South African Audi 500, 1989 (same as Audi100 type 44 in Europe/USA)

Hi again,

I have the following problem: I finally figured out that my brake
accumulator (the "bomb" mentioned so often) is not working either. I
always suspected that the breaks didn't work as well as they should
when pressed suddenly, but after I read the infos on sjm and in other
places, I am sure it's the bomb. When the engine is running, the break
pedal can be pressed down, but there is a brief delay and then it
moves further down. With the engine off, there is no more action.

The local audi dealer wants the equivalent of US$ ~500 for a
refurbished one, which is far beyond what I want to spend on it now.
There don't seem to be any other sources in South Africa and when I
spoke to a power steering repair place, he said the only alternative
was the scrap yard and that a lot of those would be around there. I
asked him how I could know whether I pick up a good or bad one, but
his only reply was "bring it along, we will put it in and tell you"
Scrap yards here take things back and return the money, so that's not
the problem. However, I would have to do quite some driving to get to
the nearest one and I don't want to change around break bombs until I
find a good one.

With no MOT here and generally little regard for safety, it is very
likely that a lot of the break bombs on old Audis don't work any more.
To be honest, it took me some time to figure out that I have a
problem.

My question: Is there any way I can see on the scrap yard whether I
get one which is still ok or whether it is gone as well? I understand
that there is a gas reservoir under pressure in there which looses
gas. Is there any way I could look into the bomb to see whether the
divide is still at the right place, or push a wire or little stick in
or anything else?

Or is there maybe any way to distinguish between a factory refurbished
and an original one? If it is refurbished, there is a good chance that
the owner had it replaced not too long ago?

One more question: How compatible are they over the years? Can I get
one from a younger car and still put it in, or is this asking for
trouble?

Thanks a lot for your help,

Christoph

P.S. I am still busy with the speedometer. I got quite a bit further
and will post the final results as soon as I get it all done. Just one
hint for now: Twisting the needle counter-clockwise did the job to get
it off.

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> Hi again,
>
> I have the following problem: I finally figured out that my brake
> accumulator (the "bomb" mentioned so often) is not working either. I
> always suspected that the breaks didn't work as well as they should
> when pressed suddenly, but after I read the infos on sjm and in other
> places, I am sure it's the bomb. When the engine is running, the break
> pedal can be pressed down, but there is a brief delay and then it
> moves further down. With the engine off, there is no more action.
>
> The local audi dealer wants the equivalent of US$ ~500 for a
> refurbished one, which is far beyond what I want to spend on it now.
> There don't seem to be any other sources in South Africa

Hi Christoph, here in UK I managed to source a refurbished "bomb" from a
Citroen Hydraulics specialist company. I paid less than a hundred UK Pounds
(180 or so US Dollars) including delivery.

http://www.pleiades.uk.com/

I don't know if Citroen vehicles are prevalent in your Country, or if any
similar company to the above exists. You may wish to make similar searches
in South Africa.

Regarding differentiating a good from a bad bomb if you do tour the
scrapyards would be along these lines....
1.Maybe.....
Failure of a bomb would be as a result of loss of pressure/gas on the
nitrogen side of the rubber diaphragm.
In which case, would the hydraulic oil capacity be higher for a defective
than a good bomb ? I seem to remember my fluid level diminishing as the bomb
died. Sorry I don't have the capacity of a good bomb to hand .....

2. A refurbished bomb is likely to have been repainted ? ( mine was )


regards
Ian

 

Hi Ian,

Thanks for your reply,

> Hi Christoph, here in UK I managed to source a refurbished "bomb" from a
> Citroen Hydraulics specialist company. I paid less than a hundred UK Pounds
> (180 or so US Dollars) including delivery.
>
> http://www.pleiades.uk.com/

I just sent them an email, let's see what they say.

> I don't know if Citroen vehicles are prevalent in your Country, or if any
> similar company to the above exists. You may wish to make similar searches
> in South Africa.

Citroen is not very common here (unlike Audi). Power steering pumps
etc are no problem to get refurbished, but the break bomb seems to be.
I got the impression, almost no-one cares, if it's gone. The Audi
dealer doesn't have one in stock and they have stock of most items
which fail regularly. I went to a specialist break and clutch place
some time ago because of my clutch and asked the owner to check out my
breaks. I told him that I thought they were not as good as the ones
from the other Audi I have. He drove the car and said something along
the lines: "You can get the wheels to lock, that's pretty good". Here,
some consider their breaks to have a problem if you press hard and the
car doesn't stop.

When I figured out the problem with the bomb myself (after reading
about it on the internet) I went back and he confirmed it immediately
when he pressed the pedal. But even with broken bomb, the breaks
perform better than most other cars he gets in.

