spongy brake feel

[johnpilky]

hi guys,having trouble with brake pedal feeling spongy and taking an age to stop car.just popped into local garage and they said it is the servo.i am at odds with this as the brake pedal is spongy and not hard to depress.the level of brake fluid has not dropped since service in may so dont think there are any leaks.new disks and pads fitted in may so am a bit confused as to why it could be the servo.could it be that the brake fluid is full of moisture and has boiled,any help appreciated,regards.:confused:

[James.uk]

First thing to do is to bleed them to get any air out of the system. Then see what effect that has and report back please. :)
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[chrissyboy]

i`d go along with what james has said ,there may be a bit of air inthe system .do that first , will save some robbing garage telling you they did this and that ,but all they did was bleed them :D the fluid shuld be changed every 3 or 4 years i beleive not just topped up .. you need to bleed the old stuff out so you have just newfluid in the system ..

[johnpilky]

First thing to do is to bleed them to get any air out of the system. Then see what effect that has and report back please. :)
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hi,will do that first off.what i cant understand is guy in garage said i have a leak on seal on servo,how he can diagnose that without investigating is beyond me,regards.:D

[HarryM1BYT]

Turn the engine off and pump the pedal several times - see how far the pedal goes down and how firm it is. Its easy to be fooled by the action of the servo into thinking the pedal is spongy. If it still feels spongy with no help from the servo, then think about it needing to be bled due to air in the system.

If it goes down much further with the help of the servo, then I would suggest the servo is fine. If the brakes seem poor and ineffective, it could be the type of pads fitted. How many miles since the new pads were fitted, they need time to bed in and reach full performance?

[James.uk]

Garage mechanics, like any other tradesmen have good and bad among their numbers. Some are brilliant, :} but some are just lazy chancers out to make a fast buck. ..:(

It's up to us to keep the chancers well away from our cars.. ;) :}
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[Brigus]

the fluid shuld be changed every 3 or 4 years i beleive not just topped up ..

The owners manual states fluid renewal is needed every two years regardless of distance travelled

[eddiemc05]

Hi maybe ur fliud is leaking into ur servo resulting in both spongy brakes and no asistance from servo, any signs of leaks around master cyl or servo, just an idea!!

[johnpilky]

hi guys,with engine turned off brake peddle rock hard,with engine on peddle is very easy to operate,but taking an age to stop car.no signs of leakage from fluid,level been the same since may.car done 2000 miles since new ebc discs and greenstuff pads fitted.correct me if i am wrong but with engine running,if servo was faulty would the brake peddle feel hard to push down.at present brake peddle is easy to push down with engine running,so does that rule out servo failure,regards.:confused:

[HarryM1BYT]

Your servo sounds to be fine, as does the possibility of there being any air in the brake lines or cylinders. If it pulls up straight, that almost eliminates the possibility of seized calipers. The servo working properly will make the pedal feel soft and a bit spongy.

Fitting new disks and pads, would suggest they should have checked the calipers and pistons were working properly too.

Another possibility is pad contamination, but that is unlikely unless the job was botched by an amateur. So I am at a loss, other than to suggest it might be you used to other cars and need to get used to the 75.

I bought mine 3 months ago and found mine took some stopping compared to my old car. I have checked it out end to end and I KNOW, there is nothing amiss - it is just different, so I adapt to it. It just needs more pressure on the pedal than I am used to. Driving my old car, with not much effort at the pedal, I could trigger the ABS on a good dry road. If you still have concerns why not see if there is a forum member near you who could test drive it?

[johnpilky]

Your servo sounds to be fine, as does the possibility of there being any air in the brake lines or cylinders. If it pulls up straight, that almost eliminates the possibility of seized calipers. The servo working properly will make the pedal feel soft and a bit spongy.

Fitting new disks and pads, would suggest they should have checked the calipers and pistons were working properly too.

Another possibility is pad contamination, but that is unlikely unless the job was botched by an amateur. So I am at a loss, other than to suggest it might be you used to other cars and need to get used to the 75.

