Terraplane brakes


trikebldr

Learning the Ropes
I started this a few nights ago, but this forum platform has some weird quirks to it. One is that it turns pics upside down, and two is that while writing it just deletes the whole thread! Maybe I write too much and that's how it tells me so! So, I'll give it one more try. So, if the pics are upside down, not my fault! I even tried making them upside down before adding them, but this site seems to like them upside down, no matter what.

I'm sure most of you know that the Terraplane used Airheart brakes, but it has been mistakenly written here that they are the 150 series. In fact, they are the 175H series of calipers. The 150 and 175 series both use the same master cylinder, though. Rebuild kits are available for the master cylinder and caliper, but at $84 for the caliper kit, I chose to go with a new one to be sure it would last a long time again. Besides, mine had sat in some water for a while at some point in its life. My original master cylinder, and it's mounts and pedal are in terrible shape, too. I bought a new master cylinder, too. Complete with both "up" and "down" levers for the master the whole brake set cost $362 for the soft-pad calipers. I opted for the softer pads to prevent too much wear on the rotor, and these sidecars don't usually have a need for higher heat applications that the hard pads are intended for. These calipers are also designed for use with 1/8" thick rotors, but Vetter opted to go heavy duty with stainless 1/4" rotors. Airheart offers spacer kits to make the 175 calipers fit the 1/4" rotors, but if you are simply replacing the original caliper with a new one, just reuse the old spacers.

You can order everything for these brakes here:
http://www.airheart-brakes.com/

I have a history with Airheart brakes that I wanted to share. When my dad and I were racing go-karts back in 1960-1963, he had a junior engineer working for him named Bob Airheart. Bob and his brother were experimenting with disc brakes in their garage and started the Airheart company. Their first offering was basically the 175 series, designed for smaller, light aircraft like Cessnas and Pipers. Today they are quite popular on the front spoke wheels of lighter hot rods. When were racing, Bob also got interested in our go-karts and saw a need for a good hydraulic disc brake for them, so the 150 series caliper was born. My kart ran one of the first prototypes which looked like the one on the right in the first pic, but without cooling fins. The first production run of these calipers, and the master cylinders, too, was highly polished! That sure didn't last long due to cost, and most racers didn't care about the shiny looks, so they became just natural finish right out of lost-wax casting.
Since my dad and Bob were good friends, we had the latest and greatest stuff all the time. It also helped that Bob's daughter, Jan, and I went to school together and had a lot of classes together! It's been interesting to watch this family owned business grow from a two car garage to a 20,000sq/ft factory, then be bought out by Hurst Corporation to become Hurst/Airheart (one of the biggest auto racing aftermarket companies in the world), and now to be taken over by Tolomatic. I lost track of the Airhearts long ago, so I have no idea why Tolomatic ended up with Airheart brakes. For many years ever car at the Indy 500 ran Airheart brakes. I was fortunate to be able to work for Bob Airheart at the 1963 Indy 500 by running parts to the teams when they would call for them.
FWIW, the 175 series calipers are way overkill for these sidecars, but the 150 series calipers have a slightly narrower bolt pattern, so a simple swap isn't possible without some modification. Also, you can order the systems for use with a proprietary mineral oil fluid for higher temp uses, or for use with standard DOT-3 automotive brake fluid. IMO, the DOT-3 fluid version is best since our hacks won't ever see the need for the higher temps in the brakes, and since our bikes use the DOT-3 stuff anyway.

The first pic shows, left-to-right, my new 175 brake set, the original 175 caliper from my TP in the middle (the master is just too ugly to post here!), and on the right is the first 150 caliper and master from the production run from 1962. This one was kept as a backup spare but never used. It now has a custom aluminum slider plate to fit a Motorvation first generation Spyder sidecar application, but again, I never needed it as a replacement. So, it is an unused 54 year old brake system! The prototypes looked just like it but without the cooling fins. It is also of the mineral-oil (red) version.

The rest of the pics show the new 175 caliper next to the original 36 year old version. just minor changes in the castings over the years, but basically identical.

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Mike324

Vetter Aficionado
Country flag
Very interesting history - thanks. So the 175 was designed for planes but was it actually used for that application? You lucky guy - I always wanted to kart race when I was a kid but we lived too far from any karting action.
 

trikebldr

Learning the Ropes
Yes, Cessna 150's, 172's and 185's used the 175 series brakes. Not sure just which Pipers used them, though. A lot of current homebuilts use them, too.
We lived in So. Cal. when we raced, so we had lots of tracks around us. It was sorta the Mecca of kart racing! Agoura, Azusa, Southgate and Oxnard were the usual, weekly, paved short tracks. In 1962 they started doing endurance races of 99 or 300 miles, and we ran those on tracks like Riverside International Raceway, Willow Springs Raceway, and even Edwards Air Force Base hosted the first 99 miler on the old abandoned streets of the WWII barracks. And, we also traveled to Sacramento for the Western Regional races, then the Nationals. And, guess who paid our expenses? We took a small crate of Airheart brakes and parts with us to sell.
 

Roulemabosse

Grasshopper
Hi Trikebldr,

I just bought a Terraplane and I had to open the caliper to remove the wheel. I noticed that there was a spacer and 1 washer between the 2 parts of the caliper. By reading your post, I understood it was to fit the 1/4po rotor. I was wondering if in the original setup there was only 1 or 2 washers. By looking your picture it looks like there was 2 washers. Thanks.
 

trikebldr

Learning the Ropes
Hi Trikebldr,

I just bought a Terraplane and I had to open the caliper to remove the wheel. I noticed that there was a spacer and 1 washer between the 2 parts of the caliper. By reading your post, I understood it was to fit the 1/4po rotor. I was wondering if in the original setup there was only 1 or 2 washers. By looking your picture it looks like there was 2 washers. Thanks.

It all depends on the washers used. It's more a matter of custom fitting the caliper gap to the rotor by adding/deleting washers until it's just right. I do recommend using precision ground washers though as they will be much flatter than stamped out washers.
 
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