Cannondale Headshok service instructions and tools
Pashlipops
My Headshok on my 2000 Cannondale F900 is making a knocking sound on rebound
near top of travel.
I have taken it to my local Cannondale dealer twice and they have given me
two stories so far:
1. Some of the needle rollers have dropped and need to be reset.
2. The shaft running through the oil cartridge is damaged and that's why
it is rough (wasn't before) and that's why it is leaking oil (didn't notice
any leaks before).
I wouldn't mind having a look inside myself.
Can anybody point me in the direction of service instructions and any
special tools required?
TIA
PP
S R Sharp
Since you say there is oil leaking, I would guess that the cartridge needs an
overhaul (new seals & oil); air in the cartridge will cause a noise as you
described. When the cartridge is removed it will be pretty apparent whether the
races moved or not. A definitive way to eliminate the cartridge as suspect is
to pump up the tire pressure (50-55psi), lock-out the fork and press down on the
handlebars. Any movement beyond the tire compressing slightly would indicate
air in the cartridge. *If* you can get the tools this is a fairly simple job-
if there isn't any damage to the cartridge parts (they're usually fine). You
may want to use a different weight oil to fine-tune the damping for your weight.
If you cut the zip ties on the boot and squish it together you can measure from
the bottom of the round "nut" below the lower headset bearing to the crown of
the fork where the O-ring is (move the O-ring); IIRC it should be about 80mm for
the SuperFatty and about 70mm for the Ultra. Do not take apart the fork
telescope. It's not the easiest thing in the world to put back together even
with the actual tools.
Your shop can send the fork back to C'dale for a complete overhaul if you want.
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David Kunz
My local REI got me the hedshok tool for $35 -- took a bit of getting to
know the bike person :). Before I bought one, my LBS (not REI) let me
borrow the shop's a day at a time -- they don't need it very often.
You'll also need a pin spanner to remove the plate above the cartridge
(the Park green handle, I think).
I have a lefty now, so this might be a little off... :).
Remove the stem.
Remove the hedshok cover and lockout lever (should pull out if I
remember right -- friction fit).
Remove the plate (this is where you need the pin spanner).
Let the air out of the shok :).
Remove the cartridge (using the CD tool).
When you reinstall, put a little fork oil in the air cylinder -- not the
stuff with o-ring expander in it! Pour out the excess.
You may need to use a piece of vacuum tubing up from the bottom to hold
the air cylinder correctly to the shock cartridge. Put them together
pusing up with the vacuum tubing -- then lower the vacuum tubing to
lewer the assembly into the fork tube.
Make sure that you use blue locktite on the cartridge threads!
If it's the bearings, you need a bit more instuction. I wouldn't
disassemble the bearings and races unless you need to. It's not hard,
but it's not necessarily intuitive. It can be time consuming and
tedious. If you do, make sure that you number the races (I used some
white fingernail polish that I borrowed from my daughter :)) -- each
race may be a different thickness (to 0.001") and needs to go back in
the same place or the bearings may bind. Also on reassembly, you need
to overhang the bearings by 1/2 their length to get them in the correct
spot in the race. I used an old innertube to hold the outer races in
place in the fork tubes while I was doing the dis- and re-assembly. If
you need me to, I'll try to put more detailed instructions together. I
think that I still have the CD tech pages that I copied around someplace :).
David
Pashlipops
"David Kunz" <david...@earthlink.net> wrote in message
news:zJFR9.14482$9N5.1...@newsread2.prod.itd.earthlink.net...
Many thanks.
When I attempted to disassemble the assembly before, I wanted to reset the
needle rollers, because I assume they need to be in the same position
vertically and my first assumption was that the noise was caused by the need
for these to be reset, as informed by my LBS (Cannondale dealer). I removed
the stem and the fork and headshok assembly from the frame, then I removed
the cap, which has holes for the pin spanner. Then I moved the outer sleeve
as high as it would go and pushed a feeler gauge up to find the position of
the bearings. I found that one of them was 10mm lower than the rest, hence
my thought that I needed to reset them all.
If I wanted to reset the bearings, I think I either need to remove the cap
from the top of the damper rod, or I need to remove the oil cartridge, or
whatever else is underneath.
I found this picture which gives me a better insight into what I cannot see:
http://www.cannondale.com/bikes/tech/kitlist/HD.3.12.DL%2080%20cartridge.pdf
with this page showing the bearings:
http://www.cannondale.com/bikes/tech/kitlist/HD.2.2.Telescoping%20ass.60,70m
m%20forks%20pre%2799.pdf
I cant find a picture of the CD tool, nor do I have any confidence that my
LBS will order me such a tool (or indeed a video, which I have found
existence of from previous postings here). Can the CD tool be used with the
cover plate and nut still attached to the damper rod, or do these need to be
removed also, and if so, is it just a case of unscrewing the nut whilst
holding the cover plate with the pin tool?
I would like to have a crack at this myself since I don't have much
confidence in my LBS, with their two diagnosi, and their wish to charge me
Ł120 ($180) for a new Headshok unit, when I could perhaps service it myself,
or at least assess what the problem is.
Thanks again
PP
S R Sharp
> £120 ($180) for a new Headshok unit, when I could perhaps service it myself,
> or at least assess what the problem is.