I bought mine 3 months ago and found mine took some stopping compared to my old car. I have checked it out end to end and I KNOW, there is nothing amiss - it is just different, so I adapt to it. It just needs more pressure on the pedal than I am used to. Driving my old car, with not much effort at the pedal, I could trigger the ABS on a good dry road. If you still have concerns why not see if there is a forum member near you who could test drive it?
hi,thanks for the reply,car stops in a straight line no problem,brake peddle easy to operate,so as you say servo is ok.would a change of brake fluid help any ie would i feel any difference in peddle feel,regards.:bowdown:

[HarryM1BYT]

hi,thanks for the reply,car stops in a straight line no problem,brake peddle easy to operate,so as you say servo is ok.would a change of brake fluid help any ie would i feel any difference in peddle feel,regards.:bowdown:

I have never noticed any change at all in the feel of the pedal on any car I have changed the fluid on.

[chrissyboy]

I have never noticed any change at all in the feel of the pedal on any car I have changed the fluid on.


??? on aleast 3 cas i have had ,when new fluid was put in and the old taken out the brakes was much more responsive .. by pressing the brake pedal and turning ignition on the pedal should go softer if the servo is ok .... i would check under neath to make sure that who ever jacked the car up has`nt pinched a brake pipe ..

[James.uk]

Changing the fluid wont make any noticeable difference to the brakes operation, unless.. There was a fault, like air in the system, that changing the fluid cured.. :}
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[chrissyboy]

Changing the fluid wont make any noticeable difference to the brakes operation, unless.. There was a fault, like air in the system, that changing the fluid cured.. :}
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it would make a vast diffrence if the fluid in the system has never been changed ,new fluid more pressure under brakeing ,why do you think they recommend you change the fluid evey 3 years ?

[HarryM1BYT]

it would make a vast diffrence if the fluid in the system has never been changed ,new fluid more pressure under brakeing ,why do you think they recommend you change the fluid evey 3 years ?

The reason is that brake fluid absorbs moisture from the air. Under heavy braking lots of heat is generated, which can be transmitted to the brake fluid which could reach boiling point turning the absorbed moisture to steam - at which point, you then run out of brakes.

That is also the reason why brake fluid should never be reused, once it has been opened.

[James.uk]

Chris.. If the prev fluid had either moisture or air in it.. then that's a fault innit? :p:

I repeat:- if there wasn't a fault before the fluid change, then there wont be any difference when braking. :)
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[chrissyboy]

Chris.. If the prev fluid had either moisture or air in it.. then that's a fault innit? :p:

I repeat:- if there wasn't a fault before the fluid change, then there wont be any difference when braking. :)
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thats not what is being said .if there is air or the fluid is old ,then changing it will make a difference:D

[COLVERT]

hi,thanks for the reply,car stops in a straight line no problem,brake peddle easy to operate,so as you say servo is ok.would a change of brake fluid help any ie would i feel any difference in peddle feel,regards.:bowdown:
To check if your braking system is working properly then find a safe area and make an emergency stop. If all is OK you will feel the pedal PUSHING BACK UP AGAINST YOUR FOOT. ( Pulsing ! ) If it does not do this then the servo is not working correctly.

Colvert. :cool:

[johnpilky]

hi guys,thanks for the replies,regards.:bowdown:

[Berger]

hi guys,with engine turned off brake peddle rock hard,with engine on peddle is very easy to operate,but taking an age to stop car.no signs of leakage from fluid,level been the same since may.car done 2000 miles since new ebc discs and greenstuff pads fitted.correct me if i am wrong but with engine running,if servo was faulty would the brake peddle feel hard to push down.at present brake peddle is easy to push down with engine running,so does that rule out servo failure,regards.:confused:

I am having similar problems to you, with poor pedal feel and a little more travel than I would expect. Pump the pedal with the car off and it goes rock hard, with the car running its a little spongy. Bled the brakes through using a pressure and one way valve bleeder and got no air out, so it has all fresh fluid now.

