Mountain Bike Reviews Forum banner

Ransom Equalizer oil change

39K views 48 replies 15 participants last post by  morellana7 
#1 · (Edited)
Cylinder Metal Machine Silver Nickel
Machine Cylinder Metal Household hardware Automotive engine part
White Style Line Metal Font
Office equipment Photography Machine Plastic Steel
Finger Lens Camera lens Nail Pliers
I quite like the Equalizer shock (2006 Ransom). But the rebound damping was getting a bit erratic so I took the shock apart to look for a problem. It was overdue for a service anyway. I'll try and attach some photos, to provide some information for other people who are thinking of doing a shock service, ghetto style.

Here's what I did (You are going to need a reasonable amount of experience of taking stuff apart, this is not for beginners. But it's not super complex either)
  1. Release air pressure, then remove valve cores to ensure there is no trapped pressure on the air side
  2. Stroke the shock by hand, if it still has some spring action then there's air pressure on the oil side. I get the same problem on DHX-A. I carefully/slowly loosened the two screws that hold the body together, and allowed the oil/air to bleed out. The set screw in the body (next to the rebound knob) might be a better way to bleed the pressure. My shock had lots of air on the oil side, which is probably why the rebound damping was getting sketchy.
  3. Remove the 2 screws to separate the body
  4. Unscrew the large shaft nut and remove the shaft assy
  5. Unscrew the piston from the shaft. I heated the piston to soften the loctite. I didn't have the factory pin spanner so I used pipe grips and filed smooth the damaged bit of piston after reassembly. Dont damage the piston in the area of the seal or bearing strip.
  6. Remove the wiper seal and quad ring from the shaft nut, being very careful not to scratch the seal cavities. These seals will probably have dirt in them, so even if you don't replace them they should still be removed and cleaned.
  7. The piston seal looked a bit worn, and I should have gone to a local hydraulic seal supplier to get a new one. But it was the weekend to I reused the old one....
  8. The rebound knob assembly screws out by turning its large hex.
  9. Turning the rebound knob allows further disassembly of the rebound assembly. But because the old oil was clean and things weren't leaking, I didn't completely strip everything down.
  10. The small spring that holds up the "platform" damping pin was broken in 2 (pictured), which is not a good sign. I scrapped the short bit and stretched the remaining bit to make it about the same length as the original spring.
  11. Remove the caps for the internal floating pistons (IFP), and loosen the bleed screw in the piston
  12. Now clean everything. Hydraulic assemblies such as this need to be very clean. Make sure your workspace and tools are clean.
  13. Reassemble the shock, except leave the caps off the IFP chambers, and don't fit the valve cores

    You now need to refill and bleed the shock. 7wt oil seemed right, compared to the old oil that was tested by putting 1ml of oil in a syringe body and counting how fast the oil dripped out. I used 50ml of oil.
  14. Have a block of wood on the bench so that when you push down on the shock body you actuate the travel adjust lever. You'll need this since the travel adjust prevents oil from moving into the IFP chambers.
  15. You probably want the IFPs about 1/2 way down the chamber at this stage, but don't worry about it. Remove a bleed screw from an IFP and squirt oil in the hole. Actuate the travel adjust lever then stroke the shaft to get oil in and air out. repeat for the other IFP.
  16. Continue moving oil around inside the shock and removing air and adding oil, by moving the IFPs and shaft. Once you have the air out then the the shock will lockout solid. If the locked out shaft is at all spongey then there is air in the oil.
  17. The final bit is setting the oil volume to the correct level. I don't know what this is so I did some thinking about it, and this is what I suggest:
  18. With the bleed screws fitted, push both IFPs as far down as you can. There must be enough oil so that the shaft fully extends before both IFPs have bottomed out. You can check that the IFPs are not bottomed by actuating the travel adjust lever then pushing down on one IFP; the other IFP will move off its bottom (the shaft must be at full stroke). When riding the shaft is going to extend a bit more against its rubber bumper. I put enough oil in so that the IFP was 5mm from bottoming out. If the oil volume is too small then the IFPs will bottom out and the shock won't fully extend. If there's too much oil then the shock will ramp up to fast at the end of its travel. If you know the factory IFP level (oil volume) then please post it.
I put the bike back together, but since the Ransom is now my third bike and is made up from old parts, it doesn't currently have a crankset. So I couldn't properly test it. At somestage I'll pick up a good used crankset so I can do a proper test ride, and use the bike as a loaner :thumbsup:
Finger Lens Camera lens Nail Pliers
Cylinder Metal Machine Silver Nickel
Machine Cylinder Metal Household hardware Automotive engine part
White Style Line Metal Font


Edit: Tried to re-post the images, but can't figure it out, sorry. Uploaded the images but that's as far as I got.
 
