Wheel cylinder rebuild kit

[DAC21]

I did not put it in the cylinder but the height is the same. The piston area where the seal goes is the same diameter and height as the clutch piston. Which begs the question why the clutch seal has a smaller center hole?

It looks like Brian will be our salvation soon for complete cylinders. I hope he sells kits too. The vendors only have so many and if they have and you want original then buy up before there aren't any. I bought originals 3/4" from Nissan many years ago and saved them for my second car which had 13/16.

Any significant breaking difference between the 13/16 and 3/4 cylinders in your mind on the 1966?

[Curtis]

In searching for 3/4 brake kits last night I stumbled across OEM 13/16 kits. The guy had 4 left out of 48 so I snatched them. $12 each plus $20 shipping.

[Curtis]

I did not put it in the cylinder but the height is the same. The piston area where the seal goes is the same diameter and height as the clutch piston. Which begs the question why the clutch seal has a smaller center hole?

It looks like Brian will be our salvation soon for complete cylinders. I hope he sells kits too. The vendors only have so many and if they have and you want original then buy up before there aren't any. I bought originals 3/4" from Nissan many years ago and saved them for my second car which had 13/16.

Any significant breaking difference between the 13/16 and 3/4 cylinders in your mind on the 1966?

Not that I can tell. I had 3/4 on and then with the restoration I put 13/16 back on.

[roysuecan]

Excellent discussion.
I'm going to look into using my old slave cylinder seal. I just replaced the cylinder as a precaution (due to pitting) and it wasn't leaking. I'll report back if I learn anything worth sharing.

[DAC21]

In searching for 3/4 brake kits last night I stumbled across OEM 13/16 kits. The guy had 4 left out of 48 so I snatched them. $12 each plus $20 shipping.

Oh that's a nice price, I sure missed that, I would have jumped for a couple. I wound up buying (in theory, I'll believe it when it ships) 2 x 13/16 Centric Aftermarket Datsun 510 kits from Summit Racing. But they are dropped shipped from Centric so availability is sketchy in my mind as no one else has them. $15 ea. shipped. No Piston, just Piston Cup seal, Cylinder Boot seal and oblong Backing Plate dust shield.

Edit: Sure enough just was refunded my payment from Summit Racing. Dead part number from Centric. Although there full 510 Wheel cylinder can still be bought.

[Curtis]

The way I figure is if the 510 cylinder is cheap enough and your cylinders are good use the guts from the 510. Then no adapter.

Depending on size of course.

[JT68]

510 cylinders are not 3/4, so the seals aren’t going work. .685 or .7 if I recall. Smaller rear cylinders will reduce rear braking force increasing stopping distance. The smaller rear cylinders were done to keep the rear wheels from locking first since 510s had very wimpy front brakes (and a very light tail end).

If you want the car to stop well, I’d recommend using the correct parts. It’s really not a great idea to start substituting critical brake components.

[DAC21]

510 cylinders are not 3/4, so the seals aren’t going work. .685 or .7 if I recall. Smaller rear cylinders will reduce rear braking force increasing stopping distance. The smaller rear cylinders were done to keep the rear wheels from locking first since 510s had very wimpy front brakes (and a very light tail end).

If you want the car to stop well, I’d recommend using the correct parts. It’s really not a great idea to start substituting critical brake components.

Pretty sure the 510 in the early years cylinders were 13/16 (.8125) So in theory piston seals from a 510 should work for 1965-1967 1600 Roadsters cylinders.

[JT68]

Yes, I thought the thread was about 3/4” cylinders.

We have both 3/4 and 13/16 Nissan cylinders and kits in stock. Guess I’ll have to add them to the website.

Something to consider, if you do change the rear (or front) cylinder sizes, you will change the braking bias-often with worse performance and stopping distances. Your pedal may feel just great, but your stopping distance has increased.

You don’t want the rear brakes locking first, that’s a very bad plan.

Smaller wheel cylinders will increase your stopping distance.

[spl310]

https://mossmotors.com/repair-kit-wheel ... 9GEALw_wcB

[Curtis]

To really see the difference of force applied to the brake shoe you need to have it calculated out. I went and used an online calculator and threw in some numbers which in no way are the real roadster numbers. It did however give me an idea of difference between the two sizes of 3/4 and 13/16. With my conjured up numbers it showed about 1/6 greater force applied for the 13/16. So that tells me there is some degree of difference. How much that matters in a 2000 pound car is left to be decided by experts. 7/8 is probably a much better wow factor.

Whether I had greater stopping distance with the 3/4 on there vs. the 13/16 now I can't tell you. All I know is in both cases when I hit the brakes hard that little sucker stops. Of course anti locks would be nice.

Since Datsun went to the tandem cylinder for safety regs I'm figuring, did they change the the outlet size for the front and rear brake to change bias with the 3/4 cylinder?

[JT68]

That’s right. It was a safety upgrade with the dual master) As I recall, the earlier cars had slightly better stopping distances (13/16) but the late cars (3/4)are less likely to lock the rear brakes first (Which often will put you in a spin if it happens at high speed).

[roysuecan]

Thanks spl310 for the Moss Motors link. I ordered a REPAIR KIT for 2 cylinders (3/4") for $10.59 and $6.00 S&H. Once they arrive, I'll still do a comparison of the clutch slave cylinder seal with the brake cylinder seal just for yuks.
What a wealth of information this forum is.

[spl310]

Thanks spl310 for the Moss Motors link. I ordered a REPAIR KIT for 2 cylinders (3/4") for $10.59 and $6.00 S&H. Once they arrive, I'll still do a comparison of the clutch slave cylinder seal with the brake cylinder seal just for yuks.
What a wealth of information this forum is.

Happy to help. Incidentally, you can buy a NEW slave cylinder cheap from AutoZone.

[DAC21]

Five more OEM 13/16 (1965-67, 1600) rebuild kits listed by the same seller Curtis got his from. There coming from Egypt so if in a hurry maybe not for you.

https://www.ebay.com/itm/Rear-Brake-Whe ... 632-2357-0

Any kit you find with a P/N listing, the 13/16 cup is P/N 44112-U4000. Or kits for B10/B110 to 1972, or 510 to 1972
Based on information from a Japanese sellers eBay listing

https://www.ebay.com/itm/DATSUN-1200-Re ... 632-2357-0