Cannondale F1000 Caad 4 revival project - Headshok Fatty D Service / Part Repair

Cycled to the shop, did not die, no bits fell off. I'll take it to work this week for a longer try-out and will take some pics.

Then off to the Cavehill trails in a few weeks, it's been rotten weather here. Though I believe that being covered in mud is part of the appeal of MTB-ing? ;)

Edit: I'll need a setback seat post too, Thomson in 27.2?

There doesn't seem to be anything the hook the hexabolt against, no threads or a specific shape it's just a round hole that goes over fork bit, I just push it down.

Yeah. It's supposed to be a super-tight press fit. It's possible that previous tried to take it off at some point.

Have a look here for an idea of why.

As long as the upper shaft is still well connected to the top cap, it won't fall to bits :)

In that thread image: "mystery thing" haha I like that.

What I have, namely a Fatty Ds are waaaaaaaaaaaaaay more basic. Open up, plonk in the spring/elastomer, plonk air damper on top, screw in top cap with lots of locktite, done. Unless something is leaking. You can take the top bolt out of the air damper and add some more oil if needed. And I can add an MC70 cartridge instead, but they are a bit £££ :(

But that's about it.

@Howard picture

Taken near work, I think those trees belong to the local group of hooded Irish crows as there was loads of crowing and circling while I stood there.

I apologized and made off.

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Looks ace. Needs a stem that matches the TT rise :)

Your damper is the same as the one in the picture, maybe a 2cm smaller, but it's the same design, basically a sealed tube with hydraulic fluid in it and a piston that's fixed to the middle of the damper rod. It should be full of oil, no air at all. But getting it air free is hard work.

The rod is in two halves - the lower half it press fit to the nut on the top cap, the upper half to the top cap itself. The lower half rotates when you operate the lockout that closes the ports in the piston.

The 'mystery thing' is a bumper for when the fork is at full extension - it's needed because the piston rests on the damper cap when there's no compression in the fork.

:)

There's a place in Germany that still sells the stems in 1.56, not sure I can find a 9 cm in that size, but can try. Looking for a stem spacer too, another hen's teeth in 1.56.

Brake boss plugs coming in the post too, otherwise water will gather in the rear and mess up the threads.

I'll take "mike the mountainbike" up Cavehill in a bit, there's a couple of trails. Hopefully I got the gearing low enough, these days people seem to use tiny front rings with rear cogs you can eat dinner from.

The single rings are quite large though. If you've got an MTB double with a sensible cassette you'll be fine.

Parts..

ORIGINAL

Stem and brakes, taken off but kept
Frame, fork but this has new elastomer in it
Sachs Quartz shifters
Coda bars and grips
Kalloy seatpost
Selle italia saddle with cutout...seems rare but great for me: Found it, it's a 1998 Vintage Selle Italia Trans Am MTS Saddle with manganese rails
Seat clamp
XTR rear derailleur
rear stay "sock" which is falling apart, not sure it'll live much longer

NEW/REPLACED
Wheels, now Mavic with hope XC old ones were bust when I got it
Cassette and front derailleur are not original i think
Shimano disc brakes
Chainset, as the Coda crank was bust and they are expensive to get used so I put a shimano hollowtech2 on
Tires are Schwalbe "Jimmy" courtesy of the manfriend...MTB is not his thing "scary downhill and slow uphill" I doubt i'll be a hardcore downhiller though! I just want to explore new paths

Stem courtesy of @BareNecessities :)

You could always flip the stem for the pro xc look

Can give it a try, not sure it's comfortable, but it's easy enough :)

Gonna ask in here so it's retained for evermore in a vaguely suitable thread - I know only @Howard will know the answer though.

Took the damper apart on my fatty ultra dlr80 over the weekend and managed to change almost all the seals. The only one I'm aware that I failed at was the one inside the top plastic screw bung (as shown in picture below. I think I need to unscrew the silver cone thing at the top of the unit as that would allow me to slide the bung off and change the internal seal. To do that, I need to clamp the shaft (ooo eerr) so plan to make a diy shaft clamp from some acrylic and employ a 19mm spanner on the flats of the silver cone.

My question is - is this right? Can you unscrew the top silver bit to allow you slide the bung off? If so, I can do this without completely dismantling the unit again and will just need to refill with oil. Nothing on the internet is making this clear - most seem take it apart from the bottom, but then I don't know how to get the fragile looking bits off the middle part of the shaft- that will only make sense to people who've been inside one of these things....

I suppose the question is - whats the easiest way to get at the internal seal on the top screw bung of a fatty dlr80 cartridge. THANKS!

