Headshock Super Fatty - first attempt on service

[Victor Haugen]

Hi all

I am new to this forum and I have a few questions.

I have a F700 that was purchased in early 2002 and I have identified the fork as a Super Fatty DL, disc spesific - 80mm. However, looking at the Cannondale Catalogue, the bike is most likely a 2001 model. A little bit strange; the serial number is LG which is supposed to be a july 2000 model, but the CAAD4 frames did not appear on a F700 until 2001 if I am right (?). Anyway, now I am trying to do a Headshock service for the first time, by replacing the O-rings and the oil.

When I de-assembled the damper I saw that something made of hard plastic had broken and been crushed into pieces:

Then I found this part in the HD166 seal kit as shown in the photo below, which I believe is the piece that somehow has been broken and disintegrated during the years:

So if I understand it correctly, is this how it should be put together (?):

And then next question, I discovered a smal O-ring that was loosely attached (with some grease or oil) to the tip of the metal shaft:

However, I can't figure out where this O-ring should be attached. I tried to put it onto the plastic shaft but the O-ring is bigger than the shaft so it doesn't seem to be the right place and it doesn't seem to have a logical function:

Is there anyone who knows where this O-ring should be attached ?
The HD166 seal kit contains a similar O-ring but it's slightly smaller....however the original O-ring seems to be in good condition still, so I might be able to re-use it.

Victor

 

[black lightning 1987]

I think you have the dates right: built in July 2000 for the 2001 model year. Just like cars, new bike models are sometimes rolled out 5 months before the start of the new year.

Craig (MendonCycleSmith) is the guy to talk to about Headshok rebuilds. Great photos, hope you will post more as it goes back together.

 

[Victor Haugen]

I think you have the dates right: built in July 2000 for the 2001 model year. Just like cars, new bike models are sometimes rolled out 5 months before the start of the new year.

Craig (MendonCycleSmith) is the guy to talk to about Headshok rebuilds. Great photos, hope you will post more as it goes back together.

Thanks for the update on dates, I will post more photos as I move on with my project

 

[Victor Haugen]

Here's a continuation on the Headshock service project.
Last edited on April 19 - 2020.

I have adopted some procedures from the Headshock Service Manual for the "Fatty 70", provided by Sheldon Brown. Although the forks are not identical, I think that some of the procedures can still be applied to this fork.

I started by turning the damping dial to the "locked" position". Then I unscrewed and removed the dial but I left the handlebar and stem on, since I was not going to de-assemble the whole fork but only take out the oil and air cylinder. Next I released the air pressure from the fork by depressing the schrader valve.

Then I loosened the outer cap of the fork with a pin spanner wrench (Park Tool SPA-1) It was very hard to unscrew and after approximately 5-6 complete turns it was loose.

Then I loosened the oil damper cartridge with a Headshock Castle Tool (HDTL146) and after approximately 12-13 complete turns it was loose.

When I lifted out the damper from the top, the air cylinder was still remaining inside the fork. What I did was I took a long screwdriver and inserted it from the bottom of the fork where the valve is, and then pushed up the damper from the bottom at the same time as I lifted it up from the top.

I unscrewed the lower cap on the oil cartridge using the pin spanner tool and held it over a tub to catch oil. Then I unscrewed the upper cap using the same tool and took out the shaft as shown in the photo below (There's a missing O-ring on the lower cap.)

Then I cleaned the threads and replaced the O-rings:

The U-cup seals seemed a bit difficult to remove so I made a tool and with this I managed to get them out:

Inserting the new U-cup seals was a bit difficult too but I finally managed it. According to the service manual for the Fatty 70, the new seals should be oriented with their larger "flared" ends towards the middle of the cartridge.

I also replaced the bleed screw inside the shaft.

Next, filling up the cartridge with oil. First I screwed back on the upper cap using the pin spanner tool. Then I started to fill up with oil from the bottom side of the oil cartridge.

After filling up with a little bit of oil, I moved the cartridge slowly up and down a few time times to get the air out of the oil. And then I filled up with more oil and repeated the procedure until I didn't hear any air anymore.

Continuing in another post (due to image upload limit)


Victor

 

[black lightning 1987]

Thanks for the great photos and information.

 

[Victor Haugen]

By the way, here are the tools and the parts that I used during the service.
From left: RockShox Schrader valve Tool, HDTL146 - Leonardi Leo Castle Extraction Tool and SPA-1 - Pin spanner.

Then, I used some parts from the HD166 seal kit and I used the HDTL168 Bullet Tool, but I did not use the HDTL187 shaft clamp tool because I didn't know how to disassemble the shaft, and thus could not replace all the O-rings (seals) inside the oil cartridge and on the shaft. I hope someone in here can share more info on this.

