A recharged accumulator is on its way.
Reading RAVE, I can see the guide for bleeding brakes.

Reading another forum (a long time ago) I think it talked about new acc being prefilled with brakefluid??

The one sent away for recharging was dry. There was a tiny amount of fluid in the hole that i unthreaded the acc from.

Am I missing something in RAVE?
Should the acc be full of air below the diaphragm? (Nitrogen above the diaphragm when fitted).
RAVE warns about catching fluid in a rag when removing acc.

Compressing the air under the diaphragm sounds OK but what stops brake fluid bouncing up displacing air into the pump? (not that I offroad it).

The scrap car I removed the acc from braked OK with the dry acc. That car managed two brake pedal pushes before the noisey pump ran. Current car, brake pump runs as soon as you touch pedal (this pump is very quiet, hard to hear in car).

Many thanks

There won't be any air in the accumulator as the high pressure Nitrogen above the diaphragm causes it to take up the entire space. The diaphragm will be hard up against the opening so you may get a tiny amount of air in there when you change it. You won't need to fully bleed the brakes after changing, just bleed any air out at the first bleed nipple on the brake modulator (the first step in the bleeding process). The most important thing is to de-pressurise the system before unscrewing the accumulator unless you want a brake fluid shower.

Diaphram taking up whole space makes sense (now you've explained it).

The old one seemed to have a void that could hold air, but the recharging guy is happy.....

Get all the pressure out of the system (ignition off, loads of pedal presses...

New oring, RAVE bleed step1 and see if the 3 amigos run for the hills. Hopefully the motor doesn't run every time the pedal is touched and ABS faults are not reported when crawling with foot on brake. Of course, this could just be the first of the worms from a freshly opened can...

Thanks again

Although RAVE bleeding process step 1 should be all you need to do after changing the accumulator, if you need to do it at all. My new accumulator just when straight on and the pedal was solid.

But best practice would be set up with the car lifted and all four wheels off then do the whole darn procedure for bleeding and fluid change. Three hours of your life you won't get back but job will stay done for a few years. When the can says "Heinz 666, Worms, Large" its generally false economy to try a short cut. If the short cut fails it always seems to take far longer to re-set into proper procedure mode than it would have done to set-up right in the first place.

Trying a not quite so short cut partial procedure after the short cut fails is generally a very bad idea. Especially on a P38 which is so brutally intolerant of not to book approaches in many areas. There are some non book ways that work just fine in the right places but you must read up and understand when they are appropriate. Experienced "I don't need no workshop manual" mechanics steaming in and trying to treat a P38 like an Austin 7, or maybe Moggie Thousand, is a major reason for the P38 un-reliability reputation.

Before doing the full bleed procedure print yourself off a couple of check-lists so you and your assistant can tick things off as you go. So easy to get muddled and out of order first time through. If you have RAVE on the computer printing out the relevant pages and sipping them into loose leaf ring binder transparent wallets as a mini manual to take out to the car is a great help. Over the years I've accumulated a number of such mini manuals which have proved very useful when aged memory lets me down.

When it comes to working on a new to you P38 the motto has to be "Hope for the best. Prepare for the worst. Expect to find evidence of sub room temperature IQ mechanics.".

Clive

PS If you've not already got a set do get the proper partial hex brake pipe spanners before you start so you don't round off a bleed nipple or finally wreck a partially rounded one assaulted by Mr Open End Is Fine.

Hi Clive, thanks for the great explanation.

There is no shortage of tools at my place 😉. Favorite phrase 'all the gear and no idea". Pipe spanners, hex sockets etc. I've had many years of snapping screws, stripping threads and chiselling delicate castings when filth is covering that last bolt.

I'm sure to make many more mistakes, if I ever feel I can't learn, that's when I'll stop.

I had a contract at a print shop and they kindly printed the manual for me. I do have garage laptops (running rave and other 'pro' software as VMs).

Before starting the full bleed, I will 'crack' all the nipples and retighten. I understand a full bleed is an excellent idea, especially given mileage and unknown history. There is a little job to be done for a ball joint boot (hoping the boots I have will fit) and a lightly corroded hose that wants checking.

This is one of those cars where I thought I knew enough to identify the usual problems. I was wrong. Lots to do, careful prioritising required.

One thing for sure, without guidance from real people who have actually done the jobs (like Gilbertd and yourself), I wouldn't even attempt this sort of thing. RAVE is great, but I need to use it in conjunction with access to a forum like this with patient people.

Thanks again, hopefully the acc will arrive this weekend and the car will remain driveable.

I can relate to everything said here. I bought my P38 (for £600) with 205k on the clock, a burst rear air spring and running on 7 due to a head gasket blowing into the Vee. Got both of those done in the first couple of days of ownership and started using it. For the first 18 months or so, I didn't trust it as far as I could throw it. Every time I used it, something else packed up but after working my way through everything, I finally got it to a state I was happy with. Everything worked and it seemed reliable. By 287k miles though the engine was getting decidedly tired and I had a dilemma. Did I spend my money on rebuilding the engine or did I sell it and replace it with a newer, lower mileage one? I decided that I wouldn't get a lot for it as the odd police spec, high mileage and tired engine meant it wouldn't appeal to that many people and if I bought another I would only have to start again doing all the odd jobs I'd already done on mine. People rarely sell a car that is perfect, they sell it for a reason. So I decided to stick with the devil I knew and it still repays me for the attention I've given it every time I use it now.

Recharged accumulator fitted.
Three amigos have run for the hills.
I can now creep along without abs faults.
Pedal no longer creeks.
Brake motor only runs every three presses (not every time I touch the pedal).

The pedal was pumped over 50 times to depressurise before I removed the old accumulator. When I did this on the donor car, the acc came off dry (diaphragm was intact on that one).

When removing the acc from the running car, the kitchen roll was overcome when the old acc dumped ~50ml of fluid. This fluid was NOT under pressure. The diaphragm was totally split and the acc was carrying a lot of brake fluid.

Clive/Gilbert- thanks for the bleeding advice. I haven't done the full bleed yet, but looking at the colour of the fluid - this is well overdue.