Datsun Roadster Forum-311s.org

I'm putting together Rear Brake Cylinder Rebuild kits (well) in advance of pulling the old Cylinders off for sleeving. I have the necessary Backing Plate Dust Boot, Cylinder Boot and C Clip. I don't have the Piston Cups, and may or may not need replacement Pistons. The early 510's also have 13/16 Bore Cylinders and use the same Piston Cup / Seal, NLA P/N 44112-U4000. Stands to reason that aftermarket 510 cylinders Piston Seals can be pulled off and used on the Roadster Cylinders. I purchased a single Raybestos 510 Cylinder for a whopping $5.92 delivered from Amazon to pull apart and have a look. While I have little doubt the seal will work, now I'm wondering if the piston is compatible as well? The Piston P/N's are different and I haven't been able to find any info if the two numbers cross over. Nabco Roadster Piston 44108-14600, Nabco 510 Piston 44108-18000.

So yes this is getting long winded, LOL. I'm wondering if any of you have an OEM 13/16 Roadster Piston laying around to take a couple measurements so I can compare it to the aftermarket 510 piston. I have included a photo. The overall length is 1.513 inches. The width of the Parking Brake Lever Channel is .23 inches. And confirmed the Piston is 13/16 wide. I'm not sure what other measurements might be of importance to determine if it is compatible.

Thanks

I have some 13/16” cylinders but I’m snowed right now. Hopefully some time next week I can dig them out.

Peace,
Pat

Habitat.pat wrote: Fri Sep 10, 2021 7:34 am I have some 13/16” cylinders but I’m snowed right now. Hopefully some time next week I can dig them out.

Peace,
Pat

Thanks Pat

I measured a used 13/16" piston at 1.517" long x 0.812" diameter. I wire brushed the little bit of surface rust from both ends before measuring with digital calipers.
Mike

23yrRebuild wrote: Fri Sep 10, 2021 6:32 pm I measured a used 13/16" piston at 1.517" long x 0.812" diameter. I wire brushed the little bit of surface rust from both ends before measuring with digital calipers.
Mike

Hummm, 1.513 510 vs 1.517 Roadster Piston, it may well be the 510 Piston from the aftermarket Wheel Cylinder could work in a Roadster 13/16 casting? BUT the rubber cylinder boots are of different design, and that might be the difference in them not working. Then again the castings could make the difference. Oh well I'll just have to wait until I can get the Cylinder off the car.

Left 510 Boot (larger hole) right Roadster Boot
Thank you

My dimensions are:
Piston overall length 1.513
Length to bottom of shoe slot 1.337
Piston diameter 0.810
Piston cup inside diameter 0.433
Piston cup width 0.284
Dust cover diameter 0.511
Dust cover width 0.161

Hope that helps

Peace,
Pat

Habitat.pat wrote: Sat Sep 18, 2021 5:28 pm My dimensions are:
Piston overall length 1.513
Length to bottom of shoe slot 1.337
Piston diameter 0.810
Piston cup inside diameter 0.433
Piston cup width 0.284
Dust cover diameter 0.511
Dust cover width 0.161

Hope that helps

Peace,
Pat

Thanks Pat, I'll give the 510 Piston the going over for comparison.

D

Habitat.pat wrote: Sat Sep 18, 2021 5:28 pm My dimensions are:
Piston overall length 1.513 OK, more or less
Length to bottom of shoe slot 1.337 vs 1.354
Piston diameter 0.810, OK
Piston cup inside diameter 0.433 OK
Piston cup width 0.284 vs 0.278, muhhh
Dust cover diameter 0.511 vs 0.550
Dust cover width 0.161 vs 0.127

Hope that helps

Peace,
Pat

Looks like maybe not going to work if I'm following along with your measurements, see above. Pat's numbers are the dimensions for an Roadster OEM 13/16 rear Wheel cylinder Piston, my numbers are for a 13/16 510 Piston. The Piston cup seal itself is 0.270 thickness for the 510, same Nissan P/N for both Wheel cylinders so that should be OK vs OEM? The Cylinder Duct Cap is the downfall in relation to the piston as I thought might be the case.

Back to your original post. Compare the original 13/16 cylinder to the roadster cylinder. My understanding is that the only difference is that the 510 cylinder is threaded for metric brake line & the roadster uses 3/8-24 fittings. If that is the only difference & your goal is to do the rebuild cheaper than buying new roadster cylinders, you could replace the brake lines on the rear end with custom lines with metric on one end & SAE on the other.

Another thing is that the company doing the sleeving may be able to supply 510 pistons or roadster dust caps.

Peace,
Pat

Habitat.pat wrote: Sat Sep 18, 2021 7:39 pm Back to your original post. Compare the original 13/16 cylinder to the roadster cylinder. My understanding is that the only difference is that the 510 cylinder is threaded for metric brake line & the roadster uses 3/8-24 fittings. If that is the only difference & your goal is to do the rebuild cheaper than buying new roadster cylinders, you could replace the brake lines on the rear end with custom lines with metric on one end & SAE on the other.

Another thing is that the company doing the sleeving may be able to supply 510 pistons or roadster dust caps.

Peace,
Pat

I bought in advance new rear hard lines from Don at Rising Sun. After hearing about the 510 cylinders possibly working with a metric adapter (myself and others have asked for confirmation that this worked, no one has come forward on 311s so far) I contacted Don telling him he had a whole another market if he could get his hard lines built with the metric fitting. He said he'd look into it but that was months ago and I'm sure he has bigger fish to fry. Bottom line I have all the parts I need to rebuild the rear cylinders providing the Pistons are okay once I get the cylinder off. They probably can be cleaned up if not $$$.

In the tech wiki in an article on using the 510 master cyl the metric to SAE difference was discussed. From the article: "I found an adapter that has 10 mm X 1.0 male threads on one end and SAE 3/16-24 female threads on the other end. I got them at NAPA, it is a Weather Head part, PN 1443". Many that have converted to the 510 master have used this adapter. If it works at the master it should work on a wheel cylinder. On my car since I was making new lines anyway I used the 510 master and made my lines from the master with one metric fitting and one SAE fitting.

Mike

dads311 wrote: Sun Sep 19, 2021 3:54 pm In the tech wiki in an article on using the 510 master cyl the metric to SAE difference was discussed. From the article: "I found an adapter that has 10 mm X 1.0 male threads on one end and SAE 3/16-24 female threads on the other end. I got them at NAPA, it is a Weather Head part, PN 1443". Many that have converted to the 510 master have used this adapter. If it works at the master it should work on a wheel cylinder. On my car since I was making new lines anyway I used the 510 master and made my lines from the master with one metric fitting and one SAE fitting.

Mike

311 Member MrWaj bought the adapters in question to use with the 510 wheel cylinders but found the Flares did not match up. If I recall he said it was two double flares coming together.

I've put the adapters on wheel cylinders, they work.