Ohlins fork seals

[Chuck]

 

Have you ever serviced the shock?

That *was* courteous of her. Nope. No doubt it'll go belly up as soon as I finish up the forks.

[Chuck]

Ok, let's pretend that someone (like me) that has never done this finds this thread with a search. I know most of you guys will give me the roll eye because it'll be very basic, but when I'm searching for a how to, I don't really mind. Back in the day, I had a Haynes manual for my duck, and it might say, "remove head." Uhh, ok. How do I do that?

So, let's get started.

First, I don't mind getting dirty.. but I hate staying dirty. I'm chief cook around here, and grease under the fingernails isn't an option. I also hate to wear nitrile gloves unless necessary. They make my hands sweat and get all wrinkley. For jobs like this, I have water soluble lotion. Apply it liberally, work it under your cuticles, around your nails, really rub it in.

2017-02-10_10-59-26 by Charles Stottlemyer, on Flickr

Washes off with soap and water, and your sweetie won't get grossed out when you are tossing the salad with your hands.

Loosen the two bolts on the clip on if you have these. That will take the pressure off the threads, and the little "Pittsburg..must be made in Ameri..what? oh? adjustable pin wrench will loosen the top cap with maybe just a tap or two from your copper hammer.

2017-02-10_11-00-00 by Charles Stottlemyer, on Flickr

There's really no reason for them to be particularly tight, the cap is sealed with an O ring. Fortunately, they weren't.

Now we can take the wheel off.

2017-02-10_10-59-45 by Charles Stottlemyer, on Flickr

Pulling out the two bolts and giving the calipers a wiggle will move the pistons back enough for them to come free.

Carefully loosen the two screws that lock the axle. Just loosen one a little, then the other. The first will be tight again. Repeat until they are both loose. Remember that when you reinstall them. Many Stelvio owners found to their chagrin that you can break things.

2017-02-10_10-59-06 by Charles Stottlemyer, on Flickr

There is a stub allen wrench in your tool kit (Imagine that!) for removing the axle.

2017-02-10_10-58-49 by Charles Stottlemyer, on Flickr

Note the spacer is on the left (port) side of the wheel..

2017-02-10_10-58-32 by Charles Stottlemyer, on Flickr

Pulling the axle will let the wheel drop down, and be removed with just a little finesse. That's why I have the 2X4s under the Pit Bull, it gives a little more height to get the wheel out. BTDT with the Centauro.

Then, we can remove the 4 little screws that hold the fender on. Slide the fender forward then down, and it'll come right off.

2017-02-10_10-58-14 by Charles Stottlemyer, on Flickr

Loosen the pinch bolts a little at a time on the bottom, and the one on the top triple if you haven't done it already, and the fork legs will come right out.

2017-02-10_10-57-46 by Charles Stottlemyer, on Flickr

Suuuure they will.   Especially if it's been sitting by the ocean for several years.   Squirt some AeroQroil, or your favorite spooge on the triples, and bolt that tool we made yesterday on. That'll give some leverage, and a place to carefully tap with a big rubber hammer while turning the leg. A special tool, cleverly disguised as a Matco screwdriver tapped in to the lower triple will help. No need to be a cave man, just tap it in with your hand. You are only trying to open up that triple a couple of thousandths of an inch.

Sure enough, the leg will come out. As it does, the clip on will want to fall. Tie it up with a zip tie.

2017-02-10_11-03-17 by Charles Stottlemyer, on Flickr

Nothin to it.

2017-02-10_10-57-17 by Charles Stottlemyer, on Flickr

Take off the other leg the same way.

Total time? About an hour, including taking pictures.

Tweeeeet! Lunch whistle, back later.

[Chuck]

Looked up the suspension settings while I was in at lunch. This was what seemed to work on the Scura and Rosie the Rosso Corsa:

 

set front shock compression +3 from full soft, rebound+6 from full soft.  Rear suspension  Rebound 24 clicks from full soft, compression 12 clicks from full soft.

 

Give it a try.. I think you'll like it. This is after you get the sag right, of course..

[Chuck]

A question. The manual says to use Ohlins grease when changing out the seals. When I asked the duck guy, the said they just used the oil for putting them together. Is this ok? I can wait and source some if I really *should* use the Ohlins grease..

[emry]

Somewhere in history there was the cross reference to a Yamaha part number for the seals, double lip if I recall. .  They lasted much longer than the performance oriented Ohlins seals... The Ohlins oil (RT43) is the same as Yamaha M1 which was spec'ed when Yamaha owned the majority share of Ohlins back in this era.

 

Suspension guys love the "spec" grease and it is really nice. But oil will work just fine. Any lube is better than none. 

[Scud]

 

2017-02-

 

 

I forget what size that is, but I bought a set of large hex wrenches, one of which fits the front axle and the rear axle. It simplifies rear-wheel removal, because you can apply force in both directions - sort of rocking the axle while sliding it out. Front solid axle is threaded, so ratchet works fine.

 

You gonna lube the steering bearings while you're in there?

[Chuck]

 

You gonna lube the steering bearings while you're in there?

Jeeese, Scud.. I'm just getting over this blown disc in my back. I'm doing a little bit, then taking a break. I may or may not change out one of those fork seals yet today. Lubing the steering head bearings would remind me of work..but I should, of course.

[Scud]

Oh, sorry to hear that. You started off like a man on a mission... Rest up and don't push yourself.

 

My Scura's steering bearings had very little grease, but I got to them in time. Maybe yours were already done. Joe's (now my) Champagne LeMans' bearings were shot and needed replacing - they were nearly dry. Lubing the bearings is easy (much easier than replacing), but getting to them... well that does a bit of work. And you are already so close. 

