Fork (was suspected brake piston) leaking

[PolInc92]

So I winterized my Super Tenere about three months ago and noticed about a month ago that the front brake piston caliper was leaking. I removed the caliper, replaced the leaky seal, and bled the brakes. I took the bike out, brakes worked fine for 30ish miles and I discovered a spoke in the rear got loose and the bike had to sit again.

As it sits now, the caliper is leaking again, but significantly less it seems. Is it just because it's cold out and chilly in the garage? I'm assuming that the seal hasn't been broken in yet and got smaller due to the cold, but I just wanted to make sure.

Bringing me to my second question. Should I have replaced the rest of the seals? If the other one IS leaking due to the cold, maybe it would be better to change them out when the weather gets warmer or should the rest be left alone?

 

[PolInc92]

What year bike and how many miles?

2012 and just over 20k miles

 

[PolInc92]

Have you ever flushed the brake fluid?

Yeah, I flushed the brake fluid from both calipers in the front, starting with the right side which was leaking and then the left side. Used new DOT 4 brake fluid as well.

As for riding, I don't mind riding in the cold, but weather has been consistently below 30, with rain showers, snow and worst of all, our DOT loves blasting the streets with salt. The ice patches everywhere have me slightly worried, the excess amount of salt is why I don't really want to pull it out until it gets washed away.

There were a few days I threw on winter gear and took it out, not gonna lie.

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[PolInc92]

Hope you get it sorted out. It’s not fun when your machine is not up to snuff.

If I can't figure it out, I'll just hold out until warmer weather and hope heat breaks it in.

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[WJBertrand]

Double check it's not a fork seal leak that's dribbling down?

 

[PolInc92]

Send pics bet you will get all sorts of help then.

At least take me out to dinner first. But in all seriousness, caliper is all put together. Pic wouldn't show much since there is a new seal there now. I can probably pull it apart in the next few days if necessary.

Double check it's not a fork seal leak that's dribbling down?

That's what I thought it was originally, but the forks and fork seals were dry. The fluid travels down on the inside of the right brake discs and leaks onto my wheel if it's locked to the left.

 

[Sierra1]

Double check it's not a fork seal leak that's dribbling down?

I was going to ask the same thing. Because, the ST1300 I had would periodically (every couple of years) start leaking, and it looked like the caliper. Closer inspection revealed that it was the fork seal; always the left on the Honda. I was told by the tech that Honda puts all of the anti-dive "stuff" in the left fork. And, according to him, it was a common occurrence.

 

[PolInc92]

I was going to ask the same thing. Because, the ST1300 I had would periodically (every couple of years) start leaking, and it looked like the caliper. Closer inspection revealed that it was the fork seal; always the left on the Honda. I was told by the tech that Honda puts all of the anti-dive "stuff" in the left fork. And, according to him, it was a common occurrence.

I actually sprayed the bike down today with water, so that should get most of the whatever the fluid was off. I'll be back home in a few and can take a look at the forks again to see if it's one of them.

Edit: I took a look at the forks again after I washed it down. I didn't see much oil, but the right fork definitely felt like it was slimier than the left fork. I wiped it clean with a rag and will see if it leaks from there again in an hour or so. If that's the case, I might buy one of those tools that get dirt from under seals before I plan on swapping them out.

Second edit: after wiping down the surface of the forks, there is nothing slimy or slippery on them anymore. Gonna watch for dripping again to see if j can pinpoint it. Maybe both are leaking, because when I pulled the caliper off, there was definitely brake fluid making its way past the seals and the seal was torn up. At least it's leaking during winter.

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[Nikolajsen]

The new seal should not leak only because of cold weather. So if it is caliber leaking, something is wrong...

 

[Sierra1]

What is damaging the caliper seal(s)?

 

[Don in Lodi]

How did the piston look when you replaced the seal in the caliper, any discoloration or maybe pitting? If it's leaking sitting in the garage pull the caliper off and let it hang, it will give you a chance for a better visual. A few puffs of baby powder will let you back track a clear fluid.

 

[PolInc92]

The piston itself looked fine, no pitting or wear as far as I can tell. I cleaned it with brake cleaner and didn't see anything. The seal around the piston looked like it had seen better days, so I switched it out with a new one, but there still seems to be a leak. I'll probably end up pulling it the caliper off when I get time in the next day or two.

As far as it being a fork seal, I scooped up one of these and it should be in tomorrow. Idk if it will work, but I'll take the $7 chance over having to tear apart the forks.

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[Checkswrecks]

Assuming you used a new seal, cleaned the piston groove and caliper bore, etc...

It's easy to roll the seal when putting it on the piston, or for the seal to hit a dry spot and roll when the piston is going in the bore. A rolled seal like this led to some of the very first Teneres leaking gasoline and the fuel tank seal recall.

 

[PolInc92]

Assuming you used a new seal, cleaned the piston groove and caliper bore, etc...

It's easy to roll the seal when putting it on the piston, or for the seal to hit a dry spot and roll when the piston is going in the bore. A rolled seal like this led to some of the very first Teneres leaking gasoline and the fuel tank seal recall.

I'm probably going to be pulling the caliper off again today, so I'll check to see if that's the case. Might just switch out the remaining three seals since I already have everything apart.

I should add that this Tenere better appreciate the fact that I fell in love with it and I'm putting up with it being difficult.

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[steve68steve]

My first thought was a burr nicking the seal. When you get it open again, feel that thing up like a cheap date - any little nick, burr, or grain of anything will cause leakage. Think of what one grain of sand will do to a fork seal - and brakes calipers are under a lot more heat and sustained hydraulic pressure than fork seals.

 

[PolInc92]

My first thought was a burr nicking the seal. When you get it open again, feel that thing up like a cheap date - any little nick, burr, or grain of anything will cause leakage. Think of what one grain of sand will do to a fork seal - and brakes calipers are under a lot more heat and sustained hydraulic pressure than fork seals.

You posted the second I pulled the caliper off. All the seals and stuff on the brake look completely dry. I'm going to inspect the other three and see if they're in as bad shape as that leaking one was. If they are, I'll swap them out tomorrow.

As far as the right fork, it's been sitting over night and it started to leak again. I ordered the seal mate and I've got my fingers crossed that it might stop the leak. I figure I'm due for replacing the oil in the forks anyway.

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[dmulk]

The slimy description on the fork sounds like a forseal. I jusr had this happen amd it ended up on my front wheel. That chrome should be dry. Sit on the bike, grab the front brake and pump the forks 20-30 times. Recheck for any slime.

Im going with fork seal at this point. A caliper with 20k on it just seems very unlikely on these bikes...

 

[PolInc92]

The slimy description on the fork sounds like a forseal. I jusr had this happen amd it ended up on my front wheel. That chrome should be dry. Sit on the bike, grab the front brake and pump the forks 20-30 times. Recheck for any slime.

Im going with fork seal at this point. A caliper with 20k on it just seems very unlikely on these bikes...

It's definitely the right seal. The caliper seal was leaking though for sure before. I know that because the leaking up front was way worse and after it sat for a month, it had no pressure on the front brake pedal anymore. Now the brakes work great, but that fork seal is leaking. Here's to it being a little piece of dirt sitting between the seal.

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[dmulk]

Be great to hear whether the seal tool works. I picked one up also but didnt need to use it because YES covered my seals under warranty.

 

[Tenman]

I've stopped numerous for seal leaks with home made seal saver. They will save you a ton of money and time. Everybody needs this tool.