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Re: Help! (Brake master cylinder rebuilding)

To: coryc@sequent.com, paulg@cme.nist.gov
Subject: Re: Help! (Brake master cylinder rebuilding)
From: Cory Carpenter <coryc@sequent.com>
Date: Tue, 13 Jul 93 08:15:24 -0700
The winning answer to my question #2 (anti-backflow valve removal) came
from Paul Gilders:

>From: paulg@cme.nist.gov (Paul Gilders)
>To: Cory Carpenter <coryc@gateway.sequent.com>
>Subject: Help!  (Brake master cylinder rebuilding)
>
>Cory Carpenter writes:
> > Question #2 is, how do I get the valve out of the cylinder casting?
>
>Well I don't know the specific Europa cylinder, but it sounds exactly
>the same as my TR6 arrangement regarding the return valve. And yes, I
>think you do have to unscrew that 1/2" hex - I had to do this with
>mine - and it took a few hours of sworking, but eventually came loose.
>I managed by just soaking mine and then using immense leverage. It
>sounds like yours is more obstinate.
>
>Kevin Brown also had a problem with his valve removal - I'm not sure
>how he managed it, but he did eventually get it loose. He was asking
>the same questions as you - getting the valve off by other means and
>using heat etc. I think it's just one of those painfully slow
>processes of soaking, heating and wrenching hard. If you haven't
>already done so, I would take it right off and get it in a vice! The
>consolation is that the casting is normally fairly strong and there is
>little chance of chewing up that hex fitting. However, I would also
>check that you can get all the rubber seals first and take your time
>to rebuild it completely while you've got everything apart!
 
I think the light heat and two days of soaking helped, but the real win
was due to the old "right tool for the job" maxim.  I was orignally
using an 8-inch bolt with a 1/2-inch head instead of an honest Allen
wrench, and it just didn't impart enough torque to the threaded
retaining sleeve.  (I was surprised to see how little force it took to
twist a 3/8" grade 3 bolt 'round and 'round!)  $7.95 bought me a real
1/2-inch hardened long-arm Allen wrench, and history was made in mere
seconds!


On question #1, the case of the stubborn fluid reservoir, I think Richard
George is on the right track: 

>From: rkg@ateq.com (Richard George x 7247)
>To: coryc@gateway.sequent.com
>Subject: RE:Help!  (Brake master cylinder rebuilding)
>
>Cory,
>
>I have a similar master cylinder on my volvo (I think its a girling one...) - 
>It just has a rubber seal on the nipple, right?  I ended up just pulling on
>the damned thing until it popped out - it took a considerable amount of force,
>and you might consider dumping some brake fluid into it from the outside (I 
>went to the silicon stuff, so this wasn't too nasty to deal with...)...

Sluicing the outside of the nipple with huge amounts of brake fluid has
loosened it to the point where I can hear the squeal of plastic on
rubber, but I still haven't managed to pull the thing loose.  I'm
thinking about putting the cap on the reservoir and applying
high-pressure air to the forward M/C port, but I have a nasty suspicion
that there's another anti-backflow valve there too.

Anyway, enough list bandwidth on this:  I'll eventually get the thing
apart, one way or another.  When I do, I'm going to try something that I
think was suggested in this forum awhile back -- using a 12-bore shotgun-
cleaning swab and jeweler's rouge to polish the M/C bore (after breaking
any glaze with emery paper or a hone).  Advance thanks to (I think) TeriAnn.

-coryc


|     >> Disclaimer: I speak for Sequent only in our hardware manuals <<     |
| Cory R. Carpenter, Senior Tech Writer  |                                   |
| Sequent Computer Systems, Incorporated | "On the Internet, nobody knows    |
|  coryc@sequent.com                     |  you're a dog."                   |


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