Hi Guys,
I had this problem for a while now, but was flushing brake fluid today and I though it will do some difference; but it did not.
Basically, when driving and ill brake in continuous motion all its fine. If I depress pedal, let go, depress let go and after third time my brakes will feel very hard almost like I have to push the pedal my self without any electronic or vacuum aid. all get back to the normal after few seconds of driving, but if repeat same pattern with brake pedal it will be "fading" again. I have noticed car behaves same after starting, depress pedal on the start and keep pressing its okay, but if I start, let the brake pedal go and move and want to brake, its "fading" again.- and again after few seconds of driving itll return to normal. this is a bit of a problem in traffic or when need to maneuver in tight parking spaces.
any ideas?
ps: no error codes
The hose for the brake bigger one, have that one checked first as mattew said.
If there is a leak in the system, the break will behave just like that...
If there is no leaks, then you might want to check the pump and the brake servo, could be the seals worn out...
I was thinking maybe T-junction under egr. was reading somewhere about hairline cracks. anyway, how to check for tiny cracks in vacuum pipes? any ideas? and how to check servo and pump?
Block the servo end or pump end off and suck the other end, then let the vacuum you have made by sucking stick your tongue to the pipe and wait, if the pipe stays stuck to you tongue for a 30 seconds or more, all is well, if not there is a leak somewhere. But primative but it works
It is very rare for the servo to fail as they are sealed units these days, back in the day when I owned BMW 02's they had twin servos with a breather filter that blocked up and trashed them. What you describe is just what I expereinced when the servos went on my 2002, trouble was as a student I couldn't afford the £500 for recon ones so just learn to drive with bad brakes... Which is why I alwasy buy manuals and always use the gears to slow down, can't break the habit of a life time
do you mean number #5 RealOEM.com BMW E61 530d VACUUM PUMP WITH TUBES ?
I had hose off from the vacuum pump and suck in through and it did not hold at whole. ignition was fully off.
I have to say, would it be worthy to replace the whole thing with rubber hose (thick one). I beat to buy whole new thing from BM it would be costing an arm and leg, this way I can use clamps to interconnect the end connectors and "T" junction under EGR.
if you have a look at the diagram, number 7 hose clip was original but not holding much. I could not pull the hose or it was not twisting that easy but I could see the oil being pushed out in small amounts. I have replaced the original clip and whoa, what a difference! I have never had my brakes working so well! I literally have to relearn to brake cos they are very sensitive now.
Well, there you go, not split but small give in clip and it was making massive difference! .
Glad that you figured out the problem :thumbsup, that actualy comes towards to what we have been saying...:thumbsup
The vacuum pump was sucking air through that point... is that correct?
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