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Clutch Master Cylinder and Tire Size questions


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Help My 1973 240Z has the following problems

1. It appears that my clutch master cylinder is leaking/blowing fluid around the reservoir cap seals. I have lost all pressure for the clutch. I have ordered a replacement cap for the reservoir and I am not really sure if that is the fix. Any ideas???

2. What is the correct tire size to replace the original tires on my Z. Originals are 175 SR 14. Is this size the same as 175 – SR70 – 14.


Thanks in advance


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1) While the master cylinder cap does kind of lock on with a twist (wouldn't want it coming off unexpectedly) I don't think the cap is supposed to do anything more than keep dirt out. The cylinder shouldn't be under pressure. I suspect you might need to replace the whole thing or at least find out what's causing the problem.

2) That sounds about right

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1) I agree with MikeW, I don't think a leaking cap will cause the clutch not to work. You don't want brake fluid all over your engine compartment but you may still have a problem with the master cylinder or the slave cylinder. Once you get the new cap try bleeding the clutch fluid at the slave cylinder.

2) This is much debate about the size of original Z tires. I have heard that the 175R14 originals were more like a modern 75 or 80 series. I think this would make it between a 185R70 or 195R70 tire. If you are looking for originality, I don't think you can find the correct size anymore. I think a 195R70 is as skinny as I would put on a stock height Z but it of course it depends on your qoal or visual preference.

Hope it helps!

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