See less See more
5
#4 ·
woofdog said:
A quick update: I've done a few runs on the rebuilt shock and it's all good. Damping is now working consistently. There are no leaks even though I reused the old seals.:thumbsup:
Just curious, how dirty was the old oil? I guess I'm wondering if the oil really needed changing or was the broken spring the cause of the inconsistent damping you were experiencing?
 
#6 ·
Hi...Thank you very much for this post!!!! was very very helpful.. Me and my friend just did rebuilt today of this shock.. and seems like it is working fine.( took us 4 hours from start to finish, to make sure to not mess anything up, and thinking 10times before we progressed each time) My orignial fault was that I had loads of oil in the positive and negative chamber. No matter how much pressure I have put the shock was always too soft. (im 95kg another aspect why bike was lowered so much everytime I sat on it ;P ) Only when negative chamber was without pressure was reasonably hard. But now after taking everything apart and cleaning, putting new oil, seems like it is working fine. I must admitt that all my seals seemed to be fine and not even worn. Oil was a bit mucky. The only bit to give me a hundred %confidence it would be to know exact amount of oil to put in. By the way I have used 10w oil for suspensions. I only had this one. But seems to be ok. I need to take my bike to check it in the terrain. I hope it withstand all day off riding at least. :) I will try my luck and contact Scott and ask them for the amount and exact specifiaction of the oil..Maybe im naive but I will try my best to find out. Woofdog have you looked for replacement of seals by any chance, did you find any alternatives, are they possible to buy from different supplier?? Once again Im very chuffed that I know how to do it, and dont have to rely on Scott, especialy these shocks soon will be obscolete.
 
#7 ·
Most of the seals are standard quad rings:
Piston seal -214 (1 off)
Shaft seal -114 (1 off)
Floating piston seals -116 (2 off) (the "traction" IFP also uses one of these as a bump stop).
The wiper seal is non-standard, its appears to be a 16x23x2 nitrile wiper, I couldn't get one locally so I'm still re-using the original.
Regarding oil volume, if one IFP is bottomed out (depth measures 74mm) then set the other one 5-10mm less than this (I used 66mm when I last did a seal change); this seems to work fine but be careful to bleed out all the air from the oil circuit before before setting IFP height.
 
#8 ·
Hi there,
I've just damaged my equalizer shock, the rebound knob broke off due to the seat post impinging on it on my Ransom 20.
The part that broke is the silver hollow threaded tube that is Loctite bonded to the pink cap.
Does this look like it can be replaced without dismantling the whole shock or removal of the oil?

Any help appreciated.
 

Attachments

#9 ·
I guess it was my turn!

The equalizer on my 2008 Ransom just puked its guts (oil) out on me today! :eekster: I guess it was inevitable since this shock had never been serviced.

It all started when I was doing a static test of the suspension when I noticed rebound was much slower than it had been on my ride yesterday... I also noticed there was some creaking on initial compression so at this point I decided to let the air out of the shock to see if I had a bearing going bad in the pivots... and that's when things went south... to make a long story short the shock starting spraying oil out of the negative air valve and in all this I manged to crack the negative schrader valve. Even though I discovered I can easily unscrew the broken valve, today's events are perhaps an indication that I shouldn't be attempting to service this myself. I may consider doing so if I can locate the appropriate parts. Does anyone know if this schrader valve can be easily obtained? I'm assuming I lost a seal which is why the oil came out the negative valve, are these seals easily obtainable or should I just send the shock off to be serviced?

Appreciate any and all advice!

Karl
 
#10 ·
As for me and my rebound knob, everybody I've spoken to says that I'll need to send the shock in for a full service in order to get this part replaced. If you don't need parts (or only need standard parts such as o-rings etc.) then I'm sure servicing yourself could work, this is not the story for me unfortunately. It would be very difficult to get anyone at Scott to supply you with proprietary spare parts.
 
