Fork seals, again!

[camos]

30W does seem a little to heavy for fork oil. I am using 15W with my progressives springs and I use a little bit of air also.. seems to work nicely for me.

But the level of the oil in the fork does make a difference..

 

Rick F.

So 30 wt hydraulic oil is about half the price of "fork" oil so I thought I would give it a try but, yes it is a bit too heavy. Looked around for some lighter weight hydraulic oil but couldn't find any lower than 30 wt. It isn't due to be changed until next year but I might try taking a little bit out this summer and see how that works.

[dna9656]

Yea, I'm not sure what to do with this. This will be the 3rd fork seal on the right, this is the 2nd one on the left side too but for now that one is fine. There was a nasty pothole on the last ride but still, that shouldn't be killing new fork seals. Using only OEM seals, I thought this last one was solid but here we are again. The fork upper looks perfect, not sure what keeps killing these new OEM seals. I'm tired of pissing around with these forks. Any ideas? Anyone have a good MKII fork upper, I cant think of anything else to do about it. I really dont want to do this job a 5th time. Anything I may be overlooking here?

 

I'm one fork seal away from selling this bike and cutting my losses.

I read here on the forum that the stealers (dealers) can get (or know where to get) your forks polished for about 1 hour's labor cost, seems to me you could find that re finisher yourself and take the fork tubes to them, they could prolly spec out a new seal for you (if ness.) so you don;t have to go through this again. In your prev. posts you talked about (what I guess is) a guard (protects the tubes from bug guts and stones) for the fine finish on the tubes... like a rubber bellows sort of thing? I would be interested in a rubber bellows thing.... know of a P/N that fits?

[CaseyJ955]

I read here on the forum that the stealers (dealers) can get (or know where to get) your forks polished for about 1 hour's labor cost, seems to me you could find that re finisher yourself and take the fork tubes to them, they could prolly spec out a new seal for you (if ness.) so you don;t have to go through this again. In your prev. posts you talked about (what I guess is) a guard (protects the tubes from bug guts and stones) for the fine finish on the tubes... like a rubber bellows sort of thing? I would be interested in a rubber bellows thing.... know of a P/N that fits?

 

Someone else just posted a pic of them here. No rubber, just a metal shield that holds onto the tube with a hose clamp. I like them because they seem to work great and have very little visual impact. As far as fork polishing, not a bad idea at all. I'll have to look into it. It's going to be another week before I get around to it so depends on what I find when I tear into it. It sounds like an extra piece of mind, that would be nice.

[CaseyJ955]

I decided to fix her and keep her, I have other priorities that trump replacing a bike at this time. I went and got a couple seals, only fixing the one leaky side and keeping a spare in the trunk, along with a few tools.

 

I checked the upper with a straight edge, it appears to be straight as an arrow (using my daily cliche point right here) and smooth as glass (tomorrows cliche point used here) with no snags using the panty hose trick. Prices for uppers on Ebay have gotten silly, and most appear pretty knackered, so I'm going to try this again. New seal, different 10w fork juice and probably less by .5". I hope to have it assembled today with a test ride and then be on my way to southern CO on it tomorrow where I will spend several days looking for land and intently watching that fussy seal. I would sure feel better if I could see even something slightly wrong with the upper fork. Time to clean her up and try again.

[Patch]

Hi Casey, does the upper tube show a dark or dull linear striping such as unpolished lines length ways on that upper tubing?

A nylon wouldn't snag on such a stripe. These stripes are usually cause by faulty core material is the bush/bushings

 

A comment on oil: we often increase the W when we are compensating for ware in mating tolerances. I'm sure many of us recall the early days of synthetics when it was suggested to refrain from using it in older high mileage engine as it usually meant seals would begin to leak.

Well moving away from a fork oil can reduce seal leaking here as well. Increasing W with synthetic (I used 0w30) has less creep action then hydraulic oils.

[Bob K.]

Tony--Have you considered taking abuncha pictures of all your fork components and posting them here? We might be able to see something and relate to problems we've had.

