daddiojigg

I had a grinding noise the other week and couldn't get to it for a couple of days. Noise seemed to be coming from rear drivers' side. Turns out that i was practically on the rivets of left rear brake pad. Both of the pads down to the rivets. Passenger side was like brand new. Changed out pads ( both sides) and of course noise was gone. Now it may be my imagination BUT , from time to time, i swear i hear a little drag on the L/S. One day i decided to feel the rotors after stopping and L/S was warmer than R/S. when i changed the pads i was careful to clean out cavity that slide pins go into and greased up pins while being careful not to overdo them.I should also state that i changed out R/S caliper two years ago as it was seized. At that time i bled both sides (yes,with techstream) and last year i bled both sides again after changing rear hubs/bearings and had good flow. What would cause the caliper piston to stick occasionally? Has anyone had similar experiences and what was the solution? Thanks

Nad1370

If you already cleaned out the slides and the bracket where the pads sits. (pads should also more freely here)
L/R caliper piston is most likely the culprit.
Piston probably has some rust build up thats dragging on the caliper cylinder.
Might've gotten moisture which rusts up in there if the piston boot has a tear over time.
There might be rebuild kits out there, but id just replace them like you did on the other side.

mnewxcv

I've had caliper issues on several vehicles: 1998 Ford Contour, 2000 Jeep Cherokee, 1995 Lexus SC300, 2003 Honda Odyssey, etc. Caliper pistons just seem to fail after a while. I would say that is a sign that it is on it's way out, especially given the extreme wear on the previous pads.

daddiojigg

well, almost 6 months to the day and the problem has come back. Cleaned all slides and pins initially and just yesterday it started again. Comes and goes but ALWAYS occurs( grinding sound) when i am in a turn and pressure is put on l/s rear axle. SOMETIMES going over a bump straight will initiate the noise but it doesn't last more that a few seconds. Usually putting on and putting off brake pedal will cause grinding noise to go away which makes me think caliper piston is sticking occasionally. Last time i squeezed piston back into caliper with ease which lead me to believe that piston/caliper was fine but now, six months later? same? Going to have to get into it later today but hoping i don't have to replace caliper and all that bleeding BS.

ukrkoz

Brake pads do not make grinding noise, unless they are worn out. Caliper piston is not touching rotor surface to produce grinding noise, unless pad is worn out. So you need to check pads first. If they are good - look place else for noise source. Like half axle. Bent dust shield.

mnewxcv

Good pads can still make noise, especially if the rotor was not resurfaced and had some grooves.

daddiojigg

I never resurface rotors. Always put new ones on if needed. Dust shield-- ripped it off two years ago when i was doing my hubs, rusted right out.

Got into it yesterday: pads were toast on L/S . R/s was fine. Suspected caliper or piston and so i replaced the caliper. Used Snap-On 'techstream' to bleed and clear all codes. Everything is good-- for now.

mnewxcv

no such think as a coincidence. Caliper was likely bad; there are few things that would do what you describe other than the caliper. I also have a left side rear drag and did my pads a few months ago. Hoping it doesn't happen again (though, I used an infrared therometer to check rotor temps after driving and it matches the right, so I suspect no more drag, that the slide pins were causing the issue in my case).

daddiojigg

"that the slide pins were causing the issue in my case" . I don't know how you did your pins , so i'll tell you how i did mine:

After pulling out the pins i put them on a wire wheel to clean them up -threads and all. Be careful with the grommet or ring on the one pin. I then get a small drill bit sized brush that fits onto a drill and spray inside the hole with a degreaser where pins go and then 'ream' the hole GENTLY to get old lube out.
I had done all this in preparation for my new calipers arrival. Well, doesn't the caliper come with a new bracket and new pins as well, so cleaning and lubing was for naught!

mnewxcv

Ha, yes it's nice when the caliper comes with the bracket so you literally are reusing nothing from the old one. My pins were a little rough looking but I just sanded them by hand and threw in some fresh grease. I think I used the purple ceramic brake caliper lube. It's been about 6k miles since and I haven't noticed any issues yet recurring.

thomas1

You might want to replace the flexible brake line going to that caliper, A friend had same problem on his Chevy Truck, did all the same stuff you did, but the culprit was the rubber brake line had swollen inside and was restricking fluid from releasing on the caliper. Replaced line and never had a further problem.

mnewxcv

That is the most likely culprit after the caliper. The Toyota lines are usually pretty reliable though depending on region. Like you said, it's like a pinched straw the brake fluid gets pushed through under force, but can not go back through without force and therefore holds the piston in. Should be easy enough to know if the problem remains with a new caliper though.

daddiojigg

rubber brake line had swollen inside and was restricking fluid from releasing on the caliper

Good to know but i wish you had said this two days ago. Still, something to keep in mind for later. That really would explain a few things. Never heard of that before, though. Thanks!