Datsun Roadster Forum-311s.org

Had a brake leak and this is what the cylinder looks like. Rebuild for $38 or replace for $140?

Pull it apart and see. If the bore looks good, rebuild If not, replace or resleeve and rebuild.

This is what I found. There is some rust. I this salvageable? Can this be honed? Or should I use some rust remover?

The pics make it look like they are probably are beyond honing. But for $20.00 if I didn't already have one I would be getting a wheel cylinder hone and see if they clean up.

I have been told that if you drag a finger nail aver the area and it catches in the pitting, it is game over.
My advice would be to have both sides sleeved and re-kitted with stock kits and you will be safe as houses with probably a life time repair

They are not exact, but you can make 510 cylinders work. They are metric, so they need a thread adaptor.

They are about $10 at Rock Auto.

I probably have at least one I could send you. It/They have been sitting in my tool box sealed up for years. I have no need for them. I saw one today and wondered why I was keeping it. Believed to be decent, didn't leak when removed.

So if the 510 cylinder works , you could probably use the innards as a rebuild kit??
Linda

Linda wrote: ↑Sat Jun 23, 2018 10:42 pm So if the 510 cylinder works , you could probably use the innards as a rebuild kit??
Linda

The 510 are 3/4", there are a couple of different designs for the dust seals.
IIRC the higher cost one is close to the roadster design. The bleeder valve is at a different angle.

I cannot speak to other peoples experiences but I can tell you that I ordered a $6 Centric wheel cylinder from Rock Auto listed as fitting a 510 just to see if it would work. LIke you, I balked at spending $140 for new "roadster" wheel cylinder.

In the photo you can see on the left is my original Nabco wheel cylinder. 13/16" bore. On the right is the $6 Centric. Also 13/16" bore. They are very similar. The biggest difference being the back part that sticks out behind the backing plate where your brake line screws into is slightly deeper on the Nabco.

I test fitted the Centric and my original brake line threaded in without any adaptations. I didn't have to bend the line to make it reach or use any adaptor. Maybe I just got lucky or someone has already modified the screw fitting but I doubt it. It was really bad. The shoes were worn almost to metal and it appeared the wheel cylinder had been leaking for quite a long while. These brakes maybe had never been off the car before is what I am thinking.

And you probably already know this but you don't have to spend $50 on 'roadster' brake shoes either. The 510 shoes fit just fine and can be found for about $15.

Well, I installed the wheel cylinders for a 510 that I purchased from Rock Auto for $13.00 each. They fit perfectly without needing an adapter. I did have to use the double shim that was on the old cylinders as well as the two bottom shims that came with the new cylinders. The brakes work just fine. Saved myself around $230.

Added this info to 311s Parts Interchange. Always good to save some cash for other parts. Also added bit about incorrect threads in the wiki and stressed the importance of using the correct fitting.

Steve

So, because it is brakes, are we sure that the line threading in is the same pitch as in the new cylnders? I have read about being able to thread in a line on other brake parts that seemed to be correct, but under the brake pressure, could blow out. So, just being extra cautious to confirm the fit?
Thx
Linda
OEM cylinders can be resleeved in stainless if you want to go that far
I like your thinking , Steve

Linda wrote: ↑Wed Jul 04, 2018 9:39 am So, because it is brakes, are we sure that the line threading in is the same pitch as in the new cylnders? I have read about being able to thread in a line on other brake parts that seemed to be correct, but under the brake pressure, could blow out. So, just being extra cautious to confirm the fit?
Thx
Linda
OEM cylinders can be resleeved in stainless if you want to go that far

You are right Linda, the threads are wrong. 510 is 10 mm metric. Yes, 3/8-24 will thread in, but its not a good plan for brakes. If you are going to do this mod, suggest you make a proper brake line with a 10mm threads.

Will update wiki with that info.

S