Soft brake pedal when engine running

[5678]

So frustrating!

Bled through my system with new fluid. No air got in as I had help and we kept a constant eye on the fluid levels. I bled a litre of fluid through it and initially the pedal felt fine. Since then It's got softer when the engine is running and I can get the pedal to the floor.

I've re bled it again today and got a few bubbles out, but not a huge amount. Pedal goes rock hard after a few pumps when the engine is off, but still goes down when the engine is running.

Have double and triple checked for leaks and there are none.

Bit concerned that I've got air in the ABS as I've seen mentioned, it's the only thing I can think of at least. Hopefully it will rain tonight and I can go out and try to fire off the ABS as I've seen suggested. Currently there isn't enough stopping power to do it in the dry!

Anything else I can do/check/try?

Thanks.

 

[5678]

Ok, it's better, but I can still get to the bottom of the travel. There was enough power to trigger the ABS in the dry so will re bleed it in a few days time.

Still open to ideas!

 

[Cupman29]

Not fully bled mate. There is definitely air in the system.

Start again with the bleeding unfortunately.

How did you do it?

 

[5678]

Tried using an Easibleed kit (which I thought was fairly successful) and then good old two man down, down, up, up method.

Fluid will run out of all corners with no trace of air at all. I've put another 3-400 ml through it today.

 

[mark123]

Have you driven it? It sounds fairly normal to me.

From my experience it always feels like the pedal is softer than it was but I think it is just that I am stood up outside the car standing on the pedal instead of inside.

If there was air in there it wouldn't go hard when you pumped it.

 

[Cupman29]

I would use the old fashioned pedal pumping method with slow full strokes making sure the reservoir is kept topped up.

In the Clio workshop manual it says the brakes must be bled in an x method doing the ns rear, then os front then os rear then finally the ns front. I have always done it this way with no problems.

Give it a try and see how you go.

 

[Cupman29]

Have you driven it? It sounds fairly normal to me.

From my experience it always feels like the pedal is softer than it was but I think it is just that I am stood up outside the car standing on the pedal instead of inside.

If there was air in there it wouldn't go hard when you pumped it.

When the engine is on the servo will also be working so might feel hard when off but soft when on. Definitely sounds like air in the system.

 

[5678]

It's definitely not normal. I've driven it and the pressure is there, it just takes all of the travel to get it.

I've bled them today in the x pattern, doesn't seem to have made a difference. Will try and have another go over the weekend and see if activating the ABS has shifted the air round.

 

[whom]

Bit of a revival...

I am having EXACTLY the same problem. I know air did get in.

How did you resolve it?

 

[Nick88]

A pressurised bleeding kit is the best way to make sure the air gets out!

If you got air in the abs pump you will need to get that to activate to push the air out of the pump!

 

[whom]

Hi Nick,

Yeah I've done all corners with half a litre ish with a pressurised thingy at around 30psi..... no luck. That was after firing off the ABS many times.

My friend has just helped me the old fashioned away and that didn't work. He was pumping it up lots then I was releasing to really force it through.

Just been out again with lots more ABS triggering and am going to bleed it AGAIN! This is getting tedious... damn my stupidity.

 

[Mack182]

i had this a few weeks ago and turned out to be a seized carrier bolt on the front passenger side released the bolt greased it up and good as new now :approve:

 

[Emma.]

I had very similar issues. Was a seized calliper.

 

[whom]

Was this while/after bleeding brakes guys?

 

[Emma.]

Didn't bleed the brakes first. But it 'felt' like there was air in the system.

Took the wheels off to bleed them and then noticed my disintegrated pads.

Replaced pads, unseized the calliper, fluid change and all is good again.

 

[Mack182]

yer i bleed the brakes and got a little better but still wasnt correct so checked calipers and found a seized carrier

 

[whom]

Ok cheers guys. This happened with just a brake bleed and I haven't touched the calipers/pads/discs or even wheels! I'll have a little check around though.

 

[scooby-93]

Another thread revival but driving me insane!

I'd removed my front brakes and stupidly the front lines had completely ran dry and emptied the MC, since then I have bleed through over 8 litres Of fluid through the car. With the up down method

With the engine off the pedal is hard once pumped twice

With engine running there is no pedal pressure however the brakes do work at the very bottom of the pedal

Since then I have rebleed numinous times with the ezeebleed kit and still the same.

I have also bought an rs tuner and abs software

I have bleed the brakes 3 times with the rs tuner pumping the abs pump and have followed the guide on how to do this correctly

I still have the same issues!

One thing I have noticed is I have a leak on the master cylinder when the eedibleed Is pressurising the system

The brakes still bleed with the nipples open and there is no air coming out

I've ordered 2 new MC to brake resivour seals I'm hoping this is where the fluid is leaking from - could it be leaking between the servo and MC?

However I don't think that will explain why i have no pedal with the engine running?

