Caliper cylinder types and flares

[BenGood]

I just disassembled my calipers, have enough pitting on the cylinder walls to need new ones (or sleeved), and now am getting the question "Inner or Outer?" Sadly did not notate this.

On closer inspection, I see now that the fitting seats on one cylinder are matched ('outies' in belly-button terms) and are Not matched on the other (one 'outie, one 'innie'). But I need help establishing which one is which. (Is there a string answering this already that you can point me to?)

[itsa68]

Sounds like the one with 2 “outies” is for use with tube ends that have double flared tube ends and should be the outer cylinder.
That would make the other an outer cylinder with 1 outie facing down for use with a double flared tube end and the opposite “innie” end facing up accept the bleeder.

https://static.carpartsmanual.com/datsu ... 40_-01.jpg

[BenGood]

After conferencing with a local, experienced Roadster man and his pile of discarded caliper cylinders (inner and outer) and his proper notes, this is what I now understand as stock:

1) The Inner cylinder: Both the Top and Bottom fitting seats appear as 'innie's (in belly-button terms). Top for the bleeder valve; Bottom for double-flare-end line (cross-over).
2) The Outer cylinder: Top fitting seat appears as 'innie'. The Bottom fitting seat appears as 'outie', intended for a single-flare end.

For most of you, this discussion seems "duh" or superfluous. But on my car, for some reason, one of my cylinders is/was an anomaly: both fitting seats are/were 'outie's for single flares. No bueno when ordering a set of pre-formed tubes from one of our esteemed suppliers.

I'll be replacing these 'wrong' cylinders with 'proper' ones. Meanwhile, I wonder where this cylinder came from? Another Dunlop system? Perhaps an SPL? Has any encountered this? A past mechanic must have just adapted, on the fly. But I don't think it worked very well -- the master cylinder reservoir was empty when I took possession of the car (non-running).

If any of this seems incorrect, please please share.

[JT68]

Do all your cylinders say Sumitomo? There are some british cylinders that are similar but use the wrong flares.

If they all say sumitomo, the PO just used the wrong cylinders.

SPL and SRL are the same and your 1&2 orientations are correct. (If you mess that up, they won't seal)

[itsa68]

Both of my calipers use the Bubble flare bridge tubes that runs from the upper outside cylinder port to the lower port seat of the inner cylinder.
The outside cylinder lower port seat is for a Double flare tube which runs up to the brass union block which has a double flare port seat.
On old sets the same is evident.

old caliper.jpg

flare types.jpg

My spare stock Nissan oem cylinders I have on hand are the 41100-14600 inner and the 41101-14600 outer.

The inner cylinder has the bleeder in the upper port seat and the Bubble flare seat in the lower port.
Inner cylinder Bleeder should face up when installed.

flare DIN bubble seat.jpg

The Outer cylinder has one Bubble flare seat port and one Double flare seat port.
Outer cylinder Bubble flare seat port should face up when installed.

flare DIN bubble seat.jpg

double flare seat .jpg

My spare stock Nissan bridge tubes have the following flares.

LH and RH caliper bridge tubes running from outer cylinder upper port to inner cylinder lower port are Bubble flared ends.

flare bubble.jpg

LH and RH caliper bridge tubes running from outer cylinder lower port to upper brass junction block ports are Double flared ends.

flare double.jpg

Cheers
Ray B.

P.S. my favorite gum is double bubble

[BenGood]

Nice replies, Fellas.

JT68:
Yes; all Sumitomo. Thanks for the other confirmations and conjecture. One day we'll learn what car/system uses the "outie" / "outie" configuration and why it ended up being sold to the PO of this SRL. In the meantime, I now know to shelve them.

Itsa68:
Thank you for the photos, explanations, and nomenclature.

I'm understanding/confirming:

INNER Cylinder:
Both Upper and Lower seat ports are the same:
Upper port seat: DIN/ISO UM 14-3 ("innie") to allow Bleeder valve.
Lower port seat: DIN/ISO UM 14-3 ("innie") to allow DIN/ISO Bubble Flair-end tube.

OUTER Cylinder:
Upper and Lower seat ports are unique from one another:
Upper port seat: DIN/ISO UM 14-3 ("innie") to allow DIN/ISO Bubble Flair-end tube.
Lower port seat: SAE UA1-3br ("outie") to allow SAE Double Flair-end tube.

BRIDGE Tube:
Both ends are DIN/ISO BUBBLE Flairs to mate with DIN/ISO UM 14-3 ("innie") seats.

BLOCK Tube:
Both ends are SAE DOUBLE Flairs to mate with SAE UA1-3br ("outie") seats.


As a sidebar to the Forum Master: It would good to see this topic be added to the Brakes section in the Tech Wiki.

[itsa68]

You are correct.

Remember that some of us do own tube benders a flaring tools and can overcome a mixed bag of cylinders by fabricating a custom line in a pinch.

Cheers
Ray B.

[BenGood]

Great. (phew!)

One day, I'll arrive to the tube-tools-plateau

In the meantime, I'll be entertaining offers for my "outie"/"outie"-configured cylinder pair.

Thanks to All.