Replacing the Rear Suspension Dust Covers

I've had enough of working under the bonnet so I've shifted to the other end of the car.  A long outstanding job has been to replace the perished rubber dust covers on the rear suspension. I need to do this before I can fill up - and power up - the hydraulics of the car. There might be a clever way to shut off just the circuit for the rear suspension but why bother? I need to crack on with replacement.

New dust cover fitted

The car needs to be up on proper axle stands. The hydraulics weren't connected up on my car but you would normally release the pressure in the system and put the car in its lowest height setting. 

Surprisingly the official Citroen workshop manuals don't seem to cover the replacement of a rear dust cover. You can find instructions for removing a complete cylinder/ dust cover unit at Section IV of Operation D.433-1 in volume 2 of manual 583. But the only copies of that available online are in French or German. Manual 518 includes a drawing of a suspension unit and cover fitted.

Rear suspension cylinder, pushrod and dust cover

You don't need to remove the whole suspension unit to change the dust cover. If you can clean away the muck and the grease - so that it doesn't contaminate the cylinder and piston - you can get away with undoing a few clips and removing just the pushrod and dust cover.

In the absence of 'by-the-book' instructions, Citroen Classics have produced a short narrative on tackling the job and you can find that HERE. you can also find a handy video from the Dutch 'DS-TT' team HERE. be warned though - it's very grainy/ low resolution. 

This is how I went about it. This is a relatively straightforward (and satisfying) job, as long as you can see what you are doing. There will also be spills of LHM to add to the general fun. 

With the wheel removed, you can begin to clean all the muck off. Pay particular attention to the front end of the rod - where it locates in the suspension arm - and the back end where the big end of the dust cover is attached.

My car just had a large jubilee clip on the big end of the cover.

I removed the clip and the protective rubber collar underneath it and peeled the dust cover away from the cylinder. I pulled out the thin white/ yellow return hose from the small outlet on the side of the cover. At this point it's a good thing to note the orientation of the outlet when the dust cover is fixed to the car. You'll need to replicate that for when the new cover is fitted to the push rod.

At the forward end of the push rod is a smaller dust cover and you will find a large locking pin. It's good to know your enemy. in situ, that pin that looks like this....

The pin secures the pushrod assembly in place on the suspension arm. The LONG leg of the pin secures the cup to the suspension arm. The other, shorter leg of the pin passes through small dust cover and a hole through the push rod. They seem to be made of treated steel and - if stuck - would rather snap then bend. 

If they have been bent too forcefully, then straightening the pin still leaves a kink in the pin which can make them difficult to pull out. In other cases, the pins are seized-in and won't move whether straight or not. If the pin won't come out easily, care should be taken not to force it. These pins shear very easily. If a broken piece of pin is stuck it will prove very difficult to remove the pushrod.

I (carefully) straightened the long end of the pin that was sticking out the back side. In my case I got lucky: the pin snapped when I tried to straighten it - but only the bent end piece. I was still able to pull both parts out without much difficulty.

Broken locking pin and new replacement pin

With the pin out of the way, I found that my cup was stuck firmly in the suspension arm. I was able to remove the Ligarex strap from the small dust cover. That exposed the rod end, ball bearing and cup. Lifting the suspension arm and then lowering it pushed the piston inside the cylinder and gave me more working room. With some lifting and jiggling I was able to disengage the front (cup) end of the pushrod, leaving the cup and greasy ball bearing still attached to the suspension arm. The back end of the rod was then pulled out of the piston/ suspension cylinder at the back end.

Cylinder and piston exposed

The suspension piston may slide out of the cylinder when you're not looking, picking up dirt from the floor as it does so - so you may want to temporarily tape it in place.

Piston slipping out of cylinder

At this point, the only thing securing the suspension cylinder to the car (other than the metal hydraulic pipe), is a small triangular securing plate that sits against a flat ledge on the cylinder. (This also stops the cylinder rotating when you remove a sphere). 