Update: I have been informed that the shaft clamp tool is not to be used on this fork.

And finally, TF2 Cycle Suspension Fork Oil, Loctite SF 7063 Cleaner, Loctite 243, and a box of grease from Shimano.

I forgot to mention that I also replaced the valve core, which by the way was not included in the HD166 seal kit but in the KF236 kit. But I suppose it's just a standard schrader valve core that can be purchased anywhere.

 

[Brian]

Awesome!! Thank you for posting this. Greatly needed in the forums.

 

[Victor Haugen]

Continuing from a previous post (due to image upload limit).
After filling up with oil until near the top I put the bullet tool on top of the shaft:

I applied a little bit of oil to the seals inside the cap and then I pressed it down onto the shaft slowly and carefully, not to damage the seals inside:

Then I removed the bullet tool and started to screw back the lower cap using the pin spanner tool.

When the O-ring contacted the edge of the cartridge I loosened the bleed screw inside the shaft by one turn with a star screwdriver, and I could hear that a little bit of air came out of the shaft.

Then I continued to screw the cap back onto the cartridge using the pin spanner tool, not too hard but until it felt tight. When the lower cap was completely fastened I tightened the bleed screw.

I assembled the parts and then applied grease to the air piston:

After that I cleaned (de-greased) the threads on the oil cartridge using Loctite SF 7063.

Ready to assemble the oil cartridge with the air cartridge: (I had to push in the valve to release the air pressure while inserting the air piston)

After assembling the damper I applied a little bit of loctite 243 (blue) on both sides of the threads and I also replaced the O-ring on the cartridge.

Finally I mounted it back onto the fork.

I don't know if this is the correct way of doing service on a Headshock Super Fatty (Ultra) DL, but so far it seems to perform well. If anyone has any more information on this please add to this thread. By the way here are the torque settings:

 

[Krazebill]

OUTSTANDING POST!! You did a superb job of describing and photoing this procedure!

 

[Skalmyk]

Solid post as I just purchased a 2002 F600 that need this exact treatment. Like the OPer I too was confused with serial number dates. Thanks for posting.

 

[Barney427]

I think here is picture of inside cartridge. I hope it works.

https://www.garrafenbtt.com/wp-content/uploads/2015/03/MANUTENÇÃO-DO-CARTUCHO-HIDRAULICO-LEFTY-PBR.pdf

 

[Zachariah]

Great job! I'd destroy that Achilles Heel air piston...if I were to do this job!

 

[Victor Haugen]

Hi all

However, I can't figure out where this O-ring should be attached. I tried to put it onto the plastic shaft but the O-ring is bigger than the shaft so it doesn't seem to be the right place and it doesn't seem to have a logical function:

View attachment 3994

Is there anyone who knows where this O-ring should be attached ?
The HD166 seal kit contains a similar O-ring but it's slightly smaller....however the original O-ring seems to be in good condition still, so I might be able to re-use it.

View attachment 3995

Victor

To answer my own question, I found this image on internet which shows a small O-ring that looks similar to mine and I think that this must be the correct place to attach it:

 

[MikeA]

To answer my own question, I found this image on internet which shows a small O-ring that looks similar to mine and I think that this must be the correct place to attach it:
View attachment 5538

Yes, that looks correct. It's a smaller diameter o-ring, stretches on like it doesn't belong there. Also, the brown o-ring is for the piston, the HD166 kit does not include an o-ring for the outside of the damper cartridge, you would have to reuse the original. Not all models have one there.

The shaft clamps are not needed for this cartridge, they are used primarily to remove a threaded on air piston. If you want to replace seals in the upper cap next time, It's the same procedure as the DD60 I helped someone with on MTBR here: https://forums.mtbr.com/shocks-suspension/headshok-experts-please-help-1135997.html

 

[Barney427]

Hi all, I am Baku,

Please let me ask ,,,I am also considering to overhaul my Headshock.
Mine is 2005 Super Fatty. But I am not sure if my cartridge is DL80 or DLR80?

Actually I did overhaul at Cannondale store in Japan in 2015. It worked very well.But I kept my bike wait during last year.
Oil is leaking from bottom.. and when I lockout it,it slide dawn 2cm...

Could anyone help me?
I marked red circle where the oil leaks from.

 

[Victor Haugen]

Hi all, I am Baku,

Please let me ask ,,,I am also considering to overhaul my Headshock.
Mine is 2005 Super Fatty. But I am not sure if my cartridge is DL80 or DLR80?

