P38A Brake accumulator?

Andy Burrell · Feb 13, 2023

Driving in slow traffic, stop/start at the weekend my wife commented on the whirring noise coming from drivers side virtually every time I touched the brakes, her hearing is better than mine!
The noise is definitely the accumulator and it does seem to activate nearly every press of the brake peddle and takes a little while to stop if the car has been parked up for a bit.
How long and how often should it run for?

kermit_rr · Feb 13, 2023

every 4 presses of the pedal when its new. if its every press then you need a new one, i'd replace if its every other press. it should only run for a second or 2, if i recall

marjon · Feb 13, 2023

most say 4 pushes before pump kicks in when fully charged, still a few in reserve but will probably need a bit more effort.
As you say it takes a while to charge if its been parked up, is there a leak somewhere.
It should charge pretty quick even if the accumulator is fubar if it holds its pressure. but will come on quicker if it is when used. (does that make sense?)

Maybe pump is sus too
J

kermit_rr · Feb 13, 2023

it does lose some pressure over time and take 30-40 seconds from fully empty.

Datatek · Feb 13, 2023

Andy Burrell said:
Driving in slow traffic, stop/start at the weekend my wife commented on the whirring noise coming from drivers side virtually every time I touched the brakes, her hearing is better than mine!
The noise is definitely the accumulator and it does seem to activate nearly every press of the brake peddle and takes a little while to stop if the car has been parked up for a bit.
How long and how often should it run for?

It's the pump running and your accumulator needs replacing. The pump should run every third or fourth press of the brake pedal. bleed back when the car is parked is normal which is why the fluid reservoir rises above max when parked. An initial run is 30/40 seconds I guess and then just a brief run every third or fourth brake application.
The pump sounds OK to me.

Andy Burrell · Feb 14, 2023

Ordered an accumulator today

Datatek · Feb 14, 2023

Andy Burrell said:
Ordered an accumulator today

To replace it, you need at least 30 presses of the brake pedal ignition off to release any residual pressure, then it's simply unscrew the old one and on with the new one, no affect on the fluid.

romanrob · Feb 14, 2023

There'll be some leakage ( use a rag around the base) after which the reservoir will need topping up. I use a rubber strap wrench to get the old one off, although there is a nut at the base you can also use

Datatek · Feb 15, 2023

romanrob said:
There'll be some leakage ( use a rag around the base) after which the reservoir will need topping up. I use a rubber strap wrench to get the old one off, although there is a nut at the base you can also use

I have done a few, the leakage is very small and I have never needed to top up after fitting.

Grrrrrr · Feb 15, 2023

Datatek said:
I have done a few, the leakage is very small and I have never needed to top up after fitting.

Might be the diaphragm had failed and it was full of fluid.

Datatek · Feb 15, 2023

Grrrrrr said:
Might be the diaphragm had failed and it was full of fluid.

That is certainly possible, but the failed diaphragm on one of them actually blocked the pipe so not much came out although when shaken, I could hear the fluid inside .

romanrob · Feb 16, 2023

Datatek said:
I have done a few, the leakage is very small and I have never needed to top up after fitting.

But i guess you at least checked? right, which is the point...i have also done a few, and always ended up adding something, however small. Whereas RAVE wd have you do a full bleed, which I have never had to do/ always got away without

kermit_rr · Feb 16, 2023

romanrob said:
But i guess you at least checked? right, which is the point...i have also done a few, and always ended up adding something, however small. Whereas RAVE wd have you do a full bleed, which I have never had to do/ always got away without

Maybe the level was down slightly to start with? From pad wear etc

Andy Burrell · Feb 16, 2023

I have changed the accumulator without any spillage and an immediate improvement in every way. The old one had a bit of fluid in it but also found the brake fluid level was much to high so used a syringe to bring it down to the correct level, must admit hadn't checked it since I got the car

What's the best way to dispose of the old accumulator if it still had some pressure in it.

kermit_rr · Feb 16, 2023

Andy Burrell said:
I have changed the accumulator without any spillage and an immediate improvement in every way. The old one had a bit of fluid in it but also found the brake fluid level was much to high so used a syringe to bring it down to the correct level, must admit hadn't checked it since I got the car
What's the best way to dispose of the old accumulator if it still had some pressure in it.

much too high.. was this after the pump had stopped running?

Andy Burrell · Feb 16, 2023

kermit_rr said:
much too high.. was this after the pump had stopped running?

Yep to the top of the reservoir, I will keep an eye on it.

romanrob · Feb 16, 2023

Ok, well i forgot to add, that you top off with the ignition on and once the pump has done its thing. If you turn the ignition/ pump on you will see the reservoir level drop from where it was, and then you level off after that. Re accumulator, I've found a guy on ebay who will recharge the accumulators on an exchange basis for 85 pounds and I've got one of his to fit at the weekend - so probably worth hanging on to the accumulator in case you want to try the refilling route

Datatek · Feb 16, 2023

romanrob said:
Ok, well i forgot to add, that you top off with the ignition on and once the pump has done its thing. If you turn the ignition/ pump on you will see the reservoir level drop from where it was, and then you level off after that. Re accumulator, I've found a guy on ebay who will recharge the accumulators on an exchange basis for 85 pounds and I've got one of his to fit at the weekend - so probably worth hanging on to the accumulator in case you want to try the refilling route

Refurbing the the accumulator must be a bugger of a job.
I paid £85 for my last new one.

romanrob · Feb 16, 2023

Yes, thats what I paid last time too, but UK prices on them have increased big time. Hopefully just until post Brexit supply chains bed in

Grrrrrr · Feb 17, 2023

romanrob said:
Ok, well i forgot to add, that you top off with the ignition on and once the pump has done its thing. If you turn the ignition/ pump on you will see the reservoir level drop from where it was, and then you level off after that. Re accumulator, I've found a guy on ebay who will recharge the accumulators on an exchange basis for 85 pounds and I've got one of his to fit at the weekend - so probably worth hanging on to the accumulator in case you want to try the refilling route

He could have had my old one for free. I chucked it a few weeks ago.

P38A Brake accumulator?

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