abs pump failing?

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abs pump failing?

safraneman

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Dec 7, 2019
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Hi, any clues please my ABS pump appears to have a fault.
Doblo JtD1.9 2008 model under ABS braking the pedal goes soft until I run out of brakes...has me reaching for the handbrake,
This only occurs when the ABS is functioning (normally)
tried downhill 50 mph emergency stop on a dry road - no problem
No warning lights
tested on a level icy road at 30 mph, ABS functions but during braking period of 3 or 4 seconds the brake pedal gradually goes to the floor whilst still vibrating due to ABS functioning
Or could it be a failing master cylinder?
Fluid level ok - passed MOT a few months ago - no leaks.
Cheers Safraneman
 
From your description it definately sounds like fault with the abs unit.

Replace the abs unit (unit from a breaker/ebay likely most economical) and please report back.

I had a similar issue with a Skoda Octavia where one of the 2 pistons in the bosch abs unit was stuck fully down in bore.
The pedal vibrated at half expected frequency and sank toward floor when abs functioning. I removed the electric motor and managed to pull the stuck piston up(not out) so that the horse shoe shaped spring worked again. Refitted electric motor and all was good again. This was only feasible/economical because the position of the unit enabled motor removal without disconnecting any brake pipes.
No fault codes show with the above fault.


Good luck
Jack
 
ordered replacement hydraulic unit (and pump motor) from BBA £320
they diagnosed hydraulic seal failure
3 day delivery of FIAT ABS replacement, (Bosch equivalent over £500)
lots of head scratching by local reputable garages not familiar with this fault
Walter at BBA was able to diagnose the cause of the ABS fault over the phone
There are two captive seals within the hydraulic unit
one of these appears to have failed.
These parts are apparently not repairable and the seals would be hard to source.
Many thanks for your prompt response Jack, but I
chose to avoid scrap yard part
Tested the Doblo in a sloping iced over car park at 15 mph
the ABS kicked in and the brake pedal hit the floor in two seconds – very alarming - the car did not come to a halt until I left the slippery surface -
an experience I do not want to repeat especially since my Doblo is a WAV
 
ABS NOW WORKING
new valve body and motor arrived from BBA
fitted and bled £80 labour
all sorted
Been out to local "ski "slope ABS tested and working fine
What a relief
Surely there must be a safer way of detecting ABS valve failure than it actually failing? I suspect it has been failing for years, but despite a FIAT garage diagnostic test and lots of scratched heads over the years - the clues were never joined up...
Could not find the correct fuse to disable it
As far as I could understand it was No 42 a 7,5 amp fuse
could find fuse nos 41 and 43 but not 42...
do you have to be a magician to fix these things
After a new clutch, gearbox lots of brake callipers and EGR problems
what else do i have to look out for on a 100,000m 1.9 JtD Doblo 2008
Fingers crossed that the Servo never fails - looks like releasing the engine mounts might be on the job list to replace that!
 
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