[urq] V8 Brake swap for UrQ - bad info worse than no info.?

[Claus Vegener]

Subject: Re: [urq] V8 Brake swap for UrQ - bad info worse than no info.?


> Have done the same to my WR 1983
> Thought my mastercylinder was untight - but I had turned the 200 20V 
> calipres upside down so they were impossible to vent.
> But before that, I exchanged mastercylinder and had to cut with a dremel 
> the seal in the brake booster to get room for the new mastercylinder.
> Yes - before it suddently got out.
> The seal is on the return side and there is no real pressure at the back 
> side of it - but untight it got. It is a return to the reservoir and the 
> little on-way bolt is a venthole
> for the booster to work and keep the seal in place..
> A year later I put back the original mastercylinder and aligned the little 
> o-ring at the seal in the brake booster and held it in place with the 
> former cut off piece of plastic - and now it is tight again
>
> Claus
> Urq-20V (3B), 034 stage II
> 560 Hp
>
> ----- Original Message ----- 
> From: "Ben Swann" <benswann at verizon.net>
> To: <urq at audifans.com>
> Cc: <benswann at verizon.net>
> Sent: Saturday, September 18, 2010 6:47 AM
> Subject: [urq] V8 Brake swap for UrQ - bad info worse than no info.?
>
>
>
> I have been in process of upgrading rear brakes to V8 calipers, carriers 
> and rotors.
> That part went fairly well and except for having a little mixup with the 
> rotors - that
> looks great!
>
> There were several "suggestions" from folks I put high credibility in 
> information I get
> on this list -  that in order to utilize the larger diameter rears I 
> needed to also use
> the V8 or 200 master cyl.  Good suggestion I thought - pretty trivial to 
> replace that -
> albiet a bit or a PITA.    One ought to presume that unless additional 
> information is
> given to the contrary that a swap is a simple swap.
>
> Now this is where someone should have provided a clue that this was not a 
> doable swap
> for mere mortals or at least there was more to just swapping the master 
> cylinder out.
> If there was BTDT on this I should have been advised..
>
> OK - The line hookup needed to bend the lines  and reconfigure the 
> hookups - old MC had
> lineson bottom and sides - new MC had a V configuration. That is not t a 
> real big deal,
> but should have been mentioned.  Not everyone presumes things need to be 
> bent or ...
>
> Here is what frosted me..
>
> The original master cylinder bore is less diameter than the V8/200 MC 
> that is where the
> disaster started.  There was a plastic sleeve in the hydraulic booster 
> that the master
> is pressed into - or so I thought it was a sleeve.  It  was held by 
> captive bolt at
> bottom - O should have also figured that since it was a sawtooth grip 
> nut - one way only
> - to stop there and re install my otherwise good working "original": MC.
>
> Yes -   I should have stopped there, but being is no caveats based on BTDT 
> were issued,
> presumed this was not a problem.  So I removed the bolt - with difficulty 
> it came out.
> The 'sleeve' was also captive by friction until I helped it free.  Free it 
> did!
> Hydraulic fluid, spring, O-ring seal, carrier/retainer, all let loose.  It 
> was not a
> sleeve but a complex shaped seal holding captive - shim, O-ring, 
> veeerylooongspring,
> shaft, retainer and hydraulic fluid under pressure!
>
> I collected the parts, cleaned my face and figured that the V8 MC should 
> fit in - It
> did, but there would be no seal.
>
> Finding that there was no ready way to use the V8 master in the original 
> booster, I
> reassembled the original components as best as I could.
>
> So now I'm left with a mess and a car I can't drive  - the funky sawtooth 
> nut is a
> special seal bolt that is one use only.  I tried to seal with copper 
> washers, o-rings -
> hard to hold captive 3000 PSI!   So what do I need to do now - replace the 
> booster?
> Arghhhhhhh!  Where does one get that special seal bolt?  What a big waste 
> of time - I
> could have just used and aftermarket proportioning valve, instead of 
> replacinG the MC.
>
> I'm venting now - a little less than I did a few wasted hours past,  since 
> this cost me
> not only money, but  a lot of unessessary time and aggravation.  I look to 
> this list a
> source of reliable information and if there is a potential problem with a 
> safety system,
> I expect a little warning.  Here-say is not a good way to disseminate 
> information -
> either you did the job and know the details(BTDT) and provide them, or 
> please don't lead
> someone to do a job that is fraught with major difficulties, especially 
> when it involves
> critical saftey components.
>
> If I had known this all before, I would have simply installed two new 
> stock calipers.
>
> I know - caveats for the info. provided on this list, but then  - why 
> bother?  That's
> all for now.
>
> Ben
>
>
> _______________________________________________
> Audifans urq mailing list
> Manage your list connection: http://www.audifans.com/mailman/listinfo/urq
> http://www.audifans.com/kb/List_information
>
> Pictures/Polls/Database at: http://autos.groups.yahoo.com/group/urquattro/
>