Triangle securing plate and bolt for securing cylinder

If these securing plates are missing or badly rusted, buy and fit replacements.

It took a bit of jiggling to eventually release the ball bearing and cup at the front end as - over the years - road dirt and grit had penetrated any gap and it become fixed.

Cup receiver on the suspension arm

I repeated the exercise on the other side of the car. I rebuilt the two units side-by-side. On the bench I removed the old boots. Turning the boot inside out revealed the Ligarex strap on the small end of the boot and this was removed. The remains of the boot were removed from the rods which were cleaned and inspected.

Very often, D owners report hearing a 'crack' sound from the rear of their car when the suspension is raised/ lowered. This is because the enormous pressures on the rear push rods and ball bearings cause a groove to wear in the hardened tips of the pushrods. When new, pushrod ends look like this.

New old stock (NOS) push rods

Whereas the pushrods I removed looked like this...

My pushrods - as removed

I used a Dremmel tool to remove the worst of the burring and to smooth out the grooves.

Before.....

.....and after.

As well as pushrod wear, the ball bearings also wear and so were replaced.

A worn ball bearing and it's replacement

And - for good measure - I found wear inside the cups.

Worn cup

Luckily I had planned ahead and had bought replacements for just about all the parts likely to wear or break. Which brings us to the dust covers....

Buying Dust Covers

There are several - or even many - versions of the dust covers on sale. Prices and quality vary.  The quality of many reproduction rubber parts is woeful. Parts fell stiff and almost as though they are made of plastic rather than rubber. For some years now, this has particularly been the case with rear dust covers - with some users reporting they are lasting less that a year.

(Photo credit: George Antoniou)

Citroen stopped selling genuine ones many years ago - with the exception of their being a batch of Citroen-branded (bagged ones) circulating a couple of years ago. I think those were genuine but have no idea if their quality matched up to the old days. Vintage originals still turn up, but are prized and highly expensive.

Recent Citroen-branded dust covers

Fed up with the quality of rear dust covers, some parts sellers have started having their own dust covers made up.

Example of a dust cover mould

Off all the reproductions, those made by Falk Lehmann in Germany are held in high regard.

Dust covers made and marketed by Falk Lehmann

These are branded FLE to distinguish them from inferior products on the market.

The last time I was in contact with Falk - shortly after Brexit - he told me that he'd stopped sending parts to the UK as it was too much hassle for a small operator. Shame. And just wait for the fake FLEs to appear! 

These days most big sellers even offer 'standard' versions at a budget price, and better quality versions at a premium price. (In some cases these are Falk's parts).

(Photo credit: Citroen Classics)

(Photo credit: Jochen Hoch)

(Photo credit: Citrotech)

Where two levels are offered, the buyer should still be able to expect reasonable wear from them. Here is what Citroen Classics in the UK say about their lower priced covers:

"Reproduction part, standard quality but we've noticed they perish faster on cars that are not used much and last longer on cars in daily use!"

And this is what they say about their better quality covers:

"Rear suspension dust cover, reproduced part, but absolute best quality available.

Material used is better than the original Citroen part."

As ever it's a case of 'buyer beware' and 'pay your money and take your choice' - but don't say you haven't been fairly warned. The price difference between standard and premium is not prohibitive and I find it strange that any choice is offered at all - especially given the prices that people are willing to pay for many other parts for a DS. 

I have a pair of cheapo dust covers I bought at Citromobile in Holland in 2017. As the time neared, I was never really happy with the idea of using these - given all the bad press about dust covers and so - more recently, I bought a pair of 'best quality' neoprene covers from Jochen Hoch.

You only realise these difference if/ when you are able to compare alternative products. Comparing the two, the cheaper ones feel more like plastic and they seem to be made of thicker material. They definitely feel less pliable. And given that flex and pliability is a key function of these dust covers, the cheap ones did not fill me with confidence. My decision is made. I'll be fitting the neoprene covers and keeping the others as - I don't know what - maybe garage ornaments?

