Mountain Bike Reviews Forum banner
1 - 19 of 19 Posts

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #1 ·
Just finished a 3 day road trip, now my Lefty has a top out clunk. SPV, 140 Max "converted" to 29er. Can anyone give me something to look for when I tear it down? I'm going to install a Quad Seal, so I guess it'll be pretty much tore all the way down, should be able to look at most everything.

Thanks,
Monte
 

·
Registered
Joined
·
29 Posts
check the airpressure in the spv- blatter - i.e. the valve at the bottom of the fork - believe the pressure should be at least 30 psi.... Had the same problem myself....
How much to have the quad-seal changed - and why? Is it possible to do it yourself - even with 10 thumbs and zero mechanical skills?
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #4 ·
I had 40 psi in the bladder, so that should have been okay. I tore the fork down, found the spring preload nuts were 1/4" off the spring, was probably the noise? Somehow I don't think so.

The bearings look fine as far as I can tell.

The damper is out of the fork now. It had a quad seal in it already, but that was leaking a little. So if the quad seal was leaking would the damper act as if the bladder was leaking eventually, because the pressurized chamber would lose it's pressure through the quad seal. My understanding of the SPV damper is that if the bladder doesn't have enough pressure it'll clunk. That's probably what was going on, if I'd added pressure to the bladder the clunk might have gone away.

I want to TPC it, so I'll see what happens there.

Monte
 

·
Registered
Joined
·
297 Posts
This drove me crazy (clunking) for about a month once, after I had the bike 1 1/2 years. Tried everything to bring the strut back up up to snuff - reset, oil change, regreasing, filter cleaning, etc. - but no improvement. Then someone on this board suggested overpressuring the bladder (>100) then releasing it before riding to back in the spec range (I like 60 psi). For some reason it worked for me. Smooth as silk again, no top out clunk. Good luck.
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #6 ·
check the airpressure in the spv- blatter - i.e. the valve at the bottom of the fork - believe the pressure should be at least 30 psi.... Had the same problem myself....

Did that, pressure was fine.

How much to have the quad-seal changed - and why? Is it possible to do it yourself - even with 10 thumbs and zero mechanical skills?

Doing it myself. I bought the seal(s) from Mendon Cyclesmith. I bought seals and a spring, so I can't tell you what the seals cost as I just paid a total for all of the parts and shipping of about $43, but I'm sure it's not much for just the seals. You replace the quad seal when/if it starts leaking. You'll see oil coming out of the bottom of the fork boot when it's leaking.

Easy to replace. On the SPV anyway, remove the bladder, dump the oil, remove the spring, now with something long shove the damper rod down as far as you can. You'll shove the damper assembly out of the bottom of the fork, careful there to catch it. Now go in with a 19mm socket on an extension from the top of the fork and lefty loosey the nut the damper rod went through. The bottom of the spring sat on it. The quad seal is what the damper rod went through in the center of that "nut".

Monte
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #7 ·
This drove me crazy (clunking) for about a month once, after I had the bike 1 1/2 years. Tried everything to bring the strut back up up to snuff - reset, oil change, regreasing, filter cleaning, etc. - but no improvement. Then someone on this board suggested overpressuring the bladder (>100) then releasing it before riding to back in the spec range (I like 60 psi). For some reason it worked for me. Smooth as silk again, no top out clunk. Good luck.

Hmmm. I'm thinking that my leaking quad seal had something to do with it. I was running only 40 psi, so there wasn't much room for pressure loss before it went under the minimum inside the damper chamber. That's my thinking right now. Anyway, that's getting replaced, should be good to go.

Monte
 

·
Hybrid Leftys aren't real
Joined
·
16,427 Posts
HAve you reset the bearings? It's not a "they look okay" thing, unless you mean you pulled it apart to reset, and the top end drops in the 1.5 inches or so down into the fork. Do a reset first off. Still topping out? It may be the leak has impacted the viscosity of your grease, it'll make the fork act like poo......:madman: If so, time for a rebuild.
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #9 ·
MendonCycleSmith wrote:
HAve you reset the bearings?

No.

It's not a "they look okay" thing, unless you mean you pulled it apart to reset, and the top end drops in the 1.5 inches or so down into the fork.

Not sure what you mean here. The fork is down as far as I can take it without taking the "nut" off of the bottom of the upper section. The SPC damper is out, the quad seal retainer is out.

Do a reset first off. Still topping out? It may be the leak has impacted the viscosity of your grease, it'll make the fork act like poo......:madman: If so, time for a rebuild.

Guess I'll look at the reset. The leak did thin down the grease, it looks like Slick Honey on there now, not Bullshot.

If an SPC damper will top out/clunk if the pressure is too low (thought I read that happens) I'm thinking that the quad seal leak had something to do with it. Sure, there was pressure in the bladder, but if the oil was escaping out the seal the pressure will be lost above the bladder.

