Grimeca caliper hose fitting

I scored a Grimeca caliper on ebay and installed it on my Commando several years ago, using the original Lockheed master. It worked fine. I recently replaced the master with a Kawasaki. After re-installing the system, I have a persistent leak at the hose/caliper junction despite using the same fitting. The existing fitting is a 3/8x24 DIN style, but I have no assurance this is actually the correct fitting. A 10mm fine bolt spins in the female hole in the caliper body as well.

Does anyone know what fitting is supposed to be used for Grimeca calipers? is this SAE or AN or a metric thing?

Manxman

Pics :

I want to have a new brake line made since this one is a dog's breakfast of adapters. The master end is a 10mm banjo. If I can't figure what the Grimeca end is supposed to be, I was thinking of getting a 10mm banjo on the bottom end as well, and making a banjo bolt from a 3/8-24 UNF bolt. is this too weird?

Manxman

manxman said:

I want to have a new brake line made since this one is a dog's breakfast of adapters. The master end is a 10mm banjo. If I can't figure what the Grimeca end is supposed to be, I was thinking of getting a 10mm banjo on the bottom end as well, and making a banjo bolt from a 3/8-24 UNF bolt. is this too weird?

Click to expand...

Yes, you can use a banjo fitting.
The thread I believe, is actually M10 x 1.0mm, not 3/8 - 24 (UNF).

L.A.B. said:

manxman said:

I want to have a new brake line made since this one is a dog's breakfast of adapters. The master end is a 10mm banjo. If I can't figure what the Grimeca end is supposed to be, I was thinking of getting a 10mm banjo on the bottom end as well, and making a banjo bolt from a 3/8-24 UNF bolt. is this too weird?

Click to expand...

Yes, you can use a banjo fitting.
The thread I believe, is actually M10 x 1.0mm, not 3/8 - 24 (UNF).

Click to expand...

Not quite. A 1.0mm pitch would be 25.4 threads per inch. I believe a 3/8-24 bolt (9.525mm in diameter)will screw into a M10X1.0 but strip when torqued. If you try it the other way around, the metric bolt goes in a turn and a half before interfering.

The 3/8" bolt can squeeze into metric hole but not visa-versa.

The Grimeca will accept a 3/8 but not a 10mm bolt.

The more reading I do, the more confused I get. Even Detroit uses a combination of SAE and metric fittings.

If you come across a website that explains brake fittings, please forward the link.

Thanks

Manxman

manxman said:

Not quite. A 1.0mm pitch would be 25.4 threads per inch. I believe a 3/8-24 bolt (9.525mm in diameter)will screw into a M10X1.0 but strip when torqued. If you try it the other way around, the metric bolt goes in a turn and a half before interfering.

The 3/8" bolt can squeeze into metric hole but not visa-versa.

The Grimeca will accept a 3/8 but not a 10mm bolt.

Click to expand...

I've just checked a couple of those old "two bolt" Grimecas from my spares shelf, and they are almost certainly M10 x 1.0.
A 3/8 UNF bolt is a sloppy fit in both, and begins to bind after a few turns.

Edit: The caliper bleed nipple threads are the same size.

http://www.rgmnorton.co.uk/buy/grimeca- ... r_3749.htm

GRIMECA ALLOY CALIPER OFTEN USED TO REPLACE THE OLD CP2696 LOCKHEED RACING CALIPER AND THE IRON VERSION FOUND ON CARS AND TRIUMPHS FROM THE SEVENTIES. THIS CALIPER IS PRETTY MUCH THE SAME SHAPE AS THE EARLIER LOCKHEED , SAME BOLT CENTRES ETC, DOES HAVE A METRIC INPUT THREAD (SEE OUR ITEM 050144).

Click to expand...

050144
http://www.rgmnorton.co.uk/buy/grimeca- ... r_2620.htm

L.A.B. said:

I've just checked a couple of those old "two bolt" Grimecas from my spares shelf, and they are almost certainly M10 x 1.0.
A 3/8 UNF bolt is a sloppy fit in both, and begins to bind after a few turns.

Click to expand...

I think I have found the source of some of my confusion. There are 3 different ISO metric standard M10 threads.
Course is 1.5mm pitch, fine is 1.0 and another one is 1.25.

If you get a hardware store bolt, it will be 1.5. Japanese car manufacturers usually use 1.0

The banjo bolt from the Kawasaki Master Cylinder was 1.5 but the Grimeca is 1.0 (I think). Another trip to the industrial fastener store may sort this out.

I had a look down the bore of both the bleed screw and the brake line attachment points with a microscope. In both holes, the taper at the bottom was scored. This is likely the cause of the leaks. Grumble, grumble... how to ream those... ?

Manxman

I think you will find all Grimeca fittings are 10 x 1mm, most if not all Japanese are 10 x 1.25 . 10 x 1.5 you probably wont find on any bike.
you probably want something like this ebay item No. 360886630210 for both Grimeca mastercylinder and caliper

If you have a 6x1 tap or screw and the same in 8 or 10-24 you can use them to check the thread pitch and then your half way there. Measure the tap drilled diameter with drill shanks. For 3/8-24 its a Q or .332 or 8.433mm. 10x1mm takes a 9mm drill

manxman,

This might be helpful.

http://store.fedhillusa.com/technicalhelphowtopdfs.aspx,

Pete

madass140 said:

I think you will find all Grimeca fittings are 10 x 1mm, most if not all Japanese are 10 x 1.25 . 10 x 1.5 you probably wont find on any bike.
you probably want something like this ebay item No. 360886630210 for both Grimeca mastercylinder and caliper

Click to expand...

Thanks to all for the help. I used a 10mm banjo on each end of a braided SS line. the Japanese master took a 10x1.25 banjo bolt and the Grimeca a 10x 1.0 banjo bolt, as madass140 predicted.

The results are great. I now have a functional front brake.

The disc is fully floating and the Grimeca has opposed pistons, so I suppose there is the potential for problems with keeping the disc centered WRT the caliper. Once I did some shimming, everything seems to work OK.

The caliper is a made-in-China Kawasaki clone that cost less than half as much as the brake line. I would like to replace it with something I have more trust in. I know someone was marketing a Master that had mounting holes compatable with the Norton switch block. Anyone know a source for these?

manxman