[steveharman]

Our 2005 R52 passed its MOT test last week (mandatory yearly checkup here in the UK).

The garage noted that the brakes were a little spongy, although they still seemed to work ok on the real & rolling roads when being tested. Also, they couldn't see any leaks in the braking system and by definition of passing the MOT test, the discs & pads were checked & found to be ok.

The braking seems to have got more spongy & less responsive in the past week. It feels like if I pump the pedal a few times that braking improves but I haven't driven the car very much to be certain & scientific.

Does anyone have any thoughts? It could be unrelated but we've also noticed an occasional knocking noise from the rear passenger side when cornering at slow speeds.

Thanks,

Steve

 

[mike1967]

Our 2005 R52 passed its MOT test last week (mandatory yearly checkup here in the UK).

The garage noted that the brakes were a little spongy, although they still seemed to work ok on the real & rolling roads when being tested. Also, they couldn't see any leaks in the braking system and by definition of passing the MOT test, the discs & pads were checked & found to be ok.

The braking seems to have got more spongy & less responsive in the past week. It feels like if I pump the pedal a few times that braking improves but I haven't driven the car very much to be certain & scientific.

Does anyone have any thoughts? It could be unrelated but we've also noticed an occasional knocking noise from the rear passenger side when cornering at slow speeds.

Thanks,

Steve

the rear brake pads have wire clips on the piston pad that must slide the pad in to the wire clip so its attached to the caliper before putting back together, if as some people have done just force caliper back on with out to this step first it causes a gap between piston and pad that feels like spongy pedal . i always pressure bleed brakes with easy bleed and change fluid totally every 2-3 years

 

[Dan Cox]

It may seem like a silly question even after it going to a mechanic but have you had the brakes bled correctly?

My R52, before I purchased it, had new rear calipers installed however the garage must not had bled all of the brakes after as my brakes felt spongy. So I bled all of them myself and now my brakes are much more responsive, and that was even after going to a mechanic, they told the previous owner they needed bleeding... but obviously couldn't be bothered to do it themselves.

Hope this helps. As for the rear passenger side making a knocking noise, maybe have your shock absorbers checked on that side of the car or even maybe a warped disc rotor which is catching the brake pad every now and then?

 

[steveharman]

Thanks, Dan, I'll give them a bleed. Rattle turned out to be an exhaust bracket failure.

Steve

 

[Dan Cox]

Thanks, Dan, I'll give them a bleed. Rattle turned out to be an exhaust bracket failure.

Steve

Not a problem, Steve.

It'll be interested to hear back off of you, after having the brakes bled by a mechanic, if this was actually the issue.

Dan.

 

[Bichindoido]

Not a problem, Steve.

It'll be interested to hear back off of you, after having the brakes bled by a mechanic, if this was actually the issue.

Dan.

Thanks, Dan, I'll give them a bleed. Rattle turned out to be an exhaust bracket failure.

Steve

Hi Steve, did it work?
I am having a similar problem. Brake feels very spongy from time to time almost no power, I did not find any leak. Liquid is 1.5 year and just in the middle of the min max marks.

 

[steveharman]

Funnily enough we'll know for sure this very dAy! Car is at the garage as we speak as this was the first opportunity to have it looked at.

Current thinking is; new master cylinder. I'll add confirmation later.

 

[steveharman]

Not great news. The new master cylinder has been fitted but the brakes "aren't much better". The actual symptoms are that the brakes will work but there's excessive travel on the brake pedal before they do.

Basically you really have to put your foot down. before much happens.

• The car has new pads & discs all round
• There are no signs of any fluid / air leaks
• The brakes have been bled several times
• The car has a new master cylinder

The next port of call is around replacing the ABS pump, but I also read that it's possible to accidentally introduce air into the pump which might cause the symptoms we're seeing? In which case this may require specialist software to put the pump into a service mode & expel any air. How did life get this complicated? ;-)

Any thoughts or advice would be gratefully received.

Thanks,

Steve



I've read somewhere that

 

[pheasant_plucker]

You need to have the brakes bled using diagnostic equipment to remove air from the ABS system.

Gerry

 

[steveharman]

Thanks Gerry. So basically find a dealer with the right diagnostic kit and get them to bleed the brakes?

Steve

 

[pheasant_plucker]

I beleive you can do the ABS bleeding routine using an Autocom CDP+ which you can pick up for about £35 on ebay

Gerry

 

[steveharman]

UPDATE: It was a faulty / on the way out ABS Pump.

£gazillions new from BMW or £29 inc postage for a used one from eBay with a 30-day warranty. Can you guess which one I went with?