[CaseyJ955]

Hi Casey, does the upper tube show a dark or dull linear striping such as unpolished lines length ways on that upper tubing?

A nylon wouldn't snag on such a stripe. These stripes are usually cause by faulty core material is the bush/bushings

 

A comment on oil: we often increase the W when we are compensating for ware in mating tolerances. I'm sure many of us recall the early days of synthetics when it was suggested to refrain from using it in older high mileage engine as it usually meant seals would begin to leak.

Well moving away from a fork oil can reduce seal leaking here as well. Increasing W with synthetic (I used 0w30) has less creep action then hydraulic oils.

The tube is nice and consistently chrome with no streaking or abnormal wear showing. I am moving to a fork oil in 10w, thats the heaviest I could get off the shelf locally and I see 5w was OEM. Next time I think I'll try motor oil, I was hoping to try 15 or 20w. I replaced the bushings and pistons when I got the bike awhile back. Thats the part that sucks, it all looks so clean and proper. One thing I'll do differently is I'll get a proper fork seal tool. The homemade one only works with the upper tube off the bike. I'm also going to add a little less oil. Both sides were holding out fine until I hit giant pothole hard enough to cause the bike to bottom out, even with Progressives. After that nasty pothole is when the leak resumed. I was golden until then.

 

Tony--Have you considered taking abuncha pictures of all your fork components and posting them here? We might be able to see something and relate to problems we've had.

 

It's already together, I'm going to get a proper seal driver to RO any issues with my homemade one. Next time it comes apart there will be pics of it all. My judgement is telling me to replace the upper in spite of any visible issues but availability is silly on Ebay. I'll go find an appropriate seal driver and get her back on her feet, and hope for the best.

 

BTW, off the top of anyones head, what size seal driver do I need for a MKII (1989), I think it's different than the MKI. Also has anyone used one of those adjustable fork seal drivers and are they worth ordering or should I just get one in the correct size?

 

Thanks again all. I'm bummed to see that I'm not the only one with fork oil on my hands recently.

[Patch]

I have tubes and lowers too I think,,, in a box on a very tall shelve.. I wanted to take them down to measure as I have a cross reference sheet for upper bushings, my shoulder wouldn't permit the effort at the time, good now tho.

 

I don't mind parting with any of those parts, cost of shipping Casey. I would need to check them first. Let me know

[CaseyJ955]

I have tubes and lowers too I think,,, in a box on a very tall shelve.. I wanted to take them down to measure as I have a cross reference sheet for upper bushings, my shoulder wouldn't permit the effort at the time, good now tho.

 

I don't mind parting with any of those parts, cost of shipping Casey. I would need to check them first. Let me know

 

If you have a known good upper for a MKII, Im in! PM sent.

[CaseyJ955]

She seems to be holding, I made the 3 hellish miles of my driveway and another 75 in the hills, then the 3 mile driveway again. If the seals were about to fail my driveway would beat them into submission in pretty short order. The 10w fluid works pretty well, seems to work with the progressives nicely.

 

I'm still aiming to get another fork upper and hopefuly lower, I cant help but feel I have not heard the last of the fork issue.

 

I will tempt it, in a couple days I'm going to ride it to southern Colorado to search for land and explore the region. This summer has been far too short!

[Patch]

Good to hear.

 

We are working on SK's truck tomorrow in the shop. He'll give me a hand to get that crate down, we'll check them out and let you know..

Pretty sure there are lowers as well no idea of the ware tho..

[Pegasus1300]

So in reading thru your list of what you have done and in looking over your account of the mishap,I don't think you have a seal problem. I think you have a pot hole problem.Any hole bad enough to cause a set of progressives to bottom out is pretty bad. I think that pot hole knocked out your seal and you are lucky it didn't take the other seal with it and maybe a bushing or a tube. Sorry but I think you are in for another rebuild with no no ther problem then the pot hole to blame it on.

 

2 other thoughts from years ago. We used to make seal protectors from a piece of heavy vinyl warped around the leg and held with hook and loop.This would move up and down with the fork and keep bugs and small rocks from causing damage.

 

It is possible to put a second spring on a seal. This would help it to seal it better.