What I am getting at is: I assume that on 80 to 90 % of the cars the
bomb is not replaced when broken, unless it is serviced at the dealer,
in which case there is probably a slightly higher chance. But they
will not use a third-party refurbished one, so there is no marked for
those here.

> Regarding differentiating a good from a bad bomb if you do tour the
> scrapyards would be along these lines....
> 1.Maybe.....
> Failure of a bomb would be as a result of loss of pressure/gas on the
> nitrogen side of the rubber diaphragm.
> In which case, would the hydraulic oil capacity be higher for a defective
> than a good bomb ? I seem to remember my fluid level diminishing as the bomb
> died. Sorry I don't have the capacity of a good bomb to hand .....

The problem is that the fluid is gone by the time the car is scrapped.
I was wondering whether it is possible to look into it or stick
something in to test how big the space in the bomb is. But I don't
know what they look like inside.

> 2. A refurbished bomb is likely to have been repainted ? ( mine was )

If anything, the ones on the scrap yard will be official audi
refurbished ones. I don't know whether they repaint it.

Thanks for your help anyway. I guess I just have to go to a big scrap
yard and try to see a few.

Christoph
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Christoph,

DO NOT tamper with the bomb!
It is not called a bomb because it looks like one, it's called a bomb
beacause it IS one.
Before removing it you must make sure it is discharged by pumping the brake
pedal several times with the engine off until the pedal goes hard. If you
don't, you will find out why it is called a bomb as you look at the stump
that used to be your hand!
I would advise you not to try to take it apart, or poke anything into it for
the same reason.

Jim.
"Christoph Bollig" <laserpower@gmx.net> wrote in message
news:8hj8b0heqceqtavsp4017ks59ep3akq1c6@4ax.com...
> Hi Ian,
>
> Thanks for your reply,
>
> > Hi Christoph, here in UK I managed to source a refurbished "bomb" from a
> > Citroen Hydraulics specialist company. I paid less than a hundred UK
Pounds
> > (180 or so US Dollars) including delivery.
> >
> > http://www.pleiades.uk.com/
>
> I just sent them an email, let's see what they say.
>
> > I don't know if Citroen vehicles are prevalent in your Country, or if
any
> > similar company to the above exists. You may wish to make similar
searches
> > in South Africa.
>
> Citroen is not very common here (unlike Audi). Power steering pumps
> etc are no problem to get refurbished, but the break bomb seems to be.
> I got the impression, almost no-one cares, if it's gone. The Audi
> dealer doesn't have one in stock and they have stock of most items
> which fail regularly. I went to a specialist break and clutch place
> some time ago because of my clutch and asked the owner to check out my
> breaks. I told him that I thought they were not as good as the ones
> from the other Audi I have. He drove the car and said something along
> the lines: "You can get the wheels to lock, that's pretty good". Here,
> some consider their breaks to have a problem if you press hard and the
> car doesn't stop.
>
> When I figured out the problem with the bomb myself (after reading
> about it on the internet) I went back and he confirmed it immediately
> when he pressed the pedal. But even with broken bomb, the breaks
> perform better than most other cars he gets in.
>
> What I am getting at is: I assume that on 80 to 90 % of the cars the
> bomb is not replaced when broken, unless it is serviced at the dealer,
> in which case there is probably a slightly higher chance. But they
> will not use a third-party refurbished one, so there is no marked for
> those here.
>
> > Regarding differentiating a good from a bad bomb if you do tour the
> > scrapyards would be along these lines....
> > 1.Maybe.....
> > Failure of a bomb would be as a result of loss of pressure/gas on the
> > nitrogen side of the rubber diaphragm.
> > In which case, would the hydraulic oil capacity be higher for a
defective
> > than a good bomb ? I seem to remember my fluid level diminishing as the
bomb
> > died. Sorry I don't have the capacity of a good bomb to hand .....
>
> The problem is that the fluid is gone by the time the car is scrapped.
> I was wondering whether it is possible to look into it or stick
> something in to test how big the space in the bomb is. But I don't
> know what they look like inside.
>
> > 2. A refurbished bomb is likely to have been repainted ? ( mine was )
>
> If anything, the ones on the scrap yard will be official audi
> refurbished ones. I don't know whether they repaint it.
>
> Thanks for your help anyway. I guess I just have to go to a big scrap
> yard and try to see a few.
>
> Christoph
> --
> Important: Emails sent to me which contain my full name
> in the "to:" or "cc:" field will bypass my spam filter.
> With most programs "Reply" should do the job.

 

Hi Jim,

> DO NOT tamper with the bomb!
> It is not called a bomb because it looks like one, it's called a bomb
> beacause it IS one.
> Before removing it you must make sure it is discharged by pumping the brake
> pedal several times with the engine off until the pedal goes hard. If you
> don't, you will find out why it is called a bomb as you look at the stump
> that used to be your hand!
> I would advise you not to try to take it apart, or poke anything into it for
> the same reason.

