Sunday, January 20, 2013

Why is Simple Never Easy?

The over original length  of the
push rod as well as the cuts and breaks

The very worn end of the push rod
 One of the things that I saw as a bonus with this transmission was that it had a hydraulic clutch. This meant no custom cables and All I had to do was locate the clutch master cylinder in the fire wall such that it lined up with the clutch pedal. It just had to mount high enough to make the stroke of the pedal match the stroke of the master and hopefully with the right leverage. The master and slave on this transmission are essentially one unit in that they are assembled and bleed by the component manufacturer and installed by dodge as a complete unit. There is no bleed nipple and there is no way to separate the components without compromising the system. Though I have found the master and the slave sold as individual units it still seems that they are made to be replaced as one and therefore if one of the two is damaged you are more or less in for some dollars. The setup I had with this transmission had some serious wear on the rod end, which obviously save money was mad as a solid piece not a swivel and it must not have been greased well because it is very worn for a truck that supposedly had only 39K miles on it. My solution was to simply cut the worn part off and thread the end for a heim joint. The shaft measured  .3125 so a 5/16/24 rod end would be perfect. In order to thread the rod I had to get it apart from the master. There is a clip that holds the whole plunger and spring assembly into the body of the master cylinder. It looks from the outside like you can remover this spring clip and the plastic retainer that holds the ball end of this push rod to the piston of the master will just come out thus freeing the push rod. Of course it isn’t that easy!!!!. That clip actually holds the whole piston assembly into the bore. So removing it and pulling the push rod pulls the whole piston and spring assembly out and the push rod is still attached to the top of the piston. Now of course the whole fricken thing is going to have to be bleed somehow when reassembled. I’ll figure that out later. The push rod is held in by a little spring tab clip that fits into the end of the piston. This really isn’t meant to come out. After messing around with some small picks I was able to get the push rod out and then after a considerable amount of more picking and cursing I got the spring tab clipy thing out. I needed to get it out because some of the tabs had gotten flattened when taking the push rod out and the only way to gently bend them back without breaking them was with the clip out. Now that the whole thing was a part I set about putting the push rod in the lathe and parting off the worn  eye rod end. Once off I set the lathe up to thread 24TPI and started to thread the end. I had a beautiful 5/16-24 thread but it was a bit tight. So I decided to take a .003 clean up pass to see if that allowed the rod end to go on fully. Well the threading tool grabbed the cheap metal (no idea what metal it actually is) and the whole threaded part just snapped off. The shaft went from 5/15 to ¼” just after the eyelet and its ¼” where it meets the piston of the master. It’s at this reduction that the part snapped. After swearing a lot I cleaned up the end and threaded it ¼-28. Of course I don’t have a ¼-28 rod end so I’ll have to get one from McMaster. The other potential problem is that not the push rod is almost exactly half the length it used to be so I’ll have to use a coupler and a 3” threaded stud to gain the length back. This will at least give me more adjustability in the end which will be a good thing. Over all not the simple job I had planned. That really should be the title of this whole project.

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The Clip that holds the push rod
into the Master Cylinder piston

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