outside brake pad more worn?

Perhaps hygroscopaparanoia would be a better term.

Reply to
Bret
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Unreasonable fear of hygroscopy.

Everybody already knows that by now.

Why the hell would I mix water with brake fluid?

I don't recommend this but just saying it has worked for me. I never changed brake fluid in my life. Some of my cars were 20 years old when I junked them, with me putting on +10 years of that. Only reason I've junked cars is they're rusted or wrecked. I never replaced or rebuilt a caliper or wheel cylinder and brakes always operated fine when they were junked. Replaced one MC in all that time. Loooong time ago. I always do occasional hard braking tests on my cars. None had ABS. If I get a car with ABS I'll change the brake fluid every couple years. Components are more sensitive to debris and corrosion.

--Vic

Reply to
Vic Smith

What does the tool cost? Who makes it?

Don't know. It doesn't say what it is on the bottle. I have always assumed it was a silicone oil. But that's an assumption. What it does say on the bottle is;

"All parts should be thoroughly cleaned and dried. Then coat cylinder walls and parts, metal or rubber with AF100 assembly fluid to improve movement of parts and protect against corrosion, or for shelf storage.

Compatible with all parts in the hydraulic system; sintered iron, aluminum, brass, steel, cast iron and rubber.

Warning; - Af100 assembly fluid is compatible with hydraulic brake fluid but should not be used as a full fill in place of brake fluid." It's a clear oily liquid, and has a slight odour that is similar to white wood glue!

I bought it because it specifically stated that it could be used inside the hydraulic brake system.

In the rust belt here, caliper rebuilds aren't just an R&R of the rubber bits. The caliper has to come off and be put on the bench. Usually the piston seal grove in the caliper has to have the gunk scraped out of it, essentially a through cleaning and inspection.

Reply to
M.A. Stewart

sorry, forgot link.

can't remember the brand of the ones i have - got them years ago - but they're the same type.

sounds like a silicone. while dot 5 is good for preservation, it's not a great hydraulic medium because it's more compressible.

this is part of why i say to use proper brake grease. if you fill that groove with grease before insertion of the new rubber, and you fill the gap around the piston before inserting the new boot, you don't get grit or moisture intrusion, and the piston/cylinder gap stays clean. if you just use brake fluid, it not only dries out, but with water being around, you get corrosion. rubber grease helps the boot do its sealing job better.

Reply to
jim beam

I agree.

Reply to
Vic Smith

no chance whatsoever. unless you're somehow clamping with force sufficient to sever the rubber - it's no more harmful than letting air out of a tire, then reinflating it. vacuum lines get pinched all the time for smog testing. no harm there either.

what is the word for "fear of brake grease"?

because you want to replicate what happens when you just use brake fluid as an assembly "lubricant" don't you?

what part of arizona do you live in?

Reply to
jim beam

Might be empty pocket syndrome.

Reply to
Bret

i can never understand this argument. it costs how much to fill the tank? or buy new brake pads? yet a lifetime supply of brake grease with its resultant improvement in reliability and therefore safety is too expensive? makes no sense.

Reply to
jim beam

jim beam wrote in news:w6ydnRGlX8YIwgTQnZ2dnUVZ snipped-for-privacy@speakeasy.net:

You REALLY want to compaire a specialized hose like a reinforced brake hose that will stand up to thousand pound pressure to a simple vacuume hose???????????????? Not good thinking. you should NEVER kink, clamp, ect a brake hose. it can lead to early failure, and I am not talking about some mythial internal flap. Look up any rep. resourse and it will say so. KB

Reply to
Kevin Bottorff

The main difference is that the brake hose is made of many plies. Outer plies have reinforcement with fibers so the hose can't expand like a balloon. If the innermost ply tears and pressurized fluid can get between plies that will cause further ply separation or tearing and obviously if you have some volume of fluid between plies it also means the flow path is being restricted.

Also, You shouldn't leave the caliper hanging by the hose. And dropping the caliper and having the hose stop the fall is even worse.

-jim

Reply to
jim

are you two for real? or is extraordinary ignorance something you're somehow either proud of or afraid to change?

on the macro level, brake hose is designed to withstand >1000lbs of internal pressure, millions of flex operations, and resist foreign object damage like sticks, stones and even loose tire chains.

on the micro level, the rubbers are multi-layered, high quality, and the fiber reinforcing between two of the layers is not only excellently strong, it's also highly flexible.

bottom line: none of these materials are in any way challenged by something so trivial as pinching. as for fear that a hose can't withstand the weight of its own caliper, well gentlemen, you'd better not do the math on the axial tension 1000lbs of line pressure creates - you might be confronted by a reality you're not prepared to handle.

Reply to
jim beam

Well, actually I was taught never to use air pressure. You can probably get away with it for years, maybe forever, but the hazard is still there.

Reply to
hls
******* You wouldnt...and when you use brake fluid to assemble a piston into the bore, you might get some small amount of moisture, but you are going to have to bleed the brakes anyway, and that will get all but the most minor traces of water out of the closed system.

I have never used a special assembly fluid and have done just fine. If I were going to rebuild a caliper and leave it on the shelf for a while, I would reconsider that....but I dont do that anyway.

Regarding pinch pliars, I wouldnt use them either. That is asking for trouble, I think.

Reply to
hls

"jim beam" wrote

1000psi in a 1/4 inch ID line will push 49 lbs axially. (I have no info on the *actual* ID of a 94 Cavalier brake hose).

Now, take a 10 lb+/- caliper, and accidentally drop it a foot (the length of a 94 Cavalier front brake hose) because your hands are greasy, and calculate the axial shock load on the crimped hose ends when it hits bottom.

Reply to
Sanity Clause

Do you know anyone who has been injured by it?

Reply to
Bret

Some would consider it discretionary spending.

Reply to
Bret

I think he is referring to the exposed part of the piston corroding?

I agree.

Reply to
Bret

but being hit with the stupid stick isn't...

Reply to
jim beam

well,

  1. "shock load" depends on the rate of deceleration. have you ever bungee jumped? what do you estimate to be the rate of deceleration of this fiber reinforced [hollow] rubber cord?
  2. the crimped end is not going to hit the ground if the hose is still attached.
  3. actual hose strengths, as opposed to rated hose strengths, have considerable safety margin, usually >5:1.

this still doesn't address the fear of the unknown for those that can't/won't bother to learn anything or who just plain want to be chicken littles, but they're too busy transmitting to ever receive.

Reply to
jim beam

that's awesome - can you get sugar out of coffee when it's dissolved too? how about adsorption - have you reverse that too?

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of course you have - that's why you're a rebuild expert - lot's of practice!

yup, you bothered to educate yourself on hose specs and material properties, do extensive testing, and have experience of extensive failure analysis - you've got all the information you need to make an informed recommendation to others.

Reply to
jim beam

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