Either one of your LBS diagnosi are potentially correct, or both of them. These
are the tools you will need for telescope and cartridge rebuild:
HD137 "outer race retaining" tool; to dis- and re-assemble the telescope.
Requires removal of the cartridge to use (inserts from the top of the fork).
You can use an old innertube w/the ends stitched up; I don't know how well that
works.
HDTL168 "bullet" tool; this is cheap and makes re-assembly of the cartridge
after an oil change much easier.
HDTL146 standard "castle" tool- for most regular Headshoks; use for cartridge
removal (release air pressure first!)
HDTL149 "fork installation" tool; nice to have but you can probably make one for
less w/PVC pipe.
HD166 seal kit for your cartridge. These are inexpensive and include all the
seals for your cart.
also, a Park green and red spanners for cartridge disassembly.
I don't know if you need a tool to remove the "race-retaining clip" (see link
below) on the telescope as the only telescopes I've rebuilt were older ones
which didn't have this part. This was designed to, AFAIK, prevent bearing
and/or race migration.
If you just want to reset the bearings and races you won't need any new parts
(light grease for the bearings), although sometimes the needle bearing retainers
crack if they've migrated up and slammed into the cartridge during fork
extension. You may want to have a set on hand for that scenario. If you want
to overhaul the telescope you will need the parts shown here (#s 2-5):
http://cannondale.com/bikes/tech/kitlist/HD.2.5.Telescoping%20ass.%2080mm.pdf
but you will need to dissassemble the telescope first and measure the races w/a
micrometer; the tolerances are very fine as you can see from the CD page above.
I can type up some info on telescope rebuild for you but, as DK already said, it
is tedious and time consuming if you've never done it before; I don't recommend
it unless you're really patient and bored. Also, I have the
removal/installation/overhaul tech manual for the cartridge in MS Word format if
you want it, email me direct.
I notice the CD website says there is fork rebuild service available in Europe,
if the prices are comparable to US$ you could have the cart & telescope rebuilt
for significantly less than the price of just a new cart (IIRC around $100 +
shipping). In addition, over here we get a new 1 year warranty on the cartridge
for leaking and when you send the fork in they tend to come back better than
when they were new (don't ask) as well as getting custom-tuning options- like
oil weight and damping shims.
PS: Dave, the cartridge tech manual I have includes instructions for the Lefty
carts, tools are completely different however; telescope is the same (if you've
done one...)
David Kunz
I you can email me the pages covering the Lefty -- or the whole thing,
I'd really appreciate it. I was guessing at the overhang for the
bearings and would like to get them right the next time that I take it
apart for regreasing. My email is correct (not mangled :)).
My LBS's manual didn't cover the Lefty, but it was sufficiently similar
that the only difficulty that we had was finding the 2 spring clips that
make sure that the bearings don't migrate.
The spring clips came out with a a screw driver and a bent spoke to use
to apply slight pulling pressure to hold it out (the bottom has 4
notches and each outer race top sits in a notch; the top has 4
projections that seat in 4 holes/slots in the top of each outer race.
The top one just comes out (took a LONG screwdriver for the lefty, but
the hedshok's probably not nearly as deep), the bottom required that I
remove a retainer (green pin spanner).
To Pashlipops:
You need to remove the cartridge and air sleeve to get to the bearings.
Cut the top cable tie on the shok boot and push the boot down. I used
an old wood clamp to hold it down.
Clean the grease off the inner bearing races and number them and mark
the fork so that you can get them back in the same place if they fall
out unexpectedly.
Remove the clips -- the lefty had one in the top and one in the bottom.
As I said above, the bottom was under a retainer.
Then, you take an old *road* innertube; cut it; cut 2 "rings" off of it;
and tie the ends off the remainder (I used cable ties rather then
knots). You're going to put this down the top of the tube and pump it
up to hold the outer bearing races in place.
Slowly pull the fork apart. Put the 2 tube rings over the bearings as
they come out to hold them in place.
If all you want to do is to reset the bearings, you can probably pull
down until they're just engaged in the outer races and push up on the
low one. I'd liberally regrease 'em also.
Otherwise, when it's apart, remove the outer races one at a time and
clean and grease it (I also numbered them on the back in case they fall
out during reassembly -- they did).
Grease the bearings and inner races.
Reassemble. Here's where it gets tedious.
The inner and outer races need to be even and at the same place that
they were before (the manual'll tell you if you forget or need to reset
them).
The bearings need to overhang the inner races by 1/2 their length
(should be 11 needles).
The tedious part will be when everything is just engaging, they'll want
to slip and slide, and when they're engaged, they can't be shifted --
the tolerance is too small. AND, they're (hopefully) heavilly covered
in fresh quality grease (I used Phill's synthetic grease) which gets all
over your hands and the fork.
After this, you wipe all the grease off your hands and the non-moving
parts of the fork; put the clips back in (the top one is another tedious
part); put the retaining ring back on the bottom; and put the air
cylinder and shock cartridge back in (as in my other post). Remember
the loctite on the cartridge! Also, liberally grease the inner races
before putting cable ties back on the boot.
I hope that S R Sharp will read this and add where I was unclear, forgot
something, or he did it a different way that mey work better :).
David