411 Master Cylinder Datsun 620 Conversion

[JH Bahn]

411 Master Cylinder Datsun 620 Conversion

cole@davidwarrengallery.com

I bought a new Datsun 620 dual master cylinder off eBay for $30 plus $9 shipping to Maui. I was getting a bit paranoid about the stock master cylinder after several different people warned me of the (I thought unlikely) dangers associated with single master cylinders. I have never had one fail on me and I have owned lots of old cars. But I did this conversion anyway.

 

The only tricky part was modifying the stock plunger rod. I removed it from the old master cylinder, rounded the ball end and cut it in half. Then I found a die that would fit and threaded both sides.

 

Once that was done I used two nuts and one of those really long nut things to enabled me to install the mc and adjust the length of the rod.

 

It worked great and was practically free! The master cylinder bolted right up to the stock mounting holes and didn't get in anything else’s way.

 

I ran a new brake line to the rear brakes and plugged the extra hole in the "T".

 

I noticed that the bore size of the stock 411 master cylinder is 7/8", and the 620 master cylinder bore is 3/4". I don't know what difference this makes. I also rebuilt all the wheel cylinders, so I can't say for sure if it was the master cylinder that made the difference, but the brakes are better now than they were.

 

[graveltrapp]

Good info, Thanks. I once had a master go on my 67 VW bus. Yanked on the ebrake, downshift like mad, and lay on the horn. ignore dirty looks and middle fingers and be really glad you just dodged a bullet and became a statistic.

[MikeRL411]

Datsunparts.com part number 1560 is a 7/8 replacement brake master cylinder for the RL411.