Brake Pedal To The Floor

[Guest Ross]

Hi, The brakes on our Alhambra 115 Auto 2000, have been poor for a while so this weekend I replaced the pads and bled the system and now they are better, but my problem is with the engine off and you apply the brake the pedal is rock solid but when the engine is running at standstill you apply the brake the pedal slowly sinks to the floor, is this normal? and if not does anyone have any suggestions?

[CasaPaulo]

>>>>>>>>you apply the brake the pedal slowly sinks to the floor, is this normal?<<<<<<<<

 

Yes it is. I had a tantrum & stamped my feet after paying plus

[davec]

have a manual galaxy and an imported mitsubishi delica auto tdi the delica does exactly what u said and sailes thro mot the tester said it was quite normal i thought id have an horrific bill

[Guest fredt]

Davec how do you get on with the delica? my father is thinking about getting one! it's not for the people carrying capacity of the vehicle but mainly for the 4WD capabilities of the vehicle! the extra seats are just a bonus as it will mainly be used for fishing! and the odd occasion that I borrow it to go mountain biking in! well its 4WD and it would save having to pedal up some of the hills :lol:

[johnb80]

Hi, The brakes on our Alhambra 115 Auto 2000, have been poor for a while so this weekend I replaced the pads and bled the system and now they are better, but my problem is with the engine off and you apply the brake the pedal is rock solid but when the engine is running at standstill you apply the brake the pedal slowly sinks to the floor, is this normal? and if not does anyone have any suggestions?

Well my Gal doesn't do it, I suspect that yours didn't do it before otherwise why would you be asking the question now. I'm amazed at the people that say yes this is normal IT'S NOT NORMAL FOR A BRAKE PEDAL TO HIT THE FLOOR. If I understand correctly with the engine running and you applying constant pressure to the pedal it continues to go down until it reaches the floor. Consider driving down a long steep hill, braking gently all the way surely your pedal is going to end up in the same place i.e. on the floor at which point you have no brakes? For my money, something's not right and you need to get it sorted PDQ.

 

Regards - JB

[Guest andeee]

This brake pedal business seems to be a bit of a conumdrum. I had to have a new set of brake pads all round, fitted at a local, family run, Ford Dealer during a routine service. After getting the car back and driving it for a couple of weeks (I dont use it every day) I felt that the brakes were "spongy" and the pedal was sinking to the floor under constant pressure when the engine was running. I was just about to tow a caravan to Spain so I took it back to the dealer to have the brakes bled. The mechanic wasn't happy even after bleeding the brakes so the boss was asked his opinion. After testing the car he wouldn't let it leave the workshop never mind tow a caravan to Spain. He put the problem down to a failing master cylinder, he managed to sourse one, and allowed me to help the mechanic fit it on the Saturday morning before I was due to go on holiday on the Sunday. The new cylinder was fitted, system bled, everything rock solid with the engine off, started the engine and AT TICKOVER the pedal again went to the floor but ONLY with immence pressure applied. The garage boss took me out to the steepest hill we could find and did several emergency stops and "holds" on the hill and the brakes felt perfect under normal driving conditions. I towed the 'van to Spain and had no problems with the brakes and have not had any since.

Perhaps there is difference between the pedal reaction at tickover and the reaction at driving revs???? :lol:

[Marky]

Mine does it and so did my audi a4 (same engine as the gal) I had before...

IIRC, there is no direct crankcase pressure take-off from a diesel engine

to assist the brake servo so this is generated by a small pump on the engine

Can't remember exactly (it was in the Haynes manual for the A4) but the

'pedal to the floor' is normal, something to do with the pressure blowing

the servo or something....trying to find the full explanation on another

forum..I'll post it when I find it....

 

Mark

[johnb80]

Diesel engines use a small vacuum pump to provide the vacuum for servo assistance. Petrol engines use the inlet manifold to use the natural vacuum of the engine. Thats where the differences end, from there on in the braking systems are the same. Braking systems comprise in it's most basic form of a reservoir, a psiton attached to the pedal (master cylinder) and pistons on each wheel be it caliper or drum. When the brake pedal is pressed the piston moves down in the master cylinder, sealing the pipe to the reservoir and applies pressure to the fluid in the pipe. The pistons on the brake cylinders and calipers move out under this pressure and eventually are prevented from moving further due to the disc or drum. As pressure is then applied the braking action occurs. If the pedal continues to fall to the floor there are two posibilities, the first is that fluid is leaking in which case evidence will be left, the second possibility in the absence of evidence is that fluid is leaking past the piston in the master cylinder and gouing back to the reservoir. If air has got into the braking system it will be compressed, that will lead to greater pedal travel and reduced braking effect because the air gets compressed whereas brake fluid to all intents and purposes cannot be compressed.

