View Full Version : Caliper Dissassembly/Reassembly
Pappy
09-28-2005, 01:05 PM
As this riding season grows closer to the end for most of us, it should be on your mind to start thinking about what you need to be replacing and inspecting as the temp's start to get colder.
One area often overlooked is the brake calipers. For some reason they scare alot of riders and while brake pads are replaced, the actual caliper is never attended too.
Our project caliper is off of a TRX450R and for the most part, all the calipers work the same way and have the same basic parts.
Pappy
09-28-2005, 01:14 PM
For a complete tear down and inspection, you will need to remove the 2 attaching bolts that hold the brake caliper mount to the spindle. A 12mm socket is needed.
After disconnecting the brake line and removing the 2 bolts, the caliper can be removed from the spindle and drained of remaining brake fluid.
The first step, will be to use a 8mm wrench or socket to remove the pad retaining pin(see red arrow) Once this pin is removed the brake pads will fall right out.
Pappy
09-28-2005, 01:16 PM
Once the pads are removed, the mounting bracket can be removed from the caliper by sliding it away from the caliper housing.
You will also remove the small brake pad locators at this point.
Pappy
09-28-2005, 01:20 PM
Once you have it dissassembled to this point, you will need an air compressor with either a blower or attachment that will allow you to safely and easily remove the pistons. Remember to lower the air pressure to around 25 psi to start. leave the bleeder valve and brake line bolt in place to prevent air from escaping. Also, keep your fingers clear of the pistons as they will pop out with a small amount of force.
The small dust seal can be removed now, and inspected for dry rot and or damage.
Pappy
09-28-2005, 01:22 PM
The seals will be removed next, and you will need a small PICK to remove them. A very small flatblade screwdriver will also work, just take your time and ease the seals out of the recesses.
Pappy
09-28-2005, 01:27 PM
Once the seals are removed, you can begin inspection for any damage or wear.
The most obvious part in the entire caliper that always needs attention is the sliders. They build up corrosion and need to be cleaned and oiled before reassembly. Check the pistons for cracks and they also can develop a ridge that will need to be cleaned. Scotch bright works great to remove the ridge and brake fluid is then rubbed on the piston to prevent corrosion and to ease re-installation.
Seals should be checked for any sihns of dry rot and cracking. If they appear fine, a light coating of brake fluid can be applied right before reinstallation.
Well, there you go. Now you can disassemble your caliper! I will continue this thread when I reassemble the unit after coating.
Pappy
09-29-2005, 07:49 PM
Time for reassembly after all components have been inspected, cleaned and replaced if needed.
Set out your seals, and you will see a wide seal and a narrow seal. The larger goes in first into the wider groove. Pretty self explanatory.
I start the seal by slightly compressing it so its more of an egg'd shape. Once started, slide your finger around and make sure its fully seated and flush.
Pappy
09-29-2005, 07:52 PM
Once you are confident your seals are installed correctly, it is time to install the pistons. A small amount of brake fluid on your finger tip and smeared on the seals is all it should take to aid in the installation. Keep the piston square and slide it in.
Pappy
09-29-2005, 07:54 PM
With the pistons installed, you will need to install one of the dust seals. These can be squeezed and fed into the opening and they will "pop" into place once inserted fully.
Pappy
09-29-2005, 07:56 PM
There is also a small dust seal on your caliper bracket that will need to be installed. There is a small lip that will hold the seal in place.
Pappy
09-29-2005, 07:58 PM
Brake pads are then inserted making sure they clear the small clip and are facing the correct way.
Pappy
09-29-2005, 08:00 PM
With the pads installed, grease the slider pin and insert it into the caliper.
Pappy
09-29-2005, 08:01 PM
And there you have it. Ready to be placed back on the spindle and reconnected!
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