Spongey Brakes after Brake Fluid Change
Discussion
Hi Guys,
I have a Seat Leon and i took the car to an independent mechanic (family friend) and asked him to renew the brake fluid. Before giving him the car the brake pedal was always firm and responded to minor inputs and was not spongey at all.
When I went to pick up the car later that day, the brakes were very spongey and I had to press the pedal much more to the floor get the brakes to bite and slow the car. I asked him to re-bleed, which he did. He bled the master cyclinder, and brakes lines at each wheel. The brakes were still spongey and not any better. The next day he repeated bleeding process and also bled the ABS pump (or the hoses that connect to it). Lo and behold spongey feeling is still there albeit a little bit less.
engine off: brake pedal is very firm when pressed
engine on: if i put my foot on the brake pedal it slowly creeps towards floor.
Does the above indicate a fault with master cylinder or Servo, or do I need a re-bleed but this time take the car to SEAT?
I have a Seat Leon and i took the car to an independent mechanic (family friend) and asked him to renew the brake fluid. Before giving him the car the brake pedal was always firm and responded to minor inputs and was not spongey at all.
When I went to pick up the car later that day, the brakes were very spongey and I had to press the pedal much more to the floor get the brakes to bite and slow the car. I asked him to re-bleed, which he did. He bled the master cyclinder, and brakes lines at each wheel. The brakes were still spongey and not any better. The next day he repeated bleeding process and also bled the ABS pump (or the hoses that connect to it). Lo and behold spongey feeling is still there albeit a little bit less.
engine off: brake pedal is very firm when pressed
engine on: if i put my foot on the brake pedal it slowly creeps towards floor.
Does the above indicate a fault with master cylinder or Servo, or do I need a re-bleed but this time take the car to SEAT?
I deleted my comment because I wasn't so sure after re-reading your post. If after several re-attempts of bleeding there is still an issue there may be something else wrong. But you have to consider the chance of something going wrong with the system, at the same time as you changing the fluid, not very likely.
Sounds a lot like an airlock in the system, did the mechanic do an all out fluid change or a bleed through type? With a bleed through, airlocks are much harder to come by, but if all the fluid was drained from the system it really does sound like air in there.
HTH
Sounds a lot like an airlock in the system, did the mechanic do an all out fluid change or a bleed through type? With a bleed through, airlocks are much harder to come by, but if all the fluid was drained from the system it really does sound like air in there.
HTH
Mr2Mike said:
If the brake pedal continues to slowly sink all the way to the floor if you keep pressure on it, then the master cylinder seals are leaking.
It doesnt sink totally to the floor, but it goes lower than it used to before the fluid change. With engine off the pedal is very solid with no sinking - what does that indicate?Robb F said:
I deleted my comment because I wasn't so sure after re-reading your post. If after several re-attempts of bleeding there is still an issue there may be something else wrong. But you have to consider the chance of something going wrong with the system, at the same time as you changing the fluid, not very likely.
Sounds a lot like an airlock in the system, did the mechanic do an all out fluid change or a bleed through type? With a bleed through, airlocks are much harder to come by, but if all the fluid was drained from the system it really does sound like air in there.
HTH
I was wondering where the comment went! I am not sure how it was drained. I think he might have drained the whole system first and then filled the new the resorvoir with new fluid. I agree with you, it would be quite a co-incidence for the M/C seals to leak just when I got a fluid change.Sounds a lot like an airlock in the system, did the mechanic do an all out fluid change or a bleed through type? With a bleed through, airlocks are much harder to come by, but if all the fluid was drained from the system it really does sound like air in there.
HTH
Interestingly, the mechanic was coming up with all sorts of theories. One of which was that the servo is probably playing up. My reading on the topic suggests that if the pedal firms up with constant pumping then the servo is ok, so I am ruling out the servo myself.
If I can rule out M/C problems with your guys help, then I can take it to SEAT and get them to do the bleed according to the correct protocol for the car.
Ayrton Senna said:
Mr2Mike said:
If the brake pedal continues to slowly sink all the way to the floor if you keep pressure on it, then the master cylinder seals are leaking.
It doesnt sink totally to the floor, but it goes lower than it used to before the fluid change. With engine off the pedal is very solid with no sinking - what does that indicate?Robb F said:
I deleted my comment because I wasn't so sure after re-reading your post. If after several re-attempts of bleeding there is still an issue there may be something else wrong. But you have to consider the chance of something going wrong with the system, at the same time as you changing the fluid, not very likely.
Sounds a lot like an airlock in the system, did the mechanic do an all out fluid change or a bleed through type? With a bleed through, airlocks are much harder to come by, but if all the fluid was drained from the system it really does sound like air in there.
HTH
I was wondering where the comment went! I am not sure how it was drained. I think he might have drained the whole system first and then filled the new the resorvoir with new fluid. I agree with you, it would be quite a co-incidence for the M/C seals to leak just when I got a fluid change.Sounds a lot like an airlock in the system, did the mechanic do an all out fluid change or a bleed through type? With a bleed through, airlocks are much harder to come by, but if all the fluid was drained from the system it really does sound like air in there.