Any help will be greatly appreciated as this is now driving me insane!

Sorry to tag you @NorthloopCup but you seam to know these cars inside out, can you offer advice?

Thanks

 

[NorthloopCup]

Another thread revival but driving me insane!

I'd removed my front brakes and stupidly the front lines had completely ran dry and emptied the MC, since then I have bleed through over 8 litres Of fluid through the car. With the up down method

With the engine off the pedal is hard once pumped twice

With engine running there is no pedal pressure however the brakes do work at the very bottom of the pedal

Since then I have rebleed numinous times with the ezeebleed kit and still the same.

I have also bought an rs tuner and abs software

I have bleed the brakes 3 times with the rs tuner pumping the abs pump and have followed the guide on how to do this correctly

I still have the same issues!

One thing I have noticed is I have a leak on the master cylinder when the eedibleed Is pressurising the system

The brakes still bleed with the nipples open and there is no air coming out

I've ordered 2 new MC to brake resivour seals I'm hoping this is where the fluid is leaking from - could it be leaking between the servo and MC?

However I don't think that will explain why i have no pedal with the engine running?

Any help will be greatly appreciated as this is now driving me insane!

Sorry to tag you @NorthloopCup but you seam to know these cars inside out, can you offer advice?

Thanks

There's a specific sequence that you need to follow when bleeding the brakes up on these mate, but I don't know it off the top of my head I'm afraid.

The only other things I can think of off the top of my head are that the seals have been over pressurised by the eezibleed and turned over on themselves, or the one way valve on the servo is faulty (unlikely this one though).

Only fix for the 1st one is a new mastercylinder mate, but it doesn't explain why the pedal goes hard without any servo assistance.

 

[scooby-93]

I've followed the correct sequence nsr, osf,osr then nsf, for bleeding then with abs pump activated nsr,osr,osf,nsr which is what Reno specifie.

One thing I did do was whilst bleeding up down method I thought I was taking air in through the bleed nipples so I had closed them slightly and that made the pedal harder to pump. - I hope this hasn't caused something to fail?

What do you mean causing the pedal to go hard without servo assistance? Surely the pedal should be hard with no servo assurance? I.e when engine is turned off?

 

[NorthloopCup]

I've followed the correct sequence nsr, osf,osr then nsf, for bleeding then with abs pump activated nsr,osr,osf,nsr which is what Reno specifie.

One thing I did do was whilst bleeding up down method I thought I was taking air in through the bleed nipples so I had closed them slightly and that made the pedal harder to pump. - I hope this hasn't caused something to fail?

What do you mean causing the pedal to go hard without servo assistance? Surely the pedal should be hard with no servo assurance? I.e when engine is turned off?

From past experience, when the seals in the master cylinder have been pushed the wrong way, the pedal doesn't usually go hard when there's no servo assistance. It just remains spongy.

 

[scooby-93]

Yeah I get you now mate, I've ordered a new MC aswell but will try the seals first and if no leaks persevere with bleeding

 

[JB21]

I feel for you pal I really do. I've had issues with mine recently where I changed everything brake related, hard lines, flexes, MC, ABS pump and it turned out to be the feckin abs rings on the front. My system ran totally empty when changing the above and I used a cheap £5 ezibleed kit and totally got all the air out the system on my own without any fancy RStuning abs module so its got to be a leak somewhere pal. I have a spare MC and ABS pump if you need them as well.

If you need any pointers in replacing the MC let me know as its a right ball ache.

 

[scooby-93]

Thanks mate but ordered a new MC how's it a ball ache to fit? Not a case of removing brake lines then the 2 nuts and piling it out then disconnecting from pedal rod?

 

[JB21]

Thanks mate but ordered a new MC :smile: how's it a ball ache to fit? Not a case of removing brake lines then the 2 nuts and piling it out then disconnecting from pedal rod?

Not as simple as that mate as its so bloody tight, I had to:-

1. remove drivers wheel
2. remove the arch lining
3. remove the upper inlet
4. pull back the firewall material on the bulkhead
5. undo the 2 flare nuts with 11mm flair spanner
6. undo the 2 10mm bolts for the MC bracket
7. undo the 2 10mm bolts for the MC itself
8. pry out the MC away from the servo (it wont come all the way out)
9. jack the engine up and remove the cam belt cover/upper engine mount
10. pull the engine forward as far as you can to get the MC & reservoir out
11. reverse order to refit

I didn't bench bleed the MC before refitting I just connected it back up, filled it and bled the system as follows: N/S R - O/F R - N/S F - O/S F. I still had a slightly spongy pedal feel after the 1st round of bleeding so then took the car to a dirt track and fired the ABS 2-3 times and re-bleed the system as above and the pedal was then solid.

Hope this helps

Phil

 

[scooby-93]

Thanks for that mate. Will give it ago Sunday