Saturday, February 1, 2020

EZ-RIDER - The Delicate Art of Caliper Piston Polishing







Caliper Piston Polishing - Why Not?


As I strive to bring EZ-RIDER back from the brink of oblivion, part of the effort is to try to save as many of the original parts as possible.  

There are many reasons for doing this, but here's my top 3:

- If you replace before trying to fix, you're doing it wrong
- If you fix and then have no choice but to replace later, you're doing it right
- if your fix means you never have to replace, you get to brag and get more stuff

So, there's really no reason why I shouldn't do my best to fix as much of the front brake calipers on EZ-RIDER as I can, which includes (of course) its two pistons - each of which represents one of the most expensive parts of the brake assembly.

The most difficult part of refurbishing the pistons was getting them out - they were completely rusted/seized in place and therefore extremely difficult to manipulate, with only about 5mm of their lip showing.  Copying a technique I saw on YouTube, I used my channel lock pliers to pull them out, but there are some other techniques in existence that someone interested in following my footsteps may be interested in knowing:

1) Some people use piston pliers.  There are specialized piston pliers available that use outward pressing force inside the hollow piston give a person a way to work them out of place.  I have a pair of these pliers on order, but I still don't have the experience of using them, so I cannot speak to their effectiveness.  One thing I know for sure is they won't damage the outer surface of the piston because they do not touch it.  A potential downside is the fact that the clearances in the caliper are very tight, so they may not be usedful to pull the pistons all of the way out.

2) Some people use the braking system itself.  They just remove the brake pads and then pump the brakes to use the brake fluid to pop the pistons out.  This seems like a great way to get the pistons out, but I think it would probably be very messy, so precautions should be taken to prevent brake fluid (which is pretty corrosive) from flying everywhere.  Still, this is a very popular method.

3) Some people use compressed air.  They hook up compressed air to the brake line and use air pressure to eject the pistons.  Putting a piece of wood in the impact area is a good idea, and if you have a multi-piston system, you need to figure out a way to work the pistons out in a way that doesn't eject one piston prematurely, leaving the other stranded in the caliper.

4) Some people use pliers on the top of the piston and just work them out as best they can, inflicting as little damage as possible aside from the lip area, because the main seal of the calipers is well into the caliper body.

In my case I (1) Didn't have the pliers; (2) Had already taken the brakes apart; and (C) Didn't have a compressor, so I ended up using technique #4.

Enjoy!




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Bill of Materials



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