Zeb Damper Top Cap loosening after a few rides

[bmwpowere36m3]

Picked up a new eMTB and it came with a Zeb Select (A2) 170 mm with RC damper... long story short, the damper top cap keeps loosening on its own. In the 10 rides I've had it, I've needed to tighten it three times. Here's a picture (yellow reference mark) showing the movement after 2 rides.

Anyone experience this?

 

[Tepi]

Ostin uuden eMTB:n ja sen mukana tuli Zeb Select (A2) 170 mm eturatas RC-vaimentimella... Lyhyesti sanottuna, vaimentimen yläkansi löystyy jättää. Kymmenen ajon aikana, jotka olen sillä ajanut, olen joutunut kiristämään sitä kolme kertaa. Tämä kuva (keltainen viitemerkki) näyttää liikkeen kahden ajon jälkeen.

Onko kukaan kokenut tätä?

[LIITÄ]169119[/LIITÄ]

Jokaisen työkalu pakkiin kierrelukite Loctiten 243 .Rasvattomaan kierteen osaan viisi tippaa nestettä,kuivaa 24 tuntia ,pysyy enemmän.

 

[bmwpowere36m3]

Jokaisen työkalu pakkiin kierrelukite Loctiten 243 .Rasvattomaan kierteen osaan viisi tippaa nestettä,kuivaa 24 tuntia ,pysyy enemmän.

Yes, I can apply more thread-locker if that's the issue... though I've never had this occur on FOX and Manitou forks. I tighen the top caps hand-tight and they've never loosened.

 

[irie]

Yes, I can apply more thread-locker if that's the issue... though I've never had this occur on FOX and Manitou forks. I tighen the top caps hand-tight and they've never loosened.

Hand tight is not tight enough, they need a gentle 'nip up' with a socket (or spanner), there's a torque setting in the documentation sonewhere. No need for thread locker.

 

[bmwpowere36m3]

Hand tight is not tight enough, they need a gentle 'nip up' with a socket (or spanner), there's a torque setting in the documentation sonewhere. No need for thread locker.

Yes, I’ve torqued it to 28Nm and it loosened after two rides. Hand-tight meant with tool, not fingers.

The first time it loosened, I simply nip’d it up with a cassette tool and it came loose too.

 

[irie]

Yes, I’ve torqued it to 28Nm and it loosened after two rides. Hand-tight meant with tool, not fingers.

The first time it loosened, I simply nip’d it up with a cassette tool and it came loose too.

Doesn't sound right. TBH if it were me I'd take it to a local LBS and get them to have a look at it.

Edit: you could perhaps try using some "Plumbers Tape" aka PTFE tape.

 

[bmwpowere36m3]

Doesn't sound right. TBH if it were me I'd take it to a local LBS and get them to have a look at it.

Edit: you could perhaps try using some "Plumbers Tape" aka PTFE tape.

Bike is from an online retailer... not taking it to a local shop. Was curious if this was a common occurance on these forks. On MTBR a couple folks stated they've seen new RS forks with loose top caps.

Could be as simple as adding some loctite... I'm just surprised it has such a tendency to loosen. I've sent a inquiry to RS... a brand-new fork shouldn't be doing this.

 

[Tepi]

Pyörä on netistä... en vienyt sitä paikalliseen liikkeeseen. Olin utelias, onko tämä yleinen ilmiö näissä haarukoissa. Maastopyöräilyssä pari ihmistä kertoi nähneensä uusia RS-haarukoita, joissa on löysät yläpäät.

Voisi olla niinkin yksinkertaista kuin lisätä hieman Loctitea... Olen vain yllättynyt, että sillä on niin suuri taipumus löystyä. Lähetin kyselyn RS:lle... upouuden haarukan ei pitäisi tehdä tätä.

Putki teippi ei lukitse.Loctite ei ole myrkkyä,se on tarkoitettu kierre lukitteeksi.Tehdas kokoaa lukitteella kriittiset pultit joilla on mahdollisuus löystyä.Temu myy lukitteen 3,5€. Suosittelen jokaiselle itse huoltajalle .

 

[irie]

Putki teippi ei lukitse.Loctite ei ole myrkkyä,se on tarkoitettu kierre lukitteeksi.Tehdas kokoaa lukitteella kriittiset pultit joilla on mahdollisuus löystyä.Temu myy lukitteen 3,5€. Suosittelen jokaiselle itse huoltajalle .

Please post in English because your post may help others on this Forum. Thanks.

 

[RustyMTB]

Was curious if this was a common occurance on these forks

It isn't but as you're discovering, the bolt that holds the adjuster on is short & needs a helping hand to stay put. These things are mass produced in a Taiwanese factory & you tend to get random faults. I service a lot of forks & regularly see leaking footnuts, globs of grease blocking air chambers, rebound adjusters rattling loose and so on. I'd say the engineering & design is generally pretty sound - with a few serious caveats- but assembly can be sketchy. Yours clearly didn't have a pre loctited bolt used as it should have, so apply loctite to the bolt & enjoy life.

