Strange grinding when coming to a stop on a hill

[ollie]

Hi all,

We get a strange metal on metal type of grinding when the truck is about to come to a complete stop on a steep hill from the rear of the vehicle. My first thoughts was the back brakes are toast so I popped the wheels and the pads are a 40% plus. I asked the dealer and they had a look and didn't find anything wrong.

This only happens on steep hills and just as the truck comes to a complete stop. It almost seems like the pads are flexing so something is comming into contact with the rotor.

Has anyone else experienced this? Ours is a 2004 V8 AWD Limited with 80,000 kms (50,000 miles).

Thanks for reading!

 

[CJ3Flyr]

Don't stop on hills!!!:biggrin2: :dancin: :jump:







Seriously, it's a Limited. Does it have air suspension? Could the auto height control be causing the compressor to run?
:cheers:

 

[ollie]

It does have the adjustable suspension and I will try disabling it on the same hills but if it is making this sort of metal on metal grinding then something is seriously wrong!

It is a very strange grinding because it sounds exactly like metal on metal, worn out brakes.

 

[CJ3Flyr]

80k in beautiful Vancouver traffic could have the pads worn out, maybe? I just re-read your post saying 40% left... Hmmmm No idea
:cheers:

 

[808BMW]

Hi all,

We get a strange metal on metal type of grinding when the truck is about to come to a complete stop on a steep hill from the rear of the vehicle. My first thoughts was the back brakes are toast so I popped the wheels and the pads are a 40% plus. I asked the dealer and they had a look and didn't find anything wrong.

This only happens on steep hills and just as the truck comes to a complete stop. It almost seems like the pads are flexing so something is comming into contact with the rotor.

Has anyone else experienced this? Ours is a 2004 V8 AWD Limited with 80,000 kms (50,000 miles).

Thanks for reading!

I have this same problem on my 2003 V6 4wd Sport Edition with 80,000 miles.

It almost sounds like the ATRAC kicking in the back (as if the rear end is so light that the body dive is unloading the rear tires enough to lose traction) but it isn't as harsh nor as hard as ATRAC kicking in on acceleration.

I've checked my brakes and they are almost brand new, but from the sound of it, we both have the same problem.

 

[CJ3Flyr]

Could the back tires be on the verge of slipping and you're getting an ABS activation?

 

[spyne]

Hi all,

We get a strange metal on metal type of grinding when the truck is about to come to a complete stop on a steep hill from the rear of the vehicle. My first thoughts was the back brakes are toast so I popped the wheels and the pads are a 40% plus. I asked the dealer and they had a look and didn't find anything wrong.

This only happens on steep hills and just as the truck comes to a complete stop. It almost seems like the pads are flexing so something is comming into contact with the rotor.

Has anyone else experienced this? Ours is a 2004 V8 AWD Limited with 80,000 kms (50,000 miles).

Thanks for reading!

My '03 Limited has done this almost since the day I bought it new. We vacation in the mountains and without fail, I get noise from the rear brakes when stopping on steep grades. I've mentioned it a couple of times when the truck has been in for maintenance work and they've never found anything wrong.

The last time it was in for service they "lubricated the brake pads" which sounds rather ominous. I had visions them applying grease to the pads and rear disks with me unable to stop and flying off a steep slope. :awais:

However, it really made a difference. I think they must have put something on the back of the pads or maybe on the retaining pins that hold in the pads to allow them to move more freely. In any case, it's almost eliminated the problem. I still hear the noise if it's over 90F, I've made a couple of previous stops and am on a steep grade. Otherwise, the noise is gone.

 

[CJ3Flyr]

BS and speculation but here goes... The T4R has some form of varying the brake proportioning based on need. I am not talking about ABS but rather F to R proportioning.

Maybe stopping in the hill is activating more or less rear brake than normal. This may cause the pads to stick/vibrate etc. That's why Toyota's fix of 'lubing' the rear brakes' hardware worked/works.

While I may not be communicating effectively it does make sense that the hill would influence the rear brakes.
:cheers:

 

[ollie]

Thanks to all for the replies. I think there are a few different things at work...given this only happens when there is significant weight transfer to the front wheels I think there is some additional brake force being applied causing the noise. Perhaps there is some additional clamping force on the pad so just as the vehicle comes to a stop we get this strange grinding noise?

It almost sounds like the inboard pad is coming into contact with the rotor itself but there are not striation marks so I guess we'll just live with it.