[urq] V8 Brake swap for UrQ - bad info worse than no info.?
Ben Swann
benswann at verizon.net
Fri Sep 17 21:47:04 PDT 2010
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
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