TR2/3/3A TR3A Hydraulic system problem

[mapleaf]

My Tr3A developed a major leak in the clutch master cylinder over the summer and when I took it apart I noticed that the rubber components had become soft and mushy. I'm wondering if this could be caused by contaminated brake fluid?? I converted the system to silicone fluid years ago and have never had a problem until now, so I'm thinking that I may have mistakenly topped up the m/c with synthetic rather than silicone fluid. Although the rubber parts in the slave and brake cylinder appeared to be okay I replaced them anyway, just to be on the safe side and now I'm trying to think of the best way to purge the brake system without possibly contaminating the rubber in the calipers and wheel cylinders. Any suggestions appreciated.
TIA

 

[JFS]

I have used denatured alcohol to purge hydraulics in both my TR3 and TR8. I converted the TR3 to silicone about twenty years ago and only replaced the MC and caliper rubbers during the last couple of years if I remember correctly. The TR8 I converted about ten years ago and recently replaced the clutch MC, slave and line -- don't think the silicone had anything to do with the replacement of old parts. I also know some owners who have merely purged with new silicone fluid.

 

[sail]

When I redid hydraulics the rubber in the replacement MC from one of the big three soon started to deteriorate leaving black mixed in the fluid. I think the rubber was just no good and had nothing to do with the fluid, which was Castrol.

 

[TR3driver]

when I took it apart I noticed that the rubber components had become soft and mushy.

The original seals would do that when exposed to American brake fluid (DOT 3/4). But "Synthetic" fluid was not available yet when I switched to DOT 5 (so no experience there), plus replacement seals appear to be made with synthetic rubber that will stand up to all common brake fluids.

 

[mapleaf]

Thanks, guys. Thinking back, it's probably been around 15 years since the conversion so maybe it was just normal deterioration. In any event, it seems like the deterioration was confined to the clutch m/c so I'll just put it all back together and purge the brake system with new silicone fluid.