Fitting the Dust Covers

The dust covers are initially fitted INSIDE OUT. It's a small thing, but it tends to cause a lot of confusion and disorientation. You need to turn the cover completely inside out and, after fixing the small end, will then turn the cover the right way out again.

How the dust cover fits (diagram credit: Greenblood)

Following my own advice, I turned the covers inside out and slipped them over the pushrod until the narrow end was over the ribbed section near the middle of the pushrod. Note in this photo which end of the push rod the open end on the inverted cover is towards. It's towards the end of the rod that has the hole through it - at the top of the photo. 

Inverted covers over the push rods

I wrapped several winds of fabric loom tape around the end of the cover. I temporarily put the locking pin through the push rod as a visual 'tell' so that I could orientate the outlet of the boot to the correct angle relative to the push rod. (Note that the wrong end of the pin is through the push rods in this photo).

Lining up the outlets and the pin holes

I did a trial fit against the car. Once I was happy with the dust cover orientation I used Ligarex strapping and a Ligarex buckle to secure the end of the boot.

You really cannot get away with using a lumpy jubilee clip here  as - once the dust cover is turned the right way out, it will rub on the clip and cause a puncture. You might get away with tightly applying one of those nylon locking belts - but they still have a lumpy bit. You want to avoid any rough or proud edge that could puncture the cover. For this reason, I was careful to fold the cut end of my Ligarex strapping.....

Cut end of the Ligarex strapping

.....under its buckle.

Cut end folded under the buckle

With one end of the cover secured, I turned the cover the right way out and slipped over the rubber protective band for the Ligarex strap. 

Protective bands for the Ligarex strapping.

If you haven't got those bands, or they are perished or split, you can buy replacements from the usual suppliers. You could probably get away with several winds of protective fabric tape - though that will be awkward to wind when the cover is fitted back on on the suspension cylinder.

I loaded the cup with grease and added a new ball bearing. Then I topped it up with grease to reduce friction between the ball and the push rod.

Greased cup with new ball bearing

I fitted the open end of the small dust cover over the cup and slipped over the protective rubber band. Before I added some ligarex strapping to secure the cover the the cup, I orientated the parts so that the hole through the dust cover lined up with the hole through the push rod, and I twisted the cup to make sure it's hole was also in line. You can temporarily fit both ends of one of the split pins through the assembly to check this alignment.

With the small dust cover strapped to the cup, the assembly was just about ready for fitting. I thoroughly cleaned up the area where the cup needs to fit on the suspension arm (it's a fairly close fit) and applied a little grease - if only to make fitting and removal easier going forward.

I also chose to replace the old rubber conical bump stops with new polyurethane one. 

Out with the old......

.....in with the new.

I made sure that the piston and cylinder end were clean and offered up the open end of pushrod/ dust cover assembly to the suspension cylinder. With the dust cover holding itself in place, i then located the cup end in its receiver on the suspension arm.

Getting ready to locate the cup end (note alignment of pin holes)

A bit of wiggling was necessary to line up the cup hole with the suspension arm and the new locking pin (pre-greased) was pushed through. If rebuilt and fitted correctly then, with the pin located, the small return outlet should be on the upper face of the duct cover. happy that everything lined up. I bent the long end of the locking pin over by a small amount.

Locking pin fitted

It took a dab of lubricating LHM and a sturdy push to locate the yellow/ white stiff return hose into the small outlet. There should be no bend or strain on the hose or outlet.

With the cup end located, in the secured the big end to the cylinder. as this straining is external to the dust cover, you can get away with a jubilee clip. 

A jubilee clip works fine (credit: George Antoniou)

That's exactly what I've done for the time being, while I assess whether the covers I've used are likely to be long-lasting.

With the leaky dust covers replaced, I can move on with refitting - and refilling - the hydraulic system.