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Discussion Starter #1
Having given my new to me 1993 2.0L 16V Audi 80 Avant a good once over I have noticed a connection between the steering pump and the ABS system. Does anyone know what this is for?

My supposition is that the steering pump is used to supply pressure for the brake modulation, but my curiosity would appreciate a slightly more detailed explanation than that.

Has anyone any idea how the ABS works on this vintage of vehicle?

Thanks

Happy new year.

Keith
 

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Hi Keith
I've got an 1991 80 2l 16v quattro, it too has this connection between the pump an the brakes , I found out that most other cars have a vacume servo run of the vacume from the inlet manifold from the engine , but this cars have power assisted brakes run from hydraulic oil presure from the power steering pump which also helps the abs when it's at full chat. I don't have a detailed explination but thats what i've found out.

Mike :57:
 

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Discussion Starter #3
Thanks Mike,

that is a pointer at least. I will do some further investigation and if I get a fuller explanation I will post it later

Cheers

Keith
 

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kieth i had a problem with my hydraulic pump a few years ago which had to be replaced 400pounds for the sake of a 20pence O ring and a missing spring on an internal valve???(where that dissappeared to is a complete mystery)the o ring failed which caused a leak (oil everywhere) i replaced the Oring but lost the pressure to the braking side -on investigation by AUDI they discoverd the faulty valve and missing spring- how the system worked with a missing spring was a mystery to the technicans-it was never found -- the technician explained that the unit is in fact two pumps in the one unit -- one half feeds the steering the other adds pressure to the braking system--in what respect the hydraulic pressure helps the ABS i dont know either-- but if i remember correctly when i lost pressure from the pump the sterering was working fine but the brakes wouldnt --they reacted as if the servo on a more basic system had failed felt very solid-a lot of effort for little braking--maybe this will help you
dave
 

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Discussion Starter #5
Thanks Dave, that is a good explanation and, on closer inspection, more or less what I have deduced. I will look more closely at the connection to the ABS unit, I may be mis-reading the pipework and have created a red herring.

Having looked at the steering pumps on other cars at the scrap yard the extra layer which is the 2nd pump is clear.

There is obviously a leak on mine also, small but there. I have been contemplating a strip down to see if it is just a seal, so the knowledge that there are springs contained within is most valuable. The number of times I've taken the top off something only to see a spring whistle out of it from an unknown position.....

Cheers

Keith
 

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kieth ---- the reason i had to have a new pump is because the pump is a non serviceable item- so if it leaks the only thing you can replace is the o ring under the drain plug- this has to be a very strong high pressure o ring not a normal type- when you remove the little cover/drain plug other bits fall out too!!!-- what i'm saying is you cant strip the pump out to replace internal parts-- audi just replace the complete pump--but i believe G+S do a pattern pump that is a lot cheaper
dave

you might get lucky and find that it is one of the pipes weeping
 

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Discussion Starter #7
Thanks Dave, I've read the "this unit is not user serviceable" bits in the Haynes (and other) manuals.

I bought a standard one from the scrap yard to take to bits, if I can, to see what is inside and to confirm that it cannot be fixed with an old Cornflake packet and some Copidex, that's the kind of sickness I suffer from.

I'll let you know the results of my investigation.

Cheers

Keith
 
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