Uneven brake disc wear

[slybunda]

Hey all, so changed the rear brake discs, pads, new calipers and fittings and 2 weeks on noticed the bottom of the pad doesn't seem to be contacting the disc. So inner part of disc closet to the disc hub is not swept.
When fitted everything was greased up and since calipers are new too I'm stumped at what could cause this on both the left and right side.
Iv probably done around 150 miles in the car so not sure if it just needs to be driven more?

 

[The_Jeff]

I'd check that the pad ears aren't hammered in too tight, grind 'em if you have to. You "should" be able to take the wheel off, any rotor retaining screws off, caliper off and grab the two pads and rotor as a "sandwich" with one hand and rattle all three things back and forth.

Is this a VW with several different size brake packages for one chassis, maybe you got a wrong part?

 

[slybunda]

Deffo correct part, it's a gen7 Toyota Celica. Rear brakes

 

[Donald]

How many pistons?

 

[KrisZ]

Something is not sitting straight, it could be the pads, or it could be the caliper itself. I see shiny new caliper, is that a reman or aftermarket one? Could have some burrs or something where the pad sits, making it not flush.

 

[slybunda]

How many pistons?

Single piston new calipers.
May take pads out and have a look at them then reassemble

 

[Vercingetorix]

I’m betting the pads aren’t big enough.

 

[Donald]

I would clearly have a look at the pad ears and how easy it is for the pad to move within the SS clips.

The piston has a tremendous amount of force pushing the pad squarely at the rotor. Even if you installed the pad at an angle, the first time you hit the brakes should push the pad parallel to the rotor.

 

[slybunda]

The pads slide on the pins. Nothing is binding since is all new. It's strange that with this sort of caliper design every thing should sit square to the disc. Find it odd why there is no pad contact at area closest to hub

Pic attached

 

[50yr Street Mech]

Check the ears on the pads and grind if needed. They should slide in the hardware with ease. New calipers ? Check for burrs. Metal or paint. Put a q-tip of high temp brake grease on the caliper slides too. Check the pads for any unwanted burrs too.

 

[slybunda]

Will do,
Pads were inspected prior to install. Calipers were also checked by me and all seemed fine. Pad pins have ceratec ceramic grease and caliper sliders have silicone grease on them.

 

[Jetronic]

Just do a bedding in procedure.

 

[slybunda]

What's the procedure?

 

[Jetronic]

What's the procedure?

you need to get heat in them from braking. brake for ten-ish seconds, then drive for 30 seconds and keep repeating. Start with mild braking and increase intensity. You should feel the brake power getting higher, and brake pedal getting firmer. Don't wait until there's significant rust on the disc, the rust will not wear off.

On perfectly flat discs and pads, 10 repetitions is likely enough, but you will need more. You don't have a handbrake on the pads so you have to do front brakes at the same time.

btw, Mitsubishi?

 

[slybunda]

you need to get heat in them from braking. brake for ten-ish seconds, then drive for 30 seconds and keep repeating. Start with mild braking and increase intensity. You should feel the brake power getting higher, and brake pedal getting firmer. Don't wait until there's significant rust on the disc, the rust will not wear off.

On perfectly flat discs and pads, 10 repetitions is likely enough, but you will need more. You don't have a handbrake on the pads so you have to do front brakes at the same time.

btw, Mitsubishi?

Ok will do this method. What speed does it need to be done from?

Car is Toyota Celica

 

[rijndael]

Ok will do this method. What speed does it need to be done from?

https://www.r1concepts.com/blog/bra...ate-guide-to-maximize-your-brake-performance/

 

[thastinger]

Ok will do this method. What speed does it need to be done from?

Car is Toyota Celica

If you go to powerstop's website, they have a brake bedding procedure that you could do...but at 150 miles I'm afraid it may be to late but it won't hurt to try it.

 

[50yr Street Mech]

Usually get up to around 40mph, and bring it to a hard stop. Do that a few times, then let them cool off. Then go on the highway and go from 60mph to 20mph a few times. You'll smell them cookin a bit ,,,see some smoke...... Let them cool a bit, repeat. Kinda hard doing it during the day on the highway, so I do it at night. Less traffic. And you're done. New brake fluid is a must, so make sure everything is bled with new fluid before you start this process. Change brake fluid every 2 years due to water absorbtion. Bleed the whole system.

 

[NibbanaBanana]

Are the new disks machines parallel? Are the pins tight? Do the pads move freely in the slideways?

 

[Jetronic]

Ok will do this method. What speed does it need to be done from?

Car is Toyota Celica

40 mph is plenty fast. Just make sure you got room, and no other drivers around.