lexixel

Hello,

I replaced my rear brake pads three years ago. Now the left side is making noises, and I just confirmed that another replacement is due.

When I did the job last time, I noticed uneven wear: the outer pad was completely worn, while the inner pad was barely worn at all. The passenger side didn't have this problem. I attributed it to the pads being installed in reverse, causing resistance from the sliding pin.

However, I find the same wear pattern now. The inner pad has 5mm left, but the outer pad has maybe 2mm left.

What do you think is causing this problem?

I greased the sliding pin but obviously the grease washed off a long time ago.

Seattle SCone

I would also check that both inner and outer break pistons are free to move.

FlopTop04

When you remove the worn pads from the calipers are the pads binding?
Sometimes rust forms behind the shims ( shiny silver metal insert pieces ) on the caliper bracket surface and causes the pads to bind up in their glide slots. I see that a lot up north where they use road salt during the winter. When I do a brake job, I purchase a pad kit that includes new shims and while disassembled I make sure the area that the shims fit in to is clean and rust free. Usually I have to take a flat blade screwdriver and flat file to get all the crud out on that area of the brake pad brackets. When you reassemble everything the pad should install easily with out any extra force.

DshngDaryl

I think you need to rebuild your caliper. You can click here for a multitude of videos that will help show you how to do it:
https://www.youtube.com/results?sear...toyota+caliper

daddiojigg

Great ideas. Do you think it might be as simple as stuck sliders?

lexixel

I don't think there's much rust around the brake caliper. When I removed the pads last time, things went smoothly.
I reused the shims. This time I'll probably get the Ferodo pads with build-in shims (last time was Brembo but they required shims, which I cleaned a bit).
I didn't change the disc last time, so I didn't remove the calipers. This time I'll replace the discs, so I'll try to do some cleaning.

lexixel

Last time, the pistons moved freely. As I wrote to my other reply, there was very little rust. I'll check this time if the pistons still move freely without resistance. I'll clean the contact surface with a brush this time.

lexixel

There's got to be more resistance on one side. I think these are dual piston calipers that don't slide. The pads have a slide pin.
I guess there are 3 places where the resistance may come from:

1. The inner piston
2. The slider pin
3. The inner surface of the caliper along which the pads glide

Can be a combination of these. I'll clean 2 & 3 and test 1 this time.

lexixel

Actually another possibility is that the OE shims don't fully fit the Brembo pads. The pads, if I remember correctly, were slightly larger.

I'm still tempted to buy the Brembo pads, because they're 60% cheaper (€10.66) than the Ferodo ones.

lexixel

I did it this morning. I think it's most likely the inner piston being sticky: it would retract just fine, but it seems the outer piston always extends first. It probably can benefit from a rebuild.

I spent a lot of time trying to clean everything. Made a big mess, unsurprisingly. More time in cleanup than the job itself.

One separate question: The caliper bolt should be torqued to 104Nm / 77lb-ft, correct?

I was cautious and wanted to torque to 70Nm. They were ok at 60Nm (I torqued progressively). One bolt felt like it was giving away before 65Nm? I immediately stopped, of course.

Although I see some websites saying that M10 bolt has a max torque of just 57-97Nm ? If that's the case, an unclean bolt probably should be torqued to no more than 50Nm for safety?

Here: https://www.engineeringtoolbox.com/m...ue-d_2054.html

lexixel

Just an update: I found out that these bolts are torqued to yield and supposed to be replaced.

digitatc

ideally we should replace the bolts, however, just add abit of blue locktite and torque it back to specs.
Flush the brake fluid, do it every other year, only cost a few bucks.

lexixel

Just checked again this afternoon: The bolt seems to be ok, but I'll get another one next month in case it acts up in future.
I think I've probably freed the inner piston: The initial wear seems symmetrical. I'll check again next year to see.

I also readjusted the parking brake shoes so now there's no drag at all. On the web people are suggesting a little drag, but the parking brake still works when the shoes don't drag at all. Why do people like to have that drag?