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Took the damper apart on my fatty ultra dlr80 over the weekend and managed to change almost all the seals. The only one I'm aware that I failed at was the one inside the top plastic screw bung

Yeah these are all the seals you can DIY.

(as shown in picture below. I think I need to unscrew the silver cone thing at the top of the unit as that would allow me to slide the bung off and change the internal seal. To do that, I need to clamp the shaft (ooo eerr) so plan to make a diy shaft clamp from some acrylic and employ a 19mm spanner on the flats of the silver cone.

No - the flats are what the lock-out dial acts upon to lock / unlock the damper. If you do what you suggest you'll destroy the damping and rebound circuit.

My question is - is this right? Can you unscrew the top silver bit to allow you slide the bung off?

No it's wrong.

If so, I can do this without completely dismantling the unit again and will just need to refill with oil. Nothing on the internet is making this clear - most seem take it apart from the bottom, but then I don't know how to get the fragile looking bits off the middle part of the shaft- that will only make sense to people who've been inside one of these things....

Not really. I wouldn't bother TBH, those seals should be OK unless you've got evidence that they have failed I wouldn't mess with the top ones.

I suppose the question is - whats the easiest way to get at the internal seal on the top screw bung of a fatty dlr80 cartridge.

Post it to TF tuned! The cone is press fit, it's forcibly attached / removed with a special kind of press.

Thanks! - will leave it then - I think.

Just curious about what this guy was up to - I can follow some of his steps - but others seem to not quite add up...

https://forums.mtbr.com/cannondale/super-fatty-m-headshok-disassembly-reassembly-step-step-my-experience-140972.html#post14055098

Yey for fork fixing!

I couldn't budge the one I got...just rusted to oblivion. OK yeah maybe if I had a bathtub to permasoak it in, a lot more time, or a garage with car tools, but I really don't...

So just going to sell the parts that work on ebay. RIP fork.

JWestland, thanks so much for sharing! Have the very same bike and fork for 20 long years, approx. 50K Km and 1!!! service for the fork. Now - still smooth - the lockout is not as tight as it used to be and I feel I should go ahead and fix it myself... I read through the few sources I could find out there and yours definitely is the most helpful one to me!

One question I still have (just to be safe): when opening the fork from the top I do not take off the massive nut, that holds the lockout (image attached), right? But start with the Parktool SPA-1 (?!) to open the fork?

I hope I did not miss that part in your documentation and would appreciate your brief reply :) Oh and one more thing: even though you're mentioning Germany as THE place to stock Headshok tools from I cannot find any shop around here (particularly Berlin area) to purchase a castle nut tool from that fitting to the Super D as well as a Ultra DLR) - anyone out there with an idea?!

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Post it to 88aide or whatever they are called

Don’t try to remove the ‘nut’

If you are super stuck I can lend you mine but I have to post it, just message if you cannot find it.

The elastomer I got on bike24 but they said it was their mistake to put it on the photo...Dr Cannondale is worth a try?

Glad you found it handy! And inspiration to even try it goes to Howard :)

Ah! Thanks for the replies : ) My fault: hexabolt not 'nut' I just read on the previous page. So I 'try' not to remove it. So first thing to do is opening the upper outer cap with a pin spanner - right? Sending them off - I actually have 3 of them - is not an option - want to learn and don't have the money. Dr. Cannondale has a fancy castle nut tool for 80€ , guess I'll continue searching. Regarding the elastomer: it does not connect to the lockout being a bit loose, does it?

The tool is expensive if you are in the UK postage is just £4.10 signed for, so for £8.20 I can loan you it :)

When mine is locked you can still push it down a tiny bit. Is that what you by loose?

That's exactly what I mean. Used to be tight and I was appreciating that a lot during long climbs. Hope to restore it by refilling the oil of the damper (at least) in the DLR. Thanks a lot for the offer - I guess that will be an ongoing project so fancy better getting one myself (or eventually trying the plier approach). I also found another shop having a HDTL146 L in stock - will that one be long enough? Hard to tell from your photos - what do you think?

Ooh I'm not sure I can dig mine up and measure it?

Howard may know if he sees your post he's the expert here :)

Hi again, got the castle tool and all worked out like a charm. Really simple procedure altogether; I encourage everyone to give it a try based on the info to be found on this thread : ) Many thanks to everyone involved! Last but not least: encouraged by my success I felt like fixing my recently purchased Ultra DLR (advertised as "just serviced") as well and was surprised to found a bit of the damper broken of. I attach a photo of it for better understanding: I was gently trying to get it of to measure and re-print it on a 3D printer but wasn't able to move it without potentially breaking it even further. Is there anyone out there who came across that challenge and can advise me how to get it off and/or even knows where to order the part?! Thanks again for your help! Best regards, Hannes

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Wtf

Indeed