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Leaking Fork Seal....Again

5K views 30 replies 13 participants last post by  Redcoat 
#1 ·
Back in March or April of this year, my right fork seal started leaking for no apparent reason. My bike had about 25k miles on it at that time. I had changed fork oil a couple of times, but the seals were original. So, I bought new Moose Racing oil and dust seals and did a thorough clean-up, oil change (Maxima 7.5W) and new seals. I'd done seals on Showas a couple of times before (Monster S2R and Suzuki GSXR), so I have the special tools, and I've had good results.

But, about 2000 miles and a couple of months later, the right fork is starting to leak again (the left is fine). I'll check more closely, but I didn't find any nicks or scrapes in the slider when I did the rebuild, and there was no binding the entire length of travel. Is there anything else I should be looking for when I tear this thing apart? Is there a better brand of seals I should use? Thanks in advance.
 
#2 ·
I had to replace mine, due to a leak in the left fork. The job was done by a professional shop which happened to be authorised for Ohlins suspensions. They told me that they use Athena (if the spelling is right) and they strongly recommend this brand. After 12.000 Km they are perfect.
 
#4 ·
Several years ago I replaced the STs seals with a softer feeling rubber advertised as low sticktion. Triple lip All Balls brand parts. They were a reddish, maybe silicon, rubber and were very low sticktion. Slid on easy. Apparently they were low sealing as well. One side leaked pretty quick. Bought regular seals from Race Tech. No problems. Not sure what you used for seals, but that's my story.
 
#6 ·
I went ahead and ordered a pair of Athena seals and a seal driver. I've been using a home made driver fabricated from PVC pipe with good results, but I don't want to do this again. I'll also spend some time inspecting for nicks or gouges in the tube. I may need some additional advice if I find any damage.

My bike is currently in pieces for a repaint (discussed in a separate thread), so it'll be a few weeks before I get to this. I'll circle back and let you know how it goes. Thanks for the input!
 
#8 ·
had a my right fork leak as well. Took it to the best suspension shop in the area, and they rebuilt it. Was fine until a year later when the fork started leaking again. That best area shop refused to warranty the work. Much more to the story, but I will never go to that shop again and recommend to anyone who asks, to avoid them. But I digress. Had my regular shop fix this new leak and so far so good and it's been about a year and half /12k miles. Good luck.
 
#9 ·
Well,
to be honest, I would probably lso not change a year old seal on warranty either .... that said, try SKF seals. I´ve been using them on what must be at least 50 forks by now, for more han 6 years, and have never had one come back due to leaking seals. Should be pretty low fricton as well, but i only have their word for that .....
 
#10 ·
Well,
to be honest, I would probably lso not change a year old seal on warranty either ....
really depends whether the customer is someone you like or a whiny arsehole you'd be happy to be rid if. if it lasted a year it's realistically not your fault.

i put a set of ariete seals (same part as i had used before) in a monster once and it was dripping oil after about half a mile on the road. just pissing out. pulled them out, could see no issue at all, put a genuine set in (marzocchi, so probably nok). no problems. wacky what happens some times.
 
#12 ·
I took my fork apart, and while inspecting for damage I found a small mark on the front of the slider. It's on the part of the tube that would normally be exposed and is about 3/16" long. Looks like a piece of lint and I can't feel it. I can't imagine that it could damage a seal, but I don't see anything else that might cause failure. Should I install the new seal and cross my fingers, or is there something I should do to the tube before reassembly? Thanks.
 
#13 ·
.

Maybe it was just the lint, or whatever debris it was, that caused the leak. I've never used one of these tools, but some say they are great. I guess it's possible to have grunge get in there and cause a leak but not damage the seal.

https://www.amazon.com/Squatch-Racing-Seal-Mate-Cleaning/dp/B07R3WDDQ8/ref=asc_df_B07R3WDDQ8/?tag=hyprod-20&linkCode=df0&hvadid=343211963494&hvpos=1o2&hvnetw=g&hvrand=4245373023739145816&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003256&hvtargid=pla-743371815774&psc=1&tag=&ref=&adgrpid=69167827175&hvpone=&hvptwo=&hvadid=343211963494&hvpos=1o2&hvnetw=g&hvrand=4245373023739145816&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003256&hvtargid=pla-743371815774

It you're comfortable trying get some high grit, 2000 or more, wet dry paper and use it with oil to buff the area of the slider you think may have an imperfection. I buffed the shaft of my 916 shock when I rebuilt it. Came out fine. Didn't go crazy with it, just a polish.
 
#15 ·
If you can’t feel it with a fingernail I wouldn’t worry about it. Even 2000 grit will dull the TIN coating, so 1) keep the polished are very small and precise , or 2) polish the whole visible portion so the finish is the same. I think I’d opt for #1, but don’t do anything at all if you can’t feel it with a fingernail. TIN is very hard and very thin.
 
#16 ·
I’ve never had any luck with the SealMate either. It seems like I can never get it all the way around without hanging up on something. I used AllBalls seals in two bikes last winter before this discussion started, so far so good.
 
#19 ·
i have only done 2 so far on dual sport bikes, kl250 super sherpa & drz 400e. both successful with much usage. i went with oem dirt n oil seals because a few others were having quality issues with after market brands. the parts were negligible compared to the effort of a potential redo. i recall using saran wrap to make sure seals were not knicked during install.

evolution suspension in San Jose did my tiger 1050. i supplied oem seals. they pointed out some pits on one fork to keep an eye on, but 10k miles later, no leaks.

some thoughts, have an experienced person review or watch your process. my gut tells me it's the quality of seals you have.
 
