Brake Issue

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Dee4
Joined: Mon 09 Apr, 2012 09:02
Posts: 10

  M roadster S50

Brake Issue

Post by Dee4 » Sun 24 Feb, 2013 09:05

Driving home yesterday, slowly driving round an island with stop start traffic, and the brake pedal went right down to the floor with virtually no braking (fortunately doing about 5mph at the time). Several pumps of the pedal brought it back to normal. Drove the rest of the way home gingerly and now don't have confidence until I know what it was. No warning lights apart from bake pad wear that came on that morning (does need new pads). Anyone experienced this? - (I've had the car for 6 years with no problems till now)

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2115

  Z3 roadster 1.9

Re: Brake Issue

Post by Del » Sun 24 Feb, 2013 09:12

Sounds suspiciously like some air in the hydraulic system. I would closely check for leaks - pipes, hoses, callipers and master cylinder - as well as the pad servicing you had planned.

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: Brake Issue

Post by Southernboy » Sun 24 Feb, 2013 09:33

1. Check under the car on the inside of each wheel rim. If you see any "wet" areas from brake fluid you may have a problem in the calliper.
2. Check the front brake pads. You will need to remove the wheels to effectively check. If they're worn, then replace them. Check the rears as well.
3. Check the underside of the car along the brake lines. If you see any brakefluid anywhere, you may have a ruptured line.You need to get it sorted asap.
4. Check inside the engine compartment above and adjacent to the brake pedals. The reservoir for the brake fluid is there as well as the reservoir for the clutch...you may as well check both, but ensure the brake reservoir is correctly filled to the prescribed level. If not top it up. You may still need to have the brakes bled if any air has entered the system.
5. In any event, if the brake warning light has been on for some while, get the pads, fluid etc checked and sorted. Not doing so is not only dangerous, but will ultimately damage discs etc. The problem may also be in the master or slave cylinders of the braking system. They have small rubber seals and plungers, which if not operating optimally, will allow fluid to pass through instead of compressing it and acting as the braking force. The problem in the callipers is similar if any of the brake "pots" are worn or faulty. That would also allow fluid to bypass and render poor braking. Brake hoses which are located at each calliper, if broken or leaking will be obvious from inspection as per item 1. above.

NB. If a warning light comes on...bear in mind that you should approach it as if there is a real fault. Any fault should be attended immediately if the warning light is RED, if it's amber, you have some relief, but it will need attention sooner rather than later.
"Normal is overrated"
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swamper
Joined: Thu 13 May, 2010 18:14
Posts: 1866

  M roadster S50
Location: Mossley

Re: Brake Issue

Post by swamper » Tue 26 Feb, 2013 00:43

good advice by Southernboy ...iv had exactly the same but on a different car....it was the master cylinder and the rubber seals had failed,so the system showed no loss of fluid.
the badness makes me do it...!

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Dee4
Joined: Mon 09 Apr, 2012 09:02
Posts: 10

  M roadster S50

Re: Brake Issue

Post by Dee4 » Tue 26 Feb, 2013 22:17

Thanks for the responses. I'll get it checked out and post a reply. If you ever have this happen it's probably the worst thing to dampen your confidence, I occasionally open her up and the one thing you are totally reliant upon is when you hit the brake pedal the brakes respond accordingly!

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: Brake Issue

Post by Southernboy » Thu 28 Feb, 2013 05:27

Yep....nothing worse than hitting the brake and you just keep on going.....kinda gets the adrenalin going though... :D
Don't forget, you still have a hand brake...which hopefully works without putting your car into a side skid...I've had one experience with my very first car. (Austin Mini..1978) where the hand brake was needed....
"Normal is overrated"
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Dee4
Joined: Mon 09 Apr, 2012 09:02
Posts: 10

  M roadster S50

Re: Brake Issue

Post by Dee4 » Fri 29 Mar, 2013 16:50

Now that I've had the brakes inspected and new pads fitted all round, I now know what the problem was:- One front pad when removed had about 2mm of pad left, but the pad had separated from the metal back plate. The other side had the same, but the pad material had "dropped out" presumably just before I braked, hence the pedal going to the floor. Yes, the brakes were grinding after, but I took it easy travelling to the workshop, I have not changed the pads in the 7 years of ownership and it had done 30k miles when I purchased it. Therefore they were either original or changed once. Moral is I suppose, don't leave them in for years on end, get them changed every say 4 years.

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: Brake Issue

Post by Southernboy » Fri 29 Mar, 2013 17:10

Pads need to be checked regularly. You should have wear sensors fitted to the pads which will illuminate a warning light on your instrument cluster when the pads get down to the point where the sensor touches the disc. There should be one sensor on the front and one on the rear. If you don't have them fitted, I would recommend you do so. It may save you the expense of new discs, and your life.
"Normal is overrated"
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Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2115

  Z3 roadster 1.9

Re: Brake Issue

Post by Del » Sat 30 Mar, 2013 09:48

Thanks for sharing the information. I’m no expert and I’ve only heard of this happening with over-heating or contamination with brake fluid or oil. Assuming everything else is fine in your system I guess it’s just down to ensuring top quality pads are used in a high performance M model.

Dee4
Joined: Mon 09 Apr, 2012 09:02
Posts: 10

  M roadster S50

Re: Brake Issue

Post by Dee4 » Sun 31 Mar, 2013 08:38

Regarding the pad wear warning light, it came on the morning this happened. It was probably from the rear pads as I would imagine that if the pad becomes detached from the backplate the sensor won't work anymore as the circuit is broken. I reckon the pads must have been OEM as it had full BMW history when I bought it. Anyway, I won't be leaving pads that long again. Now the car is 14 years old, has anyone changed other perishable items such as brake hoses?

Beemer Man
Joined: Wed 27 Apr, 2011 13:17
Posts: 72

  Z3 roadster 2.8
Location: Harrogate

Re: Brake Issue

Post by Beemer Man » Sun 31 Mar, 2013 09:45

The metal brake pipes on my 2000 "W"-plate 2.8 were badly corroded when I bought the car two years ago, so I had them all replaced (front to back and rear pipes) with copper ones.

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