 

Good luck

[CaseyJ955]

So in reading thru your list of what you have done and in looking over your account of the mishap,I don't think you have a seal problem. I think you have a pot hole problem.Any hole bad enough to cause a set of progressives to bottom out is pretty bad. I think that pot hole knocked out your seal and you are lucky it didn't take the other seal with it and maybe a bushing or a tube. Sorry but I think you are in for another rebuild with no no ther problem then the pot hole to blame it on.

 

2 other thoughts from years ago. We used to make seal protectors from a piece of heavy vinyl warped around the leg and held with hook and loop.This would move up and down with the fork and keep bugs and small rocks from causing damage.

 

It is possible to put a second spring on a seal. This would help it to seal it better.

 

Good luck

 

I just spent 4 days in the saddle, some of it over pretty ugly roads and all seems good. No more leaks. I put about 0.5" less fluid this time.

 

Yea, we do have a pothole problem. The one I hit was in the middle of a very smooth new-ish road, why there is a huge chunk gone out of it is a mystery to me. Bike didnt miss a beat and served extremely well aside from predictable lack of torque above 9000'. Nothing changes shift points faster than elevation, I sure had to grab 4th a lot until I came back down to the 4000-5000'. Aside from almost running out of fuel a couple times in rural BFE and issues with unpaved roads shes spectacular. Considering that I was trying to use her like a 1200GSA she owes me nothing. Seal problem seems to be remedied.

 

Thanks to everyone for all the help.

[camos]

I put about 0.5" less fluid this time.

So was that the solution to the problem? How much fluid did you put in originally?

[CaseyJ955]

So in reading thru your list of what you have done and in looking over your account of the mishap,I don't think you have a seal problem. I think you have a pot hole problem.Any hole bad enough to cause a set of progressives to bottom out is pretty bad. I think that pot hole knocked out your seal and you are lucky it didn't take the other seal with it and maybe a bushing or a tube. Sorry but I think you are in for another rebuild with no no ther problem then the pot hole to blame it on.

 

2 other thoughts from years ago. We used to make seal protectors from a piece of heavy vinyl warped around the leg and held with hook and loop.This would move up and down with the fork and keep bugs and small rocks from causing damage.

 

It is possible to put a second spring on a seal. This would help it to seal it better.

 

Good luck

 

So was that the solution to the problem? How much fluid did you put in originally?

 

I had originally gone with 5.5" but this time I decided to leave it at 5" At first it felt pretty soft but it turns out to be just fine. It was composed on all but the gnarliest pavement and of course, it did not care for actual country roads one bit. I see the need for a DL1000 or preferably an R1200GSA in my stable, I had a rough time getting to a few of the properties I wanted to see but I cant blame the bike for that, it did everything it was designed to do and it did it remarkably well for a 3 decade old bike. Shes a touring bike that thinks shes a sport bike, but as it turns out she knows damn well shes not an adventure bike haha.

[Bob K.]

I had originally gone with 5.5" but this time I decided to leave it at 5".

I decided on a 6" fork oil level this time around. I also made sure I pumped the forks up and down to distribute oil and then checked the level again. I was shocked by how far the oil level went down upon initial fill once the oil was distributed.

 

I have limited experience with forks, so I can only go off of what Progressive's instructions said. Anything less than a 5.5" air gap (aka "fork oil level") at the top of the fork is too much oil. Do I have that right?

Progressive Spring Instructions.pdf

[CaseyJ955]

I decided on a 6" fork oil level this time around. I also made sure I pumped the forks up and down to distribute oil and then checked the level again. I was shocked by how far the oil level went down upon initial fill once the oil was distributed.

 

I have limited experience with forks, so I can only go off of what Progressive's instructions said. Anything less than a 5.5" air gap (aka "fork oil level") at the top of the fork is too much oil. Do I have that right?

 

That is my understanding, and I mistyped, Progressive said 5.5, I filled it up to 6", not 5" as I said.

[camos]

That is my understanding, and I mistyped, Progressive said 5.5, I filled it up to 6", not 5" as I said.

