Hey guys so I have a sound coming from the front of my GX. Sounds like a rock scraping behind the brake dust shield, but its not. Checked driveshafts and parking brake and couldnt find anything so i took it to my mechanic who said it was the front diff. So i just got it regeared but its still making that sound and the shop told me my caliper was seized and missing a brake pad pin. Would a seized caliper make that sound?
Seized caliper?
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If you can create the noise by spinning that wheel off the ground, remove the caliper, reinstall the wheel, spin it again, if you can still hear the noise, it’s the wheel bearing.
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Tried spinning the wheel with it off the ground and couldnt hear it. So since its only under load, you think it would be wheel bearing? The sound is most audible at low speeds (<20) and i can hear it when im driving straight
You can get an already assembled, ready to bolt on, koyo bearings and new bolts, hub assembly from yotabearingsandhubs.com for 170 bucks. Definitely one of the best options out there. You’ll need a new cotter pin for the axle nut.
Should be pretty easy to figure out if the caliper or wheel bearing is the culprit.
Jack up the side.
For bearing - put your hands at 12 and 6 o’clock on the tire and try to move the the tire. Try again with hands at 9 and 3 on the tire. This is a standard test for wheel bearing. If there is movement, your bearing is gone. I would replace both sides at the same time.
Caliper - Pull the caliper off. Open up the bleed valve. If you cannot compress any piston back into the caliper (I use a c-clamp), you have a stuck piston. I guess you could have a piston stuck inside the caliper (so that it won’t extend out), but not sure it would create the sound you are describing. More likely you would feel pulsating during breaking.
Are you sure that your dust shield didn’t get bent toward the tire? These can rub on the tire and/or rotor and cause funny sounds.
Additionally, a stuck brake caliper is going to heat up that rotor and there will be an easily noticeable temperature difference compared to the other rotors.
Wife came home complaining of noise near the rear of the car. Sounds like something scraping the rotor and the caliper looks to have less rotor clearance than the other side, also the rotor is all chewed up.
Going to jack it up tonight and see if I can spot any culprits. Pics of the scraped rotor, and the other side for reference.
Wheel bearings can be an issue in the rear as well too right?
Going to jack it up tonight and see if I can spot any culprits. Pics of the scraped rotor, and the other side for reference.
Wheel bearings can be an issue in the rear as well too right?
Here is the good side:
And the bad side:
Looks like there is no pad left, so that explains the grinding.
Just to confirm, is it normal for brake pads to have no visible gaps? Also I didn't notice any sqeaking leading up to this. Could something else be going wrong causing the one pad to wear out faster than the other side?
I had no play in the 12/6 or 9/3 when I wiggled the wheel, but this is also the rear axel, not sure if thats the same procedure.
And the bad side:
Looks like there is no pad left, so that explains the grinding.
Just to confirm, is it normal for brake pads to have no visible gaps? Also I didn't notice any sqeaking leading up to this. Could something else be going wrong causing the one pad to wear out faster than the other side?
I had no play in the 12/6 or 9/3 when I wiggled the wheel, but this is also the rear axel, not sure if thats the same procedure.
No, they should be wearing the same on either side. Either the caliper piston itself is stuck/messed up or the slide pins are seized. I'd pull the slide pins and see what they look like. They should be greasy and more or less come right out. The slide pins have a small rubber plug on the opposite end of their bore as the bolt head. That plug can pop out and water can get in the bore, causing rust and seizure. If that happens you'll need to clean rust of the the bore (I've used a rifle cleaning brush on a drill), clean up the slide pin, and reinstall them with new grease and rubber plugs Or, you can just replace the calipers and slide pins with new parts instead of cleaning up the old ones.
Your rotors also look worn and grooved, so I'd probably replace them too. You can measure the thickness with a caliper and check vs. the Lexus minimum spec of 16 mm. FYI, OEM Lexus/Toyota new brake parts are barely more expensive than aftermarket brake parts.
Your rotors also look worn and grooved, so I'd probably replace them too. You can measure the thickness with a caliper and check vs. the Lexus minimum spec of 16 mm. FYI, OEM Lexus/Toyota new brake parts are barely more expensive than aftermarket brake parts.
If the issue are the seized front calipers on a GX470, then this may be a good time to refresh your brakes back to new condition with the oem GX460 calipers, oem GX460 rotors, and some Akebono brake pads.
And from AI:
Why GX470 Calipers Seize More Often
The GX470 (and 4th‑gen 4Runner, and 120‑series Prado) use a 4‑piston fixed caliper design that is notorious for:
• Corrosion forming behind the piston seals
• Pistons sticking in their bores
• Uneven pad wear
• Dragging brakes and overheating
This is a well‑documented issue in GXOR, IH8MUD, and 4Runner forums. Toyota never issued a recall, but the problem is common enough that many GX470 owners replace calipers every 60–100k miles.
The root cause is the piston/seal design and the caliper’s susceptibility to moisture intrusion. Once rust forms behind the dust boots, the pistons no longer retract smoothly.
