P38A brake system pressure

kermit_rr · Jul 2, 2021

system pumps up to pressure when you start up no problems and the accumulator is healthy enough with the pump only running briefly on every 4th pedal press, so far so good.
once the engine is switched off, it seems to lose huge amounts of pressure and seems to be getting worse. theres no leaks, i've never had to top up the brake fluid so i'm assuming there is a seal somewhere (in the pump?) letting oil past, back to the reservoir?
Is there anything else it could be or any checks I should do?

tomcat59alan · Jul 2, 2021

Any air in the system? Did you let the system pressurise before topping up to the full line on the reservoir?

kermit_rr · Jul 2, 2021

I've not checked for air but I've never had a soft pedal. I've never had to top up but it's due for a fluid change.. if there's a problem that's fixable I'd rather do that before going through the ordeal of a flush

RangeRoller dt · Jul 2, 2021

When’s last time you changed the fluid?

kermit_rr · Jul 2, 2021

Ages ago, do you think that's the problem?

RangeRoller dt · Jul 2, 2021

My accumulator isnt great but okay. It keeps pressure for while after shut down unless I repeatedly pump the pedal with it off. I have changed my fluid regurlarly though, just thought if it’s stuff that came with the vehicle could be yonks old. May not feel it with the servo system?

kermit_rr · Jul 2, 2021

I replaced the accumulator soon after i got it, brakes have been perfect, just loses pressure after an hour or 2, used to take overnight

RangeRoller dt · Jul 2, 2021

I wouldnt worry. Unlikely you will need the brakes 2+ hrs after switching it off, if you do turn it on again

Check for leaks or bubbles see what you can find. fluid hasn’t gone down probably not a fluid leak.

kermit_rr · Jul 2, 2021

I worry because what if it gets to the point where the pump is running all the time?

RangeRoller dt · Jul 2, 2021

If it holds pressure and brakes well it works? If it comes to ^^^ then you fix it. Don’t think it warrants replacement yet at four pumps but keep an eye on it like we all do

Nothing wrong with further investigation

kermit_rr · Jul 2, 2021

You mean ignorance is bliss?

RangeRoller dt · Jul 2, 2021

They are designed to work with engine running. works 2 hrs after is overkill

RangeRoller dt · Jul 2, 2021

You’ve got me thinking about new callipers now

£70 I want them but got enough to do with screen and mot

Grrrrrr · Jul 3, 2021

kermit_rr said:
system pumps up to pressure when you start up no problems and the accumulator is healthy enough with the pump only running briefly on every 4th pedal press, so far so good.
once the engine is switched off, it seems to lose huge amounts of pressure and seems to be getting worse. theres no leaks, i've never had to top up the brake fluid so i'm assuming there is a seal somewhere (in the pump?) letting oil past, back to the reservoir?
Is there anything else it could be or any checks I should do?

Is there a pressure regulator anywhere?

kermit_rr · Jul 3, 2021

Grrrrrr said:
Is there a pressure regulator anywhere?

There's a pressure switch

P38A brake system pressure

kermit_rr

Very

tomcat59alan

Well-Known Member

kermit_rr

Very

RangeRoller dt

Well-Sprung Member

kermit_rr

Very

RangeRoller dt

Well-Sprung Member

kermit_rr

Very

RangeRoller dt

Well-Sprung Member

kermit_rr

Very

RangeRoller dt

Well-Sprung Member

kermit_rr

Very

RangeRoller dt

Well-Sprung Member

RangeRoller dt

Well-Sprung Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

kermit_rr

Very

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