P38_Ireland · Sep 9, 2011

Hi Lads,

just checking, sometimes in the morning when i start up the TC, ABS lights dont go out straight away, and the pedal is very soft. i can hear the vacuum pump
working form when the key goes in the ignition. i did notice last week when i braked hard the ABS flashed on the dash for a split second too.

IM guess a new vacuum pump?? what you think?

jamesmartin · Sep 9, 2011

shouldnt think , air or poor fluid

P38_Ireland · Sep 9, 2011

poor fluid?? would that effect the vacuum? the fluid level is fine. and what "air" are you talking about?

Datatek · Sep 9, 2011

P38_Ireland said:
poor fluid?? would that effect the vacuum? the fluid level is fine. and what "air" are you talking about?

It's not a vacuum pump, it's an electricaly driven hydraulic pump. Air in the system, tired fluid or the accumulator is shot.

rasheed · Sep 9, 2011

money's on accumulator. also don't bother with the rave million step process, just unscrew the old and screw in the new, works fine!

Dimebag 666 · Sep 9, 2011

My ABS pump makes loads of noise when fired up 1st thing. Think this is just the hydraulics primeing. Soft pedal is usualy sign of air in the system.

Datatek · Sep 10, 2011

Dimebag 666 said:
My ABS pump makes loads of noise when fired up 1st thing. Think this is just the hydraulics primeing. Soft pedal is usualy sign of air in the system.

Or in the case of the P38, a failed accumulator

gfromleeds · Sep 10, 2011

Mine does exectly this and i thought of bleading too.didnt help
After reading this gona try acumilator? Where is this and what does it look like and how easy is it to change?

wil2813 · Sep 10, 2011

accumulator

Datatek · Sep 10, 2011

gfromleeds said:
Mine does exectly this and i thought of bleading too.didnt help
After reading this gona try acumilator? Where is this and what does it look like and how easy is it to change?

Small lump that looks a bit like a gas cylinder, drivers side just in front of the fluid reservoir. Make sure you pump the brakes a few times (LR say 30 times) to release all the pressure in the system then just unscrew it and screw the new one on. Only relevant if the pump runs everytime you touch the brakes or even worse if it runs all the time. Otherwise air in the system or tired fluid.

gfromleeds · Sep 10, 2011

Datatek said:
Small lump that looks a bit like a gas cylinder, drivers side just in front of the fluid reservoir. Make sure you pump the brakes a few times (LR say 30 times) to release all the pressure in the system then just unscrew it and screw the new one on. Only relevant if the pump runs everytime you touch the brakes or even worse if it runs all the time. Otherwise air in the system or tired fluid.

Yup sounds like it
Just checked it and the pump runs every time i stamp on the brakes plus it still quite warm after a run about half an hour ago
is this somthing that could pertantialy lead to brake failure?

rasheed · Sep 10, 2011

No. It will lead to loss of ABS and TC and you'll have to stand on the brake with both feet but this will not lead to failure. There are failsafes built in for precisely that reason.

P38_Ireland · Sep 11, 2011

good answers lads, have a spare in the garage, will fit it and see if theres a difference. thanks guys

gtland · Sep 11, 2011

When you bleed the brakes do it as per RAVE. It really does make a difference. Rasheed and Datatek are right that changing the accumalator is done to death in RAVE, but the bleeding procedure does need to be followed. And unless anyone knows differently it needs two people.

rasheed · Sep 11, 2011

its not necessary to bleed them if only doing the accumulator (but do depressurise first as Data said and I forgot to mention). however if you do decide to bleed them then gtland is right, you should follow rave precisely and it does take two people. and if you're doing all that you may as well change out the brake fluid because you've done 70% of the job anyway.

incidentally, be careful how you dispose of the old accumulator as it'll still be capable of a respectable little "ka-boom" if someone were to decide to drill it or cut it with a flame etc. etc...

seanmull · Sep 11, 2011

if you need to bleed the brakes hope you dont have to bleed them on your own its not easy much easier with two people

tomcatrr · Sep 12, 2011

Don´t forget to bleed the modulator ( it´s easy).

I run 3 years with air in that.... I can´t believe the air that was leaving from the "master" bleed

gfromleeds · Sep 22, 2011

Right my new accumilator arived today how does it come off?
Do i just depresureze and unscrew? Will i need any tooling to get it off? Do i need to bleed it or anything after?
Im only gona get one shot at this cos im going away tomorrow so has to be done right first time tonight
Anyone offer any advise of anything i should do/look out for?

Endeleus · Sep 22, 2011

I did my accumulator last week using this method with no problems...

Depressurise the system - with the ignition off, depress the brake pedal fully 30 times, then wait a couple of minutes, and do another 5

Wipe round the bottom of your accumulator (I used a degreasing wipe) so you don't knock any grime in to the pipe when you take it off.

*** Place some rags round the bottom of your existing accumulator to catch spilt fluid when you take it off ***

I used a chain wrench to get my old one off - was easier then trying to get enough force with a spanner on the bottom nut

Fit the O ring to the new accumulator and screw in to place. (I did mine hand tight, then used a strap wrench to tighten properly).

I didn't need to bleed my brakes, and the ABS / TC warning lights which have been intermittent for a while have gone out at last.

P38_Ireland · Sep 22, 2011

Endeleus said:
I did my accumulator last week using this method with no problems...

Depressurise the system - with the ignition off, depress the brake pedal fully 30 times, then wait a couple of minutes, and do another 5

Wipe round the bottom of your accumulator (I used a degreasing wipe) so you don't knock any grime in to the pipe when you take it off.

*** Place some rags round the bottom of your existing accumulator to catch spilt fluid when you take it off ***

I used a chain wrench to get my old one off - was easier then trying to get enough force with a spanner on the bottom nut

Fit the O ring to the new accumulator and screw in to place. (I did mine hand tight, then used a strap wrench to tighten properly).

I didn't need to bleed my brakes, and the ABS / TC warning lights which have been intermittent for a while have gone out at last.

how did you depressurize the system?

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