Thanks a lot for your warnings. I will defenitely keep them in mind.

However, I think I didn't make clear what I intend to do. I will try
again:

- I am assuming that more than 50% of the old Audis in South Africa
drive around with a broken bomb (as explained in detail in my earlier
message).

- If this is the case, more than 50% of the bombs on the scrap yards
will be bad as well.

- When I go to a scrap yard to get one, I would obviously like to get
a good one first time round. They refund the money if I return it, but
I still don't like the idea to get one, to put it in, to take it out
again and to bring it back.

==> I need some way to destinguish between a good and a bad one on the
scrap yard. And that is where my questions started.

I thought of two ways:

1.) If there is anything which tells me whether it is the original one
or whether it is a factory-refurbished one, I have a starting point.
The latter has obviously a much higher chance to be a good one than
the first one.

2.) If there is anything which I can see, test or whatsoever on a
scrap bomb, it would help. That's where the "poke into it" came from.
My idea was that if the bomb lost all of it's gas, the devide between
fluid and gas might not have moved back in the end. My idea was:
- take a scrap one
- look into it or stick something (a small wooden stick for example)
into it just to see whether this deviding part is further back than on
a good one. I obviously don't want to leave the stick in there.
Carefully sticking a small wooden stick into a bomb which wasn't used
for months will certainly not make it explode.

So if anyone has an idea on how to perform a test on a scrap bomb,
please let me know.

In the mean time I did some more research on 1.) above:

I have two Audis, one 1989 and one 1988. Both are type44 and both are
called "500" here. I believe the older one corresponds to the 5k and
the "newer" one to the 100. Anyway, the bomb works fine on the older
one and not at all on the newer one (which sort of confrims my 50%
assumption, just with a very small sample). I lifted them both up a
bit and climbed underneeth to see whether I could find any
differences. And I did:

Model No:
good: 443 612 061 H
bad: 443 612 061 B
--> I don't think the H and B has much significance, but I might be
wrong

No under the model no:
good: 032-4317-182-541/75
bad: 032-4317-052-541/80
I guess these are seriel numbers and don't think the differences are
siginifcant.

Extra letters on the round part oposite the pipes:
good: "FS"
bad: "A4"
no idea, what they mean.

Additional number:
Now, this could very well be significant:
good: A bit to the right of what I think is the serial number, the
good one has "087/EE" It is not engraved as deep as the serial number,
it must have been done with a different machine.
bad: There is nothing like this.

My thoughts: The good one is refurbished, and the additional number
was added when it was refurbished. If this is true, it would help to
look on the scrap yard for one whith similar additional numbers.

However, a test as in 2.) above would still help, since even a
refurbished one might have gone past its life time.

Thanks for any help,

Christoph

P.S. I have taken a few photos of those numbers, if anyone is
interested to put them on a web page, please let me know.

--
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in the "to:" or "cc:" field will bypass my spam filter.
With most programs "Reply" should do the job.

 

In message <j0vcb0phakf68fftlli8ebsbeng9rdi2pu@4ax.com>
Christoph Bollig <laserpower@gmx.net> wrote:

> Anyway, the bomb works fine on the older
> one and not at all on the newer one (which sort of confrims my 50%
> assumption, just with a very small sample).

.... and once you've fixed the faulty one, your small sample will suggest
that the bomb never fails!

> Model No:
> good: 443 612 061 H
> bad: 443 612 061 B
> --> I don't think the H and B has much significance, but I might be
> wrong

The final letter is a VAG revision identifier, and suggests to me that
the bomb in your old car is a newer version than that in your new car.
This would mean that the bomb in one of the cars has been changed -
almost certainly a newer part has been fitted to the older car.

--
Peter Bell (Note Spamtrap - To reply, replace 'invalid' with 'bellfamily')

 

Christoph,
The "bomb" is such an easy thing to change, it takes about a grand total of
about 20 minutes to do on my '87.
No, there is nothing you can push into the thing that will tell you if the
internal diaphragm is good - it appears that, over time, the rubber
diaphragm becomes (or _is_) permeable to the nitrogen. Over time, it leaks
out (either to the brake fluid, or the power steering fluid, or both) and
you lose the assist when the engine is off. The procedure for making a
non-rechargeable accumulator into a rechargeable one - one that, should you
lose the charge, you can get filled at your local heavy equipment service
station (pressure accumulators are used on backhoes/excavators/etc. - where
loss of hyd. pressure in an engine stall would also be deadly) is somewhere
on Audifans.com. With a discharged bomb (zero pumps of the pedal to total
loss of brake assist) all it takes is a drill, a dremel tool, a magnet (to
remove cuttings), the correct tap, and a high pressure Schraeder fitting
(get the one that holds over 3k psi). The one I have on my car was done by
Russ Southerlin (I hear he's not doing them anymore) - it hasn't needed a
charge since I got it a couple of years ago.
All the usual disclaimers apply.
Cheers!
Steve Sears
1987 Audi 5kTQ - rechargeable accumulator installed and working at a
fraction of the cost of a new one.
1980 Audi 5k - with the old school vacuum assisted brakes...oh, is that
_new_?
1962 and '64 Auto Union DKW Junior deLuxes - brake assist = long brake pedal
(SPAM Blocker NOTE: Remove SHOES to reply)

