Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
Brake pedal going to the floor ?
I've just finished replacing all the brake pads, started up the engine, pumped the brake pedal as normal, when the pedal felt right, gave it a nice strong push and held it there.
It started going slowly down to the floor ( bulkhead, what ever ) did it a few more times with the same result. Switched off the engine, opened the bonnet and checked fluid level of brake master, plenty , walked around checking for possible leaks, none
Then left it for a while and repeated the above with the same result. Still sitting in the drivers seat, with the engine switched off, pressed the pedal while pondering the problem, it did not go down then pressed as hard as I could, still won't go down started the engine, it goes down, stop the engine and it stays put. First thought was master cylinder piston seals by passing
Any one else experienced this ?D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
12th Nov 2009 11:24 am
Rescue01
Member Since: 14 Jan 2008
Location: Aberdeen
Posts: 2499
After changing the pads the pedal will sink slowly till the pistons come back into contact with the pads.
If the pedal is solid with the engine off and you start it up while holding the pedal down it should sink slighty as this is the vacuum servio kicking in.
If the pedal is sinking to the floor then i suspect you have "nicked" a seal in the master cylinder normally due to pumping the pedal to the floor after changing pads,the seals go past a section of the master cyl which they normally dont and may get "nicked" on a slightly rougher surface.
Hope this helps.Its not the height of the fall but the sudden stop at the bottom that hurts!!
12th Nov 2009 11:35 am
stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
Mine did this six months into ownership. I was holding the car on a slope, waiting for traffic, and my foot eventually hit the bulkhead, needing me to pump to get brakes back. I recreated it once I got home. However a trip to the dealers and they said that they couldn't find anything wrong with it, but that it was normal anyway
Not convinced that it's normal, however it has never repeated since. I wondered if I had a shred of swarf trapped in the master cylinder seal that allowed a minute amount of bypass, and that this was then dislodged by the full travel to give me back 100% seal.
Hmmmm, now I think of it, my brakes are much better now I've had the vacuum recall done; maybe I should try again now the servo is back at max power...I'll report back...Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Transgenic tomato anyone?
12th Nov 2009 11:51 am
crwoody
Member Since: 09 Mar 2009
Location: Littleborough
Posts: 2109
I've noticed the sinking pedal effect with mine while stationary, it's only when you press very hard on the pedal though, much harder than in normal driving.
I think if you applied this amount of pressure while driving, you would stop with the ABS chattering long before the pedal got to the floor, not sure what causes it but I don't think it's a fault as such.Clive
12th Nov 2009 11:51 am
Discoeast
Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
Rescue01, I agree with what you say, but the pedal goes all the way
down with the engine running, about 45 seconds, and will not with
engine stopped. Even with both feet pressing as hard as I can I should
still be able to replicate the fluid by passing the seals. Looks like a
visit to the stealer.D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
12th Nov 2009 11:54 am
Rescue01
Member Since: 14 Jan 2008
Location: Aberdeen
Posts: 2499
Thats weird
is it in the chassis range for the brake recall Its not the height of the fall but the sudden stop at the bottom that hurts!!
12th Nov 2009 11:58 am
Discoeast
Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
Yep, had the call from LR, weird sounds about right, It's never
happened before D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
Last edited by Discoeast on 12th Nov 2009 12:08 pm. Edited 1 time in total
12th Nov 2009 12:07 pm
crwoody
Member Since: 09 Mar 2009
Location: Littleborough
Posts: 2109
Mine's just had the brake recall last week, out of curiosity, I just went out and tried it again, it takes about 10 seconds of very hard pressing to bottom out but thats not all the way to the floor, it stops about half way. I'm sure it went further down before the recall work.Clive
12th Nov 2009 12:07 pm
Discoeast
Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
One thing I did not mention was that the brake pad warning had
come on before I changed the pads, and is still on now. Could
I now be in some sort of safe mode controlled perhaps by the
ABS D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
Member Since: 01 Aug 2005
Location: Cornwall
Posts: 2575
It's normal.
I happened to read summat about it a couple of days ago whilst searching for brake pads for wifeys Audi. Was on a brake parts website somewhere under FAQ's.
Something to do with diesels & vacuum pumps.
I queried it with my dealer a couple of years ago & had it checked ... all ok.Long succession of Disco's since 2001...
SIII Lightweight - neglected & rusting. Bulkhead, A panels, vent panel & outriggers now disintegrated - Next years project!
12th Nov 2009 8:30 pm
Discoeast
Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
Slimer, yes, both, still need to get the warning reset by LR.
OK, took it out for a drive yesterday, brakes working fine in
normal conditions. Did the stand still hold the pedal down a
few times and it only went down about an 2 1/2" but stayed
there. The first 1" felt a bit mushy, the last 1 1/2" would go
down slowly, went home and left it. On the way to work today
brakes feeling better, would say same as what crwoody
describes in his post. Service is due, so I will get it checked.
Thanks for the replies guys D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
13th Nov 2009 7:01 am
stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
If you've changed both sensors, the light should have gone out by itself, unless you've run out of brake fluid in the reservoir or the new sensor connections weren't made properly or they were damaged on install...Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Transgenic tomato anyone?
13th Nov 2009 7:51 am
Discoeast
Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
Quote:
the light should have gone out by itself,
Didn't know that Tnk's stapldm. Thinking back
I only heard the front one "click" when I plugged it in, I
have a long range tank and the back one is a b d
to get at, need to check it out going to have
a few more minor injuries D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
13th Nov 2009 8:30 am
Discoeast
Member Since: 19 Feb 2008
Location: Boksburg
Posts: 800
Yep, back sensor not plugged in properly, light out D3 bullbar-spots-roof rack with spots-ladder-long range tank-swing out spare wheel carrier- upgraded tow bar-dash console-internal water tank-duel awnings-drawer system & T T.
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, walked around checking for possible leaks, none 
then pressed as hard as I could, still won't go down 
Tnk's stapldm. Thinking back
d
