[mudson]

I've recently fitted a Manitou Minute MRD w/ Absolute damping to my Nicolai Helius CC. The fork is the 130mm model

First couple of rides: good. The fork disappears and is stiff as a stiff thing. I like this fork!!:thumbsup:

Could be a little more plush I think, so I'm giggling the pressure: put fork upside down as per instructions and as I deflate the fork (slowly as per manual) I notice the fork is sucking down. Basically the fork is losing travel, so that when I set it to where I think I need it (c. 60 psi) I have only 95mm of potential travel.

I notice also that if I re-inflate to, say 150psi the fork extends to allow a potential 128mm of travel. But if I deflate (real slow, as in reeeaallly slow) eventual the fork sucks down again. :madman:

I leave the fork at 100psi and about 100mm of maximum travel. Then I notice the Absolute damping is no longer working at all. Throw the lever all the way to the right: no change. :madmax:

So I'm stuck with a < 100mm fork with no means of controlling low speed compression damping. And I'm not wholly sure the fork is still safe to ride.

A few people have stripped this fork down: is there something serious amiss, or is there an easy remedy? I live in New Zealand and bought from ChainReaction Cycles in UK and have had a world of pain dealing with them. Manitou are not common here in NZ so I am hoping I can service the fork myself. I'd like some advice before diving in!

Any ideas? I like this fork but it seems to be very sensitive to fettling.

Thanks

 

[Jayem]

No specific ideas, but if that travel-adjustment is based on an air-chamber and not a mechanical lock-down, it wouldn't be suprising, because manitou has had a lot of trouble with their travel-adjustments, usually problems with the seals leaking, and the fork will settle-down while you ride. Sounds pretty similer to what you're experiencing. This is one reason I stay far away from air-forks with travel adjustments.

 

[avam]

This past week I noticed the exact situation with this fork as you. I started to disassemble, but decided to take it back to my LBS and let them decide what is wrong as this is a warranty situation. I just dropped it off yesterday so no answer yet. I have about 20 hours and 120 miles on this fork. The fork was working well until the last couple rides. It felt like it would continue to work ok, but I was worried as you are and of course want the full 130mm of travel.

Your dampening problem is that you do not have enough oil in the right leg. I have been experimenting with different oils and noticed that you have to have the right amount. The service guide and owners manual differ in the oil level requirement. I have found that 140mm down from the top of the tube is not enough oil. It needs to be closer to 130mm. Be careful when you take the red adjusting cap off as there are two ball bearings and two springs in holes under that cap when you take it off. They are easy to drop. From there you just unscrew the damper assembly. Be careful as you pull it out of the fork as the inner tube that it goes down into (where the oil is) can be pull out too and then the oil will drain out into the outer part of the fork. I continue to use a twisting motion as I pull up the dampener assembly. Let me know if you need help with this.

 

[MartinS]

Jayem, I don't think his model has IT, it is a set 130mm.

 

[mudson]

Thanks for the replies.

To confirm this is the fixed-travel 130mm MRD Absolute I have. The fork should have the same amount of travel regardless of pressure.

Avam, keep me posted on your fork and whether the travel loss issue is simple to resolve of a warrantee issue.

I'll check the oil height, but the Absolute damping was working fine on the couple of rides I've had on the fork, including locking out. It's only since the pressure jiggling that its not longer working.

I'll find the service manual for the fork - I found it on the buried on the Hayes site and I might have a look inside...

 

[mudson]

Update: damping returns

The problems of the fork may not be as terminal or potentially dangerous as I thought.

This morning I find the bike back to pretty much where I started and as I had it before on the rides I've had with the fork.

The Absolute damping is back and working from light platform to lock-out.

The fork still only has 95mm of potential travel but it seems (hitting kerbs and bunny hops) to be fully functional - not ideal though

So did the pixies break into my garage and fix it? I think not. As per manual instructions the fork was inverted for the pressure jiggling. The bike has hung the right way up all night.

Still, how awkward and not very "Absolute" it that!

I may go into the fork this week to see if I can understand the workings better.