 

I accept that it may have happened on other cars, the fact it's the same engine is completely irrelevant, the engine provides vacuum only.

 

I mentioned this situation to a mechanic mate yesterday and he hadn't heard of it, he asked the garage's MOT tester if they were aware of it and he said that he would fail the vehicle immediately if the above was noticed!

 

Regards - JB

[CasaPaulo]

>>>>>>>>I'm amazed at the people that say yes this is normal<<<<<<<

 

I'm one of the contented 'amazing people' who fully accepted the professional explanation given me by my Seat Garage, in having a slightly soggy pedal when new front pads were fitted, especially too, as I had queried their competence and had them redo all the bleeding process. Even though they'd forecast it prior to fitting, citing the scored front discs AND I could push the pedal to the floor.

2 years on I have the the irrefutable evidence of a further 20k safe miles, tested on mountains! I have absolutely excellent brakes, which I've just pressed totally to the floor! whilst pumping the pedal when stationary (engine on) rock solid otherwise. If my brakes are faulty may they stay that way for ever. I still don't believe the Seat garage lied on this safety issue.

[Topbloke]

as an M O T tester we have been advised that this is not a problem the reason it sinks is that they are "over servo'd" what the hell that means i don't know. but it is only on diesels but not just gals bamas and sharans, passats vauxhalls et al

[johnb80]

Well I learn something new every day, it must be an age thing I suppose not expecting a brake pedal to hit the floor. Perhaps it's adopting older principles a la Flinstones !

 

Right off to give my Ford Dealer an ear bashing for supplying my Gal with faulty brakes. I can't wait to hear his comments when I say 'theyre faulty because the pedal wont reach the floor" !!!

 

Regards - John

P.S. How many others on here have pedals that DON'T reach the floor ?

[CasaPaulo]

>>>>>it must be an age thing<<<<<<

 

AT LAST, well it's something we agree on! You're probably a kindly Old Curmudgeon but in hinting I'm a tad potty for putting up with dodgy brakes, when I said they are NOT. You should've forseen a reaction of sorts, especially as I sought PRO advice. Then painting a misleading scenario of a brake pedal on the floor whilst going down a hill (wrong!) Ignoring those who insist their diesel car brakes are perfectly safe & official MOT testers. Mine has been tested twice! But still stubbornly inferring you are RIGHT.

Your correct it's an age thing! or pig headedness in my case.

I say the modern system is safe, you wish to contradict citing only basic old fashioned braking principles. By the way are you really sure (100%) you can't pump your brakes (diesel only) as if bleeding, then keeping the pressure on, the pedal will not slowly sink to the floor?

 

Another stubborn argumentative...............................

 

Paul

xxx

[davec]

sorry for delay FredT i love it its the L300 one which i think is easier to get parts for based on L300 its heavy on fuel but 4x4 system is excellent its not too bad to work on and the trim levels are good have super exceed which has suede seats,fridge,cystal roof,loads of chrome back seats fold to double bed airconx2

L400 has superselect 4x4 but mine is more than enuf for me had it for a year new exhaust and tyres straight thro MOT first go

[johnb80]

>>>>>it must be an age thing<<<<<<

 

AT LAST, well it's something we agree on! You're probably a kindly Old Curmudgeon but in hinting I'm a tad potty for putting up with dodgy brakes, when I said they are NOT. You should've forseen a reaction of sorts, especially as I sought PRO advice. Then painting a misleading scenario of a brake pedal on the floor whilst going down a hill (wrong!) Ignoring those who insist their diesel car brakes are perfectly safe & official MOT testers. Mine has been tested twice! But still stubbornly inferring you are RIGHT.

Your correct it's an age thing! or pig headedness in my case.

I say the modern system is safe, you wish to contradict citing only basic old fashioned braking principles. By the way are you really sure (100%) you can't pump your brakes (diesel only) as if bleeding, then keeping the pressure on, the pedal will not slowly sink to the floor?

