Hydraulic "bomb" pressure unit

urquattr085 · 18-11-17, 10:03 PM

Hi all

Need some help/guidance please

Disassembled the hydraulic pressure unit on my car only to find there is no O-ring (item 3 in diagram below)

Part no. 857612079, does anyone have the spec/size for this, can't find it anywhere on line or one for sale!

Many thanks

Geoff

mikes2 · 18-11-17, 10:43 PM

Judging by the diagram, a new accumulator will come with the o-ring

urquattr085 · 18-11-17, 10:49 PM

Hi Mike.
Accumulator is working fine so don't need to replace.
Have been going through all the hydraulics with new copper sealing rings to cure a couple of leaks & noticed lack of O-ring when I came to refit to the regulator

urquattr085 · 20-11-17, 10:25 PM

After lots of cross-referencing part numbers/suppliers, it would appear this pressure unit is also used on some late 70's & 80's BMWs, notably 6 series.

Research into these cars & parts indicates the o-ring on the brake pressure accumulator is 15.3x2.4mm.

Ordered a pack of 2 for the grand sum of £4.06

Will see how they fit & post result for future reference.

sinbin5t · 21-11-17, 06:58 PM

Only just seen this

must have been

, well done finding that tiny part with a cross reference to BMW.

urquattr085 · 21-11-17, 07:03 PM

Quote:

Originally Posted by sinbin5t

must have been

Would be more like it .....

Hours of research, they are on their way, will be happy to post that they fit

sinbin5t · 21-11-17, 07:06 PM

Quote:

Originally Posted by urquattr085

Would be more like it .....

Hours of research, they are on their way, will be happy to post that they fit

Yep Z's galore i think

I am sure they will be bang on and you will be a happy man !

vorsprung durch technik · 21-11-17, 07:21 PM

Quote:

Originally Posted by urquattr085

Would be more like it .....

Hours of research, they are on their way, will be happy to post that they fit

As Bruce i also missed this one, well done for spending hours cross referencing, hopefully we will all benefit form your tenacity. Nice one.

urquattr085 · 21-11-17, 09:29 PM

Quote:

Originally Posted by vorsprung durch technik

As Bruce i also missed this one, well done for spending hours cross referencing, hopefully we will all benefit form your tenacity. Nice one.

Ta

I actually really enjoy that sort of research. Surprising what else you find out.
What else is there to do on these dark nights

sinbin5t · 21-11-17, 09:53 PM

Quote:

Originally Posted by urquattr085

Ta

I actually really enjoy that sort of research. Surprising what else you find out.
What else is there to do on these dark nights

That could be misconstrued

18-11-17, 10:43 PM	#2
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	Judging by the diagram, a new accumulator will come with the o-ring __________________ 1991 90 quattro 20v sport 1991 90 quattro

18-11-17, 10:49 PM	#3
urquattr085 Senior Member Classic Audi Club Member Join Date: May 2016 Location: Displaced Northerner in Essex Posts: 1,528	Hi Mike. Accumulator is working fine so don't need to replace. Have been going through all the hydraulics with new copper sealing rings to cure a couple of leaks & noticed lack of O-ring when I came to refit to the regulator __________________ 1985 WR quattro 2010 A6 3.0Tdi Allroad 2010 A3 1.4 tfsi Sport - Sold but still in the family 1984 80 Quattro - Sold many moons ago 1981 Coupe GT - Sold to buy above

20-11-17, 10:25 PM	#4
urquattr085 Senior Member Classic Audi Club Member Join Date: May 2016 Location: Displaced Northerner in Essex Posts: 1,528	Update After lots of cross-referencing part numbers/suppliers, it would appear this pressure unit is also used on some late 70's & 80's BMWs, notably 6 series. Research into these cars & parts indicates the o-ring on the brake pressure accumulator is 15.3x2.4mm. Ordered a pack of 2 for the grand sum of £4.06 Will see how they fit & post result for future reference. __________________ 1985 WR quattro 2010 A6 3.0Tdi Allroad 2010 A3 1.4 tfsi Sport - Sold but still in the family 1984 80 Quattro - Sold many moons ago 1981 Coupe GT - Sold to buy above

21-11-17, 06:58 PM	#5
sinbin5t 4 ring whore! Classic Audi Club Member Join Date: Jan 2010 Location: Where a spike points skywards Posts: 12,960	Only just seen this must have been , well done finding that tiny part with a cross reference to BMW.