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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I am still driving, squeezing out the final good weather days before winter. Hopefully, I will get through today and tomorrow before I get a chance for some disassembly. What I will do is drain the hydraulic fluid, redo the banjo fitting connection, and remove/rebuild the slave cylinder. Then if the problem persists, I will remove and investigate the master cylinder. Until this car (1964 MGB), I have always rebuilt the hydraulics (seals) rather than buy new master/slave cylinders. But now I have the new Lockheed master cylinder. The slave cylinder was a new aftermarket unit I installed 5-6 years ago when I started the restoration. The clutch components (pressure plate, clutch disc, throw-out bearing) were installed new when I rebuilt the engine last year, about 5000 miles ago.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As near as I can tell, this is a one time thing – the free play starts to increase about two miles into a 60 mph cruise and when the coolant temperature approaches normal operating temperature (185 F). Most of the time, the drive is as I described – very brief city driving, 12 miles on the highway, and then into the next city for a couple of miles to work. I will get about 80% free travel on the clutch during the highway drive – depressing it restores it to maybe 40% travel after the first push and after 2-3 more pushes (standard shifting), I will be back to normal (maybe 5% free travel). Fluid levels are unaffected. Sometimes, I take an alternate route home which is almost twice as long but has two highway drives and goes like this – 1 mile city, 8 miles highway, 2 mile city, 17 miles highway, home. That is usually my drive to get cheaper petrol so I do it about once a week (more frequently during convertible season just for the extended drive). And the problem then also occurs in the initial warmup highway drive, not on the second highway leg but then that was only one trip.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Barring any unforeseen circumstances, I’ll have an answer in a few days. Hopefully, as I am short of backup cars. My 72B is partially disassembled – just about ready to pull the engine/transmission in order to put my OD transmission back in as well as fix the rear engine seal (plus install speedi-sleeve). The 67 BGT has been idle for about four months due to excessive oil consumption (~80-100 miles to the quart) and its up next for a rebuild when I get done with the 72. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>David Councill<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>64 MGB<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>72 MGB<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>67 MGBGT<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> PaulHunt73 [mailto:paulhunt73@virginmedia.com] <br><b>Sent:</b> Wednesday, November 09, 2016 12:28 AM<br><b>To:</b> David Councill; MG-MGB@yahoogroups.com<br><b>Cc:</b> mgs@autox.team.net<br><b>Subject:</b> Re: [Mgs] [MG-MGB] Clutch problems with thermal component<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt'>Firstly the tilt in the later clutch master - that was to clear the larger brake reservoir cap on North American models when they gained the dual circuit system, but was fitted to all MGBs. AFAIK the tilt rotates the master cylinder about the centre-line of the bore, so everything should remain in line. Whilst the pipe could be moved to mate up with the master outlet, if the position of the bore changed relative to the pedal that could cause problems.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>1. If you continue highway driving, after you have experienced the long travel and corrected it with a couple of pedal presses, does it happen again? Or does it only happen once no matter how far you drive? If it only ever happens once then it looks like a master seal problem.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>2. Another test, once you feel the slackness, stop the car where safe without using the clutch, and see if you have any free play in the release arm. If there is, then something would appear to be nudging the piston back into the bore. However, there should be a spring inside the cylinder which is constantly trying to push the piston out, and that should continually being taking up any free play. The purpose of this is to take up any and all play from there on i.e. in the release bearing and friction plate, it is this that makes the MGB clutch self-adjusting for wear.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>As another part of this test, at various temperatures, by pushing on the release arm move the push-rod and hence the piston all the way back into the cylinder, let it go, and it should ease its way out again. Make sure the master reservoir has some space at the top to avoid the fluid overflowing.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>PaulH.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><blockquote style='border:none;border-left:solid black 1.5pt;padding:0in 0in 0in 4.0pt;margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>----- Original Message ----- <o:p></o:p></span></p></div><div><p class=MsoNormal style='background:#E4E4E4'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>It is a bizarre problem. I was hoping someone might have had similar problems. Since my last email, I have made two 15 mile drives with the same very predictable issue. The master remains the primary suspect because the issue happened after replacing the master cylinder. The slave cylinder was an aftermarket replacement I put in about 4-5 years ago but the only thing I have done with it is to drain the brake fluid.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>...</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p></blockquote></div></body></html>