 

[steve_sordy]

I altered the number of spacers on my Fox 38 fork. The top cap was aluminium of course, but the sides of the hex were very low indeed and I was concerned about rounding them off when loosening and also when tightening to get the required torque, an unbelievable 40Nm! (I later discovered that I had got the wrong figure, it should have been 25Nm, so its a good job that I was sceptical!) I bought the proper sized socket (32mm) for the job, but the inside of the socket had a chamfer inside that would have reduced contact with the hex nut. I ground down the socket and then flattened it off. Total time took less than 15 mins.

Once I'd done the job on the spacers, I tightened the top cap by feel. I knew (at the time) it was less than the required amount. I am convinced that if I had used that amount (40Nm), I definitely would have rounded off the top cap, despite all my precautions. A few days later I checked the fork pressure and it was down, so it must have been leaking through the top cap interface. I removed it, greased it and then retightened it, again by feel. No further problems. I still don't know what torque it was, but I'm certain it wasn't 40Nm!

 

[bmwpowere36m3]

Response from SRAM is to bring/contact a shop and they'll open a claim and they can contact a service center... what a pain. So I submitted a claim with JensonUSA we'll see what they say.

When I get a chance, I'll pull the top cap up and inspect for threadlocker or lack of. For now, I'm too lazy and busy to do so... plus I probably have to release the pressure in the fork, compress and then the damper top cap will extended enough past the CSU for a look.

 

[RustyMTB]

I probably have to release the pressure in the fork, compress and then the damper top cap will extended enough past the CSU for a look.

No you don't. The loose bolt merely secures the compression adjuster knob. The compression adjuster assembly itself is screwed into the stanchion, no amount of compressing the fork will make that move an inch. Literally all that is required is a drop of loctite on the bolt & to screw it back in & then you're golden.

 

[DylanJM]

No you don't. The loose bolt merely secures the compression adjuster knob. The compression adjuster assembly itself is screwed into the stanchion, no amount of compressing the fork will make that move an inch. Literally all that is required is a drop of loctite on the bolt & to screw it back in & then you're golden.

I don't think OP's issue is with the compression adjustment knob coming loose. They are talking about the actual fork top cap (that requires a cassette tool to tighten) coming loose. Look at the picture again and the marks they have made in yellow.

 

[RustyMTB]

Hmm, looks like you're right, my bad. I misunderstood the assignment. To release the damper assembly, you would normally split the fork to separate the damper shaft from the lower legs. I'm now wondering if the damper assembly could rattle loose at all if it were connected to the lower legs as no one would ever normally unscrew it before releasing the foot nuts & I don't think the shaft has free rotation.

 

[bmwpowere36m3]

No you don't. The loose bolt merely secures the compression adjuster knob. The compression adjuster assembly itself is screwed into the stanchion, no amount of compressing the fork will make that move an inch. Literally all that is required is a drop of loctite on the bolt & to screw it back in & then you're golden.

Hmm, it’s NOT the small cap screw securing the compression knob that’s loosening. It’s the damper top cap, threaded into stanchion with the cassette interface.

I want to verify the presence of factory applied thread-locker and whether the stanchion is fully pressed into the csu. That’ll require unthreading the top cap and the damper can only extended so far, thinking like a grip2 unit. Maybe it’s different.

 

[RustyMTB]

my bad. I misunderstood the assignment

Yeah, I get that. The only way to unscrew the damper assembly is to disconnect the damper shaft from the lower leg or at least it should be. I'm now thinking you have something very wrong with the fork if the assembly if it's coming loose - it should not be able to rotate since it's one whole connected assembly bolted to the base of the lower leg.

 

[RustyIron]

it should not be able to rotate since it's one whole connected assembly bolted to the base of the lower leg.

Nah, the damper shaft can rotate. He just needs to tighten the cap a little more. if Loctite makes him happy, then that's ok, too. It's not a big deal, and takes less time to fix than it does to take the bike to the shop... or to read this whole thread.

 

[bmwpowere36m3]

Nah, the damper shaft can rotate. He just needs to tighten the cap a little more. if Loctite makes him happy, then that's ok, too. It's not a big deal, and takes less time to fix than it does to take the bike to the shop... or to read this whole thread.

Nothing like overkill… I released the air pressure in the fork, compressed it and undid the damper top cap.

When I extended the top cap, the factory thread locker was visible, but it was covered in oil. Whether it went together oily or the thread tolerance is shit…. I cannot say. Plus there’s little blue bits/strands of thread locker everywhere. Pre-applied/dry stuff.

The only thing not visible without pulling the damper out is verifying no stanchion gap (fully pressed in).

After wiping the top cap…

 

[Tepi]

Kierre lukite on liimaa,kun se avataan kerran, se ei lukitse. Avauksen jälkeen aina uusi lukite neste.

 

[bmwpowere36m3]

To follow up... I've had a few rides since and there's no movement of the cap. So success and I didn't have to waste time shipping it back for just loctite.

I pulled the damper assembly out of the fork and cleaned the top cap and stanchion threads. Re-installed the damper assembly, added new fluid to lowers and blue loctite on the top cap threads.

I also increased the torque to 30 Nm if memory serves. The loctite had a day or more to cure before I rode it.