#11 ·
That's sad to hear. If I find anyone here in Canada that will sell that part I'll let you know. I read some other threads where snapping off the negative schrader valve on this shock is rather a common mistake (so I don't feel so bad) and perhaps this part is a bit more available because of it. Time to start rattling some LBS cages... :D
 
#16 ·
Thanks for the reply Scar.

Yes I removed the valve from the top chamber but I cannot figure out how to get the caps past the internal ridge.

I have used a threaded bolt to screw into the cap but it will not pull off, any ideas?

Is it just a case of forcing the cap off past the ridge?

Phil
 
#17 ·
Yeah, it's just a case of brute force past the ridge.
The seals are pretty tight.

If i remember right I managed to use an old steel tyre lever to lever it up and out with a short bolt (shuffling the tyre lever round the bolt so it pulls it out as straight as possible).
It helps if you wiggle it as your pulling.

Scar
 
#18 ·
Hi,

I gave it a go yesterday and could not manage to remove the caps. I screwed a small bolt into the cap and whilst trying to pull the cap of the bolt ripped the thread from the cap.

I cannot find anyway the get any leverage under the cap and cannot get it too move at all and now one cap has no thread in it.

Any ideas?
 
#19 ·
You can just bleed it without removing them if you wanted.
Just bleed it through the bleed hole on the back.

Remove the valve from the top chamber and the valve core from the negative chamber.
Remove the bleed screw (making sure to be careful and pic out the rubber seal under it with a small allen key) and pump the shock slowly a few times to remove the old oil.
Then get a small syringe with fresh oil and pres it firmly into the bleed hole, and extend the shaft and it will suck in the oil.
Extend it fully, then compress the shock again until you see the oil starting to appear in the bleed hole.
Repeat adding oil with the syringe till there is still oil left in the syringe at full extension.

The next trick is to make sure you've got all the air out, and ideally needs 2 people.
(or one and the shock in a vice)
To do this you need a little oil in the syringe, and the plunger about half way.
Keep the syringe pressed into bleed hole, and pull up on the plunger to create a vaccuum.
Hold it firmly and watch for bubbles coming up into the syringe.
Compress the piston slightly and re-extend (this dislodges any trapped bubbles in the piston.)
Repeat until no bubbles are coming out or you need to put more oil into the syringe.

When bled properly the shock will be completely solid with the bleed screw is put back and tighened.
This works as when you remove the travel adjuster assembly the 2 pistons in the piggyback are closed off, so the piston depths stay constant.
Admittedly you still have some oil in them, but if your just replacing the main piston seal then thats all you need.

Scar
 
#20 ·
Managed to bleed the shock successfully via the rear bleed hole which was straigh forward enough in the end.

Since putting the shock back on my bike I am still getting the same issue as before.
The negative chamber(bottom chamber) is still losing around 100-150PSI quite quickly when riding the bike, not sure if this is a seal that needs replacing as the rest of the shock seems fine.

Phil
 
#21 ·
yeah, that sounds like either the pistonhead seal or the shaft seal.
If the lockout still locks out fully, then the air can't be getting into the damping oil and its not the pistonhead.

Check the main shaft for any marks or scratches at all, check the shock in a water bucket when fully pumped up, and also another simple check is to replace the schrader valve on the negative chamber.
Very cheap job, and the valves rubber can degrade over time when used at very high pressures.
Could be something as silly as an old valve, and a non-sealing valve cap leaking.

Scar
 
#22 ·
I have been through the above checks and am almost certain the valve on the negative chamber is the cause.

It doesn't seem to be leaking pressure once pumped up but the issue I am experiencing is that when I remove the shock pump for the valve it is instantly losing around 150psi, so I am having to pump my shock to over 400psi to get it to hold around 300psi for my riding weight.

Is it a straight forward job replacing this valve and do you think Scott will supply me with this part, I am going to call my local Scott dealer on Monday regarding this.

The above posts have been much appreciated as it has helped me to carry out a service on my Equalizer shock for £8 a lot cheaper than £105 with Scott.

Am I correct in thinking the whole valve needs replacing or just the Schrader pin inside?

