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Flashing abs light

Posted: Wed Jan 02, 2019 12:01 pm
by POE
Hi , my abs light has suddenly started flashing , had it before when light stays on but not flashing? Any ideas ? Thanks

Re: Flashing abs light

Posted: Sat Jan 05, 2019 10:07 am
by brinkie
Your car is a 1989 Turbo if I have read your signature correctly, that means your car has the infamous ATE MkII ABS system installed.
Is it flashing with the engine running, when you hit the brake pedal or just when the ignition is on? It could have multiple causes, the most likely (and most expensive to rectify) cause is a leak in the black sphere on top of the brake cilinder. This is a pressure accumulator and also acts as a brake booster. Did you notice any problems or differences in braking?

The same ABS can be found in Jaguar, Saab, Mercedes and Alfa cars from the 1990s. I have found a test procedure online: http://www.saabservices.com/saab_abs_li ... light.html

"With the key in the run position and the engine off, (radio off too!) pump the brake pedal until you hear the pump begin to run. Listen for the pump to stop running. Then step quickly and firmly on the brake pedal 10 times in about 5 seconds. If the brake fluid and antilock lights come on prior to the 8th repetition you should replace the accumulator. If the lights come on within 4 repetitions, consider the vehicle unsafe and replace the accumulator immediately."

Another useful document about the MkII ABS:
https://www.alfabb.com/bb/forums/attach ... system.pdf

Re: Flashing abs light

Posted: Sat Jan 05, 2019 9:19 pm
by balto8
Now comes the issue of finding a suitable replacement at "non Jaguar" prices. I've been searching for a suitable replacement at a “480“ price. It looks like mitsubishi pajeros should fit, also Ford Sierra, Granada, Scorpio and some VW of the same era share the same sphere. It would need to be checked that the thread size is the same as I've found some as cheap as 80$ and some others for 400€. Thread size is 0.52 inches / 13.3 mm. Inner diameter 6 mm.

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Also useful info here

https://www.rangerovers.net/repairdetai ... c/abs.html

And here

viewtopic.php?t=35151

Would this one fit??

https://www.ebay.es/itm/For-Mitsubishi- ... 1438.l2649

Re: Flashing abs light

Posted: Sat Jan 05, 2019 9:34 pm
by jamescarruthers
Why can it not be recharged like a Citroen suspension sphere or accumulator?

Re: Flashing abs light

Posted: Sun Jan 06, 2019 12:52 pm
by POE
Hi , thanks for reply , it flashes while running and i think i have a spare accumulator hiding in shed ,so does it basically screw off ?? Thanks again "kev"

Re: Flashing abs light

Posted: Sun Jan 06, 2019 5:24 pm
by balto8
Yes. It does screw off. But you'll need to link some kind of rod to make lever with the allen key. Put lots of paper around the abs pump as a good quantity of brake fluid will come off the accumulator. I have asked some of the Ebay sellers about the thread size and I am waiting for answer to ckeck compatibility.

Re: Flashing abs light

Posted: Wed Jan 09, 2019 3:43 pm
by nicklee
it might be worth considering that these accumulators only last about 8 years because the high pressure nitrogen gradually creeps out of them, i think even when they aren't in service. So if the one in your shed has been sitting around for a long time it might not be any better than the one in the car...

Re: Flashing abs light

Posted: Wed Jan 09, 2019 3:53 pm
by jamescarruthers
nicklee wrote:
Wed Jan 09, 2019 3:43 pm
it might be worth considering that these accumulators only last about 8 years because the high pressure nitrogen gradually creeps out of them, i think even when they aren't in service. So if the one in your shed has been sitting around for a long time it might not be any better than the one in the car...
I've spoken to Pleiades‎ and they are willing to have a go at recharging your accumulator-- I guess it depends on whether they have the right threaded adaptors, but I would be pretty hopeful as they say they recharge other accumulators. Personally I would send your spare there to get it recharged then swap it in to the system. ‎ Is the pressure written on the side or do we need to start digging through books to find this info?‎

The price would be £45, which isn't exactly cheap but I think is cheaper than a new one. On hydraulic Citroen's the spheres can be recharged indefinitely as long as the sphere is okay and the membrane inside is still good.‎

You can ask for Martin who runs the place although it was his colleague who I spoke to who said they could do it. If you speak to Martin, tell his James Carruthers sent you (Geordie with BX, XM and C6's in the past).

