Topic

Of course. Thank you

Mike Satur is making me up a set of Rivnuts which is much to be preferred and I bought a Hydrolastic pump yesterday so this job is on fairly soon.

Mike sent the parts and they arrived this morning. The usual artistry in stainless steel, Now I just need patience and a few other bits. I shall be making a Rivnut tool out of a 12.9 bolt as this will be a key part of the installation. These rivnuts are going to take a lot of collapsing being made of stainless. Should be fun once the weather turns.

Or not. The adaptor is a BSPP thread. All available valves I can source are BSPT and will not fit the adaptors. If anybody has experience of this setup, can they please let me know where the valves may be obtained?

Much research later, I think the thread I need is called BSPM which is an obsolete standard now called G and relating to BS2779 which is another obsolete standard now called ISO-228. The one place I found that stocks them calles it a BSPM taper but I am sure it is a parallel thread so I have ordered four of them and I hope that they will fit the adaptors. Fun this modification lark!

None of the above. At the third time of trying, I obtained 1/8" BSPT valves which fit. The pair of displacers I ordered arrived today. I decided to buy one of each to have a pair ready to swap in and then take the pair removed, modify them and fit those so I was less time pressured should the weather turn either good or bad. Which would be fine were they not both rear ones. So I'm in a quandary. Rear ones appear to be more failure prone so I suppose that is a good thing but it does mess my plans up. The front ones are at least supposed to be easier to remove so I suppose I can still do a side at a time but I regas at work so I'm off the road for a bit longer than I'd like. Still, looking on the bright side, both the lower diaphragms are dry. I haven't drilled the tops yet; The units supplied were by no means as good as those pictured so I might still have a duff pair...

Bumped the topic as my reply didn't show up in the recent topics list, for some reason that is beyond me?

I received your reply off board Cobber. Thank you.. the rear displacers actually differ by more than just the cone. They are not only dimensionally different, which is a minor issue but the internal damping is different, too, which will upset the handling balance- not really an improvement after the trouble taken to get the gas pressures right. For that reason, I shall fit the correct part.

Haus of Parts, run by a Mr Rex told me to go and do one, I had a bargain and the parts fitted. The fact that they bait and switch which is against the law should inform prospective users of this company.

Drilled the first one. No gas at all. No fluid either soI am guessing that it might still be serviceable. Just ordered some more rivnuts so I can experiment, I'm a little reluctant to waste my one spare in a suspect unit but now I can. I would like to have the first one ready to try this week.
After a bit of a think, I can thread the small hole and screw in one of the adaptors without the rivnut and see if it will hold 50 PSI. If it will, then I can be fairly certain that the diaphragm will make the trip without too much danger. If it does then unscrew it and install the rivnut.

I understand that the Nitrogen pressure in the top part of the Sphere is 150 psi ( 15 bar) The fluid pressure below this is 400 psi BUT this is static, i dont know how the bounce will affect these figures.

A displacement of the suspension sufficient to halve the volume of the nitrogen in a sphere would double the pressure within the nitrogen chamber. Two chambers are linked by fluid so each would be reduced by the same amount although the drag through the interconnecting pipe will delay the response of the rear sphere. Then add in the unequal displacements front and rear for bump response and you start to wonder why you want to know! Dunlop rated the spheres to 800psi max so transients will be around 3/4 of that to allow a safety and wear margin, say 600 psi.