Alfa Romeo 147 / GT Rear Brake Discs and Pads Change
The target vehicle
Always observe jack stand safety. On the 147 that there are simply too few places you can safely jack up the car, so adding an axle stand as support is often tricky. Never jack the car up using the rear suspension crossmembers, unless of course you are in the mood to replace them. I am not going to point out the jacking and stand points on your car, that falls outside of the scope of this article.
You will need the following tools:
- Flat bladed screwdriver
- 19mm, 17mm, 13mm spanners
- Small wire brush
- Lump hammer
- Impact driver
- Wheel brace and locking wheel nut key (if you have locking wheel nuts)
- Caliper rewind tool
Other Things You'll Need
Penetrating oil is essential. Standard WD40 doesn’t cut it. Try plusgas or WD40 specialist fast release penetrant; there are also many other brands available. Also, you'll need some red or blue locking compound for the slider bolts.
Wear gloves when working on the car, it’s so much easier to clean yourself up afterwards. I would also advise a decent dust mask when doing brakes. The dust off them is really nasty.
There are many brands for braking components out there today that have varying reviews in terms of performance, I always select brands that I perceive as premium brands when it comes to brakes because, quite simply, I want the confidence that when I hit the brake pedal I have the best possible components in place to stop my car. This is why I chose Brembo specifically.
My 147 now has Brembo all round for disks and pads, they’re good quality and they’re one of the few brands that provide the fitting kit with the pads. Remember those sprung steel pieces removed earlier? Brembo gives you shiny new ones as standard. Also, in the disk box is a pair of new positioning bolts.
Stage 1 - Wheel off
Once the car is safely on stands you can remove the rear wheel exposing the wheel disk behind it.
As you can see from the pictures my disks were fairly well worn and had been an advisory on the MOT test as they were almost to tolerance. Also the caliper and carrier had heavy deposits of brake dust and a bit of corrosion. Later, once the disk had been removed it was apparent that the backing plate was also corroded and covered in brake dust.
Stage 2 - Remove caliper
The bolts indicated in the image below are the slider bolts that need to be removed to allow the caliper to be separated from the slider. These are fairly small and easy to get off. If in doubt penetrating oil is your friend but for these you really shouldn’t need it.
The caliper is now free to be tucked back out of the way. You can remove the handbrake cable at this point for more leverage if required. Make sure the caliper is supported so that there is no stress on the flexible hose.
Stage 3 - Remove brake pads and positioners
As you can see my pads were as well worn as my disks, apparently the previous owner really got their moneys worth. Using your screwdriver, lever out the pads and the small metal plates used for alignment. Once that is done, set about cleaning the general area up with your wire brush. Make sure the sliders and carriers are corrosion and dust free, it makes reassembly much easier.
Stage 4 - Remove / loosen slider
Due to the way the rear suspension is put together you have two choices on this, loosen the carriers sufficiently to allow you to remove and replace the disk, or remove a proportion of the rear suspension setup. I opted for loosening the Carriers following removal of the caliper. These bolts will likely need penetrating oil.
I don’t have a very good photo of the bolts for this, the picture above shows the top bolt for the slider, the bottom bolt is vertically below this about 4-5 inches (10-12.5cm)
The top bolt will come all the way out but the bottom bolt will only come out partially unless the suspension arm is removed as it fouls on the arm at about 40% removed.
Stage 5 - Remove the old disk
The next step is to remove the positioning bolt indicated in the left hand picture above using an impact driver. This should come off fairly easily, I’ve done a few over the years and as long as your socket fits perfectly, 12mm for this one if I recall correctly, there should be no issues.
So, having removed the disk positioning bolt and the top slider bolt as well as having loosened the bottom slider bolt you should now be able to coax the disk off. If it feels stuck a couple of taps around the edge with a copper and leather hammer will dislodge it. The picture above shows the new and old disks from my car.
To finish this step, wire brush time again, clean up the backing plate until there are no loose pieces of rust or brake dust. If you have some spare paint this is a good time to repaint the backing plate.
Stage 6 - Rewind the caliper
Firstly, whatever you do, don’t compress the piston in an attempt to retract it, there are threads inside that will be destroyed if you do and then you will need to go and buy another caliper.
Before you rewind the caliper make sure you remove the cap on the brake master cylinder and wrap a rag around to opening, there’s a good chance some will come out.
You will need a rewind tool as in the picture above, the piston should be screwed clockwise to retract. A tip, if the piston is not changing position in the caliper but is turning, try turning it anti-clockwise for half a turn and then clockwise again, this sometimes helps it to pick up the thread inside better. It took me quite a while, several scraped knuckles and a lot of swearing to figure that one out. When complete the piston should be in the fully retracted position as indicated in the above picture.
Stage 7 - Reassembly
Reassembly is basically the reverse of removal so I won’t go into detail, you can see from earlier sections what you need to do.
- Put the disk in place and fit the positioning bolt. Loosening the calliper carrier makes placing the disk easier.
- Apply some locking compound to the slider bolts and refit
- Fit the sprung steel pad alignment pieces
- Apply copper grease to the back of the new pads as in above right photo
- Fit the pads
- Refit the caliper
- If you removed the handbrake cable, refit that now
- Refit the wheel