outside brake pad more worn?

I use a tubeless tire valve stem and a bicycle pump. Attach the tubeless tire valve stem to the bicycle pump hose, check for leaks, then hold the rubber end of the stem on the caliper hole (brake fluid inlet) and pump. Stop when the piston is almost all the way out. Remove the piston by wiggling with hand. If contaminated with petroleum, clean with isopropyl alcohol, then coat with brake fluid or brake rubber grease.

how do you replace the plating after you've removed it?

how do you prevent the brake fluid from causing rust in the presence of water?

we agree on that, but nevertheless, many workshop manuals illustrate piston removal with a compressed air gun...

if you use a proper cleaner/solvent, you don't need to blow anything dry

- they dry in still air in seconds.

i just pump it out on the vehicle by leaving it connected to the hydraulics - no special tools needed. as soon as it's ready to be wriggled free, or even just held in by the piston boot, i pinch off the brake hose [with the correct hose pinch tool], then remove the caliper. easy. and quick.

forget the brake fluid - that's a cheapo hack used by guys cutting corners and trying to minimize service time that will cause problems down the road. do what they do in factory caliper assembly - only use a proper rubber-compatible brake grease.

Yep, you can use a low pressure system like this and be safe enough, but NEVER use a compressor to move the pistons out of the bore. That can be fatal.

The pistons can be removed with a compressed air gun, a person just has to be sensible about it. Careful pulsing of the air pressure is the sensible way. If the piston is so tight, because of whatever, that an excess of air pressure has the potential of danger, a caliper piston tool is needed to twist the piston loose. The tool grabs the inside of the piston. The tool can be used instead of air pressure. I don't have the tool because my vintage 1960's army green upright bicycle pump with a tubeless tire valve stem has never failed to get a piston out.

Low pressure? My vintage 1960's army green upright bicycle pump will pump 75 PSI into a bicycle tire!

brake hydraulic pressure is >1,000psi.

indeed.

but pumping it out with the existing vehicle hydraulics requires no skill or additional tools except a proper brake hose pinch tool, which anyone doing brake service should have anyway.

I use plugs that I made. Take the appropriate threaded brake tube nuts, snip the tubes off flush with top of the nuts and then braze the nut to the snipped tube. You now have a plug with the tube flare that you can screw into the female part to seal the system. For a female brazed up nut plug, take an old brake hose, hack-saw off the ends of a rubber hose (female fitting) and braze the hole closed. I've also used a bolt with a nylock nut and copper washers on banjo fittings. Whats the correct hose clamp tool cost?

If a person doesn't have the special grease they gotta use something compatible, which would be brake fluid. I use EIS AF100 Brake Cylinder Assembly Fluid.

jim beam wrote in news:6Omdndz1rvLpdwXQnZ2dnUVZ snipped-for-privacy@speakeasy.net:

I hope to heck you don`t use that grease to reasemble the piston into the caliper. It is for the sliders only. brake fluid is the approved assembly fluid installing the piston. KB

jim beam wrote in news:CKKdnV66qNLhjgTQnZ2dnUVZ snipped-for-privacy@speakeasy.net:

snip

there are no proper brake hose pinch tools. the brake hose should never be pinched in any way. that will damage the hose on the inside. KB

So is EIS AF100 Brake Cylinder Assembly Fluid by Parker Automotive. I've been using it for years from the same bottle. It goes a long way.

Yep. There was some talk here a while back about brake hose interior material creating a "check valve." Though I don't buy the "check valve" theory as anything but a 1 in a billion chance, if I wanted the improve the odds I would pinch the hose. This pinching business is probably due to hygroscopaphobia. That's the unreasonable view that brake fluid sucks up atmospheric moisture like it's being rained on by a thunderstorm. Same deal with using brake fluid to lubricate a caliper piston when you put it together. It won't turn to water and rust up your piston and bore. Just don't do it in the swimming pool.

--Vic

i have a pair of this type - impossible to over-pinch. the advantage is that you can pinch a hose off before there's any leakage - depending on the work you're doing.

well, i wouldn't unless i had the right grease. you can get it at pretty much flaps that's worth anything. really shouldn't be doing work on the brake actuators without it.

is that a silicone?

common misconception, but like the other bizarre and ridiculous braking myth, "hose flaps", completely untrue.

if people learned about hose construction and polymers, they wouldn't propagate troll stories like this.

hygroscopic means it absorbs water. hygrophobic means it doesn't. what do you think hygroscopaphobic means?

but brake fluid /is/ hygroscopic. look it up in any spec sheet.

yes it will. put a degreased nail in a mix of brake fluid and water and tell us what happens. and how quickly.

any delay in corrosion onset you may experience with brake parts in this situation is due to good luck and any component plating you may not have yet removed.

read the spec sheet kevin - it specifically /is/ safe for brake rubbers. in the old days it was used for caliper assembly too. except that now it's too expensive for bean counters so now they use cheaper stuff. it's still good enough for you though.

You could always use the regulator to lower the pressure.

Fear of brake fluid absorbing water, should he have put a smiley on it :)