HTH
Interestingly, the mechanic was coming up with all sorts of theories. One of which was that the servo is probably playing up. My reading on the topic suggests that if the pedal firms up with constant pumping then the servo is ok, so I am ruling out the servo myself.
If I can rule out M/C problems with your guys help, then I can take it to SEAT and get them to do the bleed according to the correct protocol for the car.
As said, there is only a leak if when constant pressure is applied, the pedal continues to drop. If it is simply dropping further than you expect (that spongey feeling) but still stopping, I am 99% sure you have an airlock. The only doubt in my mind is that fact you say it have been pretty comprehensively bled. I might suggest a draw through method of bleeding would possibly sort this, I.e. the fluid is sucked through from the bleed nipples rather than pushed through using the pedal.
The only other option I can think of, is that due to brake fluid being hydroscopic, there is moisture in the fluid. If the fluid was brand new this is very unlikely, but it is a possiblity.
Thanks very much for all the input so far guys, I genuinely appreciate it.
I agree Robb F that it would be a strange co-incidence to have problems with servo/master cylinder on the day I get my fluid changed. I think there is an airlock in the system.
NSA: I agree with you that the order of the bleeding can make a big difference. The threads on SEAT forums also seem to suggest this. My original mechani just seemed to bleed in a random order!
Anyhow, I have booked the car into an independent VAG specialist called 'Independent Automotive' in Coventry. They will change the brake fluid again and re-bleed for £50. They are aware of the previous fluid change and current spongey feel.
I will let you guys know what happens.
PS: SEAT main dealer quoted me £100.80 to have a look at it! I nearly had a heart attack when hearing that price.
I agree Robb F that it would be a strange co-incidence to have problems with servo/master cylinder on the day I get my fluid changed. I think there is an airlock in the system.
NSA: I agree with you that the order of the bleeding can make a big difference. The threads on SEAT forums also seem to suggest this. My original mechani just seemed to bleed in a random order!
Anyhow, I have booked the car into an independent VAG specialist called 'Independent Automotive' in Coventry. They will change the brake fluid again and re-bleed for £50. They are aware of the previous fluid change and current spongey feel.
I will let you guys know what happens.
PS: SEAT main dealer quoted me £100.80 to have a look at it! I nearly had a heart attack when hearing that price.
Hi Guys,
As promised i said I would let you know how i got on with the VW/SEAT specialist.
Basically, they checked my braking sytem then changed the fluid and bled the brakes in the correct order and the brakes are now perfect. So it was air in the system after all and not anything to do with m/c or servo.
The garage used a machine to pump new fluid into the sytem while the old fluid comes out at the same time. The mechanic told me that this significantly reduces the risk of airlocks in the system (just as you suggested Robb F), but as nsa said, the correct order of bleeding is also important.
I want to thank you guys for your help and opinions - they were much appreciated.
Hopefully this thread will be useful to somebody in the future who is experiencing similar problems to what I had.
As promised i said I would let you know how i got on with the VW/SEAT specialist.
Basically, they checked my braking sytem then changed the fluid and bled the brakes in the correct order and the brakes are now perfect. So it was air in the system after all and not anything to do with m/c or servo.
The garage used a machine to pump new fluid into the sytem while the old fluid comes out at the same time. The mechanic told me that this significantly reduces the risk of airlocks in the system (just as you suggested Robb F), but as nsa said, the correct order of bleeding is also important.
I want to thank you guys for your help and opinions - they were much appreciated.
Hopefully this thread will be useful to somebody in the future who is experiencing similar problems to what I had.
Edited by Ayrton Senna on Friday 20th January 22:51
Pooky67 said:
:Topic revival:
I've got this problem with my Seat Leon after asking a small garage to change the fluid.
Looks like I'll be booking into a specialist to have them take a look.
Would any one care to recommend a brake fluid? DOT4? DOT5.1?
Hi mate, I've got this problem with my Seat Leon after asking a small garage to change the fluid.
Looks like I'll be booking into a specialist to have them take a look.
Would any one care to recommend a brake fluid? DOT4? DOT5.1?
I am pretty certatin it is DOT4. (i used a company called Pagid from Euro Car parts).
Yes it is worth paying a specialist to make sure everything is all ok.
Hope you get it sorted.
hello
so glad that i read up on this forum
i changed the rear callipers and thus found out this problem of bleeding seat leon brakes, i had to take it to kwikfit as they had the right tools for the job but were unable to regain the really hard brake pedal so they didn't charge me! i had exactly the same experience as senna, however over the last week they are getting better !!so i must go with the air in the system theory that is working its way out, some how!
i'm i imagining this or is that possible?
thanx in advance, jez
so glad that i read up on this forum
i changed the rear callipers and thus found out this problem of bleeding seat leon brakes, i had to take it to kwikfit as they had the right tools for the job but were unable to regain the really hard brake pedal so they didn't charge me! i had exactly the same experience as senna, however over the last week they are getting better !!so i must go with the air in the system theory that is working its way out, some how!
i'm i imagining this or is that possible?
thanx in advance, jez
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