DNM Shock rebuild

rumble · Sep 4, 2009

After no help from DNM in china and not being able to find any information anywhere, i decided to pull down my DNM shock and try to repair a leaking oil seal.

I first cleaned up most of the dirt off the ouside of the shock to make disassembly easier. [DNM Shock 1]

Back off the two lock nuts that hold the spring in place. The bottom retaining bracket that holds the spring can then be lifted slightly and slid over the chrome shaft. Once this is removed the spring is also easily removed. [DNM Shock 2]

Next i undid the middle alloy nut which holds the oil seals and all the oil back. As mine had no or little oil in it the chrome shaft was easily pushed in and out by hand. I kind of know that if it had oil in it, the travel of the shaft would be fairly rigid and smooth. Im not sure if the shock was in good condition if there would be pressure in the area, i think not but maybe someone can answer this. [DNM Shock 3]

When you pull out the centre shaft you reveal the main, or only , piston and shim stack. In the centre of the shims is the piston, this does have to go in a certain direction, the photo shows the piston facing the bottom of the shock shaft. [DNM Shock 4] [DNM Shock 5]

Inside the oil seal section is; the oil seal, and some other seals which i dont know the name of. The oil seal is the black seal on the left. [DNM Shock 6]

When i pulled out the seal the silver spacer in the middle looked squashed and not the correct shape. Not sure yet how im going to get another one of these. The oil seal i am going to try and get from a bearing place. [DNM Shock 7]

I am going to need some help on how to refill the shock with oil so anyone please help. Any questions or comments please feel free to leave them.

Nick

bradisfun · Sep 5, 2009

how much did u pay for it and if it came with a bike do u know how much it is worth new

rumble · Sep 5, 2009

didnt come with the bike, but paid just under 200$ if i remember correctly.

rumble · Sep 27, 2009

Bit of an update, not that it seems that anyone cares......

Hoey Suspension in adelaide believe it worth while fixing. Apparently he had one come in a while ago and the sliver (aluminum) spacer split on that one too. Just machine a new one and put it back together. I think its going to cost around $80.

sean01 · Sep 27, 2009

did he say why the spacer looks like it does...and did he tell you how to fill it with oil...

tormentandglory · Sep 27, 2009

Wow, there's a lot of shims in there. I rebuilt a fastace shock a while ago. The alloy bit at the end of the shaft popped off, pulled the thread clean out. I made a new end for it and after a bit of dicking about it went back together.
You need to pull both ends of the shock body off, and remove the floating piston. When its all cleaned, put the bottom end back in first (the end with the shaft in it). Push the shaft all the way in and fill it with oil. You'll need to gently pump the shaft a bit to bleed out the air. Fill it right to the top, making sure that the shaft is all the way in. Now you need to refit the floating piston without trapping any air under it. Thats kinda tricky to do. Then screw the top back on and repressurise it. Its supposed to be nitrogen but i use air... The rest you already know how to do.

Its very important that you fill it when the shock body is compressed, otherwise it will end up over-full with oil and it will hydraulic lock and pop the seals very quickly.