---
Why GX460 Calipers Are Less Likely to Seize
When Toyota moved from the GX470 (120‑series) to the GX460 (150‑series), they updated the front brake system:
Larger, thicker rotors
• The GX460 uses a thicker rotor, which requires a larger caliper body.
• This redesign also changed the piston layout and seal geometry.
Improved piston seal design
• Toyota revised the dust boot and seal arrangement to reduce moisture intrusion.
• This is the biggest factor in reducing seizure.
Better corrosion resistance
• The GX460 calipers tend to resist internal rusting better than the GX470 units.
• Many GX460 owners report 150k–200k+ miles on original calipers with no sticking.
Reduced thermal load
• The larger rotor dissipates heat better.
• Lower heat = less seal degradation = fewer stuck pistons.
And from AI:
Why GX470 Calipers Seize More OftenThe GX470 (and 4th‑gen 4Runner, and 120‑series Prado) use a 4‑piston fixed caliper design that is notorious for:
• Corrosion forming behind the piston seals
• Pistons sticking in their bores
• Uneven pad wear
• Dragging brakes and overheating
This is a well‑documented issue in GXOR, IH8MUD, and 4Runner forums. Toyota never issued a recall, but the problem is common enough that many GX470 owners replace calipers every 60–100k miles.
The root cause is the piston/seal design and the caliper’s susceptibility to moisture intrusion. Once rust forms behind the dust boots, the pistons no longer retract smoothly.
---
Why GX460 Calipers Are Less Likely to SeizeWhen Toyota moved from the GX470 (120‑series) to the GX460 (150‑series), they updated the front brake system:
Larger, thicker rotors• The GX460 uses a thicker rotor, which requires a larger caliper body.
• This redesign also changed the piston layout and seal geometry.
Improved piston seal design• Toyota revised the dust boot and seal arrangement to reduce moisture intrusion.
• This is the biggest factor in reducing seizure.
Better corrosion resistance• The GX460 calipers tend to resist internal rusting better than the GX470 units.
• Many GX460 owners report 150k–200k+ miles on original calipers with no sticking.
Reduced thermal load• The larger rotor dissipates heat better.
• Lower heat = less seal degradation = fewer stuck pistons.
Rear calipers from a 460 dont fit a 470 as they have some slight differences - wouldnt be an upgrade if they did.
It would just be the fronts that are larger and thus an upgrade.
Your rear caliper may be just fine if the issue is simply running out of pad....may just need pins greased so long as the piston is moving well.
GX470s and GX460s have the same rear calipers but different rotors. Just order GX470 or 4th gen 4Runner parts for the rear and you'll be fine. Your pads wearing unevenly indicates there is a problem with the slide pins or the caliper itself (probably the slide pins). The pads will wear unevenly if something is stuck/seized and they can't move freely. This will also cause the vehicle to pull to one side while braking as one brake will be stronger than the other.
Agreed, time for new rear calipers, rotors, and pads. You can get reman calipers from NAPA that are pretty good, or pick up new ones at your Toyota/Lexus dealer for slightly more. I'd also replace and grease the slide pins as they are probably also corroded. I really like Sil-Glyde synthetic brake grease.
For the rear you can replace the caliper bracket only. My brackets, pins and seals were done after 15 years in the rust-belt. They were beyond refurbishing. I had done that many times over the years.
I bought brand new CMX calipers. They are galvanized and rust a lot less than OEM. I put the caliper part (piston) on the shelf as spares and only used the bracket assembly from the kit. It was still a lot cheaper than buying loose parts. They are identical to the OEM parts and it completely solved the problem of sticking pins because everything will be new. Doing it this way gives you new pins, brackets and pin bushings. No need to bleed brakes and the hydraulic part is still OEM.
I bought brand new CMX calipers. They are galvanized and rust a lot less than OEM. I put the caliper part (piston) on the shelf as spares and only used the bracket assembly from the kit. It was still a lot cheaper than buying loose parts. They are identical to the OEM parts and it completely solved the problem of sticking pins because everything will be new. Doing it this way gives you new pins, brackets and pin bushings. No need to bleed brakes and the hydraulic part is still OEM.
Mechanic said rear calipers were fine after refurbishing. But front calipers are seized and are causing a pull. I’ll be doing the gx460 upgrade on the front. There’s no tradeoffs or oddities with that upgrade is there?
Hello bcomnes,
Here's the thread you should read about the upgrade.
It should work with 17" or larger wheels (OEM is 17" for GX470).
If you live in the rust belt, or need to replace your front calipers for any reason, this is a very good upgrade.
I've done it to my own 2007 GX and for someone that brought their GX in for repairs / brake work.
Enjoy.
Tom
Here's the thread you should read about the upgrade.
It should work with 17" or larger wheels (OEM is 17" for GX470).
If you live in the rust belt, or need to replace your front calipers for any reason, this is a very good upgrade.
I've done it to my own 2007 GX and for someone that brought their GX in for repairs / brake work.
Enjoy.
Tom