Rebuilding remote reservoir Ohlins

Going to start refreshing the shocks on my WR 390, reading through the Ohlins manual ( thanks again Steve J ) it says to use Husqvarna automatic transmission oil in the shocks , I'm assuming this is NLA , so what do you knowledgable chaps recommend ? Also , how do I recharge them with nitrogen , and to what p.s.i ???

Cheers !

I have just spent money and got it done, they seem to know where to get the seal head kit and whatever else. Do you have access to a high pressure cylinder of nitrogen and a regualtor capable of going to 400 psi, maybe 200 would suffice I would assume that is how one does it. That oil is an aircraft hydraulic fluid and available in 5 gallon pails, 55 gallon drums and in bulk. If there isn't a shock oil probably cartrige fork oil as that is often recomended for the automatic transmissions.

Might as well put the shafts on a flat plate and check as they can get bent in crashes.

When I assembled the nitrogen fill shocks for the 155mm howitzer for the U.S. ARMY that are used in the sand box today we filled them with 200psi. Even the off road and heavy duty gas shocks for 4x4's and cars today are filled with 200psi. On the howitzer barrel shocks we had a hydraulic test machine to fully cycle them. I wonder if the rebuilt olins should be fully cycled before the gas is charged in them and the suspension springs are put on them.

Which makes me think of what oil to use. Some hydraulic oils displace water and moisture. Now every hydraulic oil runs at different max temps. The B&M racing auto tranny suggested we ran Ford type F in our GM tranny after they were rebuild with the b&m kit. It has a higher flash point. It should be more stable when the oil gets hot.

Just my thoughts.

Safety first.
When disassembling anything that uses the gas shocks or gas shock track tensioners on equipment today be careful read the owners manual very carefully. The pressure must be released before disassembling any gas type shock. The parts have been known to fly and take lives. Be careful and understand how things work and are disassembled before you start. These are under high pressure.

I know our local bike shop has nitrogen for filling shocks. Give a local shop a call.

Thanks for all the replies , I was hoping it would be relatively straightforward, until I started to read the manual last night . I'll maybe strip them down and paint them , then ask one of the specialist shock companies to regas them etc.

I wonder how much the tools cost to install the gas in the shocks. If it's the cost of having the shocks recharged once with multiple bikes it maybe worth buying.

The local tire shop has nitrogen for car tires, its a self contained system with a pressure tank. I doubt it goes high enough for what is needed for shocks. I haven't seen the one at the local bike shop. Probably the same thing only high pressure.

Back in the day I had a bike using fox airshox and ended up getting a nitrogen tank set up to charge them . I was told by the welding supply shop that a 400 psi regulated was needed to be able to deliver the needed pressure and that was the smallest regulated able to do that . If I remember correctly , I was told to use DRY nitrogen . I can't remember the reason after all these years . Maybe things have changed over time but you may want to check it out before investing . Good luck .

Not sure a vintage ohlins shock is gonna take any lives, but when it came to do my 79 ohlins I sent them to a guy in s.c. and he only could get 1 apart and said they were un rebuildable but he just so happened to have another pair all ready rebuilt. So he sent them back and I had to soak the 1 shock for days but I did get it apart then I sent them to W.E.R. and now they are like new. You can strip them down but don't paint them till you get them back from the rebuilder. There is some kind of sequence when you add the oil and the gas and you have to get all the air bubbles out of the oil when you add it. This is the only thing besides machine work on my bike that I cannot do in my garage. good luck Moe.

doing my own shocks is something i would like to learn but for the money i will send them to drew at WER and know they are perfect.

Ohlins shock oil and Husky auto transmission oil are the same. Both high quality hydraulic fluids of the same viscosity. Both dear as poison too!

You should be able to get a regualtor off ebay delivered for $50 or so. It would be an inert gas one and there are adapters to go to carbon dioxide cylinder standard. The brand I like has 150, 200, and 400 psi output models. Then just hose, brass hose/ferule etc stuff and a tire chuck thing. But you do need the cylinder. I think Gueniss is supposed to be pumped with nitrogen most beer is just carbon dioxide. I have that end covered though I never even thought to check the pressure in a shock. I had/still do/ a real small cylinder, regulator hose etc I carried for a while after I lost my pump to plug into the cigarette lighter for tires. More work than the guys that have the air tanks but smaller. There is no water in nitrogen. I put a cylinder stem into a regulator at the high pressure gague and fill one tank off another because the welding shop won't sell the flex hose for manifolds, then along came ebay and I got the flex hose now.

My lined cutting torch needed rebuilding. It's a o ring kit with other washers. My welding vendor refused to sell me the rebuilding kit because of the accidents that covered from other guys rebuilding there cutting torches. I found the kit on eBay and my torch works like new. Never twist o rings when installing them.

I rebuilt my ITC's on my 83 CR500 myself, wasn't too difficult. While your remote reservoirs have some differences, here's a few points that may help. #1, buy the Ohlins fluid, it is not that bad a price and you'll know you have the right stuff. #2, make yourself a tool using a cheap hardware store turn buckle to depress the seal head, similar to the one in the manual only simpler. You can use a piece of all thread in a vice and through the eye of the shock to support the shock body while you work on it. The one I built is overkill, I expected the seal head to be much more difficult to depress than it was. #3, if you disassemble the shim stack, carefully lay the pieces out in order and reinstall in the same order. #4, once you've reassembled your shocks, charge them with shop air to from a compressor and submerge them in water, look for bubbles indicating a leak. Best to find leaks now before you've had them gas charged and are back on the machine. #5, take them to a dirt bike shop and have them nitrogen charged, mine are at 165 psi, others may have suggestions as to pressure on remote reservoirs like yours. It is far, far less expensive to pay to have this done than buying even the cheapest nitrogen kit to recharge them yourself, unless you plan on doing several. The primary purpose of the nitrogen charge is to prevent oil foaming (although it can have a minor effect on spring rate), so not having an exact specification for pressure probably won't ruin your shock performance. #6, cleanliness (this should have been #1).

The advantage to sending them to someone like WER is that he can change the damping to fit your needs.


That's my two cents worth, I am now bankrupt.

About the pictures:
1st and 2nd pics. The tool I built to compress the seal head. Really didn't need two turnbuckles, should have just extended the notched metal piece on one side to act as a lever. From what I see in the manual, something similar will work on your remotes.
3rd pic, Keep everything in order.
4th pic, Ohlins fluid, the only way to go unless you get advice from someone who regularly services these shocks.

Just for information, the Ohlins manual states that the shocks (both remote reservoir and piggybacks) must NOT be cycled (stroked) prior to gas charging.

Last step of re-assembly in the manual states they should be charged to 185 psi.
Steve

Thanks for all the input guys , I didn't notice that part in the manual where it mentioned the psi. I must stop speed reading

There is a shock rebuilding company about 30 miles from me , so I think I will give him a call next week , if he starts quoting telephone numbers to me for rebuilding , then I think I'll build a few tools and do them myself.

I always prefer to do jobs myself , apart from maybe saving a few bucks. it gives you a feeling of satisfaction.

I'll let you all know how I go on .

Cheers guys

Hi would you please be able to send me a Ohlins manual for the remote reservoir rear shocks for
my Husky 1980 390cr and were can i get seal kits from.
Your help would be much appreciated.
Regards Ric
South Africa

Sent you a pm to get your email address, soon as I have it I'll send you a copy.
Steve