How To Remove Piston From Caliper

Hey Gang

Many people email or phone and inquire me all sorts of questions, I shall weblog this today, and so add it to the tips page, equally I am sure that this will help some of you lot out?

But Many CB750 Honda'southward that you have picked upwardly, have been found, non running and sat in a k, a barn or even in a field for bloody years and when you effort and motion the dang thing, the forepart cease refuses to budge, so you whack the caliper with a hammer, brick or kick it, and the bike will motion, albeit stubbornly.

OK, the principal problem is that the bike has sat for such a long fourth dimension and information technology is open to the elements etc, the brake fluid soon turns to gel and blocks the chief cylinder and some of it gums around the piston in the brake caliper itself.

Other factors to weigh in besides is, as the elements can be brutally harsh and extreme at time, and so what happens is the rut and the cold will brand the steel piston sweat and and then cndensate etc.

Thus causing rust spots or even a rust ring effectually the piston, the body of the caliper is made of Aluminum and that wont rust but will oxidize a bit, and mix all that together and of course, the piston cannot retract when you printing the brake etc every bit the Pitts of rust are touch the rubber O-Band seal and gets jammed.

Right, to move a bike I sometimes have a big Prophylactic mallet with me, so that mode if the brake is stuck, a skilful belt on the center of the Caliper will usually gratis upwards the piston enough, for y'all to become the bicycle to movement and load it upward and have it home.

At present, yous can employ an air line to effort and blow the piston out, and that may work, simply many times it will not.

Once home you recall most what yous have to exercise, and the all-time thing for me is to remove the restriction caliper from the subclass on the forks.

I offset undo the brake line as this can be a task and sometimes you may demand to suspension the old steel line equally the 10mm heads tend to round off after a couple of hard tugs on a wrench.

And then pull the lines off and disengage the drain nipple.

Then, Just using a Allen Wrench, I remove the 2 locating bolts and the Caliper volition in fact fall into two pieces, then one time that is done you are prepare to go this puled apart inside.

Now you have the Caliper and a messy table, but now prepare to get-go work and what I do is fit an sometime set of handlebars in the vice, then I fit a working chief cylinder and brake line, I then hook this up to the brake caliper and using a new bleed nipple I really drain the brake line, and then at that place are no air bubbling and and then one time she is all set, I lock the bleed nipple up and fill the reservoir on the master cylinder.

Slowly, press the brake lever and you lot will see that the brake pad will start to motility, equally at that place is so much force per unit area coming down that line that at times i have tried a air line and no luck, only the stock main cylinder will actually push nigh two tonnes of pressure level out.

You WILL see the restriction pad motion then pop out, and after that, y'all will cheque the reservoir to see if there is enough fluid in there every bit you don't want to exist sucking in air.

And then, y'all will feel the force per unit area in the brake lever and will find the piston starting to move, now, I lay the brake caliper on a piece of work surface and encompass that with a few old rags etc, as the piston will Pop out simply you will too get a big amount of fluid post-obit the piston and the rags volition soak that mess up.

You will also notice that the piston will not only have rust Pitts on information technology, simply there will be a real mess behind that piston and inside the cylinder wall will be coated with all sorts of grunge.

I ever replace the bleeder nipple too as ordinarily the old one will be quite rusted and the bleed hole will be blocked and non function.

You lot will get plenty of old fluid and new, going all over the place, and then brand certain that you lot have enough rags at hand as brake fluid will eat pigment.

Now, what I do is is pull the old O-Band out of the caliper trunk as I ever replace with brand new O-Rings and then what I have to practise is clean the inside of the caliper body upwardly as information technology is covered in old fluid etc.

Now, you cannot use sand paper or anything abrasive in there, else the fluid will get past the piston and onto your brake pads.

So, what I practise is I make clean the caliper with lacquer thinner from Habitation Depot, then I remove the O-Ring with a pick, and then what I exercise is basically hone the inside with a Safe wheel in my dremel.

The Rubber wheel is enough to clean off any bad deposit's of fluid and gel from former fluid and then information technology will smooth the aluminum to a shiny terminate, but non hurting the body at all.

Only this will clean the inside so polish, the piston volition slide nicely and not grab anything.

I accept just made a little video, so you can roughly run into what I practice, and that way y'all should be able to understand the process, I know- my accent is a little strange, just you become accepted to it, I did.