Citroen GS rear suspension revision

The big operation to repair and overhaul the rear suspension of my Citroen GS has begun. I am doing this because a few years ago there turned out te be water in the right rear suspension arm bearings that caused the bearings to rot out and to have damaged the tubes. The tiny roller bearings move directly on the tube, so this causes uneven movement and also the splines of the stabilizer rod were worn out because of the wear.

I started by jacking the car up at the rear and removed both suspension arms. Plan is to replace the tube on the right side (left side is in perfect condition), replace the stabilizer rod and replace all 4 bearings (two on each arm).

First stage of the repair; dismantle suspension arms

  • Rear left suspension arm

  • Suspension arm removed

  • Wear caused by corrosion on the surface of the support tube

Axle support tube removed

And then the axle tube was out. Surprisingly, it went quite smoothly using the special tool i rented from the Dutch GS/A club. While pulling it out required a lot of force, once it started moving, the rest was fairly easy. Installing it back in went well too, using a reverse application of the same tool.

In the photo, you can see the old, pitted tube on the right and the new one I ordered from Französische Klassiker on the left.

Next, I installed the control arm bearings with seals. Interestingly, each set of bearings only includes one seal, which seems odd. The installation went smoothly, but I’m now missing one seal, so I’ll need to track down a replacement. I was only able to reuse one of the old seals.

The next step is cleaning everything thoroughly and applying some rust prevention on and around the subframe (now’s the perfect time since it’s so accessible). After that, I can start reassembling everything.

I also had the suspension spheres repressurized at Chyparse. Both were down to 28 bar instead of the original 35. They were installed in 2010, so that’s not bad at all! The service cost €31 and was done while I waited.

Pulling the old support tube out and mount new bearings

Rust prevention and treatment

While the subframe was still lowered, I took the opportunity to clean areas that would be difficult to access later. I treated the upper exterior of the fuel tank and the subframe with Owatrol oil to prevent rust. Additionally, I replaced the fuel lines and installed new connector rubbers on the high-pressure LHM lines. I also installed the new stabilizer bar because the old one was so worn that it had developed play in the crown ring of the suspension arm.

When it came time to refit the suspension arms, I could only install the right side because I was still waiting for the seal for the left suspension arm.

Sub frame lowered

Refitting and adjustments

As soon I received the seal (code G45-52-4 INA) I ordered at Motionparts, the repair could be continued. The control arms have been installed with new bearings and seals. The position of the arms was checked using the marking on the rod (a barely visible scratch, which I made slightly more visible with a marker for clarity).

Next, I adjusted the lateral play by pressing the control arm against the friction ring using a homemade tool made from a piece of threaded rod, an M10 nut, and a thick spacer. Measurements were taken with a digital caliper, and adjustments were made using shims.

The nuts on the stabilizer bar were coated with thread locker and tightened. Then, I roughly set the height by positioning the control arm in the middle of the two rubber stops and securing the height regulator connection to the stabilizer bar. Initially, this resulted in a rear height that was too low (250mm), but after readjusting, it was nearly perfect (270mm, where it should be 272mm). The height is now perfectly even on both sides, unlike before the repair, when the right control arm was mounted one tooth off.

Fit the suspension arms and correct height

So far, there are no leaks, so I’m declaring the operation a success—for now! However, I did discover a slight leak in the T-joint at the front. Ironically, I replaced this part two years ago and installed it with Ligarex, but I probably didn’t tighten it enough. It seems my tinkering isn’t quite done yet!