1960s Brake booster washers flat or lock?

[dbzsjones]

I just got my booster back from Karps Power Brake Service, and it looks great, but it came back without the mounting hardware. Off to the store for 4 3/8-24 nuts, but should I be getting flat or lock washers?

[Clewisiii]

Mastercylinder to booster. Split washer.

[dbzsjones]

  I wasn't specific enough, I'm looking for what goes behind the firewall and holds the booster to the firewall.
Thanks,
Del

[Clewisiii]

I cannot remember if these are the same nuts that hold the entire brake pedal assembly to the firewall. That is packed away. I might be able to get a glimps in my parts car. But the inside is trashed right now.

[TJ Hopland]

Later I think it was common to use the type where the toothed washer is part of the nut. Not sure if those had a name, I suspect the name depended on the brand. 

[dbzsjones]

The booster came back with 1 of the 4 nuts on it and it was a normal nut, but it could have been whatever the rebuilding had lying on the bench to make sure the threads were clean after the plating.

[Clewisiii]

I see no washers on the inside.

[TJ Hopland]

Looks like what I always heard called a 'Stover locknut'.   I would guess thats a brand name, not sure if they are still around or not.   

[Clewisiii]

Stover nuts can still be found. Just not everywhere. Uses a deformation in the thread to lock in place.

[dbzsjones]

Stover lock nut no washer it is, thanks for the help!
Given the location and visibility of the nuts, and availability considerations, I may settle for a nylock nut.

[59-in-pieces]

Del,

Here is a close-up of the interior nuts and toothed washer used in a 59.
Hope this helps.  (expand the picture to see the teeth more clearly, but they are there)

Have fun,
Steve B.

[35-709]

Later I think it was common to use the type where the toothed washer is part of the nut. Not sure if those had a name, I suspect the name depended on the brand. 

They do have a name, they are called KEP nuts, you can Google that name on the internet and get a large variety of same.  FWIW, if that were my booster, I would use flat washers and nylock nuts.  Not a big deal unless it is a show car and you think the judges will look under the dash to see what kind of fasteners you used.   

[tcom2027]

Later I think it was common to use the type where the toothed washer is part of the nut. Not sure if those had a name, I suspect the name depended on the brand. 

Flange or flanged nut.

tony

[dbzsjones]

Thanks all, not a show car so not worried about a judge sticking his head under the dash, just wanted to make sure I attached it appropriately.  So it looks like locking nuts are the theme, with a preference for KEP or Stover.  I do have a latent AR tendency that wants to get things as close to authentic as possible even if it's not a show car.

[59-in-pieces]

Del,

The toothed washer is OEM - and cheaper, but who am I to get involved in such a life changing, earth shaking decision.

Have fun,
Steve B.

[dbzsjones]

Cheaper and more accurate!  How often does that happen in this hobby?  Must be my lucky day.