 

Maybe we need a Fork-off Maintenance Checklist - like Docc's tank-off and wheels-off lists. I like the sound of that... Hey! Fork-Off.   

[Chuck]

Ok, ok Scud. Put down the rubber hose..don't hit me again.. I'll do it. The last time I rode the Mighty Scura last fall, I actually unhooked the steering damper to see if it was causing the very slight "weird" feeling from the front end. It wasn't, so I looked at the shagged tires, and decided it was probably them. It may be, but I really should have a look. Thanks for the reminder. Fork off, indeed.

[Chuck]

Ok, I have the "front fork specifications card" in front of me. It say.. 105mm. I've seen the number 90 bandied about on the interwebs. I still haven't found anything much here. Will someone that knows tell me which is right? Is it with the spring and spacer installed? From the fluid level to the top of the outer tube with it bottomed out?

I'd like to do this once..

[docc]

Haha - I remember this "air gap" (*luftkammer*) business being so confusing. I use 100mm.

 

Less "air gap"= stiffer, more air "chamber" = softer?

 

Spring/spacer in? Can't remember.

[Chuck]

So, I went to an Ape forum, and answers were all over the place, too. Spring in, out, damper rod up, down, 90mm, 110mm.. This shouldn't be that hard..

Fortunately, one of mine has never leaked, and the forks have worked beautifully. I'll pull the cap tomorrow, measure it with the spring in and the damper down. Whatever it is.. that will be what I use.

I'll report back tomorrow.   It's supposed to rain. I really enjoyed playing out side today..it's rare to have 60f, sunny, and no wind to speak of in February.  Thought about going for a ride, but there's still salt on the roads. Nah.

[Chuck]

As an Airframe and Powerplant mechanic, I'm licensed to fix anything the flies.. from a free balloon to a triple 7. (!) Naturally, the FAA doesn't expect a guy to instinctively *know* everything about all. What they *do* expect, though, is for a guy to be able to find the micro fiche.. uh, well it's on CD now.. from the manufacturer and follow the instructions.

Ok. I downloaded the manual for the Ohlins Road and Track 43 fork, and here are the instructions for changing out the seals:

Changing seals
Put the fork legs upright for 15 minutes.
1
Grip the fork leg in a vice. Use soft jaws.
2
Unload the spring preload completely by
turning the adjustment screw counterclockwise.
Use a 12 mm or a 17 mm
wrench.
Make a note of the number of turns.
3
Carefully remove the top nut assy.
CAUTION!
Do not damage the O-ring and do not
drop the flat key into the fork leg.
4
Remove the preload tube.
5
Slide the outer fork leg up until the top
bushing is just above the inner leg.
(Approx. 140 mm from complete bottom
position. This is to make sure there is no
oil above the top bushing).
6
Slide the outer tube completely down.
(Fork seal touching fork bottom).
7
Push the piston rod down completly.
NOTE!
When measuring the oil level, always
have the spring installed.
Measure the oil level using the top of the
outer tube as the zero mark.
Note the measurement.
8
Remove the spring and tip the oil in a
clean container.
9
Remove the outer tube, clean the seals
and check for damage, if the seals are
damaged remove and replace. If the
seals are OK, then apply �hlins grease
(green grease 148-01).

 

Sweetie's calling me for lunch.. back in a few.

[Chuck]

Here we go. Upright.. check. soft jaws.. check. Notice I get my supplies from the same place as Wiley Coyote..

2017-02-12_11-12-02 by Charles Stottlemyer, on Flickr

Back out the blue nut all the way. Count the turns. This controls spring preload, and if you don't count the turns, you'll have to go through setting the sag again.

2017-02-12_11-12-18 by Charles Stottlemyer, on Flickr

I'd already loosened the top nut assembly when it was on the bike, but it wouldn't have been necessary. You'll feel a click when the damper rod comes loose from the top assy.

"Do not damage the O-ring  (well, duh) and do not
drop the flat key into the fork leg." (I have no idea about what they are saying, there.)

2017-02-12_11-12-36 by Charles Stottlemyer, on Flickr

[Chuck]

Pull everything up

2017-02-12_11-12-50 by Charles Stottlemyer, on Flickr

and "remove the preload tube."

To do that, pull the preload tube down against spring pressure and slide a 17mm open end wrench on the jam nut.

2017-02-12_11-13-14 by Charles Stottlemyer, on Flickr

Turning the ratchet will unlock the jam nut, and you can spin off the assembly.

2017-02-12_11-14-07 by Charles Stottlemyer, on Flickr

Now, you can remove the preload tube.

You'll notice the damper rod has slowly sunk into the bowels of the shock. Not to worry. Grab the top and slowly pull it up.

2017-02-12_11-14-28 by Charles Stottlemyer, on Flickr

If you don't pull it up slowly, it'll shoot oil out.

Remove the nut and the long tube inside the piston shaft.

2017-02-12_11-14-52 by Charles Stottlemyer, on Flickr

What this tube does is push on a spring loaded needle valve when you turn the rebound adjusting screw on the top of the fork. Need I say that if you dump the oil out, that spring and needle valve will eventually fall out into the oil,and maybe get lost? 

Next, there is a stamped gizmo.. it's not named on the parts blow up.. that you can fish out with a piece of welding rod or coat hanger with a 90 degree bend on the end..

2017-02-12_11-15-17 by Charles Stottlemyer, on Flickr

Now is the time to measure the air gap. On my fork, the oil just comes to the top of the spring. That is right at 4.6 inches. Converting that to metric, it's 116.84mm. Hmmm. The manual says 105mm. I'll probably go with that.