 

In article <hte7b0d57d0vn7pou5u5lnfjipptm3l072@4ax.com> Christoph Bollig,
laserpower@gmx.net writes:
>One more question: How compatible are they over the years? Can I get
>one from a younger car and still put it in, or is this asking for
>trouble?

The bombs on my two UK Avants are slightly different.

[1] is an early 1988 (pre-revision) 100 CD Auto model with self-levelling
suspension.
[2] is a late 1988 (post-revision) 100 base model with std. suspension
(and subject of my 'Brakes hissing' thread).

On [1] the bomb is part no. 857 612 061B, [2] is now stored elsewhere so
can't check. [1] has an extra port for the suspension (not present on
[2]) and the smaller end is a round shape, while it is a squarer shape on
[2]. Apart from that the fittings appear to be in the same places
although I suspect the banjo connections may be different - in the same
way they are on the pump. i.e. latter models used o-rings, earlier models
copper washes. You can use a new style pump with old style banjos but not
vice-versa, so I suspect the same may apply to the bomb.
[1] gives me about 15 assisted brake presses, [2] gives 0!

Gary

 

Hi Steve, Peter and Gary,

Thanks for all your advice.

> The "bomb" is such an easy thing to change, it takes about a grand total of
> about 20 minutes to do on my '87.

Ok, it took me about an hour to get the car lifted up and onto the
stable stands. Then it became dark, so I decided to continue tomorrow.
Ok, without my two little helpers (2 and 5 years old), I would have
probably done it in half the time.

> No, there is nothing you can push into the thing that will tell you if the
> internal diaphragm is good - it appears that, over time, the rubber
> diaphragm becomes (or _is_) permeable to the nitrogen. Over time, it leaks
> out (either to the brake fluid, or the power steering fluid, or both) and
> you lose the assist when the engine is off. The procedure for making a
> non-rechargeable accumulator into a rechargeable one - one that, should you
> lose the charge, you can get filled at your local heavy equipment service
> station (pressure accumulators are used on backhoes/excavators/etc. - where
> loss of hyd. pressure in an engine stall would also be deadly) is somewhere
> on Audifans.com. With a discharged bomb (zero pumps of the pedal to total
> loss of brake assist) all it takes is a drill, a dremel tool, a magnet (to
> remove cuttings), the correct tap, and a high pressure Schraeder fitting
> (get the one that holds over 3k psi). The one I have on my car was done by
> Russ Southerlin (I hear he's not doing them anymore) - it hasn't needed a
> charge since I got it a couple of years ago.

Thanks, that's interesting. Only last week I thought "If somehow I
could put a valve in there and pump the stupid thing up again ..." But
I thought it was just one of my crazy ideas and dismissed it. I didn't
even consider to ask here.

I found a few old threads on audifanc (late 1997 and early 199,
espectially this one (which seems to be the original procedure):

http://www.audifans.com/archives/1998/02/msg00441.html

Is that still the procedure, or are there any refinements, which were
developed till then? I tried to search, but couldn't find any.

Anyway, I am not there yet. What I did today:

I went to a scrap yard, but they had only one and that looked like my
older one (no extra numbers). I took it since they only charged ~$20
(but canot return it). I will now try to exchange it tomorrow. If it
works (which I doubt), fine. Otherwise, I will consider the recharge
or I might go to a bigger scrap yard and have another try to find one.
Will see.

> All the usual disclaimers apply.

Of course, with this one you have to be a bit more careful than with
the odometer advice (btw, I also got an old instrument cluster. They
sold it for ~$15, since it was marked as "doesn't work, spares only".
I took it apart with my two little helpers and there you are: The
little gear is still ok. I am wondering what condition that Audi must
have been in, with only 101k-km on the clock after 15 years. An old
mechanic pointed that scrap yard out, which is a bit on the country
side (as opposed to the Cape-Town places, which are as far away from
here). He said, that on the countrysite they take better care of their
cars and go longer distances less often. The engine I once got from
that place is as new .

But back to the bomb: Will let you know whether it's ok or not.

Thanks again,

Christoph (who should have gone to bed earlier, I might be so tired
that I forget to pump the peddal before the job).

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What is a "brake bomb"? is it a Wheel cylinder?