 

Another stubborn argumentative...............................

 

Paul

xxx

In answer to some of your points:-

1) Yes I'm sure that mine doesn't go down to the floor under gentle pressure.

2) If it did I don't care who tells me thats ok, it's NOT ok as far as I'm concerned and I would not drive it.

3) You want to drive with 'dodgy' brakes thats up to you mate, just keep well clear of me and my family thats fine

4) How many times have you heard of 'expert' advice being given and being totally wrong. Could it be you choose to accept the 'expert' opinion because it's what you want to hear.

5) You say I'm citing old fashioned principles, really, please enlighten me how a modern system works - does it not have brake fluid in a pipe working pistons ? does it not have a master cylinder to create the pressure, come on tell me.

 

Just think about it, if you were buying a car and the salesman said 'The brake pedal will go all the way down to the floor but it's ok, our expert says it is" would you really still buy that vehicle? I think not

 

I challenge you to explain on here the reasoning behind the pedal hitting the floor. There's no way that pedal can go down UNLESS the fluid is leaking somewhere i.e. to the outside world (a leak) or past the master cylinder seals (no leak). The fluid has to go somewhere because it can't be compressed.

 

Obviously you think it's a desireable thing, I wonder why Ford don't mention it in their sales brochure as a plus point.

 

You are entitled to your opinion as I am to mine, I like my brake pedal the way it is and no way am I having it 'fixed' like yours :P

 

Regards JB

[Dave-G]

:P I have tried really really really hard to get my pedal to the metal,but it just wont go down more than about 20% :P

[johnb80]

Obviously yours is faulty too :P

 

Maybe Ford will do a recall if there's more of us !

 

Regards - JB

[MrT]

Just a thought, how does the ABS system release pressure on a wheel? It must somehow allow the fluid to "pass back" to release the pressure on a particular brake cylinder? Perhaps this "pass back" is allowing the pedal to drop?

[johnb80]

No it doesnt allow fluid to pass back, it modulates the pressure. Effectively a piston moves up, reducing the pressure in the brake line and then it moves back down again restoring the pressure to create the cadence braking effect. If the system worked by allowing fluid back under a longer duration emergency braking eg high speed on ice the brake pedal would end up on the floor which I'm sure you would agree is what most of us don't want.

 

Regards - JB

[seatkid]

Brake pedal to the floor = faulty braking system

 

Either a leak (check fluid level), leaking seals in master cylinder (fluid running back to reservoir) or possibly leaks in the ABS block

 

The only difference between the diesel and petrol variant is the diesel has a vacuum pump as opposed to using the manifold vacuum. Once your pedal is on the floor your braking will be limited or worse still, will gradually release. You can pump the pedal in all cases to refill the system from the master reservoir.

 

From your description however, you may be being misled. If the vacuum servo is empty (stood, engine off and vacuum leaked out or pedal applied several times) the brake pedal is very hard (i.e. no servo assistance). If you then have your foot on the brake when you start the engine, as the servo vacuum is restored (takes 3 or 4 seconds), the pedal will feel as if it is sinking quite low. This is normal and is due to the servo assistance being restored. With servo assistance the pedal will feel softer. But it should never go to the floor.

 

BTW a soggy or spongy brake pedal after a brake pad change is normal when the discs are in poor condition (scored/worn) and it can take some time for the pads to bed in. Even then, peak braking effort may not be acheived. On the other hand, new pads plus new discs the brake pedal feel should be correct from the start. Not changing discs is a false economy ,usually the pads wear much quicker on a worn disc than a new one (in the case of my Golf pads lasted only 14k as opposed to 40k when new discs fitted)

 

As a general rule of thumb, I recommend new discs every second pad change. or sooner if the discs reach their limit of thickness, become badly grooved or warped (run out)

[Another?Maybe!]

Testing my brake pedal tomorrow.... def going back to dealer if it goes down to floor.... no way would I drive in this condition... as said earlier, there is absolutely no reason for this to happen if system is working correctly. Dangerous or what?

 

PeteR

[Phil Neal]

did we get a consensus on this, my mechanic has just mentioned that he thinks my servo maybe on the way out? should it hold firm if you rev it a bit?

 

how much was a new servo (parts) and where is the best place to get them (ECP and GSF dont do them....)

 

99/00 vw sharan 1.9tdi 53k miles.....7k to cambelt...