Morning all, having some trouble with the mrs 225 wondering if anyone can help? Basically since I bought the car 8 months ago I've noticed the brake pedal travels a very long way in relation to how applied the brakes are. The car still stops on a dime if you give it a full pressure punch but the brakes just feel very soft and very long. It almost feels asthough there's half an inch of free travel where any pressure is non existent and the brakes don't respond at all! This is most evident when sitting on cruise control for a distance, it feels exactly the same as when you change a set of pads and push the pistons back in and on first application the pedal sinks to take up any free space. Ive tried a few fixes but none made any difference. Bled the system countless times with a pressure bleeder, cleaned and greased front and rear calipers, fitted new pads and discs all round, fitted braided lines and then bled some more. My next move is to either purchase the additional module for my RSTuner to activate the abs purging sequence or look at the calipers. Had a similar fault on a 182 years back, turned out to be a faulty rear caliper the piston was retracting back into the body instead of sitting up against the pad. Anyone point me in the right direction before i possibly waste more money?
Seems to be, there's no drag on any of the wheels when jacked up so I'd assume all brakes and handbrake are releasing correctly.
Kind of have the same sensation in mine, but was hoping that braided lines and new fluid would shorten this. It's not major, but I would like more initial bite.
Are all the pistons working on the fronts? Try taking the pads out and push the pedal to see if they all move, don't go too far though as the pistons might pop out leaking fluid everywhere. We've just rebuild my brother's Brembos using the seal kit from BiggRed (£30 on eBay for all 8 seals) and the difference is night and day compared to before.
It sounds like your front in-board pads are sticking. Give the callipers a good cleaning followed by a seeing to with a fine file then do the same to the backing plate on the pads to make sure that they move freely without risk of catching/snagging.
Would a sticking pad not cause a stiff pedal with resistance as opposed to my long soft pedal? I'll certainly take it on board though and give them a thorough clean up. How difficult is the caliper rebuild kit to do? DIY mechanic stuff?
Fairly simple, it's the first time we've done it. Basically we did: open brake master cylinder put some cling film over it and screw cap back on (this holds most of the fluid in the system for when you undo the brake line). We then pressed the brake pedal down and wedged a piece of wood between the pedal and seat to keep it held down (not sure if it was needed but we did it anyway). Open the bleed nipple closest to you and drain out whatever comes out. Take caliper off and pads out. Undo the 14mm bolt holding the brake line in and have a rag just to catch any last drips. We put an M10 bolt through the banjo of the braided line with a washer either side and a nut on the end, just to keep it clean and stop any drips (shouldn't leak anymore if you've held the pedal and cling filmed the MC). You could just put a latex glove over it though. Once the caliper is off it's just a case of draining the fluid out of it, take the dust seals off and carefully lever the pistons out using a flat head screwdriver on opposite sides. Make sure you don't mark the pistons on the outer bore that sits inside the caliper. Once they're out use a knife blade to pick out the inner seals, again don't score the inside. Clean the caliper up and inside the bores with brake fluid or brake cleaner. Lubricate each inner seal with brake fluid as you out them back in. Lubricate the pistons and slide the dust seal over into the piston recess and push the piston back into the caliper. Back on the car and reverse of removal. Bit of a long winded explaination in know lol
Got any significant play in the wheel bearings? That can allow the disk to rock and push the pads back too far.
You'd think so but no - The pistons move back but the pad goes nowhere thus the travel. Suplimemtal damage occurs to the inside face of the disc to due to the pads not moving far enough away from the braking surface. Heat builds and blah, blah, blah... more expense.
Oh dear doesn't sound good. I'm going to strip the calipers down and rebuild them then give everything a good old clean see where we stand then.
This is why I advise all my customers to drive out the pins, clean everything properly, add a little copper grease and reassemble every 6 months... ot bring it to us and we charge an hours labour to do it for them (£40+VAT) It's essential maintenence in our eyes that saves your brakes from replacement every 18 months and aids correct balance steering/brake feel. You also wouldn't believe how many people don't realise that fitting brake pads isn't as simple as taking them out the box and pinning them in.
Long Brake pedal are good for the short legs peoples which not feel easy with teh short brake pedal,all is much appreciated and everything according to their system,with this accident reason gets lowed and lives secured.
