Subaru Impreza WRX
Replacing the front discs and pads should not take the entire weekend, especially with a qualified mechanic friend in tow
’Heating the dowel failed, even when the damn thing started to glow’
1995 SUBARU IMPREZA WRX SPORTS WAGON
It may not be particularly fast by modern standards, but my Impreza has more than enough grunt to get you into trouble, especially with the poor brakes it came with as bought.
Twin pot calipers and 277mm rotors are hilariously small when it comes to bringing 220bhp and 1270kg to a halt; it was one of the issues tackled in the Impreza’s 1997 ‘big brake’ upgrade.
I’ve run PSA cars for years, and even the basic turbodiesel models contemporary to the Impreza ran 276mm ventilated discs with half the power. Clearly that extra 1mm paid off.
With no margin (and no ABS), the Impreza’s brakes had to be improved.
The previous owner had sorted the rear discs and pads, but not the fronts. Having read up online to see what – if any – upgrades could be achieved with my Sports Wagon’s limited hardware, Tarox’s Sport Japan discs and fast road pads seemed to be the best means of making good on a bad job, and should bring things to a halt more quickly.
Grooving and dimpling the disc face makes a bit more noise when clamped by the pads but gets rid of heat more quickly. It seemed like a worthwhile compromise.
My mechanic friend, Alex, agreed to take the job on; having done more than his fair share of brake rebuilds in his time (and having just taken on a magnificent MG Magnette MkIV automatic) we reckoned a solid morning’s work would see the Impreza stopping as intended.
Alas, no. Work had to be abandoned the first time when I realized that
I’d ordered the wrong pads for the Impreza’s Akebono calipers.
After the correct set of pads landed on my desk a few days later, I limped the car back round to Alex’s with the offside front brake stuttering badly with a warped rotor.
The fun and games started when we tried to get the caliper carrier to let go of its charge. With everything else freed off and cable-tied up, the dowel wouldn’t budge. Heating it from all angles with a blowtorch failed, even when the damn thing started to glow, likewise an entire bottle of XCP lubricant that didn’t do the trick.
Alex realised the problem when he removed the nearside wheel to see if anything differed – and we soon got our answer. Like many cheap Imprezas, my car had been owned in the dim and distant past by someone who valued aesthetics over functionality; they’d managed to paint the caliper and carrier gold, but left off the rubber boot that protects the caliper carrier dowel from contaminants. It had seized solid as a result. Brute force, more XCP and a massive drift finally persuaded the carrier dowel to yield.
With the new pads built up off the car, another problem quickly became evident – two of the four caliper pistons weren’t really working, betrayed by wildly varying pad heights across the disc. No wonder the rotor had warped.
We relied on Alex’s Magnette all weekend as a reconnaissance vehicle, mostly to buy new tools; unlike the Impreza, its behaviour was bordering on angelic. On the third trip out to acquire new tools (and even more XCP), we nipped into town to buy a monstrous G-clamp to chivvy the Subaru’s dead pistons back into life. Luckily, they all responded to a bit of TLC, but in the long run, PLZ 8004 is going to need a new set of calipers.