Phil
 
#23 ·
It doesn't seem to be leaking pressure once pumped up but the issue I am experiencing is that when I remove the shock pump for the valve it is instantly losing around 150psi, so I am having to pump my shock to over 400psi to get it to hold around 300psi for my riding weight.
Actually what you're describing sounds pretty normal for the negative chamber. If you use the two stage valve on the Scott pump correctly, you don't actually lose any air when you remove the shock pump. When you re-attach the pump you definitely do lose pressure because the pump has to be re-filled with air before it can give you a reading. Because the negative air chamber is quite small, this tiny bit of air is enough to drop the pressure in the chamber a significant amount and gives the false impression that it wasn't at proper pressure.
 
#24 ·
Hi yes I am definitely using the two stage pump correctly as I have used this for years, the shock normally loses around 30psi but now it seems to be losing around 150 psi every time I pump it up, I have even used a friend's Scott shock pump with the same result.

Is this a common issue with the negative valve to wear over time?
 
#25 ·
If you think its the actual schrader valve that's leaking, you can test this theory by dripping some soapy water over the valve to see if it starts bubbling. If it does first try tightening up the valve core... there's a special tool for doing this or you can sometimes find the tool built into the top of a metal schrader valve cap. If that doesn't work then just replace the core... you can get these at auto-parts stores or you could pull one from an old tube.
 
#26 ·
So, just wanted to thank this thread for giving great guidance when tinkering with my Equalizer.
Have been struggling to get it to work correctly and think I have nailed it with the last 5th oil change/bleed/service. Started out as that normal service because of oil puking out of the positive air chamber. Opened it up and cleaned and lubed everything and got it back together. But after a couple of rides the same symptom appeared. Oil in the air/air in the oil. Ordered new IFP seals, changed them and crossed my fingers. Unfortunately this only worked for a couple of rides more until this strange other symptom appeared. With the shock newly bled and mounted on the bike the shock just sunk to the bottom of the travel once I sat on it. Then once I got off it slowly went back to top again, like if the rebound was set to full damping. This worried me since I thought I had thrashed the shock completely. I opened it up again and found a massive amount of air in the oil, the IFPs almost at the top of the chambers. After some thought, I decided to change to a new piston seal because I suspected that air was bleeding into the oil through the seal from the negative chamber. So I ordered and changed the piston seal, making sure to bleed it thoroughly once again. And Now I think that I got it right. I've changed to Motul 2.,5wt oil and that really adds a lot in small bump sensitivity. I hope that it will still handle bigger hits well, but it fells very responsive right now.

A note on bleeding the air of the shock, since i've now done it a lot of times.
After pumping in new oil and doing a first bleed, make sure to let the shock rest for a while to let the bubbles collect.

Keep ifp screws fastened, don't mount the positive chamber lids.

Then slowly turn the shock over (rebound knob end upwards).

Push lever and compress the shock slowly halfway. You will probably feel an initial burp of air when the air collected moves through the rebound valve.

Now, while keeping the shock half compressed, turn it over again so the rebound knob end aims downward. This will let that escaped air to collect under the ifps.

Keep shock half compressed! Pour some oil on top of the ifps and then unscrew the ifp screws.

Carefully press the air out from under the ifps, release shock and let it suck in fresh oil.

Now here's what i had trouble with. If you don't unscrew the negative valve core you might have some air left in the negative chamber and that will restrict the piston to fully extend. so make sure to pull the piston end fully out and press the valve to release that last millimeter of air.

Now, set the ifps correctly and mount the ifp screws.

Now you can turn the shock over again, wait a couple of secs and check that you don't have that burping sensation again. If so, you have to repeat the whole sequence again until it is a fully smooth sensation (this can take up to 5 times).

Yeah, and then I modified the ransom to 650B and corrected the geometry a bit but that's a different story.

Sorry for a long post.
 
#28 ·
Ditto.
Never quite got the liveliness I wanted out of the equalizers.

Switched to a Xfusion O2 R.
Just had to tune the aircan to lower the chamber volume and it works a treat.
Ramps up nicely at the end of stroke where the ransom linkage can get a bit nasty.

Sold the frame now though, as your always fighting a compromise with the wild leverage ratio changes the linkage has.


Scar
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top