Hey guys,
I just swapped out my front pads. All that went great. Then later tonight I noticed a few drips of fluid up by the reservoir cap. Almost looks like there are overflow cut outs that are there on purpose. (very small) I did have to push the pistons back in a bit so I am sure there is more fluid in the Res now. As I squeased the brake lever I got a little more to come out, then it more or less stopped. seems ok now.
Does all this seem normal or do I have a problem? I am under the impression that the diaphram is doing what it is supposed to.
I can say that before this I had no leaks on the Res at all.
Thanks!
Hope everyone is getting to enjoy riding in the early North East Spring! Rode to work 6 times already!
Quote from: xanthras on March 25, 2012, 06:17:12 PM
Hey guys,
I just swapped out my front pads. All that went great. Then later tonight I noticed a few drips of fluid up by the reservoir cap. Almost looks like there are overflow cut outs that are there on purpose. (very small) I did have to push the pistons back in a bit so I am sure there is more fluid in the Res now. As I squeased the brake lever I got a little more to come out, then it more or less stopped. seems ok now.
Does all this seem normal or do I have a problem? I am under the impression that the diaphram is doing what it is supposed to.
I can say that before this I had no leaks on the Res at all.
Thanks!
Hope everyone is getting to enjoy riding in the early North East Spring! Rode to work 6 times already!
Yes. You're going to have excess fluid after replacing the pads. You need to remove the cap to see how much is in there.
Also, over-tightening the top screws or tightening them unevenly can cause it to leak.
Now might be a good time to go ahead and purge the system. You can use Valvoline Synthetic DOT 3&4 fluid. It's about 3.49 a can at most major auto parts retailers. You can also pick up a mighty-vac or other equivalent vacuum pump to assist you.
It's good to flush the system regularly. For most riders, that means replacing the fluid with each pad change. Once a year is ideal for a street rider, once every 2 years is the longest I'd recommend going. Beyond that you risk boiling the fluid with heavy use.
If your fluid over-flowed, it means someone topped the brake fluid off at some point. Never ever do this. Fill the fluid to the full line when you install new pads, and let the fluid drop as the pad wears. If the fluid ever falls below the low mark, it means you have a leak that needs to be fixed immediately.
Brake fluid is not something that is consumed the way oil is. The level drops as your pads wear. The brake fluid reservoir is large enough that you can go through the pads and be running metal on metal before the fluid runs out.
Here's what you should do now:
1. Flush, fill, and bleed the system.
2. Fill the fluid to the full mark.
If you want to ignore my advise about flushing the system:
1. Use a syringe to remove enough fluid to get the level down to the full mark.
Never over fill your system. The brake fluid needs some room to expand... Over filling can cause pressure to build up in the system, which will cause brake drag, and possibly brake failure. The proper fluid level is the full mark, with new pads... And wherever it already is with used pads.
^ +1....
Also, when you replace the pads, bleed the calipers as you spread them back out...DO NOT force the brake fluid back up through the system! You can cause serious damage to the calipers by doing this. Just crack the bleeder with an 8mm wrench as you spread the caliper and direct the fluid into a container using some extra clear tubing.
alright. That all makes sense. I think I know why it is a bit over full. I did a flush/ re-fill with the old pads in about a year or so ago so I probably put in a little too much. I will remove a little.
whats is the explanation for not forcing the pistons back in? I have been doing that on my cars forever.
Thanks guys!
There are one-way valves in there. When you force the fluid back up the wrong way, you run the risk of blowing the seals on the valves and then your brake will always leak fluid the wrong way past the valve and your brake "feel" will never be just right. Plus it helps to keep fresh fluid in there anyways, so when you bleed the old stuff out, you top off with new fluid and you are better off.
My 2 cents, anyways.
I really don't agree with the above advise... I reverse bleed my race bikes - seems to work better than a standard bleed, since I'm not pushing fluid against the direction air bubbles like to go.
There is a valid concern about pushing gunk up into the master cylinder, but there isn't really a 1-way valve in the brake system, other than the porting in the master cylinder that's required to make the brake system work.
Quote from: burning1 on March 26, 2012, 12:28:00 PM
I really don't agree with the above advise... I reverse bleed my race bikes - seems to work better than a standard bleed, since I'm not pushing fluid against the direction air bubbles like to go.
There is a valid concern about pushing gunk up into the master cylinder, but there isn't really a 1-way valve in the brake system, other than the porting in the master cylinder that's required to make the brake system work.
+1
Big fan of the Phoenix reverse brake bleeder tool on air bound systems.
-Jessie
I am not saying that you can't do it, I just don't think it's a good idea and have always been taught to bleed the brakes with the bleder screws. Why force the old fluid back up the line the wrong way when you can crack the bleeder and force the calipers open with much more ease?
my 2 cents
Thanks guys. For now I am just going to continue on with what I am doing. Good insight on both sides. Didnt know about that concern.