[urq] Brake pressure regulator

Tue Jul 15 15:58:33 PDT 2008

Interesting to note that the Family Album says the proportioning valve
wasn't changed on the urq until the RR came along, despite the switch to
G60s much earlier.  The RR got the bigger rear ventilated discs, which
is probably the reason for the change.  I wouldn't be too worried about
the bias change between the single and dual piston calipers up front.

Now, if you have a leaky valve already, there are likely cheaper
alternatives than stock.  I still have an old leaky one somewhere that
I've been meaning to try to rebuild, but I haven't heard of anyone
having success.

Eric R.
'86 urq
'92 urS
'93 urS

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
Behalf Of Maurits Jonkergouw
Sent: Tuesday, July 15, 2008 6:31 PM
To: Audifans
Subject: Re: [urq] Brake pressure regulator

I stand corrected.... I only upgraded to G60. The 23.81 mm master
cylinder 
AND pressure regulator are both stock. I just noticed this browsing my 
maint. history files and remembered I *should have* upgraded to the 25.4
mm 
master (P/N 447) cylinder instead (yeah, that was a real bummer) but
still I 
never locked the rears during panic stops.

>I did the 5000 G60 upgrade and master cylinder upgrade (bigger 23,8 mm 
>P/N
>443 611 021 also from 5000) but kept/replaced the stock pressure
regulator 
>(P/N 803 612 303), and I never locked the rears during emergency stops 
>because of a wrong bias. FWIW.
>
> Regards,
> Maurits
>
> 1986 quattro GV
>
>
>
>
> ----- Original Message -----
> From: "milisen " <milisen at hotmail.com>
> To: ""urq" " <urq at audifans.com>
> Sent: Tuesday, July 15, 2008 10:33 PM
> Subject: Re: [urq] Brake pressure regulator
>
>
>>
>>
>> -----Original Message-----
>> From: milisen  <milisen at hotmail.com>
>> Sent: 7/15/2008 4:35:01 PM
>> To: wbremer  <wbremer at maine.rr.com>
>> Subject: RE: [urq] Brake pressure regulator
>>
>>
>> Hi & thanks for the answer,
>>
>> if its not too much bother I'd be glad if you could check the product
>> number!
>>
>> I'm actually very interested in this option despite I'm trying to 
>> keep
>> the urq original. Has anyone here with an adjustable valve
experimented 
>> how the handling changes when you apply more brake power to the back?
I 
>> suppose left foot braking works really nicely with more power to the 
>> back! Talking of...has anyone
>> dared to try left foot braking with the urq?
>>
>> Approximately how much did the valve cost?
>>
>> Cheers,
>> Johan H
>> Helsinki, Finland
>>
>> -----Original Message-----
>> From: wbremer <wbremer at maine.rr.com>
>> Sent: 7/15/2008 1:24:06 AM
>> To: 'milisen ' <milisen at hotmail.com>
>> Subject: RE: [urq] Brake pressure regulator
>>
>>
>> Johan:
>> There are manual, adjustable brake bias valves that are often used in

>> the earlier urqs when someone converts the front brakes from the 
>> single-piston calipers to the double-piston G60 calipers.  When this 
>> conversion is done,
>> the factory front/rear brake bias valve (the one that is leaking on
your
>> car) is somewhat dangerous in that the rear brakes can lock up in a
panic
>> stop.  A company called Tilton makes them here in the States.  If you

>> want
>> to investigate that approach, I'll find the model number of the one
that 
>> I
>> put on my Euro '82 urq.  It has a handle and five different
front/rear 
>> bias
>> positions.  It is an easy install (maybe you need to get one extra
short
>> brake line made) and it has worked on my car without problems since
1996.
>> Bill
>>
>> -----Original Message-----
>> From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
>> Behalf
>> Of milisen
>> Sent: Monday, July 14, 2008 12:37 PM
>> To: urq at audifans.com
>> Subject: [urq] Brake pressure regulator
>>
>> Hi q-friends,
>>
>> sorry I haven't been that active on the list lately. But now to my
>> question.
>>
>> after a spirited drive with my -88 MB on the countryside, I noticed 
>> that
>> the
>> brake fluid level was low. I traced the problem to the brake pressure
>> regulator (not sure thats the right name, but it is the device that
sits
>> below the brake master cylinder, which divides the pressure between
the
>> front and the back in case of a falure)
>>
>> well back to the problem. The pressure regulator seems to be leaking.

>> Has anybody repaired this, or do I have to search for a new one? I 
>> suppose its NLA
>>
>> cheers,
>>
>> Johan H
>> Helsinki, Finland _______________________________________________
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