Dunlop Sumitomo Brake Calipers

[JT191]

I remember reading "Dunlop", inscribed in the back of what was left of a front brake pad. "Sumitomo" was inscribed a little shallower.

I took a look at the brake caliper, and it has "Dunlop" and "Sumitomo" in raised letters around the back of the circumference of the inner and outer halves.

Some searching and the only vehicle that jumps out as using "Dunlop Sumitomo" calipers happens to be the original Datsun Fairlady.
DatsunParts.Com sells the caliper halves and rebuild kits, and they look remarkably similar.



There are some other minor references of Jaguar, BMW, Aston Martin, MG, etc., maybe using these calipers, or a company in England lists Dunlop and Sumitomo among the calipers they rebuild for these vehicles.

I am wondering if the inner and outer halves are the same between the Bellett GT and the Fairlady. Because these pieces attach to a central cage or frame by four bolts, the halves could be used on a number of different vehicles, and the different frame would call for different pads. The Fairlady and Bellett use different pads, but the caliper halves might be the same.

Someone down under matched the Bellett seals to another car that wasn't a Datsun. Has anyone matched them to the Datsun? Rebuild kits and brake replacement parts are plentiful for the Fairlady. I'll post what I find out unless someone already checked out this possible lead and posts all the answers before I find out anything.

[JT191]

Bad news on interchangeability. The Datsun Fairlady Roadster calipers are 2 1/8 inch piston size. The Bellett GT calipers are 2 1/4 inch piston size. That 1/8 inch larger size difference might have made a big difference in marketing 40 years ago ("Our Bellett has bigger brakes than their Fairlady..."), but it puts a dead end on using the readily available Fairlady caliper parts.

The outer caliper piston is also built into the cage or frame or bracket, whichever you choose to call the middle piece that bolts to the spindle. The Fairlady uses an inner and an outer piston assembly, both of which bolt to the center bracket that attaches to the spindle. If the Bellett used the bolt on outer piston assembly, then it would just be a matter of removing the originals and bolting on a set of new Fairlady piston assemblies.

On to the pistons. The piston design is rather unique. Normal pistons are just cup shaped with the rim of the cup riding against the pad. The Fairlady pistons appear to be flat top. The Bellett pistons have a raised button in the middle of the cup, that extends through the pad shim and rides on the back of the pad itself. Some people have said they discard the shims and allow the pad to ride against the piston. This would do two things: First, there would be a point load in the middle of the pad. Second, the shims angle the pad so that the rear edge bites at an angle like a surf board riding on a wave of water. Without the shim, the pad bites on the leading edge and torques down.

I am not having much luck cross referencing the seals with European cars using the original Dunlop calipers.

[2ldohc]

Good work on the brake research JT. Pity it didn't work out to be an easy swap.

Cheers,
R.

[JT191]

I haven't run out of loose ends to run down yet.

One of the Japanese auctions for brake pads shows the pads fit:
1966- Bellett 1500/1600/1800
-1974 117 Coupe 1600/1800

and

-1969 Mitsubishi Colt 1500
-1971 Mitsubishi Colt 1500SS

These are the full pads with the hole in the center top and the hole or slot open to the side on the top left and right edge. This is not the single hole pad that shows to fit a large range of 1960's and 1970's cars, but has no holes that line up with the Bellett caliper pad pins.


I think this is the same car that someone down under said the brake seals match to the Bellett. But, much like the early Skyline brake rotors that everyone says they like to use, they didn't sell 60's Colts in the Western Hemisphere either.

[dave]

They did here in Australia (assuming we're Western hemisphere); in the same dealerships as Belletts in some situations (see brochures pages - some Aussie brochures show "Mitsubishi Australia - Concessionaires" or something) but the bad news is that the original Colt is rarer here than even the Bellett, so the likelihood of parts is... that's probably gonna be another dead end!

But it's info.

[JT191]

They did here in Australia (assuming we're Western hemisphere)

That's Eastern Hemisphere. I should have said Old World vs. New World. But the South American automotive market evolved out of sync with the rest of the world, there are always odd cars showing up down there.

I located a database of caliper repair kits (seals), that identifies most of the piston sizes. As it turns out, 2 and 2 1/8 inch size seems to be the average size for a brake caliper. 2 1/4 is rarer and somewhat large. There are some mid sized pickup trucks using that size. On paper, the Bellett is an extremely light weight car with a caliper piston size that is used on a lot of cars that weigh 1000 or more pounds heavier.

I found 7 sets of caliper repair kits that have promise. And they are not expensive. My next step may be to obtain the 7 seal sets, compare them to the Bellett seals, and try to locate a piston seal and a dust boot from the group that matches.
With any luck, this might be a solution.

[malonecp]

Hi, I would be very interested to get a copy of the database of repair kits. Have you been able to proceed any farther in your search?
Thanks,
Chuck M.

[dave]

You must be the guy that Oldcolt Craig was talking about at the Strathalbyn Swap Meet the other day!

Welcome on board! I like the S600/S800... it's on the list of cars I must own before I die!

[JT191]

I found 7 sets of caliper repair kits that have promise.

I thought I already followed up with the dismal results...
Maybe it was too depressing...
http://www.bellett.net/forums/viewtopic.php?f=35&t=365

Of the six available sets, two had piston fluid seals that might be close, but not close enough to bet your life on.

The dust boots were not even close. There is a larger step down in the top of the piston on these than on others. And a unique attachment method.

I'm down to tracking down seals and pistons in Japan. When the budget allows, I will have someone go into the dealership parts department and just order the parts.

[malonecp]

Guys,

There is always some way. As you said I can always make the parts. Custom lines can be made. Looking at your pictures gave me some hope at updating to something with more common parts.

I have an 1967 Honda S800 with Dunlop calipers. I plan to rebuild them in a month or so. I am just trying to find the best way to go. Original or updated. The reality is I probably will only put 1000 mile a year on the car so the best option will probably be original with stainless pistons. This way I will not have to rebuild them again.

I have been collecting parts for a second car to rebuild, but too much is really missing. I have not decided yet on the plan for the second honda. It is cheaper to buy another car already running and use the parts I have for spares.

Thanks for the update
Chuck M.

[toomanybelletts]

I dont know if this is worth mentioning , but I have in one of my cars GTcalipers with E TYPE JAG rear pistons in it . Unfortunately I have to put S/hand pads in as the pistons are taller , but the seals from a Jag may work ??? -Craig