internet research, most of the comments are leading to the same cause.

 

[Afan]

I just ordered new master cylinder from Partzilla - they will send the fastest. And I have good experience with them.
Smart man would probably buy 2-3 times cheaper MC elements/parts and rebuild it himself, but I'm kinda "mech. challenged" - big percentage I would screw something up while rebuilding. And replacing the whole master cylinder should be easy - even for me.
And I'm also in rush to make it done before I leave for the trip 3rd week in June. I know, I know... I should've fix this way, way before the trip, but my procrastination was running in 5th gear...

Thanks for help, I'll keep you posted.

 

[Rabbit]

I just ordered new master cylinder from Partzilla - they will send the fastest. And I have good experience with them.
Smart man would probably buy 2-3 times cheaper MC elements/parts and rebuild it himself, but I'm kinda "mech. challenged" - big percentage I would screw something up while rebuilding. And replacing the whole master cylinder should be easy - even for me.
And I'm also in rush to make it done before I leave for the trip 3rd week in June. I know, I know... I should've fix this way, way before the trip, but my procrastination was running in 5th gear...

Thanks for help, I'll keep you posted.

Full replacement is a wise decision. Likely what your dealer would do anyway

 

[vinay]

Good luck on the replacement of the brake master and keep an eye on the tightening torques. There are downsides to both overtightening as well as undertightening of the hose connectors. If it doesn't solve the issue, also consider checking the brake rotors for trueness as I mentioned in my previous post. Thinking of it, as your rear brake master also operates a front brake piston, you'd have to check that one too just to be sure. But considering you don't have issues with the front brake itself, this is less likely to be the cause. Good luck!

 

[Afan]

As I mentioned in my previous post, on 5/30 I ordered the master cylinder from Partzilla. Even I ordered with the expedited shipping, but it's still not even shipped.



I would hate if they 2 weeks later cancel my order because then I need to cancel my trip

 

[Afan]

I was thinking to cancel the order myself and buy on some other place but I believe there is no guarantee either.
On hondapowersportsparts.com is $50 more (Partzilla Total: $169.99):

 

[Afan]

Talked to Hondasportsparts - also "Backorder, no ETA".
Should I search in England or Taiwan?!?

 

[potter0o]

https://japan.webike.net/products/24326159.html

You could use the real time quotation link to confirm details for your situation.

 

[Ajay750]

UK Honda parts supplier Fowlers have the part in stock & they do ship to USA. Whether the cost of shipping & delivery times makes it worthwhile, only you can decide, but its an option - link - Fowlers

 

[dduelin]

If you have relationship with an authorized Honda dealer you could ask the parts manager to order the part directly from Japan under a critical parts order. I did this several times for customers, once getting the parts overnight. If the part is available in Japan it can be in the parts manager hands inside of three days. I could see a less experienced parts department associate might not know Honda offers this option. I did not know about it but my service dept manager told me how to do it.