Revisiting DDS3 - a 1992 Trek 9000 Fork

npn

Retro Guru
MADB":2nyq73xj said:
From what I can remember there is a circlip in the top that needs removing. Use these to get it out. I think you need to compress the forks to get to it.

Blue Spot Tools 08705 Internal Circlip Plier, 150 mm https://www.amazon.co.uk/dp/B07B52YT8D/ ... EEbPEW40N8

I think then you pump them up to about 100 psi to push the lowers off.

Yes, I've done that part, funny enough with the same tool.

I did pump it once to 100psi and it didn't do anything. I was afraid to pump the thing more...
 

FluffyChicken

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Re:

I've taken mag forks higher, lol.
Once they pop oil just goes everywhere ;-).

Leave them upside down to see if oil can sleep into the seal area.
Unfortunately I've never played with these forks.

As for the air taop caps, stick a socket set over the valve so it hits the metal, then tap it with a hammer. If they are like the Marz. XC forks, the cap moves in a but and you just use a thin screwdriver to remove the ring.
 

npn

Retro Guru
Re: Re:

FluffyChicken":2xemi5s7 said:
I've taken mag forks higher, lol.
Once they pop oil just goes everywhere ;-).

It sounds like a science experiment. Any tips on how not to blow a hole in my head? lol Did you use a manual pump or a compressor? Also, don't the seals get damaged? I doubt I'll be ever able to find any replacements. All I want to do with this fork is change the oil and clean it inside really good. For whatever reason, even with no air, it compresses very hard.
 

FluffyChicken

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Just get the top caps out then, poor the oil, clean them up as best you can.

The seal may well be common seals if you are lucky.
Can you read what it says on them at all, or measure the inner and outer diameter as best you can.
 

npn

Retro Guru
Re: Re:

FluffyChicken":lymvu5om said:
As for the air taop caps, stick a socket set over the valve so it hits the metal, then tap it with a hammer. If they are like the Marz. XC forks, the cap moves in a but and you just use a thin screwdriver to remove the ring.

Success!

Check this out. Another success story in this forum!
 

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npn

Retro Guru
Yes, even with your typo autocorrects ;)

I'm surprised of the simplicity of the design on this fork - it looks like oil and air is mixed inside. Also the "adjuster rod" - I can't tell exactly how it works as it only basically screws tight or loose and when the topcap is out it unscrews completely out.

For the record, I measured about 55ml of oil that came out + some spillage.

Any thoughts on how to flush all the gunk out at this point (without having to remove the stanchions from the lowers) ?
 

FluffyChicken

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Oil is in the lower part, lubricates it, creates the damping It'll either be some holes that get smaller or two surfaces creating a tight oil path or a mixture of the both (see mag21 for that).

So when full extended the oil is still in the lower part of the stanchion.

This creates an air volume at the top you bump that up and that creates the spring.
You adjust that air space to alter the spring rate.

Anyway, cleaning.
A bit of WD40, rinse around, slightly soapy.water, rinse around.
A bit of oil, rinse, repeat the oil till clearing.
Should be clean enough.

But normally just a few short films of oil can clear it up.

Wait for what others thinks works well.
:)


You then compress the forks get a ruler and fill with oil (with a few compressions to get air out). Using the ruler to measure from the top of the station to whatever the instructions say ....
Normally, or wing it and guess.
 

npn

Retro Guru
More pics...

There's the rod that screws at the bottom. But it also looks like there's a screw inside that keeps the stanchion from extending out of the lower. What do you think?
 

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