So if you put in less oil than Progressive recommended, how would that affect the seal?

[Bob K.]

So if you put in less oil than Progressive recommended, how would that affect the seal?

The Progressive instructions indicate not to put in more oil than that which gives a 5.5" air gap at the top. That's with the springs out and the forks completely compressed. The instructions indicate any oil level less than that is "safe".

 

I'm just theorizing here. Putting in more oil than Progressive says is "safe" might result in not having enough air gap once the springs are installed and take up a bunch of volume, so one might get some hydrolock (and resultant overpressure on the seals) if one hits a hard bump.

 

On the other end of the spectrum, I think we only need enough oil in the forks to make sure all the valving has enough oil to use. The only downside I can see is that a large air gap leaves more room for the air to compress, thus resulting in lower air pressure and softer suspension on hard bumps.

 

I dunno. Maybe somebody who understands how all those dang fork parts work can explain it better.

Edited October 8, 2018 by Bob K.

[dna9656]

Yea, I'm not sure what to do with this. This will be the 3rd fork seal on the right, this is the 2nd one on the left side too but for now that one is fine. There was a nasty pothole on the last ride but still, that shouldn't be killing new fork seals. Using only OEM seals, I thought this last one was solid but here we are again. The fork upper looks perfect, not sure what keeps killing these new OEM seals. I'm tired of pissing around with these forks. Any ideas? Anyone have a good MKII fork upper, I cant think of anything else to do about it. I really dont want to do this job a 5th time. Anything I may be overlooking here?

 

I'm one fork seal away from selling this bike and cutting my losses.

 

There are businesses that resurface hydraulic actuator rams and accumulators; and a fork is a kind of accumulator as it absorbs surges in hydraulic fluid flow like a shock absorber on the truck, except it had the suspension's spring integrated with it and we traditionally call it a fork due to there being 2 of them acting in tandem. Like you don't all ready know that... SORRY!

[camos]

A little confusion over filling to 5" or 6". Filling to 6" should be safe. Filling to 5" is overfull which I think might cause the seals to blow out.

[CaseyJ955]

The Progressive instructions indicate not to put in more oil than that which gives a 5.5" air gap at the top. That's with the springs out and the forks completely compressed. The instructions indicate any oil level less than that is "safe".

https://www.venturerider.org/forum/attachment.php?attachmentid=114623

 

I'm just theorizing here. Putting in more oil than Progressive says is "safe" might result in not having enough air gap once the springs are installed and take up a bunch of volume, so one might get some hydrolock (and resultant overpressure on the seals) if one hits a hard bump.

 

On the other end of the spectrum, I think we only need enough oil in the forks to make sure all the valving has enough oil to use. The only downside I can see is that a large air gap leaves more room for the air to compress, thus resulting in lower air pressure and softer suspension on hard bumps.

 

I dunno. Maybe somebody who understands how all those dang fork parts work can explain it better.

 

I never wanted to go over after reading the 5.5" max on the Progressive inlay. I figure anymore than that and the oil will have no place to go in a bottom-out situation and force the oil past the seal causing yet another joyous occasion to pull the forks apart. I'm around 6" down now and it hung in there just fine while I was wandering greener pastures. I even hit a few unexpectedly large irregularities in CO and NE that had to be close to bottoming out, yet the seal hangs in just fine. I'll still keep the fork parts on hand for when it does pop again. I'm quite pleased with being able to do this whole Colorado thing without one mechanical failure, for the first few hundred miles I was constantly glancing at it to make sure it was sealing.

 

I did right away notice the forks were softer, not sure if it was different fluid or just a little more air and a little less oil. It does ride pretty darn nice.

[CaseyJ955]

A little confusion over filling to 5" or 6". Filling to 6" should be safe. Filling to 5" is overfull which I think might cause the seals to blow out.

 

Agreed, maybe I was cutting it to close with the 5.5", which is why I dropped 0.5" while filling this time. The progressives are beefier than the OEM springs and will displace more fluid when dropped back into the fork, but the 5.5" rule is what I heard with those springs. I guess next time I have them apart I'll consider 6" the magic number.