Technical Brake pedal goes to the floor when ABS is activated

[Mad85]

2005 1.3 diesel Doblo; whenever I brake hard enough to activate the ABS, the pedal goes straight to the floor. I suspect it may be due to air in the ABS pump however bleeding it normally did not help. Does it need a special tool to bleed it properly? Brake fluid level is not going down and there are no obvious leaks

 

[Popitinpete]

2005 1.3 diesel Doblo; whenever I brake hard enough to activate the ABS, the pedal goes straight to the floor. I suspect it may be due to air in the ABS pump however bleeding it normally did not help. Does it need a special tool to bleed it properly? Brake fluid level is not going down and there are no obvious leaks

The pedal will travel a long way more when the ABS is active, it won't feel like normal braking but should not drop to the floor, is it definitely going all the way to the floor.

 

[Pugglt Auld Jock]

When ABS activates the biggest thing you'll notice is that the pedal will pulsate slightly - or maybe somewhat more than slightly - under your foot as the pressure is modulated to the wheel which is failing to grip. I wouldn't say the pedal will go anywhere near the floor. It's entirely possible to have air in the ABS module but this usually happens when, perhaps, a pipe has been changed and the fluid has been allowed to drain completely. To bleed it you'll need to be able to drive the pump for which you'll need something like Multiecuscan, the dealer tool or some other sophisticated electronic diagnostic tool. In MES it's, from what i understand, in the "adjustments" - Hydraulic Unit Bleed. I've never had the need to do this so I'm just away to run MES in simulate mode and look for it.

 

[Mad85]

The pedal will travel a long way more when the ABS is active, it won't feel like normal braking but should not drop to the floor, is it definitely going all the way to the floor.

Yes it is definitely going to the floor and needs to be pumped a few times afterwards to get some feel back to the pedal. This only happens when the abs system is triggered. However I am 100% sure it is not normal as i have other cars with abs and none behave like this.

 

[Mad85]

When ABS activates the biggest thing you'll notice is that the pedal will pulsate slightly - or maybe somewhat more than slightly - under your foot as the pressure is modulated to the wheel which is failing to grip. I wouldn't say the pedal will go anywhere near the floor. It's entirely possible to have air in the ABS module but this usually happens when, perhaps, a pipe has been changed and the fluid has been allowed to drain completely. To bleed it you'll need to be able to drive the pump for which you'll need something like Multiecuscan, the dealer tool or some other sophisticated electronic diagnostic tool. In MES it's, from what i understand, in the "adjustments" - Hydraulic Unit Bleed. I've never had the need to do this so I'm just away to run MES in simulate mode and look for it.

I haven't had the van for long. Pretty sure it was involved in some light accident in the past so might have had to be removed. I guess I will try to bleed it normally and see if it improves things

 

[Pugglt Auld Jock]

I haven't had the van for long. Pretty sure it was involved in some light accident in the past so might have had to be removed. I guess I will try to bleed it normally and see if it improves things

Just been into my MES and I can see lots of options for opening and testing the ABS valves. I'm not really very sure how to do the bleed though. I'll be asking the lads down at Harrison's next time I'm in there. In all the years I've been messing about with cars I've never had the need to do an ABS bleed but I'm always very careful to ensure the system stays full of fluid by air locking the master cylinder cap and/or blocking the end of any pipes when I open them to air.

 

[chris3234]

Just been into my MES and I can see lots of options for opening and testing the ABS valves. I'm not really very sure how to do the bleed though. I'll be asking the lads down at Harrison's next time I'm in there. In all the years I've been messing about with cars I've never had the need to do an ABS bleed but I'm always very careful to ensure the system stays full of fluid by air locking the master cylinder cap and/or blocking the end of any pipes when I open them to air.

Does it not have a bleed procedure listed?

 

[Popitinpete]

Yes it is definitely going to the floor and needs to be pumped a few times afterwards to get some feel back to the pedal. This only happens when the abs system is triggered. However I am 100% sure it is not normal as i have other cars with abs and none behave like this.

Sounds like it has been disturbed in the past then possibly, taken off when in the accident maybe? sounds like the ABS pump needs bleeding, it's done in 'service mode' via a laptop usually. I would take it to an independent fiat specialist and have it done

 

[portland_bill]

... whenever I brake hard enough to activate the ABS

... i have other cars with abs and none behave like this.

First priority of course should be sorting the loss of brake pedal.
The Fiat genuine Panda manual shows the use of a pressurised pot, attached to the master cylinder to force the fluid through. No special instructions, just bleed at furthest wheel first, moving around to the nearest last, usual procedure. Gunson do an EeziBleed unit that uses air pressure for this task, but I've no idea if they have updated that to fit later reservoir caps. Used one only once, terrible mess, so needs care, and lots of rags. Otherwise, a normal bleed should work.

Apart from testing and teaching purposes, I have only felt ABS work once in my lifetime of driving. Your phrases suggest this is not an uncommon experience, which should be concerning you. You could do well to ponder all the circumstances when the ABS activated, and try to think what could have been different, could you have anticipated the event, or avoided it with earlier changes to speed or position, were there clues to others' actions, etc. Good luck, and take care out there.

 

[Popitinpete]

First priority of course should be sorting the loss of brake pedal.
The Fiat genuine Panda manual shows the use of a pressurised pot, attached to the master cylinder to force the fluid through. No special instructions, just bleed at furthest wheel first, moving around to the nearest last, usual procedure. Gunson do an EeziBleed unit that uses air pressure for this task, but I've no idea if they have updated that to fit later reservoir caps. Used one only once, terrible mess, so needs care, and lots of rags. Otherwise, a normal bleed should work.

Apart from testing and teaching purposes, I have only felt ABS work once in my lifetime of driving. Your phrases suggest this is not an uncommon experience, which should be concerning you. You could do well to ponder all the circumstances when the ABS activated, and try to think what could have been different, could you have anticipated the event, or avoided it with earlier changes to speed or position, were there clues to others' actions, etc. Good luck, and take care out there.

Owner states loss of pedal only happens when hard braking hard enough to activate the ABS. Pedal travel and feel is normal otherwise, he has to really try to make it go to the floor by basically making the car skid.