01487 831239
‎Unit 12a  ,Brookside Industrial Estate
Sawtry
Huntingdonshire
United Kingdom
PE28 5SB‎

Re: Flashing abs light

Posted: Wed Jan 09, 2019 4:10 pm
by nicklee
the recharge is certainly worth a go! £45 is a quarter of what I paid Jaguar for a new one ;)

Autozone seems to think:

"Nitrogen in the accumulator is pre-charged to approximately 870 psi. During normal operation, the pump and motor assembly charges the accumulator with brake fluid to an operation range of 2000-2600 psi."

https://www.autozone.com/repairguides/G ... 528004ab76

Their figure for the brake fluid pressure is correct as far as i'm aware so the nitrogen figure could well be accurate too...

Re: Flashing abs light

Posted: Wed Jan 09, 2019 5:38 pm
by jamescarruthers
Just checked my book:

Accumulator:

Capacity: 250cm^3
Operating pressure: 135-190-bar
Initial pressure, upper chamber: ‎88 bar
Minimum pressure, upper chamber: 33 bar

The book also says "the upper chamber is filled with nitrogen gas to a pressure of 8.4 MPA (84 bar)..."

84 bar = 1218.3 psi‎

Re: Flashing abs light

Posted: Wed Jan 09, 2019 6:06 pm
by POE
Thanks everyone for their input and hopefully get some time this weekend to sort accumulator out , thanks for the info on getting recharged and definitely be giving it a go and hopefully fixes problem 😁

Re: Flashing abs light

Posted: Thu Jan 17, 2019 12:05 pm
by balto8
The guy from this Ebay add came back to me

https://www.ebay.es/itm/For-Mitsubishi- ... 1438.l2649

Size of the thread is correct: 13mm

I have asked him about working pressure ranges but I doubt he'll be able to answer this one

So it is just a matter of givin the thing a try. I will in the next months as I've recently gone through ITV/ MOT after a few months fixing things and I am not ready yet to put the car back in the garage, just want to enjoy the car for a while longer.

Re: Flashing abs light

Posted: Thu Jan 24, 2019 7:13 pm
by nicklee
Just a thought on this. When you refit the accumulator (whether it's new or recharged) you should use a new small rubber washer with a circular cross section. Unhelpfully i have no dimensions for this, but one came with my jaguar accumulator. Without this - and given the pressure the break fluid is under - the accumulator may not seal...

Re: Flashing abs light

Posted: Sat Apr 18, 2020 8:23 am
by Gez72
Hi , can you update me on this thread , my accumulator on my 1990 480 is showing the same symptoms and looks like it needs replacing or recharging . Just need to know where I can get one and also if anyone has had any success in re charging one

Thanks

Re: Flashing abs light

Posted: Sat Apr 25, 2020 9:26 pm
by balto8
As final info related to the MKII ATE ABS pressure accummulator.

First read this https://www.volvo-480-europe.org/forum/ ... hp?t=35151
The cheap option fitting part is WABCO STC2784 https://www.island-4x4.co.uk/pump-accum ... -1024.html
Thread size is the same. The original one is tightened with an allen key on top, but this one needs a 16mm on the bottom. I tightened it with an oil filter tightener. Comes with the O ring.
Braking now feels much more firm, as it should be. Prior to the bottle replacement I could make the ABS warning light depressing the brake pedal 7-8 times, now the thing holds it's pressure right and I can press the pedal over 25 times before the pump starts to build pressure back in the bottle.

Fast, non expensive replacement that should be done to any MKII ABS if you haven't done yet.

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Re: Flashing abs light

Posted: Sun Apr 26, 2020 8:18 am
by jamescarruthers
This is invaluable information to keep a big section of 480s on the road. Thanks so much!‎