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Leaky Slave Cylinder Line


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Hey Guys,


I am having a problem with my slave cylinder. I have a Scarab bell housing attaching a Muncie M21 4-Spd to a 327 Chevy motor in my '72 Z. I have recently replaced the clutch slave cylinder, clutch master and the lines in between. The master is a stock '72 replacement unit. The slave is from a late '70's 210 model. The upper hydraulic line is steel with the correct fittings and the lower line is the proper rubber replacement from Victoria Brit. This car has had the Chevy driveline and Scarab bell housing since 1978 (I built it for a friend back then), so I just copied the parts that were already there.


The difficulty that I'm having is with leakage around the copper washer that seals the lower rubber line to the inlet port on the slave cylinder. It is a tiny leak, but enough to introduce air into the system so that the trans gets tough to put into gear after a drive. I have never seen such a stubborn leak! The threads on the cylinder and on the line go together fine with no slop, and the washer seats nicely around the threaded part of the hose and the gasket surfaces of both the hose and the cylinder are clean and burr-free. I have used several copper washers of varying thicknesses but the leak keeps returning. I am not stacking the washers, either. Any help would be greatly appreciated. Sorry for such a long post, I just wanted to give a thorough description.




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Well, I looked very closely at the inlet port of the Slave Cylinder and found nothing out of the ordinary, with the exception of a slight amount of rust at the bottom part of the hole. It was not in the threads, but in the conical indentation made by the drilling operation prior to threading during manufacture. This is no big deal considering that the sealing surfaces are between the shoulder of the inlet hose and the machined boss around the inlet port, which is sealed with a copper gasket. With that in mind, I took a closer look at the machined seat for the bleeder screw. Sure enough, there was a tiny streak of rust on the bleeder screw seat! Upon closer examination with a bore scope and a magnifier, that streak of rust is a tiny channel that is letting a small amount of fluid out and air in. Further examination using Prussian Blue revealed that the bleeder screw is not seating properly either, mostly due to this rust. I have another cylinder on order, of course with a week's wait.

I have been bitten yet again by the new part demon! Why doesn't anything work right the 1st time? Oh well......




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