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MG MGF Technical - Fitting new break pad
|I've just got a new set of green stuff Pads, but have no idea how to fit them, can't be that difficult i'm thinking can anyone let me know the procedure.|
|OK, This is essentially a simple job, but for best effets you need a selection of tools. These include a jack, axle stands, wheel brace (security wheel nut socket!), A short flat bladed lever or a flat bladed mid size screwdriver, (between 9 and 12" in overall length should do) 12mm ring spanner or 12mm socket and ratchet, wire brush, 'Coppa Slip' (or any copper based grease) and if possible a can of spray brake cleaner.|
Break the torque seal on all front wheel nuts, half a turn each is enough. Jack up the front of the car and support on axle stands. The theme here is to maintain a safe working area under the wheel arches. Once the cars weight is supported securely on the stands remove the road wheels. Open the bonnet to give access to the brake master cylinder.
It matters not which side you start with. Turn the steering to give better access to the brake caliper and pads. Take the screwdriver (I don't expect many have any other types of 'lever'!!) push it into the space between the outermost pad and the outer part of the caliper. (When looking at the disc edge on and directly over the caliper there is a 'window' slot in the caliper body through which you see the pads. This is where I refer.)
With the screwdriver in place gently lever the pad and caliper apart. This has the effect of returning the caliper piston back into its bore and freeing space for the new pads which will be thicker due to being new and unworn.
During this proceedure keep your eye on the fluid level in the master cylinder as if the cylinder has been topped up as the level drops due to normal wear on the brake pads, you find that when returning the pistons back into the caliper body it displaces fluid back to the master cylinder. Often this leads to overflow so have a rag around the underside of the cylinder to prevent fluid getting onto paint as it eats it!!
Also have a water supply handy, such as a refilled 'Fairy washing up bottle', (Blue Peter should have a few to spare!) and if you get a spill quickly spray it with water and wash it away. Keep water away from the master cylinder reservoir!! Brake fluid is Hygroscopic and absorbs water so it is easily washed away.
You will soon reach a point of max retraction with the screwdriver, which unfortunately will not be enough retraction usually. Now manually slide the caliper inwards by hand so you can very carefully place the screwdriver between the inner pad and piston. Gently lever the piston inwards to give that little bit more clearance.
Now take the 12mm ring spanner or socket and undo the lower of the two exposed normal bolts that sit either side of the caliper body with the heads facing towards the centre of the car. Remove this bolt. Swing the cvaliper upwards, pivotting on the remaining bolt. Be aware of a potential for the flexible brake pipe to be caught so do not stretch it. If you have to turn the steering to the straight ahead position which effectively gives more free length on the brake hose.
Remove the brake pads. They may well be stuck in the caliper carrier, so a few gentle taps should dislodge them. Use the wire brish and the scewdriver (as a scraper this time!) to clean the areas where the edges of the pads engage with the caliper carrier. Use the spray brake cleaner to remove brake dust from the whole caliper area, if available, otherwise carefully brush away the dust. (Note that brake dust is supposed to be less harmful than it used to be but whatever the current advice it is best not to breathe any!)
On the removed pads you will see metal plates stuck to the rear backing of the pads. These are anti squeal shims and should be removed and cleaned. If I remember correctly the EBC pads do not come with any anti squeal additions.
Offer the pads to the carrier and check that they are a sliding fit in the grooves. If not it may be neccessary to clean up the 'tongues' on each pad until they do. Excess paint is often a reason for the stickiness and is easily filed away. If it still remains a tight fit then file a little metal away until it is.
Now refit the anti squeal shims with a couple of dabs of copper grease to the back of the new pads. There are little metal tabs on these shims that help locate the shim and these can be bent slightly to suit. Then add a light smear of copper grease to the 'tongues', to promote a sliding fit and resist corrosion, and fit the new pad snugly against the disc. Repeat for the other pad.
Now swing the caliper back down and position it so it slides over the pads and shims. The persistance earlier in retracting the piston pays dividends now! Note that there are also anti rattle springs, the little bits of twisted wire on the top centre of each pad, and these have to be inside the caliper when it is closed onto the pads. This should happen automatically, but I have seen the occasional rogue end sticking out of the caliper 'window'. Line up the caliper with the lower bolt tube and refit the bolt. 45 Nm is the correct tightening torque.
This side is now complete, but before starting work on the other side pump the brake pedal a few times to take up the 'slack' between the piston, pads and disc of the brake you have just finished. The reason for this is to help reduce the potential of fluid loss from the master cylinder as I have previously described.
The other brake is a repeat of the above and when done again pump up the foot pedal to remove free play This to ensure that you can't drive off with so much free play that you have a brake pedal to floor experience!!
Refit wheels etc,
Ofete forgotten is the simple fact that it takes up to about 250 miles use before the brakes are bedded in to the point where they achieve full performance. In this period you MUST restrict braking to be as gentle as possible and do not brake for long periods. The reasons are simple and it is because there is not full pad to disc surface contact until each has this mileage. In the meantime the brakes will feel cr@p on the first few applications, but then may feel nearly normal. Don't be fooled as when hard braking arrives the contact areas overheat and you end up with fade.
I have tried many types of pad and created different brake set ups for my cars in the past. On the F I have experience with EBC Green Stuff in both standard and 280mm disc conversions and I can whole heartedly recommend them for use with standard 240mm discs.
The above description is somewhat detailed but the job is not complicated or difficult. I have gone into extra detail to help cover little extra things that you would almost certainly find out whiclst doing the job, but by raising them here it may ease your fitting process.
|One for the FAQ Greg ???|
This thread was discussed between 16/04/2000 and 17/04/2000
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