 

[avam]

My LBS will be contacting Hayes on Monday to discuss the travel issue. You could e-mail or call them. I have found they do e-mail back pretty quickly. The service manual was of no help to me in trying to diagnose the problem. I'll let you know what happens.

[email protected]
888.686.3472

 

[mudson]

I've emailed Hayes to see what response I'll get.

I've not had time to strip the fork down yet. But any pressure changes I make decrease the travel when I return to the correct sag... :eekster: So the fork is essentially useless now and I certainly wouldn't ride it in its current state.

Hopefully Hayes deliver on the CR front and I can get riding again soon.

 

[mudson]

Hayes customer service result

I got the following from Hayes over the issue:

Heya Mick, sorry for the delay in getting back to you. Had to converse
with the boss as how best to help you out being that you're in New
Zealand. That makes things a trite bit difficult for the both of us most
definitely.
What we determined is that the o ring on your air piston isn't
equalizing the pressure properly and is allowing pressure to bypass it
and build up underneath the air piston, causing the fork to suck down.
The fix is relatively easy, but will require you to disassemble the fork
and replace to o ring on the piston with a quad ring that I can provide
you. Actually I'll be giving you a couple as it's easy enough to nip one
of the seals your first time installing it. A little care is needed to
avoid that, but I'd rather give ya a couple of spares than have you
writing back in the event of accidentally nipping the seal. Head 'em off
at the pass, as they say.
The link to the service instructions can be found here:
http://www.manitoumtb.com/guides/Forks/MRD Service Guide[1].pdf?
cvar1=6%2F26%2F2008+9%3A05%3A44+AM
and the service instructions for the air spring begin on page 10. There
is a good picture of what likely has transpired on pg 11, section 9.
From here, I just need to get your address so I can send the seals off
to you. Once you install them and get some time on the bike, keep us
informed on how the fork is performing. It helps me help you as well as
others who may find themselves in the same set of circumstances down the
road, and that makes for better service for all.

John Trusky | Technical & Warranty Support

Ph: 888.686.3472 | Fax: 414.462.0214
6750 W. Florist Ave. Milwaukee, WI 53218

Hayes Bicycle Group | www.hayesbicycle.com

Can't ask more than that given the circumstances, so far so good on that front. Of course I'd have liked the fork not have an issue - but then if was more cautious I wouldn't have bought a year one fork...

As soon as the seals arrive I'll strip and rebuild and see how it goes.

I'll post up when the fix is in and report back on how easy/difficult it all was and the result.

 

[avam]

Glad to see the response. I'm still waiting for my fork to be returned. Fortunately my LBS is letting me use their demo bike so I am not missing any riding.

If you can, take some good pictures of all the parts together when the fork is disassembled. I have a feeling I will be fixing my fork someday myself.

 

[mudson]

Good CS from Manitou

I received pretty promptly (given how far they came) new seals for the air piston foc from Manitou in the US. :thumbsup:

I rebuilt the fork exactly as per the service manual. It was pretty easy.

I think my fork was a friday afternoon effort:

1. There was no semi bath oil in the fork at all
2. There was no lubrication on the fork leg seals or foam rings, dry, nada.
3. The air-piston seal was actually an o-ring as fitted. There was no visible sign of damage, but I replaced with the quad seal Manitou sent as shown in the picture in the service manual.

I've done a short ride and everything seems back to where it was, but better as the fork is now super smooth.

I used Silkoline 5wt fork oil in the damper and Mobile 5w50 in the semi bath and air piston.

I'll report back after I've got some real miles on the rebuild.

 

[Jhanney]

hi i experienced a suck down as well. i need help in understanding the technical jargon i am a noob.. i got the seals from manitou.. which leg pistons seals is the one i replace?

 

[Jhanney]

Hi all as i was replaced the seal in the compression leg and started to fit things back, i am now experiencing a vacumn in the negative air chamber so its super sucked down. the blue knobbie bits at the end of the lower piston externally is affecting jammed so i can't get any way of slotting my 15mm wrench to unbolt it. any one knows how to help me?