This Instructable will show you how to turn a picture hook into a mud guard for your mountain bike which will keep mud out of your brake callipers in the depths of winter.

If you can use a saw and a drill then you can make this mud guard very easily. It takes only a few minutes to create something that looks professional and works well.

The brakes on my bike are Shimano SLX which I have added retainer bolts instead of cotter pins to keep the pads in place. you should be able to do this modification on any brake calliper which uses a central screw in retaining bolt to keep the pads in. 

You can see the problem in the pictures - in one the calliper is clean and the other is dirty after a ride through miles of mud. The mud reduces the braking power by contaminating the pads and acting as a lubricant. That is also when you get squealing brakes. 

The brake callipers and pads have an opening to them, for increased ventilation. In the wet , muddy cold winter conditions ventilation is not a problem but keeping the brake pads dry and clean is.

The mudguard woks by stopping rain and mud getting into the gap and therefore keeps the pads clean and dry.

You will need;

1. Two picture rail hooks (the type that is in the photo below which hang on a rail rather than get nailed into the wall)
2. Rotary tool with cutting disk (or hack saw)
3. File or sanding attachment for rotary tool
4. Drill with an assortment of metal drill bits
5. Safety gloves
6. Safety goggles
7. Screw in retaining bolt if you are converting from a cotter pin set up.

Before we get into the details of how to make this Instructable I have decided that this modification needs a name. "Brake calliper mud guard" is too boring. I am going to call it a "Picture Hook Anti Sludge Thingie" (PHAST). Clean dry brakes should give you greater confidence and make you faster anyway so this sounds appropriate. Anybody else got any better ideas?

LEGAL DISCLAIMER (well, I am a lawyer after all!): If you decide to do something similar to this to your bike you take full responsibility for any damage to yourself, the bike, any other person or any other property as a result of such a modification. Brakes are an essential safety item on your bike and you should not touch them or modify them unless you know what you are doing. Do not attempt this modification if you are not confident of your own mechanical skills. If in doubt speak to your local bike shop mechanic (who you should be supporting anyway).

Step 1:

Offer up the hook to the calliper. The "tab" will be too long so measure how far down you need it to go. Mark up where you will need to cut and where you will need to put a hole for the bolt to go through. In the picture you will see that I marked it up with a Sharpie. You may also need to bend the curved bit slightly to make it fit the width of your calliper.

Next repeat step two - after all, "measure twice and cut once" is a good maxim and avoids you cutting too short. If you want to you can bend the bottom of the tab so that it is straight, which will make it easier to cut.

Put on your gloves and safety goggles and cut the bottom off the hook "tab". Then check that you did measure correctly. I used a rotary tool with cutting disk but a hacksaw would also work. I cut from the inside just in case I slipped and marked the metal - if the mark is on the inside you can't see it but a big scratch on the outside would annoy me.
<p>Nice job! It's great when you can easily modify things like this for different purposes than they were intended.</p>
<p>Thanks. As soon as I saw it I knew what it could be used for. I enjoy that as well, particularly if it looks like it was meant to be.</p>

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