Monte
 

·
Registered
Joined
·
1,173 Posts
MendonCycleSmith said:
HAve you reset the bearings? It's not a "they look okay" thing, unless you mean you pulled it apart to reset, and the top end drops in the 1.5 inches or so down into the fork. Do a reset first off. Still topping out? It may be the leak has impacted the viscosity of your grease, it'll make the fork act like poo......:madman: If so, time for a rebuild.
How much do you charge for a rebuild?
 

·
Hybrid Leftys aren't real
Joined
·
16,427 Posts
Duncan1104 said:
How much do you charge for a rebuild?
$35 for labor seals and oil. Other parts additional. Please note that I give a good volume of info here, and don't solicit work via the forum. Should you choose to pursue it, please respect the forums rules of no commerce conducted via the boards, and PM or email me with questions! Thanks :thumbsup:
 

·
Hybrid Leftys aren't real
Joined
·
16,427 Posts
Monte said:
MendonCycleSmith wrote:
HAve you reset the bearings?

No.

It's not a "they look okay" thing, unless you mean you pulled it apart to reset, and the top end drops in the 1.5 inches or so down into the fork.

Not sure what you mean here. The fork is down as far as I can take it without taking the "nut" off of the bottom of the upper section. The SPC damper is out, the quad seal retainer is out.

Do a reset first off. Still topping out? It may be the leak has impacted the viscosity of your grease, it'll make the fork act like poo......:madman: If so, time for a rebuild.

Guess I'll look at the reset. The leak did thin down the grease, it looks like Slick Honey on there now, not Bullshot.

If an SPC damper will top out/clunk if the pressure is too low (thought I read that happens) I'm thinking that the quad seal leak had something to do with it. Sure, there was pressure in the bladder, but if the oil was escaping out the seal the pressure will be lost above the bladder.

Monte
The quad seal can't contribute to clunk. It's just a seal to prevent oil from puking into the fork. Low pressure can make it clunk though. Make sure you are actually pressurizing the bladder, sometimes the pin doesn't get depressed, and you just pressurize the pump. Try a 1/8" ball bearing in the valve to act as a "valve pin extender" if that's the case. Since it's all apart (sounds like) you can't do a reset at this time. The fork needs to be together (well, at least the top end in place) to do one. ;)
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #13 ·
MendonCycleSmith said:
The quad seal can't contribute to clunk. It's just a seal to prevent oil from puking into the fork. Low pressure can make it clunk though. Make sure you are actually pressurizing the bladder, sometimes the pin doesn't get depressed, and you just pressurize the pump. Try a 1/8" ball bearing in the valve to act as a "valve pin extender" if that's the case. Since it's all apart (sounds like) you can't do a reset at this time. The fork needs to be together (well, at least the top end in place) to do one. ;)
Top end of the damper assembly? Does the damper have to be in place? I've seen that in the pictures in the thread, but don't understand why it needs to be there. I'll try the reset as I put the fork back together.

Monte
 

·
Hybrid Leftys aren't real
Joined
·
16,427 Posts
Monte said:
Top end of the damper assembly? Does the damper have to be in place? I've seen that in the pictures in the thread, but don't understand why it needs to be there. I'll try the reset as I put the fork back together.

Monte
Wait till it's all together. Top end needs to be there, to prevent the fork from disassembling itself :eekster:
 

·
Registered
Joined
·
1,173 Posts
MendonCycleSmith said:
$35 for labor seals and oil. Other parts additional. Please note that I give a good volume of info here, and don't solicit work via the forum. Should you choose to pursue it, please respect the forums rules of no commerce conducted via the boards, and PM or email me with questions! Thanks :thumbsup:
Oops, my bad, sorry.
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #17 ·
MendonCycleSmith said:
Wait till it's all together. Top end needs to be there, to prevent the fork from disassembling itself :eekster:
Been running the lower in and out, it stops both ways, hasn't fallen out. Yet. Am I lucking out, or something else?

Monte
 

·
Hybrid Leftys aren't real
Joined
·
16,427 Posts
Monte said:
Been running the lower in and out, it stops both ways, hasn't fallen out. Yet. Am I lucking out, or something else?

Monte
Need more detail. Is the fork back together yet? No point in resetting (or even discussing it) without this being the case, regardless of what you've been doing.
 

·
meh....
Joined
·
3,588 Posts
Discussion Starter · #19 ·
MendonCycleSmith said:
Need more detail. Is the fork back together yet? No point in resetting (or even discussing it) without this being the case, regardless of what you've been doing.
I put the top cap of the lower back on and tried to reset the bearings, didn't budge. I looked at the little grease track left by the bearings and found that one is stopping 1 1/2" above the other 3, so yeah, a reset is needed. I thought I had tried the reset properly, with the top cap of the lower back on. As far as I can understand it I should have been able to reset it, but couldn't. Maybe I wasn't pulling the lower down hard enough. How hard do you have to pull?

Anyway, I took it all the way down. I'm using wadester's thread to reinstall the bearings. See how it goes tonight.

Monte
 
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top