C5 (X7) mini project including custom made cunifer suspension pipes

[Jay-Bruce]

As y'all probably know, our C5 had the usual terminally rusty suspension pipe work around the rear firmness regulator:


With the rear hoses rusted into the firmness regulator:


And I had a weeping suspension cylinder, and a drooping back axle caused by a failing firmness regulator, and the LDS pipes are rare/unavailable, and ridiculously priced

So, I imported a low mileage used firmness regulator from Australia:

... and bought a pair of new cylinders from Euro Car Care.

And so it began, that which would not unscrew was cut off, and new or newish bits started to get fitted until we had the new suspension cylinders on, connected to the new firmness regulator:


The cylinder hose bolts were given lashings of a marine anti-seize compound:



Stainless fasteners were used for the firmness regulator and it's hoses going to the cylinders:


The cylinder bolts were re-used, but new nyloc nuts and stainless washers were used to secure them, and those in turn were waxoyled to keep them new:

[Jay-Bruce]

Next up I had to pipe in the firmness regulator to the BHI, even if I could have gotten hold of the part from citroen, I wasn't paying their asking price for the pipes, and none of the aftermarket community has made a replacement solution, so I had to get creative... Way-back when I first looked at this, initially I was going to try and replicate the citroen fittings:



Then I decided to make it a one piece nipple:


While pretty, I guessed those nipples could twist the o-ring... I actually contemplated a 3 piece redesign of that nipple to allow the bottom threaded section to rotate freely relative to the o-ring groove, but even to me this was an over-engineered to expletive solution. So I took myself aside and forced myself to an Elon "First Principles" moment, which culminated in me deciding to ditch the nose gubbins from the nipple design, and coat the threads going into the port with a hydraulic thread-sealing compound. So the simplified part looks like this:


These are then ran into the LDS ports with a thread sealant applied:




Our C5 (X7) is now running on 4 of these new simplified nipples:

You'll see I've replaced the flexi pipe from the ally union to the firmness regulator with a cunifer pipe, and on the other side of the union, the fore to aft pipe is also new cunifer, all connected using my new fittings. They ran up to pressure no leaks etc, no dramas, so I'm going to say I've got a very effective and reasonably cheap solution to the unobtainable LDS pipe fittings.

Then once the joints were proven, the shiny new bits got waxoyled to stop them going rusty and this prevent future problems getting pipes/hoses off for maintenance:

[Jay-Bruce]

I also did a bit of rattle busting, found some undertray gubbins was loose at the front bumper, so it got treated to m6 bolts and nyloc nuts:



At the back end, the exhaust heat shield had succumbed to galvanic corrossion and was lying atop of the backbox making a terrible din, so large, digestive biscuit sized, aluminium penny washers were made, and secured with nyloc nuts on the original studs, on which the threads were chased with a die nut:

3x of them one needed a new stud, which was a stainless bolt, stainless penny washer, rubber washer, inserted from the boot floor, then on the underside a rubber washer, a stainless penny washer, a nyloc nut, then the heatshield, and new coaster sized washer, stainless penny washer, and stainless nyloc. So, that aint coming off in a hurrt

I gave the wheels a ruddy good clean, and wire wheeled, then painted the wheel bolts:

[Jay-Bruce]

It's all back together now, but I'll need to wash it before I photo it, so I made a start on the detailing while it was on the ramp, I gave the chrome (it's an exclusive) rubbing strips on the bottom of the doors a clean, particularly where they meet the paintwork which is a bit of a grime trap, here you can see it sitting on it is wheels for the first time after all the hydraulics work:


Tomorrow I am going to get the tracking down, which should be a scoot as I've freed off, cleaned and greased the trackrod ends and the rear toe control arms, which now have new fastners for their locking bolts, after that I need to give it a blerry good clean.

I initially took the car into the workshop on Saturday 1st, to do a drop link, then did the exhaust heatshield, brought it back out on Sunday 2nd as the duchess needed it Monday 3rd, took it back into the workshop Tuesday 4th and brought it back today, having had two days off, one was easter Sunday, t'other was when I had aching knuckles. Everything Ive mentioned in this thread, bad the CAD work, has been done within 7 days working on it, not a bad weeks work

[MattBLancs]

Cracking progress on all fronts Jay.

