Master cylinder banjo bolt size: What is measured?

[docmel]

So I see 10, 11 and 12mm banjo bolts out there. What is measured to determine what banjo bolt size I have? Is it the size of the socket that fits it?

[JBinNC]

The banjo bolts are specified by their threads, either inch or metric.

But the banjos themselves in the aftermarket are often specified in metric, even if they are used with inch size bolts. For instance, a 10mm banjo and a 3/8-24 banjo bolt. It can be a little confusing.

Jim

[docmel]

Damn. So how do I tell what size banjo bolt I have now? (I'm sure its metric)

What is measured on the bol to detrmone the size?

[JBinNC]

Damn. So how do I tell what size banjo bolt I have now? (I'm sure its metric)

What is measured on the bol to detrmone the size?

Already answered: THE THREADS

Jim

[shank1kole]

Buy some thread pitch gauges in standard and metric along with the little board that you can screw bolts into to identify, you will use them all your life. The pitch gauges come in a little feeler gauge like set up(folding knife) type.they are cheap and at all hardware/auto stores

[confab]

The banjo bolts are specified by their threads, either inch or metric.

For instance, a 10mm banjo and a 3/8-24 banjo bolt.

^^^^^^^



Test fit a 3/8-24 bolt in it. If not? Try some metric thread pitches. They're straight thread. Not tapered.

Then use the closest banjo fitting. 10mm line fitting over a 3/8-24 banjo bolt, for example.

Measure it like a regular bolt.

[tzienlee]

serious dude, if you cant even measure a bolt,... get a shop to do it,.....

[10scDust]

Using a micrometer, or a set of Vernier calipers, measure the outside diameter of the threaded area on the bolt.
Like mentioned, using a thread pitch gauge will give the thread count once matched up, (SAE is how many per inch, metric is how far from one to the next).
It's a little more difficult, but using a scale held up to the threads and accurately counting.

Banjo bolts are not a special thread unto themselves, basically they are a standard sized bolt drilled out for fluid to travel through, thus the need for the copper crush washers.

*note: If it is an industry standard socket head bolt, (folks call them Allen head), measure the height of the head, and that measurement is the diameter of the bolt.

[10scDust]

*note: If it is an industry standard socket head bolt, (folks call them Allen head), measure the height of the head, and that measurement is the diameter of the bolt.

We are talking a standard, run of the mill, common Allen head bolt (socket head cap screw).
Not any other type of cap screw, i.e. low head, hex head, button head, flat head, etc bolts