#20 · (Edited)
I am SO confused! I think the correct dimensions for my fork seals are 42x54x11. That's what the listing for the Athena seals I'm installing indicated, but they sent me 43x55x11 seals. They don't fit.

So I went back and looked at the invoice for the Moose Racing seal I just removed, and it says 43x54x11. I double checked the MotoWheels website, and 43x54x11 is what they call for. If it's actually supposed to be a 42 ID, that would explain the leak.

I've asked for a refund or exchange from the Athena vendor, but I'd like to make sure I get the right size this time. Can anyone verify if 42x54x11 is correct?
 
#21 ·
Not exactly sure what bike you have, but Duc Showas are eiter 41 mm (older) or 43 mm (newer) Measure the lower legs, seals should be the same. I know of no Ducati with 42 mm seals, but if you just measure the seal ID with a caliper, it might come out at 42 mm. The SKF seals I use are 43x54x11, but measure maybe 42.7 on the lip.

55 mm OD seems incorrect, however ....
 
#23 ·
My bike is an '06 ST3s, so it sounds like the 43mm ID should be correct. If that's the case, the Moose seals were the right size. The 55mm OD definitely doesn't work, so I'll have to wait and see what the Athena vendor will do for me. Thanks for the input.
 
#26 ·
Thanks for the input Redcoat.

After checking several manufacturers, it looks like you get a mix of 42mm and 43mm recommended IDs depending on the supplier. Athena doesn't list a seal for the ST3s, but I went with the 42 x 54 x 11 that they say is correct for most Ducati forks contemporary with my ST. The vendor turned it around quickly (thank you Gotham Cycles!!), and I was able to get the new seals installed yesterday. The 42mm ID was tighter than the previous 43s, but went on with no issues.

As I mentioned earlier, my bike is in pieces getting painted so it'll be a couple of weeks before I'm able to put any miles on it. I'll keep you posted. Thanks for the help!!
 
#27 ·
I've had a 50/50 success with Seal Saver tools in the last 20 years. not bad...

I gave mine to someone to try 5 or 6 years ago, never got it back. Don't remember who has it.:rolleyes:

My M900 was leaking on one leg last month after returning from a trip, so I grabbed a piece of clear plastic from a blister pack out of the trash and cut it up, made my own Seal Saver. Worked a charm! Seals maybe 3 years old, maybe 5000 miles.


I remember talking to an American Honda Tech Rep back in the '90s when the ST1100 showed up with little fork guards on the forks. They protect the wiping area just above the seals.

Anyway, he said they had crunched the numbers on warranty claims and came up with a number of around 75% of all fork seal claims were due to bugs being smashed on the fork slider and dragged into the seal.

So pay attention to the front of your fork sliders after a ride, be ready to wipe off dead bugs if necessary. Many bikes have guards to protect the sliders, many don't. Monster fender doesn't protect the slider as well as an old 900SS fender.

That's all I got.
 
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#28 ·
So pay attention to the front of your fork sliders after a ride, be ready to wipe off dead bugs if necessary. Many bikes have guards to protect the sliders, many don't. Monster fender doesn't protect the slider as well as an old 900SS fender.

I replaced a seal that had truly failed, leaking a puddle on the garage floor, this winter; sealmate wouldn’t fix it. On the way down to WCM, the new seal was leaving a dirty ring on the chrome and a sheen of oil that you could feel and see on a finger tip, and a very small amount at the bottom of the leg. I wiped it clean every time I stopped and 3 days later it had dried up and stopped leaking. The tech at the dealer said this sometimes happens on a new seal while it beds in.

YMMV; it depends on how bad the leak is.



Sent from my iPhone using Tapatalk
 
#29 ·
Paint work is done (for now), and I've been able to put a couple hundred miles on the new seals. So far, everything looks good. I'll circle back if that changes, but I think I can call this one solved (fingers crossed). BTW, a couple of shots of my new paint are below. This used to be an all red bike.
 

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#31 ·
Back in March, I had to play "musical fork seals."

Despite a well respected suspension shop supplying the fork and dust seals, both did not fit on the first round (sizing off) or second round (material too hard). 3rd round I got it right.

Regarding sizing, just because my caliper measured the new seals at 43 x 54 x 11 does not mean it would fit my 2006 ST3s. What I found was the material behind the rubber was equally important as the proper size. The best way to describe it is the seals measured correctly but would not fit because they were very stiff underneath their rubber.

What I learned is that the manufacturer's application tables are not always correct - K&S. I had too much confidence in the well respected suspension shop. Best to see my independent Ducati repair shop for parts. They did not use the OEM stuff by the way, but K&S and BikeMaster (Athena imprinted on dust seals I think).

The correct fork seals available to me from the shop according to my invoice was K&S# 16-1044S. The dust seals were BikeMaster #429092.

Would recommend a purpose built seal driver. I used motion pro locking ring but I think it was overkill.

I used 15 wt max brand something oil as recommended for street and track use. I find it too stiff for the rough canyon roads. Next time, go back to 10 wt.

I heated the fork tubes lightly with a propane torch to help installation. Advised by both Ducati shops.

Though I bought the compression tool, I found it easier to make my own rig a contraption since the compression tool still requires a third hand to insert the a spacer/stop plate.

Best part is that even though I thought I knew something about forks, having already done a Kawasaki KL fork and DRZ400 Showa fork, I still learned new stuff with the Duc 42mm SHOWA's.
 
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