I renewed all my spheres and fitted one of McKay 1 's magic box's recently but still get an ocasional "clunk" from my nearside rear suspension. I don't see any wear around it but don't know exactly how to test the hydraulic unit. is it similar to a shock absorber?

Hi Blobby,

Sounds like your sphere is empty. If there's not enough "spring" in the sphere it cant push the piston back out of the strut fast enough when going down the offside of a bump in the road. As the wheel travels out of the wheel arch (body rising relative to the road) the swinging arm lowers. The rod which fills the gap between the piston and the swinging arm is fixed at the swinging arm end only. The end at the piston can float freely. However, if there's enough pressure in the sphere the fluid being pushed out of the sphere will cause the piston to follow the rod as it travels out of the strut. In which case a gap between the end of the piston and the end of the rod never materialises and the whole transition is smooth.

However, if the rod travels out of the stut faster than the piston cal follow it then a gap appears between the end of the rod and the piston. Once the car is over the bump and the body is on the way down the rod is then pushed very quickly back in to the strut by the swinging arm. The "clunk" you hear is the end of the rod striking the inside end of the piston.

To make it worse there's a plastic "cage" inside the piston which keeps the rod in the centre of the piston. However, if the rod starts moving back and forth relative to the piston then the plastic cage gets mashed in the process and the rod ends up jammed off-centre between the piston sides and the plastic cage.

I see you're in Falkirk. I'm only a couple of miles away. If you can take your sphere's off and bring them to the house I can test them for you to confirm what pressure is left in them or if they're empty. I could recharge them also but I need to check how much Nitrogen's left in the bottle. Alternatively you could just replace the rear sphers with new ones.

Please let me know if you want to test them.

Cheers

noz

Could it be the arm bearing?

Hi Noz, the general ride in the car was vastly improved after fitting new spheres from Plaedes (Not sure if I'm spelling this right) and then again by Roy McKays box. all fitted in the last six months or so, I only feel the clunk on hitting a fairly big pot hole and then I only find potholes in the road are usually on the near side!
I appreciate your kind offer and may take you up on a test of the spheres when the weather is better as I've no garage of my own. I will also give all of the bushings a good looking over as soon as possible.
I've had a busy two or three months with the car, first a broken pulley on the engine that drives the hydraulic pump. Citroen mechanic? Then a brake cable jumped out of its seat in the equaliser box. Had to strip the whole lot down to get it back in. then I had air in the fuel line and didn't read about the problem posted in the forum about the heater till I'ld bought some valves from Citroen thinking the touble was in the priming pump!