Roadster!

[MtnGoat]

It did...I had to do it. Just a couple miles, but it was pretty awesome.

[MtnGoat]

Hmmm. A brand new 510 wheel cylinder vs the leaky Roadster one.

510 vs roadster wheel cylinders_sm.jpg (139.54 KiB) Viewed 5906 times

510 vs roadster wheel cylinders2_sm.jpg (129.31 KiB) Viewed 5906 times

[MtnGoat]

Boy, these sure look like my 510 cylinder, down to the 11/16th's size
http://www.datsun-roadster-parts.com/index.php?id=730

[spriso]

Keep in mind that the Roadster wheel cylinder will have a SAE thread on it, while the 510 version will be metric!

Michael

[MtnGoat]

crap. I hadn't tried the thread. I'll have to do that.

another option is honing and rebuild, seems simple enough, never done it. Can that work reasonably well? Kits are ten bucks, plus I'd need a hone

if it turned out the thread on the 510 one did work, I'd do both sides so they didn't vary in response. I know there would be a small difference in response overall, too.

[spriso]

You can always build a new hard line with a SAE fitting on the one end and a metric fitting on the other! Likewise, there are metric to SAE adapters that can work too.

We have seen people try to thread the SAE fitting into metric slaves (or master cylinders) and then complain when they leak! The thread is very close, but it is not the same-- remember your life depends on that brake system-- so use the correct parts!

Michael

[MtnGoat]

The front bleeders are super funky, flat bottomed things.i can't figure out how they function. Sure in practice you do the same things, but..

[dcuplover]

check out Micheal's site to see if you really think you can go against his suggestions.....beware of what you think versus what others know

[MtnGoat]

I"m just askin questions and making observations

[MtnGoat]

Of course Mike was correct. I got out my metric and SAE tap sets and used the thread gauges to have a look at where the brake line comes in. Sure enough, the roadster cylinder is SAE there and the 510 is metric. So much for that, unless the roadie rear wheel cylinder sources completely dry up.

That leaves me with repair or replace.

I pulled the boot and piston, cleaned up the bore in the cylinder for a close look.

roadster rear wheel cyl interior sm.jpg (130.12 KiB) Viewed 5867 times

I've seen badly pitted ones, this isn't one of those. Still, those dark marks most of the way down are small indents, I can barely feel them with my fingertips, and there's a couple smaller ones which are similar on the other side where you can't see 'em in this shot.

Is this something a hone can handle, or is the deal with hones just putting some new crosshatch in a worn, but smooth cylinder?

[Byron510]

These are your brakes, and need to be treated with the utmost importance. As a machinist, and imperfection that the seal has to ride over is a place to wear the seal and failure is inevitable. This applies to where the seal runs down the bore.

Bore size however is also critical, as the seals do not allow for a huge amount of variance. This also goes for out of round or a barrel or hour glass shape you hone into the bore – these are diametrical changes that need to be within spec. Hone lightly and check your work.

Honing the bore for hydraulics has absolutely nothing to do with cross hatch, but has everything to do with surface roughness. So, in a few words, you want that seal surface shiny smooth - not exactly a specification, but it is a goal. For those scientific, an Ra of 1.0 – 2.5 micrometers is optimum surface finish, but it’s unlikely you’ll have the equipment to measure it.

Choice of honing stones need to also reflect the material that you are honing. A honing stone is itself designed to break down in use, keeping it sharp and cutting at a consistent rate. A stone designed to break down on steel at a certain rate certainly will not break down in aluminum at the same rate. The stone will plug and likely gall the surface putting you backwards. Just something to be mindful of, pick the right stone for the material. When you ask the parts guy at Pep Boys/Napa ect about this - he'll no doubt stare at you like you are from Mars and then tell you it doesn't matter if used on steel or aluminum. If he does say this, then you know what level of intellect and professionalism you are dealing with.

So, I'm not saying don't do it. You certainly can. But there are a few things to balance while completing the job. Personally - I just buy new ones if the option is there. However, the quality that comes out of some manufacturers today also makes me disassemble and clean everything before I assemble and put it in the car myself. Call me untrustworthy – but it’s for good reason; Life is good.

Byron

[MtnGoat]

Thanks for the expert opinion Mike, OK I'm buying a new one!

[MtnGoat]

Done, $100 bucks at Dean's outfit in SoCal. Got some front bleeder screws as well, the current ones are a vise-gripped disaster.

[MtnGoat]

Got the wheel cylinder this morning. That's when it hit me...I shoulda ordered rear shoes at the same time, the current ones are soaked with brake fluid on the left side. Oh well, another order.

In the meantime, got the car on the lawn and cleaned up a bit more on Saturday...

photo (10)sm.jpg (331.08 KiB) Viewed 5804 times

photo (12)sm.jpg (220.81 KiB) Viewed 5804 times

photo (13)sm.jpg (312.49 KiB) Viewed 5804 times

[MtnGoat]

Opened up the box, and along with a wheel cylinder and front bleeder screws, I found a free Roadster mouse pad, cool.

photosm.jpg (144.84 KiB) Viewed 5782 times