DHX clean out

[DownhillerDeano]

Keen to disassemble my DHX to change the oil and clean seals and flush out any shit that may be in there..its off an 06 bike which I know for a fact never had a rebuild.

After a bit of searching I came across this rather use-full thread:

http://forums.farkin.net/showthread.php?t=110221&highlight=fox+dhx+rebuild

However, out of the three pictures, only the first appears no matter how many times I tried reloading the page, but anyway, is there anything I else I need to know first?

I am rather technically minded and have full acess to good quality tools, and if worse comes to worse can just use my VAN R shock if I end up having to send the DHX5 to Dirt works for a rebuild or something.

Is there anything in particular I should look out for whilst I have it stripped down? Obviosuly any O-ring that comes out will get replaced with a newie.

As for the oil. I have various weights of fork oil, namely 5, 7.5 and 10w. I'm thinking I will probably be using the 7.5w, but is there a specific rear shock oil as stated in that thread or will fork oil of the same weight do??

Cheers all

Dean

 

[Sov]

You'd really want to use rear shock oil, not fork oil. Shock oil is usually has smaller viscosity changes with temperature so works better with the lower oil volume and higher temps you'd get in a rear shock.

I would also suggest starting by depressurising the reservoir, taking off the cap and then measuring your IFP height. Don't go by what's stated in the guide as it may differ depending on stroke/length etc.

 

[b_S]

That guide is a bit rough and ready, there's quite a few small pointers to consider but it's not my place to give (mis)advice on this. Read up a bit more about it before jumping in the deep end, it's an easy job but you should go in to it with a bit of an idea about it...

 

[DownhillerDeano]

Thanks for that info guys. I have found a few useful threads on ride monkey. Couple of guys on there really know their stuff.

Good point to about measuring the depth of the IFP before fully stripping it.

How did you get the IFP out? Cycling thru the strokes several times allowing oil to 'push' it out?

 

[Sov]

I normally pop it out via compressed air. With the DHX, I think you can also take out the bleed screw in the IFP, then find a suitable bolt, thread it in and pull! Don't know what size it is though.

 

[DownhillerDeano]

Another reason for wanting to disassemble it too is I cannot turn my bottom out resistance knob, and I'm hpoing once I have it stripped down I can have a close look at this too, perhaps there is some shit in the thread, although I can't see how it'd venture up that far

 

[addmin]

can you post the links to threads you found on ride monkey?
im keen to service mine also
cheers,
matt

edit: there is no need; i used my own brain to find them instead of getting someone else to do it

 

[DownhillerDeano]

addmin, you go first, let me know how you go

Unless I'm working or hungover, sunday is looking good, after the you yangs ride day (sat) to do this and my 40's aswell

 

[addmin]

addmin, you go first, let me know how you go

Unless I'm working or hungover, sunday is looking good, after the you yangs ride day (sat) to do this and my 40's aswell

lol . i was gonna ask if you could post a report and maybe some pics of the process and the results...

 

[DownhillerDeano]

lol . i was gonna ask if you could post a report and maybe some pics of the process and the results...

I'll see how I go first before sharing with everyone how compitent I (believe I) am!

 

[DownhillerDeano]

Ok, a bit eager to have a look at the internals and see how everything works so after todays awesome day at the You Yangs I put my spare shock on the stab so its still rideable, thus allowing me to take my time doing the DHX properly.

First impressions, the main body nut/seal wasn't overly tight. The reservoir end cap was slightly tighter but I didnt struggle using a tool any longer than 12" to undo both of these when securly clamped in a vice.

Once I had the shaft out I removed the end nut holding the shim arrangment so I could clean these down. So far so good, they were quite clean.

Once the end cap was off I measured the IFP before removing. It was set at 37mm. I then proceeded to drain old oil and remove the IFP.

I then flushed the whole body out using a real thin oil and have cleaned and dried everything before assembly tomorrow.

I still have two questions...

What would happen if I were to put the IFP back in but set it to 33mm? Obviously air chamber would become bigger but are there any advantages/disadvantages to running it at min(33) or even at max(40mm)?? In particular, would it change between a linear and progressive stroke.

When its time to replace the IFP back in the reservoir will it matter where the shaft is, ie. fully compressed or extended

Aswell, how the hell am I to know how much oil actually goes in if I doing this submerged (so as to reduce air bubbles)?? I've read its about 100mm or thereabouts that it needs?

 

[Pebble]

I have a really detailed Fox Vanilla RC rebuild manual (great step by step pics and explanations). PM me your email address and I'll send it to you - it might help even though it's not specific to your shock.

 

[Sov]

I would have measured the IFP height before undoing the main seal head. When you undid the seal head and pulled out the shaft, you would have sucked the IFP back into the reservoir a little.

When you're putting the IFP back in, it doesn't really matter where the shaft is positioned, so long as it's at the same position as when you originally measured the IFP height.

Re. IFP height, If you put it back in at 33mm the air chamber would be smaller so it would be more progressive. You may however run into issues with the IFP hitting the volume adjuster at bottom out. You can work out your limits via a bit of maths. IMHO though, with a DHX5 there's really no need to mess with IFP heights as the volume adjuster pretty much does that for you.

Also, about your last point, you don't really need to know how much oil goes in, all that matters is that it's bled properly and that the IFP is set to the correct height. You don't need to completely submerge it, the key thing is to make sure the piston assy does not trap any air before going into the body. You can do this with a bit of inner tube and a hose clamp - see pic. Similar thing for the resi.

 

[DownhillerDeano]

I would have measured the IFP height before undoing the main seal head. When you undid the seal head and pulled out the shaft, you would have sucked the IFP back into the reservoir a little.

When you're putting the IFP back in, it doesn't really matter where the shaft is positioned, so long as it's at the same position as when you originally measured the IFP height.

Re. IFP height, If you put it back in at 33mm the air chamber would be smaller so it would be more progressive. You may however run into issues with the IFP hitting the volume adjuster at bottom out. You can work out your limits via a bit of maths. IMHO though, with a DHX5 there's really no need to mess with IFP heights as the volume adjuster pretty much does that for you.

Also, about your last point, you don't really need to know how much oil goes in, all that matters is that it's bled properly and that the IFP is set to the correct height. You don't need to completely submerge it, the key thing is to make sure the piston assy does not trap any air before going into the body. You can do this with a bit of inner tube and a hose clamp - see pic. Similar thing for the resi.

Thanks for imformative post and good picture.

I actually measured just for the sake of it, the level of the oil from the end of the main body shaft...was 30mm down with the IFP @37 so theres a good starting point anyway.

Cheers
Dean