59bisquik Posted February 28, 2016 Report Share Posted February 28, 2016 I replaced the brakes and lines on my 55 C1B and installed a rebuilt master cylinder. Once I got her all filled up and started to bleed the brakes, I would get some air out, but the bottle that I was purging into never seemed to fill up. I grabbed my stock master cylinder and put it on, only to find out it leaked out of the cylinder bore. SO, I took the rebuilt one and put it on the vice to try and bench bleed it. Only to find it didnt pump out any fluid. I then took it apart to find that the valve assembly was in backwards. I put it together correctly and it is now pumping, but leaking from the bore also. I must of damaged the rear seal installing it. Opinions needed... 1) Should I purchase another one from one of the sponsors and give it a shot? 2) I have a dual master cylinder setup from a Jeep that I was going to install when I went to discs up front, some time down the road. Should I grab an adjustable proportioning valve and toss that on? 3) I would prefer not to get M/C rebuild kit, because I already screwed one up. I need to have her on the road by April for Viva... It seems that everything is one step forward and two steps back. Sorry guys, but getting frustrated and running short on time. What would you guys do? Quote Link to comment Share on other sites More sharing options...
NiftyFifty Posted February 28, 2016 Report Share Posted February 28, 2016 I would always recommend going for the safer upgrade to a dual MC, but yes, you will need a couple of proportioning valves, or one that handles front and rear..but then your all set up when the front disc set up goes on, rather then doing the job twice Quote Link to comment Share on other sites More sharing options...
59bisquik Posted February 28, 2016 Author Report Share Posted February 28, 2016 If I am using just the Jeep dual M/C, would if work just hooked to the M/C? Why would I need two proportioning valves or? Quote Link to comment Share on other sites More sharing options...
NiftyFifty Posted February 28, 2016 Report Share Posted February 28, 2016 You need the proportioning valves because the MC direct pressures are not likely what you want for a 4 wheel drum set up, there is no residual valve to hold pressure on the rears likely in that MC alone, and you will definitely need them again once you have disc, because that Mc is made to work with the original jeep prop valve and those size of brakes. Quote Link to comment Share on other sites More sharing options...
59bisquik Posted February 28, 2016 Author Report Share Posted February 28, 2016 This is really sounding like it's easier to just get another stock one and try it since front discs are quite a ways down the road and I need to get her driving in a couple weeks at the latest. Quote Link to comment Share on other sites More sharing options...
NiftyFifty Posted February 28, 2016 Report Share Posted February 28, 2016 Easier yes...but in that case I would just buy a kit if your MC has no pitting on the cylinder wall, rather then the big expense of a new stock MC Quote Link to comment Share on other sites More sharing options...
JBNeal Posted February 28, 2016 Report Share Posted February 28, 2016 Getting into a hurry when working on these brakes can be a recipe for disaster, so it's best to take a steady disciplined approach to the task at hand. Rebuilding the master and wheel cylinders can be problematic due to pitting in the bores, which can lead to leaks. Over honing of these bores to eliminate the pitting can also lead to leaks. I ran into this on the '48 and the '49, and since replacement components were not readily available, I opted for sleeving through White Post Restorations, which has worked well for over 15 years on the '48. I still have some sponginess in the '49, which I suspect is due to pitting at the bleeder screws as I have dust accumulation at the threads, even after cleaning post system bleeding, year after year. Sleeving is more expensive than the replacement parts that are now available, as well as having a longer turnaround time, but I am unsure as to the new replacement quality compared to refurbishing. The other reason I opted for sleeving was for mental insurance after having a wheel cylinder blow out on a test drive which led to complete system failure...NOT FUN. I was able to limp home in my rural area, but the pucker factor was quite high. I suggest ya look at the big picture on this rebuild, as meeting short term goals should lead to meeting a larger goal without risking meeting that larger goal. I have found that arbitrary deadlines are good at keeping momentum going on a project, but if they cannot be met through unforeseen circumstances, then let the deadline pass and focus on the goal at hand. This minimizes waste of resources in that the task is only completed one time without detriment to other tasks. 2 Quote Link to comment Share on other sites More sharing options...
Jeff Balazs Posted February 28, 2016 Report Share Posted February 28, 2016 There could be an issue with how much fluid the Jeep dual M/C moves. It is designed for use more modern brakes with 3/16" brake lines. Some models are specifically designed for 4 wheel discs. As already mentioned brakes are nothing to be rushed. They need to be well sorted before any serious driving. There is a lot that can go wrong during the process of reviving the system on one of these old trucks. Jeff Quote Link to comment Share on other sites More sharing options...
59bisquik Posted February 28, 2016 Author Report Share Posted February 28, 2016 Looks like I will order another master cylinder and hopefully it will be here by next weekend... Thanks guys. Quote Link to comment Share on other sites More sharing options...
HanksB3B Posted February 29, 2016 Report Share Posted February 29, 2016 Best way to go ! Always have two master cylinders, one installed and working the other rebuilt when you have time and are not in a crisis. I'm also planning to change to discs up front and am also interested in seeing pics and hearing how other forum members accomplished this. I'll be lurking, Hank Quote Link to comment Share on other sites More sharing options...
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