HOW TO : Replace Front Brake Pads and Discs (Rotors) Prius Gen 2

That is a good point about cleaning. How would you get the old out of there? The old rubber is a concern too. How would you clean it? Hate to leave any water in it, and solvent would be a risk perhaps? The grease old and new look about the same, but how would they react?

 

For sure I disconnect the neg. cable. Don't want any disasters! Haha.

Was just reading on amz listing on the syl glide that some say they use it to lube the shims etc too. I wonder? I had the Permatex green stuff for the metal already but makes one think.

 

If there's any concern about the rubber, then one of the easiest things to do is stop at the dealer and buy the rubber kit. You get all the rubbery bits (pin boots, piston boots, piston seals, bleeder covers) and other miscellaneous small bits to do both sides. (If you're not going to disassemble the calipers and replace the piston seals and boots, you can just hang on to those parts as spares.)

And if you buy that kit, your grease question gets simpler, because it comes with a little right-sized packet of the specified glycol/lithium soap grease in it, so there's no problem mixing it with the original stuff.

I don't specifically know if there's an adverse reaction between the original glycol grease and a silicone. I'm just going by the conventional wisdom to be very leery of mixing different grease types. For that matter, I don't have any inside knowledge of why Toyota's so adamant about not using a silicone there, but for whatever reason, they kind of are; aside from the manual, they've issued additional service bulletins reconfirming that the glycol stuff is all they want there.

 

I cleaned the pins, but not the bores, no issues.

 

LOL..I have enough brake lube of any kind to do 100 cars now..Haha. Love the small sample size.

 

I never heard of this brake fluid testing. Where does one get these strips?

 

Here's an example:

https://www.brakebleeder.com/product-category/brake-fluid-testing/

The 15-pack of individually-wrapped combination coolant and brake strips makes a nice option if you don't need a lot of them.

 

WARNING: I bought an electronic one from Aliexpress and it is utterly useless. I can get it to read "perfectly fine" to "replace because you have no braking power left" by submerging the measuringprongs a little more.

That strip looks like a pH strip used in chemistry. Not versed on the process of aging brake fluid, but sounds like it could be trustworthy.

 

The brake fluid and coolant strips are a great thing for everyone with a Prius. Others may disagree, but I think anyone with a Prius should check both fluids as a part of preventative maintenance maybe once a year, 6 months or whatever maintenance schedule you think is best for you. Degraded fluid can damage rubber seals, cups, and rubber parts in the brake system making for more expensive repairs. Bad coolant can start to damage the radiators if the coolant isn't kept in good condition due to loss of effectiveness of the additives that are specifically added to the coolant to help the aluminum not degrade. If both test good, I don't think there is any reason to change the fluids. If the results are marginal or bad then it's best to flush, fill, and bleed to save from expensive repairs down the road.

Don't forget when you test that you have 2 completely different coolant systems to check.

BTW, Amazon also has this same product at the same price, but maybe with free 2-day shipping.

Amazon.com : brake fluid test strips

 

Nice article. New pads are always ready to install. If they came with anything on them that needs to be cleaned off, there would be a huge liability issue for the manufacturer. I never press pistons in, forcing potential contaminated fluid into the ABS system. I always use a drain bottle with a check valve in the hose. When you open the nipple, and start to press the piston back into the caliper, the fluid will come out and fill the hose to and past the check valve. On a commercial bottle, the silicone hose is the right diameter. Too large of a diameter, like vinyl hose) will allow the fluid past the check valve to drain in some arrangements.. No air will go back because the fluid cannot move backward above the check valve . (Don't open the valve so far that fluid comes out around the threads, or the essential containment may be compromised..)

 

I’ve never opened bleed valves when pressing in caliper pistons. I can see the arguments for doing it, but I’m sceptical about the need, and suspect it’s more risk than reward. Never had a problem either. I do semi-regularly replace the brake fluid though.

 

To have more risk than reward, there would have to be a risk, though I'm not sure what that would be.

If the rubber cap is missing from the bleed screw (and presumably has been missing for a while), then there can be a real risk that opening the bleed screw will be difficult, even to the point you could strip or damage something trying.

But if the cap is still securely in place and undisturbed, using the bleed screw goes just as it does in the storybooks. (Corollary: be sure to put that rubber cap back on, so things will go that easily next time too.)

 

Storybooks, lol.

Are there any repair manuals (aka shop manuals) advocating the practice?

To be fair, a similar case: I’ve never seen Repair/Shop Manual mention of basting out and replacing brake fluid in reservoir before commencing a brake fluid replacement, but that does seem a good/benign idea.