My front "bumper undertray" was also loose like that, I did a small M6 bolt pointing down from above so goes:

Bolt head, penny washer, plastic radiator support structure, penny washer, Nyloc nut, bumper's undertray, engine undertray, penny washer, Nyloc nut.

The above means only have one penny and one Nyloc to remove to get engine undertray off. (And I've holesawn an access hole for sump plug)

Does / should the V6 have the full length engine undertray? My (2.2) was missing, so a cheap replacement off eBay:

Aftermarket undertray

This is held on with M6 nuts and penny washers and rivet nuts - no naff plastic push rivets for me!

[DHallworth]

That's a great result, Jay.

Are you going to be selling these nipples? I'd be interested in having a few of them for when I start work on these cars.

David.

[GiveMeABreak]

I've just had a read through and an excellent write up, top marks from me too Jay.

This just has to be a positive for X7 owners who intend keeping their vehicles. At least X7s with these mods will be well preserved when discovered in future barn finds.

[Jay-Bruce]

Thanks for the positive feedback guys!

And yes, I do plan on selling the fittings, I'll need to get a price to make a reasonable batch of them, and put together a product offering with the nipples, the thread sealant etc. As you only need a couple of drops of sealant per nipple, I'm thinking of buying a batch of small syringes, including a syringe of thread sealant along with the nipples as a kit. I'm aware I'm sailing close to the wind with pressure ratings of the pipe only being ~25bar above the systems relief valve pressure, so I've used high-quality stainless tube nuts, special thick-walled higher-pressure cuni-pipe, custom-made nipples and industrial-grade thread sealant, but that adds to the cost.

I'm also aware of the need to curtail the costs when packaging this as a retail offering, not only from the end user's point of view but also because the price could be a deciding factor when approaching Pleiades and Euro Car Care about them stocking my LDS system as resellers. I'm currently sitting at ~£250 retail price, including VAT, for a full kit to repipe a C5(x7) from BHI to both firmness regulators, and this would include all the cuni pipe, stainless nipples, stainless tube nuts, industrial grade thread sealant, a couple of extra stainless tube nuts and unions for replacing pipes in sections.

That price is more than I'd like it to be, but I'm also aware that:
A: It's a complete kit for less than the list price for the BHI to rear firmness regulator pipe from Citroen
B: It's small batch of custom-made stainless bits which is inherently expensive
C: This stuff will last forever so it will pay for itself
D: Because it's being engineered to be usable by a DIY mechanic, using brake pipe type technology, I'm operating close to the limits of the components rated working pressures, so I cannot really afford to lose any integrity of the fittings to corrosion or poor manufacturing tolerance, hence quality stainless pipe nuts rather than eBay chinesium ones.

That being said, I'm still exploring options to bring the price down, so watch this space....

[MGmike]

Excellent work Jay...
One order for a couple of sets for my C6's waiting for you...

Oh, and when you sell the 3.0 I'll be waiting also

[Sloppysod]

Well done Jay, hopefully, , I will never have to deal with this problem,. However, you never know what Mr MOT decides to snag, .
I have bookmarked this thread/post so I know where to go, when needed.

[aerodynamica]

Wow great work there Jay, this is a good solution. I'd be keen on the single pipe that goes from the little alloy two way joiner to the firmness regulator. I replaced mine with a CuNi pipe joined on to two of the original ends using 2 straight joiners and pipe formers. It was always kind of a temp solution although holding well.

[Jay-Bruce]

Thanks Graeme, PM me your mobile number, I've got a good, low mileage almost new original of that pipe, that I could sell you, I'll send some pics to your phone, and or I could sell you some of the stainless bitties to flare up an end to end cuni replacement like the one I've pictured?

[CitroJim]

Top work Jay! Most excellent

[Jay-Bruce]

Cheers mate!

[KennyW]

Jay,
Great work and I think I will change to your fabby design for my Hydraulic pump.

One question what thread sealer /lock did you use ?

My rear pipes are also very badly rusted considering doing your mod.

Kenny