My friends brakes are razor sharp, mine are spongy and require a lot of pressure to get more braking effort out of them.

I have put mine down to contaminated/overheated or shafted pads. I checked them out and they have loads of meat left on them, but I guess a garage must have ******** something up and got grease or fluid on the face of them in the past.

[COLVERT]

I am having similar problems to you, with poor pedal feel and a little more travel than I would expect. Pump the pedal with the car off and it goes rock hard, with the car running its a little spongy. Bled the brakes through using a pressure and one way valve bleeder and got no air out, so it has all fresh fluid now.

My friends brakes are razor sharp, mine are spongy and require a lot of pressure to get more braking effort out of them.

I have put mine down to contaminated/overheated or shafted pads. I checked them out and they have loads of meat left on them, but I guess a garage must have ******** something up and got grease or fluid on the face of them in the past.
There is more to this than meets the eye. Even with contaminated pads the pedal should NOT feel spongy. You can't squash the pad material even if it's ****.
I think inspite of your best efforts you STILL have some air in the system. It is the ONLY LOGICAL answer to the spongy pedal.



Colvert. :shrug:

[James.uk]

:iagree::wss:... You still have air in the brake lines... :o

From memory I think you should start bleeding with the wheel on the shortest line to the master cylinder.. But I am not certain, so best to get that confirmed..
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[Greeners]

Find a post by Bigg Russ, you need a T4 to bleed it so it can open the valve in the ABS unit to allow the fluid to pass through.

[johnpilky]

hi guys,brakes been bled and filled with new fluid.under normal braking not much difference to brake pedal feel ie still spongy,but when under harder braking it has a slightly better feel to it ie stopping the car quicker than before,regards.:drool4:

[David Lawrence]

hi guys,brakes been bled and filled with new fluid.under normal braking not much difference to brake pedal feel ie still spongy,but when under harder braking it has a slightly better feel to it ie stopping the car quicker than before,regards.:drool4:



There's been a lot said on this subject. It would be really great to get someone with a spongy feeling pedal to bleed the brakes on a T4 to confirm if this really works or not to cure it.

[geofftl1000r]

I have bled many cars and bikes. Nothing has ever behaved the way the brakes on my 75 did.
The brakes seem to be working ok, but took my daughter and myself hours to get a firm peddle back.
The Ezibleed kit could not force fluid to the front left or rear right. Instead, we had to revert to: peddle down, open/close nipple, peddle up.....many many times. Was as if something (ABS Valve?) was blocking the free flow of fluid.
The brakes are good and pull up straight but I have yet to find a nice slippery surface to invoke ABS.

[HarryM1BYT]

I have bled many cars and bikes. Nothing has ever behaved the way the brakes on my 75 did.
The brakes seem to be working ok, but took my daughter and myself hours to get a firm peddle back.
The Ezibleed kit could not force fluid to the front left or rear right. Instead, we had to revert to: peddle down, open/close nipple, peddle up.....many many times. Was as if something (ABS Valve?) was blocking the free flow of fluid.
The brakes are good and pull up straight but I have yet to find a nice slippery surface to invoke ABS.

The advice for my last car with ABS, was to bleed them with the engine running - I don't know if this might also apply to the 75.

[Greeners]

Have a read of this (http://www.the75andztclub.co.uk/forum/showthread.php?t=63314)

[COLVERT]

I have bled many cars and bikes. Nothing has ever behaved the way the brakes on my 75 did.
The brakes seem to be working ok, but took my daughter and myself hours to get a firm peddle back.
The Ezibleed kit could not force fluid to the front left or rear right. Instead, we had to revert to: peddle down, open/close nipple, peddle up.....many many times. Was as if something (ABS Valve?) was blocking the free flow of fluid.
The brakes are good and pull up straight but I have yet to find a nice slippery surface to invoke ABS.
Loose gravel will do the job. However it could be that the ABS is just not working at all !!!


Colvert. :confused: