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Re: [Mgs] MGB rear brake questions

To: mgs@autox.team.net
Subject: Re: [Mgs] MGB rear brake questions
From: David Ambrose <stargazer1@cox.net> gAP9qbEHja082KH9EI0wD9GvOXkcYkP86JXxYKGOtMINPOiahbkIUZGf0s9Vj5+YyHjUbgc5OKTFTw==
Date: Sat, 23 Oct 2021 11:33:50 -0700
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You have the wrong wheel cylinders. The GTs have a different (larger) 
rear brake cylinder than the roadsters. The roll pins are in different 
locations to prevent them from inadvertently getting swapped. I don't 
think you want to use the GT cylinders on a roadster as it would put too 
much braking in the rear which will make the car very tail happy under 
emergency braking.

Cheers,
Dave

On 10/23/2021 10:44 AM, wkilleffer@epbfi.com wrote:
> Thank you for your reply.
> As far as the type of wheel cylinders, I don't recall that there was a 
> choice as to whether they were for a GT or a roadster. The only choice 
> was either Lockheed brand (maybe) for more $, or an aftermarket for 
> less $. As far as I know, the back plates are original, but I've only 
> owned the car for 20 years. Its engine is not original, so who knows 
> what else could have been swapped.
> Can you shed more light on the whole speed bleeder thing? And how do 
> do pedal pumping bleeding when you're by yourself?
> The fluid is making its way back to the wheel cylinder, so no lines 
> are crimped. But thanks to the poor fitment of the bleeder thing with 
> the tool, I can't tell if the air bubbles are coming through the brake 
> lines or are air being drawn into the bleeder because the fitment 
> isn't good.
> Yes, I did the clutch system a couple or three years ago. It was a bit 
> frustrating, but seems ok now.
>
> Thank you,
> -William
>
> ------------------------------------------------------------------------
> *From: *"Robert's New iPad" <mgbobh@gmail.com>
> *To: *wkilleffer@epbfi.com
> *Cc: *mgs@autox.team.net
> *Sent: *Saturday, October 23, 2021 1:36:03 PM
> *Subject: *Re: [Mgs] MGB rear brake questions
>
> The rear-brake question opens more questions.    MGBs had rear 
> cylinders to fit the Tourers and the GTs, different sizes of cylinders 
> and different back plates.    The roll pins located the cylinders in 
> the correct backing plates.
> Thus the questions arise:  Tourer back plates and new GT cylinders? GT 
> backplates and new Tourer cylinders?  Car modified before you got it? 
>  Wrong cylinders ordered/shipped?
> Having wrestled through this with my GT, it was years back and now I 
> do not recall which cylinders (size and pin location) are Tourer or 
> GT.  Someone will know, though, and that challenge easily mastered.   
> GT cylinders are larger, suited to the additional weight of GTs.  If 
> you have to swap parts, do it the way MG built itâ??they got it right.
> As you replaced them years ago, my bet is that the vendor shipped 
> wrong cylinders.
> As to the bleeding, my experience has been that ordinary pedal pushing 
> has done fine for me on many cars, though I did install speed bleeders 
> on this GT.  They are an easy exchange and work OK, but the savings of 
> 1/4 cup of brake fluid doing the job are hardly worthwhile.   If the 
> rear brakes are difficult to bleed, have a close look at the metal 
> pipes on the axle.  A car that has been flat-bed carried may have had 
> the straps wrapped around the axle, crushing the tubes.  Thatâ??s not an 
> unusual thing to find.
> Since you are changing hoses, have you changed clutch hose?  These 
> break down internally whilst appearing fine externally. As you do the 
> change, do it swiftly, w/o interruption, as introducing a bubble into 
> the line is altogether too easy, and bleeding the clutch line has made 
> many an owner irate.
> Bob
>
>
> On Oct 23, 2021, at 1:04 PM, wkilleffer@epbfi.com wrote:
>
>     Hello everyone,
>
>     The car I'm working on is a 1974 MGB roadster. I decided that I
>     wanted to replace everything relating to the brakes and their
>     hydraulics except for the metal lines. I ordered the parts from
>     Moss but had to sit on them for a couple of years before actually
>     starting the project.
>
>     So, I got the new master cylinder installed, which is probably one
>     of the more challenging things I've ever done on the car. Next
>     step was working on the rear brakes. The rubber hose in the back
>     was pretty simple, but the issue is with the wheel cylinders. I
>     replaced them maybe twenty years ago and didn't have any trouble.
>     But these new ones have a roller pin on them that doesn't line up
>     with the holes on the brake's backing plate. It's been too long to
>     try and swap them with Moss, and I'm not sure that would do any
>     good anyway because I don't recall that there were too many
>     choices for that part. You could get a cheaper aftermarket or a
>     more expensive part that may be made in England. I went with the
>     cheaper one.
>
>     Has this been an issue for anyone else? I could probably drill
>     another hole in the back plate to match the roll pin, but that
>     seems like one of those DPO solutions. Also, I don't feel like I
>     should have to entertain such a notion anyway. The part should fit
>     and function correctly. The current wheel cylinders are probably
>     ok to re-use, but I liked the idea of all new parts. The front
>     brakes are also on the agenda, but we're not there yet.
>
>     The next question has to do with bleeding the rear brakes. I
>     started to bleed the brake furthest from the MC using a vacuum
>     tool I got at a well-known less expensive (think shipping at a
>     port) tool store. It's been a letdown for several reasons, among
>     them that the bleeders on the wheel cylinders seem too small for
>     the bleeder fittings that came with the tool, which causes the
>     tool to draw a great deal of air through its system. I seemed to
>     barely be able to get any fluid through the system. The trouble I
>     have is that I am single and live alone, so I don't have any
>     readily available sources of help. If the brakes are going to be
>     bled, I have to do them by myself. Does anyone have any advice on
>     this topic?
>
>     Thank you,
>     -William
>     1974 MGB
>
>     _______________________________________________
>
>     Mgs@autox.team.net
>     Donate: http://www.team.net/donate.html
>     Suggested annual donation  $12.75
>
>     Archive: http://www.team.net/pipermail/mgs
>     http://autox.team.net/archive
>
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>
>
>
> _______________________________________________
>
> Mgs@autox.team.net
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> Suggested annual donation  $12.75
>
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    <p>You have the wrong wheel cylinders. The GTs have a different
      (larger) rear brake cylinder than the roadsters. The roll pins are
      in different locations to prevent them from inadvertently getting
      swapped. I don't think you want to use the GT cylinders on a
      roadster as it would put too much braking in the rear which will
      make the car very tail happy under emergency braking. <br>
    </p>
    <p>Cheers,<br>
      Dave<br>
    </p>
    <div class="moz-cite-prefix">On 10/23/2021 10:44 AM,
      <a class="moz-txt-link-abbreviated" 
href="mailto:wkilleffer@epbfi.com";>wkilleffer@epbfi.com</a> wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:1031194420.116434484.1635011091394.JavaMail.zimbra@epbfi.com">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
      <div style="font-family: arial, helvetica, sans-serif; font-size:
        12pt; color: #000000">
        <div>Thank you for your reply.</div>
        <div>As far as the type of wheel cylinders, I don't recall that
          there was a choice as to whether they were for a GT or a
          roadster. The only choice was either Lockheed brand (maybe)
          for more $, or an aftermarket for less $. As far as I know,
          the back plates are original, but I've only owned the car for
          20 years. Its engine is not original, so who knows what else
          could have been swapped. </div>
        <div>Can you shed more light on the whole speed bleeder thing?
          And how do do pedal pumping bleeding when you're by yourself?</div>
        <div>The fluid is making its way back to the wheel cylinder, so
          no lines are crimped. But thanks to the poor fitment of the
          bleeder thing with the tool, I can't tell if the air bubbles
          are coming through the brake lines or are air being drawn into
          the bleeder because the fitment isn't good. </div>
        <div>Yes, I did the clutch system a couple or three years ago.
          It was a bit frustrating, but seems ok now.</div>
        <div><br data-mce-bogus="1">
        </div>
        <div>Thank you,</div>
        <div>-William</div>
        <div><br>
        </div>
        <hr id="zwchr" data-marker="__DIVIDER__">
        <div data-marker="__HEADERS__"><b>From: </b>"Robert's New iPad"
          <a class="moz-txt-link-rfc2396E" 
href="mailto:mgbobh@gmail.com";>&lt;mgbobh@gmail.com&gt;</a><br>
          <b>To: </b><a class="moz-txt-link-abbreviated" 
href="mailto:wkilleffer@epbfi.com";>wkilleffer@epbfi.com</a><br>
          <b>Cc: </b><a class="moz-txt-link-abbreviated" 
href="mailto:mgs@autox.team.net";>mgs@autox.team.net</a><br>
          <b>Sent: </b>Saturday, October 23, 2021 1:36:03 PM<br>
          <b>Subject: </b>Re: [Mgs] MGB rear brake questions<br>
        </div>
        <div><br>
        </div>
        <div data-marker="__QUOTED_TEXT__">
          <div dir="ltr"><span class="Apple-tab-span" style="white-space:pre">  
</span>The
            rear-brake question opens more questions.    MGBs had rear
            cylinders to fit the Tourers and the GTs, different sizes of
            cylinders and different back plates.    The roll pins
            located the cylinders in the correct backing plates.</div>
          <div dir="ltr"><span class="Apple-tab-span" style="white-space:pre">  
</span>Thus
            the questions arise:  Tourer back plates and new GT
            cylinders? GT backplates and new Tourer cylinders?  Car
            modified before you got it?  Wrong cylinders
            ordered/shipped?</div>
          <div dir="ltr"><span class="Apple-tab-span" style="white-space:pre">  
</span>Having
            wrestled through this with my GT, it was years back and now
            I do not recall which cylinders (size and pin location) are
            Tourer or GT.  Someone will know, though, and that challenge
            easily mastered.   GT cylinders are larger, suited to the
            additional weight of GTs.  If you have to swap parts, do it
            the way MG built itâ??they got it right. </div>
          <div dir="ltr"><span class="Apple-tab-span" style="white-space:pre">  
</span>As
            you replaced them years ago, my bet is that the vendor
            shipped wrong cylinders. </div>
          <div dir="ltr"><span class="Apple-tab-span" style="white-space:pre">  
</span>As
            to the bleeding, my experience has been that ordinary pedal
            pushing has done fine for me on many cars, though I did
            install speed bleeders on this GT.  They are an easy
            exchange and work OK, but the savings of 1/4 cup of brake
            fluid doing the job are hardly worthwhile.   If the rear
            brakes are difficult to bleed, have a close look at the
            metal pipes on the axle.  A car that has been flat-bed
            carried may have had the straps wrapped around the axle,
            crushing the tubes.  Thatâ??s not an unusual thing to find.</div>
          <div dir="ltr"><span class="Apple-tab-span" style="white-space:pre">  
</span>Since
            you are changing hoses, have you changed clutch hose?  These
            break down internally whilst appearing fine externally. As
            you do the change, do it swiftly, w/o interruption, as
            introducing a bubble into the line is altogether too easy,
            and bleeding the clutch line has made many an owner irate.</div>
          <div dir="ltr">Bob</div>
          <div dir="ltr"><br>
          </div>
          <div dir="ltr"><br>
            On Oct 23, 2021, at 1:04 PM, <a
              href="mailto:wkilleffer@epbfi.com"; target="_blank"
              rel="nofollow noopener noreferrer" moz-do-not-send="true"
              class="moz-txt-link-freetext">wkilleffer@epbfi.com</a>
            wrote:<br>
            <br>
          </div>
          <blockquote>
            <div dir="ltr">
              <div style="font-family:'arial' , 'helvetica' ,
                sans-serif;font-size:12pt;color:#000000">
                <div>Hello everyone,</div>
                <br>
                <div>The car I'm working on is a 1974 MGB roadster. I
                  decided that I wanted to replace everything relating
                  to the brakes and their hydraulics except for the
                  metal lines. I ordered the parts from Moss but had to
                  sit on them for a couple of years before actually
                  starting the project.</div>
                <br>
                <div>So, I got the new master cylinder installed, which
                  is probably one of the more challenging things I've
                  ever done on the car. Next step was working on the
                  rear brakes. The rubber hose in the back was pretty
                  simple, but the issue is with the wheel cylinders. I
                  replaced them maybe twenty years ago and didn't have
                  any trouble. But these new ones have a roller pin on
                  them that doesn't line up with the holes on the
                  brake's backing plate. It's been too long to try and
                  swap them with Moss, and I'm not sure that would do
                  any good anyway because I don't recall that there were
                  too many choices for that part. You could get a
                  cheaper aftermarket or a more expensive part that may
                  be made in England. I went with the cheaper one.</div>
                <br>
                <div>Has this been an issue for anyone else? I could
                  probably drill another hole in the back plate to match
                  the roll pin, but that seems like one of those DPO
                  solutions. Also, I don't feel like I should have to
                  entertain such a notion anyway. The part should fit
                  and function correctly. The current wheel cylinders
                  are probably ok to re-use, but I liked the idea of all
                  new parts. The front brakes are also on the agenda,
                  but we're not there yet.</div>
                <br>
                <div>The next question has to do with bleeding the rear
                  brakes. I started to bleed the brake furthest from the
                  MC using a vacuum tool I got at a well-known less
                  expensive (think shipping at a port) tool store. It's
                  been a letdown for several reasons, among them that
                  the bleeders on the wheel cylinders seem too small for
                  the bleeder fittings that came with the tool, which
                  causes the tool to draw a great deal of air through
                  its system. I seemed to barely be able to get any
                  fluid through the system. The trouble I have is that I
                  am single and live alone, so I don't have any readily
                  available sources of help. If the brakes are going to
                  be bled, I have to do them by myself. Does anyone have
                  any advice on this topic?</div>
                <br>
                <div>Thank you,</div>
                <div>-William</div>
                <div>1974 MGB</div>
              </div>
            </div>
          </blockquote>
          <blockquote>
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