P38: Is it my brake accumulator

[RatCav]

Hi there

Been doing lots of reading and cross referencing and I think I know the answer, but would like to confirm.

ABS and Traction control light will always stay on a while after start up (30+ secs or so). I can hear a pump going for it from under the hood (could be either the suspension or brake pump .. not sure as both fitted and both plugged in).

While the lights are on the pedal is soft and not much braking is had even with the foot to the floor.

When lights go off the truck brakes on the button (new pads and disks all round and calipers cleaned and greased).

Every now and then the pedal will go softer, and sometimes the ABS/TC lights come on and the brake pedal is so soft it will go to the floor at the slightest touch and little/no braking will happen.

I can hear a pump going on/off all the while the truck is running. As said I am unsure if it is the EAS or brake pump. Haven't looked that far.

Am I right this is early signs the brake accumulator is on its way out?

Cheers

Neal

[zim]

When you drive along, lights are off, put on brakes - it brakes ok, but then lights come on and pump kicks in. (Basically nothing is being stored in the accumulator)

If the above is true, then i'd put money on it being the accumulator unit.

They're easy to swap.

G

[RatCav]

That's about it .. suspicions confirmed. Cheers.

[duncmc]

Or you could have air in the system.

[Aragorn]

I'm going to join in with this thread rather than starting my own.

Just took my new P38 along for its MOT. First time i've driven it on the road, and its apparent theres a braking issue with it.

The pedal is very soft with lots of travel and doesnt do much. Every time you brake, the ABS/TC lights come on, then go out again. If you really heave on the pedal it feels like its pulling to one side.

Is it worth trying to "normally" bleed the brakes first? or is it fairly certain that its the accumulator thats failed?

[elbekko]

Can you actually hear the ABS pump running? Check the fuses and relay first.

[Aragorn]

i can certainly hear something buzzing away when i turn the ignition on. Will need to put my head under the bonnet to verify its the ABS pump.

Nice failure sheet:

https://www.dropbox.com/s/x2gjeb1u6lu4znd/Vehicle%20MOT%20History%20-%20GOV.UK_2016-09-07_12-00-47.png?dl=0

[Aragorn]

Ok so went and collected it and had a quick check of the brakes.

Ignition off, pumped pedal 30 times. Pedal remained spongey with lots of travel, felt like a normal car with air in it, rather than going rock hard like a car would normally do after you've used up all the assistance. Not sure if thats normal on a rangey, i suspect not.

Ignition on, listened for pump, pump ran for approx 5 seconds then stopped. A single application of the brakes caused the pump to fire up and run for about 1-2 seconds.

I'm thinking theres probably two faults here, i think theres air in the system and it needs bled, and i think the accumulator has failed. What do you think?

In good old p38 fashion its also managed to develop faults it didnt have before, the bonnet catch is now not catching on the drivers side, and theres a "bonnet open" warning that wasnt there before. GRR

[David Sparkes]

In good old p38 fashion its also managed to develop faults it didn't have before, the bonnet catch is now not catching on the drivers side, and there's a "bonnet open" warning that wasn't there before.

That's because the switch that monitors the bonnet open (or closed) condition is on the RH catch, thus if the RH catch (UK drivers side) fails mechanically you get the warning.

The snag you find is that the battery is in the way, and when you remove the battery, if the correct procedure isn't followed, the alarm battery is tested, and life gets noisy (or you find another fault).

Copious spraying of the mechanism and exposed cable with a 'universal lubricant', perhaps after removing the external radiator grill, plus repeated exercising of the release cable and mechanism, may bring a temporary reprieve.

Note that disconnecting the battery, correctly or incorrectly, will trigger 'not set' alarms for all four windows, and the sunroof (if fitted), when the battery is reconnected.

Universal tip for those new to the 38A:

Never EVER leave your keys in the car, on the seat or in the ignition, UNLESS you have wound the drivers window fully down, so you can recover the keys after the auto-locking of the doors takes place.

Regards.

[Aragorn]

yeh i guess its just got stuck, just typical that its working fine and i've had the bonnet up and down numerous times until the MOT guy manages to break it.

I've only got one key, and the fob doesnt work, so removing the battery probabaly isnt the best idea at this stage I do have the security code thing though. Another job on the todo list!

[RatCav]

Swapped accumulator and system works fine and dandy. Lights go out almost immediately on startup. Just got to find the dodgy ABS sensor now.

 

Cheers for the help peeps.