Brakediscs at the back
When you decide to go for a non-gti model of your dream car, a lot of times it comes fitted with drums at the back. The much cooler brake discs at the back are reserved for the more expensive GTI or 16V versions of the car you buy.
The drums, as you all know, look a bit dull. In our quest for the perfect modded car, there *is* something we can do about it. In the article below I will describe how I fixed this. Note: my car is a Citroën ZX but I have seen the same kind of conversion applied to both Pugs (205) and Renaults (Clio). I don't know if the same applies for non-French cars but i suspect it does.
When I bought my car, it came with drums as well. I kept them standard for a while but after a year or so I enquired with my dealer if it was possible to have discs instead of drums. It turned out this couldn't be done without fitting a complete new rear axle. You cannot fit the wheel arms with the discs to an axle that came with drums. Because a new rear axle is way too expensive, I decided to look for a second hand item.
I had some addresses from companies specialised in second hand parts for French cars. When I gave them a call they said they could sell me one without probs. That was good news. They asked 200 quid for it so that wasn't too bad. What I didn't know was that this is the price for the axle, including the discs but without the brake pads and calipers.
When you intend to do this kind of conversion, make sure the axle comes with the calipers, as they are *very* expensive when you have to buy them new (Citroën asked 500 quid for a set !!). Thankfully, I found out that the 200 quid was the price without calipers. If I wanted the calipers as well, it would cost another 35 quid. Compared to new Citroën items this was a bargain so I went for them.
If you want to pull off this kind of conversion, check with your dealer first. In the case of the ZX the only versions that come with discs are the Volcane and the very rare 16v. Most of the Volcanes are 5-doors and I have a 3 doors. I checked with my dealer if this would be a problem but apparently the axle was the same for the 3-doors as the 5-doors. (there is a difference between the axles of the Volcane and the 16v, so check with your dealer)
When I went to collect the axle it was pretty dirty. It was covered in oil and dust so I gave it a thorough cleaning before I carried on. Cleaning the axle will also make the lowering a cleaner job.
We had to do no extra modifications as the Volcane rear axle would fit a non-Volcane ZX without problems : just plug 'n' play. I don't know how this goes for other cars so again, check with your dealer. The only problem might be ABS. I'll explain.
The first versions of the ZX had 2 different axles : one for cars with ABS and one for cars without ABS. In the later versions (like mine) Citroën have decided to go for one axle, for both ABS and non ABS cars. There is a sensor and some cables for the ABS but if you don't have ABS, just remove the cables and the sensor. So, no probs there either.
When I went to collect the axle there were still shocks in it (Citroën uses torsion bars at the rear, we have no springs at the back). I decided to leave the shocks in there, not knowing in what kind of condition they were. I knew that mine were pretty much shagged after driving around 40000 miles with an 80mm drop at the back, so things could only get better. (I ordered 4 new yellow Koni shocks but they had delivery problems)
Installing the rear axle is not that difficult. Just have a good look how the old axle is attached to the car, remove it and fit the new one. I used a ZX related manual, similar to Haynes. We jacked the car up and put struts under it. The back of the car was about 40 inches of the ground. You really need the space so you can move around freely under the car. If your front bumper is close to the ground, make sure it doesn't crack when you jack the rear of the car up that high !!
The axle is pretty heavy. We didn't weigh it but I think it's about 60 kilograms. It's also a difficult item to carry around, because of its shape. This means it's a 2 man job unless you're a regular competitor for "Strongest man of the world".
The only worries are the handbrake cable and making the 2 rear disc brakes actually work. In the case of the ZX we had to change the last part of the brake lines under the car to make the discs work. Each side of the axle required a flexible and a fixed part. I also needed a new handbrake cable. I ordered these parts from Citroën. They cost another 75 quid. Not cheap.
My car is light grey and black on the outside. To show off the brakes I decided to paint the brake calipers in fluorescent orange, to get a bit of an F1 McLaren color combination. It looks the bollocks. If you want to paint the calipers you might as well do it before installing the axle.
My previous axle was lowered so we had to do that to the new axle as well. We decided to drop it one spline to see what the effect would be. When we jacked the car down it rested on its rubbers and was way too low. We couldn't even get the jack from under the car. As it turned out it was already lowered 2 splines (about 85-90mm drop). We left it at 2 splines. My previous drop was about 80mm so it's a bit lower now.
Does it make any difference?
Well, the difference is huge. Before the conversion I had to push my brake pedal pretty far to brake. Basicly, the further I pushed it, the harder the car would brake. That's gone now. When I touch the brake pedal now, I feel the brakes biting immediately. From then on I can steadily apply more pressure to stop the car. I takes some getting used to. I found myself braking way too early for bends, very annoying.
I've also noticed that the car doesn't go nose down anymore under heavy braking. It stays flat. That's pretty strange at first and again takes some time getting used to. I guess the new rear discs do their work well. I've checked my manual and there is a possibility to adjust the brake balance of the car. So far I haven't touched because it's fine. The last difference is the cornering. The car is much stiffer now at the back. I checked with my dealer and he said that that is a typical Volcane feature. Apparently the Volcane has thicker torsion bars which give a more firm ride. That's a nice bonus. The only negative point is the brake dust on my rear wheels. Before the conversion the wheels stayed clean but now they're covered in dust.
Pictures