[urq] UrQ brake booster/servo

[Eric Renneisen]

I have reluctantly become an urq brake servo expert of late...

The rebuild kit can be had from John @ Sportwheels (970-945-2708) for
~$50.  He seems eternally busy, so don't expect a quick response.  (I'm
not complaining, just setting expectations--he's been very helpful).
He'll need to know if yours is cast iron (painted black) or aluminum
(unpainted, but probably covered in black grime).  One of the seals is
different between the two.

Sean created an excellent rebuild procedure for the AL unit, which is
posted on Martin's site here:
http://www.quattro.ca/Urq/Brake_servo_guide.pdf
The cast iron rebuild is very similar, but I'm working on a document
that shows the differences.  Anyone who needs it can contact me for an
advance copy.

Finally, I discovered that a nearly identical replacement can be found
on the E23 BMW 7 Series (1986 and earlier here in the US).  The rod that
attaches to the brake pedal is shorter, but everything else is the same.
I picked one up in a boneyard because I broke the plastic end cap of my
original AL unit while removing the oil seal.  I'm pretty sure you could
take the rod (and attached plunger) from the cast iron unit and put it
in the bimmer part to obtain a weight savings and the screen filter on
the inlet.  You'll still need a rebuild kit, because the bimmers have
the same leakage probs we suffer.

The later bimmers with hydraulic assist (E28 5-series, E24 6-series, E32
7-series) appear to have a similar booster with just a differently
positioned mounting flange.  I haven't touched one of these yet, but
they use the same bomb and pressure regulator, so I'd bet the innards
are the same.  If someone just needs parts for an AL unit, it might be
worth trying to find a cheap one of these.

Eric Renneisen
'93 S4
'86 urq
'85 urq
Chattanooga, TN

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
Behalf Of AUDIJIM at aol.com
Sent: Thursday, April 28, 2005 8:47 PM
To: urq at audifans.com
Subject: [urq] UrQ brake booster/servo


Aloha,

Could someone please direct me to who or where has a parts list to
rebuild my 
leaking brake booster/servo. (ETKA calls it a brake booster, P/N 857 612
107 
A) I thought I remembered that there was a posting of someone who might
have 
done this recently.

Thanks,

Jim Furdyn
1983 UrQuattro #900170 
1987 4000cs Q
1987 5000cs TQ 279,000 miles
1996 A6 Quattro Avant 
1987 Mercedes Benz Truck model 1219
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