Hi

I would guess that it's a DLR cartridge, based on the model and production year.
If I am not mistaken, DL means "Lockout" and DLR means "Lockout+Rebound".
And if it's a ULTRA it means that the fork is 150 grams lighter.

Maybe this document may help you identify the fork and cartridge type:
http://jumpsport.cz/media/files/4_HeadShok-Fork-pages(1).pdf

But I have no idea what causes the oil leak... maybe some seals are broken ?
By the way, nice bike!

Best regards
Victor

 

[Barney427]

Hi

I would guess that it's a DLR cartridge, based on the model and production year.
If I am not mistaken, DL means "Lockout" and DLR means "Lockout+Rebound".
And if it's a ULTRA it means that the fork is 150 grams lighter.

Maybe this document may help you identify the fork and cartridge type:
http://jumpsport.cz/media/files/4_HeadShok-Fork-pages(1).pdf

But I have no idea what causes the oil leak... maybe some seals are broken ?
By the way, nice bike!

Best regards
Victor

Hi Viktor,
I really appreciate your replying.

I have checked your Link, I found that my Headshock is Fatty DL, So I think Originally cartridge was DL80.

Yes, I am deeply shocked when I saw tiny tear of oil.... It comes again.. just 4 years have passed....
I really regret that I left my bike in house for a year.. I did not check air at all. so I think you are right.
Oil Seals are broken...

I am going to get KF236 or KH022. In Japan, Cannondale stopped repairing Headshock and they told me they dont have any parts for this Headshock anymore. same situation in Norway?

Thank you,You have Diskbrake and super nice gradation looks very mint condition!
I love your colour and other colour of that era. they were so cool!

Best regards.

 

[MikeA]

Hi all, I am Baku,

Please let me ask ,,,I am also considering to overhaul my Headshock.
Mine is 2005 Super Fatty. But I am not sure if my cartridge is DL80 or DLR80?

Actually I did overhaul at Cannondale store in Japan in 2015. It worked very well.But I kept my bike wait during last year.
Oil is leaking from bottom.. and when I lockout it,it slide dawn 2cm...

Could anyone help me?

Baku, you are correct, It's a DL80, but it is different than Victor's DL80 in this post. The most significant difference is that your air piston is threaded on to the damper shaft. The movement on lockout indicates oil has leaked from the damper. The 2005 and up DL and DLR forks were good forks but are known for needing more frequent service than the older ones. 5 years isn't bad.

The blue schrader valve cap at the bottom isn't original and tells me that it has been repaired with an air cylinder kit, or has a complete replacement damper. Either way, you will need both the KF236 kit and the KH022. The KF236 has the seals for the oil damper, but the air cylinder seals in that kit are for the original larger piston. KH022 is the seals for the air cylinder upgrade you have.

You will need the tools Victor used, including the shaft clamps he didn't need.

 

[Victor Haugen]

I am going to get KF236 or KH022. In Japan, Cannondale stopped repairing Headshock and they told me they dont have any parts for this Headshock anymore. same situation in Norway?

I'm actually not sure if any workshop here in norway are still servicing headshock forks...But so far I have been able to service it my self. Next project would be to replace the needle bearings which I luckily found for sale on eBay, but it will necessarily require more tools and to gain more knowledge. I also found a few races for sale on eBay but I am not sure if the sizes are correct, as they have different thickness, for example:

HDR2F/014 0.356mm (.014")
HDR2F/015 0.381mm (.015")

But I assume that if I lubricate often and if no water gets under the boot, the races will hopefully last for many years.

Thank you,You have Diskbrake and super nice gradation looks very mint condition!
I love your colour and other colour of that era. they were so cool!
Best regards.

I thought disc brakes were standard at that time (2005) on mountain bikes, but it seems that your fork has a mounting point for it so maybe it can be retro fitted ? Anyway it looks cool with v-brakes too and I like the color of your bike.

Yes, my bike is in almost mint condition. It's fun to have a nearly 20 year old bike that weighs just over 10 kilos and that looks like new. I have upgraded everything on it during the years, except the wheels.


Best regards
Victor

 

[MikeA]

Victor, If you decide to service the bearings, I strongly recommend you buy the HD137 race retainer tool. Using the inner tube method in the manual you referenced will be a frustrating nightmare. Also, there is no need to replace the bearings or races unless they are damaged or rusted, so don't buy anything until it's disassembled. Normal maintenance is disassembly, cleaning, greasing and resetting the bearings.

The races come in different thicknesses because that's how the bearings were shimmed to specification at the factory. The outer races are usually all the same thickness, but the inner races varied, and must go back in their original position. The only way to know which are in your particular fork is to measure all of them as you remove them.