Yerf Dog 3203 Mechanical Disk Upgrade Project- No Weld

Lasakro

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I've been wanting to do this for some time now. I found only 3 projects with really good pictures to follow but 2 of them required welding, which I don't do, and the 3rd had the disk between the bearing and sprocket. Now there is no key way in the shaft there so I don't know how he pull that off.

In my modification the aluminum, bolts, washers, nuts and spring I had. I purchased the disk, caliper and shaft collar. This took about 5 hours, design, build, more design and more build. Tropical Fay just moved in so it hasn't been tested yet. If the aluminum doesn't hold I'll switch to steel.

Major design difference: Caliper fixed, Disk floats. This may make some really bad noise, don't know...

These were sourced through MFG Supply:
4-9306 - Heavy Duty Disc Brake Caliper. Fits Manco and more $29.99
212369A - 6-3/8" Dia Disc & Hub, 1" Bore, 1/4" key with setscrew $34.20
And Amazon:
1" ID Shaft Clamping Collar $5.71

Hopefully these pictures will help someone else down the line. Enjoy:

PICS 1 & 2
1) These show how the caliper top is mounted to the old brake band bracket. The bottom to a new 1"x1/8" alum. strip. I used 67mm bolt center to center to keep the pads on the outer part of the disk, almost to the edge.

2) I replaced the 2 caliper 3/8" fine bolts and lock washers. They are very tight. Lower caliper mounting bolt has a 3/8" std. nut and 2 washers, all used as spacers to align with the outside of the bearing holder. That bolt was replaced with a longer one.

3) Notice the new break cable mount held on with 10-32's.

PICS 3 & 4
4) Old band mounting bracket bent for now, Will cut off later if this all works out.

5) Caliper holds the disk from rubbing on the bearing bolts. Shaft collar, non-keyed, holds the disk key to the inside of the key slot while the disk holds the key in. In hind sight I could have used a sloted shaft collar. Both disk set screws were removed so the disk will float as the pads wear.

6) The disk fits nicely under the frame tube and axle bracket.

PIC 5
7) Cable lengthening bracket 1”x1/8” is 75mm center to center (bolts). When the caliper was apart I used a drift punch to move the actuator arm pivit pin to the other side while also switch the arm.

8) A long 5/16” bolt one the cable extension holds one end of the spring while the other end is held from a 10-32 tapped into the frame.

9) The new cable mounting bracket moves the cable out about 35mm.

Wish me luck :)
 

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mckutzy

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Overall I think this will work out good..Looks good.
Off hand.. Youll need to sand the pads to the rotor and resurface the contact patch of the disc with a rough paper. This breaks off the factory surfaces and makes a good bedding face for the pads to grip...
It sounds kinda off, but Ive had good results with this method, on the last several bikes I have built with These exact calipers.
 

Lasakro

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Yea I've run it up in the air and everything is holding, with some serious factory surfaces being honed. No strange noises. It was hard to judge the pad to disk edge but not now. Tomorrow I'm going to lengthen that lower caliper bracket by about 10mm. I won't get it out until after a new 30 series arrives Monday. My spline hub is so warn it barely disengages below 1500.
 

Lasakro

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I'm wasn't satisfied with the setup above. Very poor stopping. I ordered BMI Parts and Karts caliper mount and fixed the disk to the axle. Not much better.

Ordered a 10" disk is where I'm at on this.
 

Lasakro

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I made a longer plate to mount the caliper 2 inches further from the axle and make room for the 10" disk. My wheels are 20" so for those with smaller will probably have problems with the caliper adjustment bolt hitting the rim.

Overall stopping is just ok but i'm hoping it'll get better once the pads bed in.
 

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Lasakro

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In conclusion this works great after the pads bedded in. It doesn't take much pressure to lock the axle up so I'm staying with this setup.
 

Gasteffens

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Looks good, I'll have to keep this in mind for the one we just picked up. I just ordered a new band, and it stops good enough for us for now but if we keep it long term this may be a nice upgrade.
 
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