Are these forks serviceable?

[Obo]

Just pulled one of the fork apart on my ST1300. I had blown a seal 2 weeks back, as was obvious by all the oil down the side of the bike and the fork leg.

I disassembled the fork tonight and gave it a quick cleaning and inspection.

It appears that water may have gotten past the dust and oil seals and interacted with the steel back-up ring and one of the bushes causing a build up of rust on the fork case (2 spots) and pipe. (1 croissant shaped spot)

Any thoughts on the best way to clean these, and if you think it's still OK or is it toast and needs replacement?

I was debating about using some CLR on a microfiber cloth to see if it would gently wipe out & off, but am worried about damaging the surfaces. Simple Green and brake cleaner didn't remove it.

Already going to clean the area where the oil seal, clip and back-up ring are with a soft Scotchbrite pad for the bit of oxidization there, but that's not a sliding surface.

Here's some photos, because



The score marks above may be from me wiping the fork out after somewhat de-greasing it. I'll check them closer later on as well as what looks like it might be a crater in the photo. (didn't see that in person)

The 2 bushes that I took off look OK, but I bought new ones with the intent to replace them anyway. I'm just more wondering about the rust spots.

I also noticed one almost round spot on the fork pipe that is pristine. It stands out slightly odd as the rest of the fork all around is worn/dull in comparison. I'm also wondering if it's a dent. I may have to see if I can check the run out of it somehow. It's right above the rust stained spot - so perhaps the water is slowly getting in there?



Regardless, let's start on the thoughts on the rust cleaning

Thanks!

 

[RaYzerman]

I'd start with vinegar instead of CLR, use the CLR later if you have to. The crater is OK as long as there are no burrs above the surface.

 

[dduelin]

I have had very good luck with using WD40 and 0000 bronze wool to remove rust discoloration on stainless steel items. The clamps on my NC are carbon steel and every fork oil change reveals brown staining on the tubes where the triple clamps compress. A light buffing with the stuff polishes the tube clean again. I learned this on boat parts many years ago. Steel wool will leave microscopic dust behind and accelerate the corrosion process. As Joni Mitchell sang - rust never sleeps. Any rust pits or craters render the fork tube unserviceable. Once the chrome surface is compromised it's done...... corrosion has made it's way into the steel under the chrome finish and will continue to rust and lift more chrome finish away. The raised edges will damage the new seal sooner rather than later.

 

[Sunday Rider]

Wow, I guess sealmate wasn’t gonna fix that. Hope all goes according to plan.

 

[Obo]

No luck with cleaning vinegar. Trying to source some bronze wool locally.

 

[ST1100Y]

Methinks the tube (shown in the last pic) is shot...

I'd replace both tubes, both slider bushing sets, seals and dust seals...

(just been there on my 1100, RHS fork seal looking moist, replaced seals, again moist... each tube showed a very shiny spot rearward where the seal works...)

 

[STRider]

I have had very good luck with using WD40 and 0000 bronze wool to remove rust discoloration on stainless steel items. The clamps on my NC are carbon steel and every fork oil change reveals brown staining on the tubes where the triple clamps compress. A light buffing with the stuff polishes the tube clean again. I learned this on boat parts many years ago. Steel wool will leave microscopic dust behind and accelerate the corrosion process. As Joni Mitchell sang - rust never sleeps. Any rust pits or craters render the fork tube unserviceable. Once the chrome surface is compromised it's done...... corrosion has made it's way into the steel under the chrome finish and will continue to rust and lift more chrome finish away. The raised edges will damage the new seal sooner rather than later.

I was going to suggest 0000 steel wool until I learned of the existence of BRONZE wool! Thanks @dduelin !

 

[motornut]

I have rebuilt hydraulic cylinders, If you have access to a lathe, chuck it in and use your steel or bronze wool to polish it up. That also helps with micro scratches that are vertical. Careful not to get to aggressive with the abrasive a light pressure is enough.
You can also check this way to see if the forks are bent too. You need to make allowances for off center chucking though, I am not sure about tolerances on these forks. The heavier rams are fairly tight on the area that passes on the bushings.

 

[dduelin]

I have rebuilt hydraulic cylinders, If you have access to a lathe, chuck it in and use your steel or bronze wool to polish it up. That also helps with micro scratches that are vertical. Careful not to get to aggressive with the abrasive a light pressure is enough.
You can also check this way to see if the forks are bent too. You need to make allowances for off center chucking though, I am not sure about tolerances on these forks. The heavier rams are fairly tight on the area that passes on the bushings.

