Brake Groaning/Squeaking Issue After Changing Pads

Just joined Priuschat after seeing it pop-up several times on Google searches and noticing that the members here seem to have a lot of useful information about Prius issues.

ISSUE: (2015 Prius V, 84,000 miles)

My issue is very similar to what a few others have posted. I'm having groaning/squealing issues with my 2015 Prius V rear brakes. It's most noticeable when backing out of the driveway in the morning but, as time has gone by, it's worsened a bit. It now continues for about 50 feet or so after I get out of my driveway and go forward...and also now occasionally happens when I leave work in the afternoon to drive home. I'm concerned that the brake pads may also be dragging when I am driving during the day and affecting my MPG, but not so hard that I can hear it.

BACKGROUND:

Thinking it might be a good way to save money and learn a new skill, I decided to try and change my brake pads myself for the first time.

I followed the instructions on the NutzandBoltz Youtube channel for changing rear pads and lubricating caliper pins.

MATERIALS USED:

Wagner ThermoQuiet pads
CRC Brake Quiet
Permatex Brake Capiler Lube

WHAT I DID:

(after disconnecting the 12v battery) I removed the OEM pads and hardware and replaced them with the new pads and hardware I bought. The old shims (and possibly a couple V-shaped springs) didn’t seem compatible so I discarded them (THIS MAY HAVE BEEN A MISTAKE).

I removed the pins, wiped them off, and heavily greased them with caliper lube before replacing them in the calipers. I used a brake piston tool to push bake the brake pistons. I did not blead the brakes because I didn’t think you needed to do that with a Toyota Prius. I then put CRC brake quiet on the back of the new brake pads, put the calipers back, and replaced/torqued the wheels.

Ever since doing the work, the rear wheels have been getting more and more noisy.

MY GUESSES ON WHAT HAS GONE WRONG (and possible fixes)

1. Caliper piston has gotten gummed-up by pressing directly-on CRC brake quiet substance and is no longer retracting smoothly (fix: thoroughly clean-off brake pads and pistons, lubricate pistons well).
   
2. Too much grease on caliper pins gumming things up (clean excessive grease off pins)
   
3. Non-OEM brake pads with no shims are inferior to OEM ones (buy new OEM pads and shims and put on).
   
4. Brake fluid needs to be replaced (have replaced)
   
5. Rotor going bad (replace rotors)
   
6. Something else I don’t understand (try to get advice here to fix or take to dealer to have repaired professionally).

Taking the car in to get fixed I’d like to avoid, if possible, as I expect it would be fairly expensive (along with getting a story about why I have to may a massive amount of $ because I messed something up), but I also don’t want to throw a bunch of money at the problem trying to fix it myself and then end-up needing to take it in to have repaired anyway.

Any recommendations of what you’d do? Thanks in advance for any advice.

-Cary

 

Thank you both!

Yesterday I went ahead and ordered new OEM pads, shims, and hardware for the rear wheel that I plan to install as soon as they arrive. When I'm installing them I plan to also take a look to see if the piston is gummed-up by the CRC brake quiet, clean-off the metal-to-metal contact surfaces, and lubricate the hardware with permatex when I put it on.

I wasn't thinking/aware at all of the Permatex rubber swelling issue. I can't remember 100%, but I think those pins did have small rubber rings at the bottom.

So...if the pins have the rubber rings, should I go ahead and get new pins too (i.e. will the old rings be permanently swollen) or can I get away with just cleaning them off and putting-on non-swelling grease? Similarly, is any residual grease in the pin slots be something I have to deal with, or will the new grease sufficient to protect the pin rings from any leftovers?

Also, for a future brake change (say in another 100k miles or so) do I need to get new shims along with new pads and hardware, or can I re-use the shims? The hardware looked pretty bad when I changed the pads, so I'd definitely replace it, but the shims just looked dirty and otherwise not degraded at all.

 

To follow-up on how things turned-out...

Just over a month back I replaced the rear pads and hardware with OEM pads and hardware. I also used brake cleaner to clean-off all the orange anti-squeak gel, as well as pressure washing any grime-off generally. Finally, I used the recommended lubricants for the pins and new hardware that I put in the calipers.

The one possibly questionable thing I did was in regards to the rubber O-rings. I ordered new OEM pins, thinking they'd have the O-rings with them, but the pins I received had no rubber O-rings included. That being the case, I initially tried to clean-off the rubber O-rings I had by wiping them off then soaking them in soapy water.

Initially, I put the pins back in with the cleaned and re-lubricated O-rings, but it seemed like the pins were A LOT more resistant to moving with the O-rings in so, experimentally, I tried the pins without the rubber rings and they moved a lot more freely. I reasoned that, perhaps, the rubber rings were optional as they weren't on the new pins and the lack of the rubber rings didn't seem to cause any problems.

So, put the brakes back together without the rubber O-rings on the pins. I've been driving the Prius V for about a month now and the squeak is completely gone and no apparent ill effects from not having the rings on the pins.

If I had to guess, I'd say the squeaking was from a combination of not having shims on the pads and swelling of the rubber O-rings.

That said, no further problems.

Is there any risk anyone can think of regarding leaving the rubber O-rings off the pins? The calipers seems to move around a lot better without them.