My ‘05 accumulated a lot of miles and I was pretty good at changing fork oil at regular intervals. I think it was at around 70,000 miles I started rotating the fork tubes 90 degrees at an oil change to hopefully even out abrasion wear from road grime and impacts from foreign objects. Did it matter? Probably not

 

[Willsmotorcycle]

I was going to recommend 1000 grit emery paper, I YouTubed it... still confident with 1000, but this guys is a mcgyver. Polish it, reassemble, ride it... Figure out the next play August 22.

 

[Obo]

Well it's done as best I think I can...

I grabbed the WD40 and a kitchen Scotchbrite pad and some elbow grease and started on the chromed tube.
Slowly the discoloration came off.

Next I did the same and cleaned the inner fork tube where the oil seal sits as it was somewhat oxidized. Almost shiny now.

Then it was "how do I clean the inner part of the fork tube?" as I couldn't reach that far.
I grabbed a wooden chop stick and with using a razor knife I slit it up the end. I then inserted a strip of the Scotchbrite pad like a propeller.
After a liberal spray of WD40 in the tube and on the pad, I inserted it into the tube with the other end of the chopstick in my drill.
As it spun it lightly drug the pad around the tube and removed the inner rust stains.

I did find one tiny crater on the fork tube that you could feel a lip with your fingernail, but was almost too small to see. Wet sanded it with 2000 grit and WD40.

The fork tube then got a quick scuff and some silver spray paint to cover up the spots where it was worn by road debris over the last 20 years.

Assembly will likely begin tomorrow night and then I'll start on the 2nd fork which hopefully won't be an issue. (fingers crossed that this one doesn't leak either.)

 

[gmtech94]

Looks good ,they clean up nicely with that system . I would also recommend some 10000 micron wet paper with oil to finish them .

 

[RaYzerman]

If WD40 (mainly naptha) took it off, was it really rust or some petrol/rubber based residue? Although I can't imagine how it got there.

 

[Obo]

If WD40 (mainly naptha) took it off, was it really rust or some petrol/rubber based residue? Although I can't imagine how it got there.

From what I saw, there was rust on the steel backup washer that's under the oil seal. It was traceable in the oil seal grooves, down the split gap in the upper bush to where I assume the lower bush sat in a static rest position. None of the other non-oil based cleaners I tried had any luck. The surface on the chrome tube was also as smooth as could be so I was worried the rust what somehow in the chrome. I knew the aluminum had to be surface based as it couldn't have been scorched fork oil or worn copper from a bush.

 

[RobertT]

i had an issue with my ST's fork tubes as it kept on leaking oil and needed to rectify the issue, basically rebuild the front shocks from the bottom up. I ordered the anti friction rings and seals from Honda. The fork tubes were also shot, luckily there is a place in JHB South Africa that does what they call " hard chroming" I send the stanchion tubes there via courier and they did their thing- it looked amazing when i got them back, could have passed as new. i also learned in the process that tiny rocks and debris can form sharp edges on the stanchion tubes that can damage the oil seals even though the ST does have a type of " deflector" on the front forks. all sorted now and the ST is going strong.

 

[Obo]

You can also buy a neoprene type cover to protect them. Not sure how well these work.

 

[RobertT]

could be a plan, looks similar to the ones on my YZ250 for protecting the front shocks

 

[docw1]

Like these:

Fork Guards

NOJ Neoprene Fork Guards help protect fork tubes and fork seals from rocks, dirt, bugs and road debris and avoid costly fork seal replacement. They are stretchy and durable and will not deteriorate from fork oil. Simple installation with velcro-like backing. NO NEED FOR FORK REMOVAL. Sold in...

nojgear.com

 

[Al st1100]

You can also buy a neoprene type cover to protect them. Not sure how well these work.

If water got in there it could cause the tubes to rust but if checked and cleaned perodically they should be fine.

 

[dtcoleman]

I replaced the fork springs and rear shock on my 1300 last year. I ordered springs from Traxxion Dynamics and picked up new bushings and seals and oil from the dealer. It was perfect timing to adjust the oil weight as well. The process was pretty simple as well.

Looks like you have it all under control. As someone mentioned about the Seal Buddy. You should make yourself one. It's easy. I've used mine a few times because I find myself on gravel roads. Any debris really is a problem. Wondering if your proximity to the ocean has anything to do with the corrosion?

My two cents.
Dave