[cam01speak]

I had this weird thing happen on my 2017 XLE with 40K on it with original brake pads. I was going downhill fast and tried to brake. Just then the brake pedal started shivering and rattling and hammering started on the brakes. so, I eased on the brakes and brought the speed down, repeating that couple of times. This happens only when trying to brake from high speeds (about 75 mph or so). What may be the cause of this? Is it time to change the pads and clips? Hope the ABS is not screwing up and engaging when they are not needed to?

 

[Penzfan]

Sounds like the ABS system is working as designed

 

[Rickvmax]

Did you notice any burning leather/Kevlar smell to go with the shivering and rattling feel described? I'm just wondering since you also mentioned that you were going downhill fast and tried to brake...

 

[Vtec44]

I think it’s best to look at your brake wear and change out the brake pads as soon as possible. That’s a lot of miles for the original brake pads.

 

[gwgang1]

If you frequently brake hard at high speed/downhill, then your brake pads wear out faster. If you don't feel the same vibration at lower speed/softer braking, then it's likely just ABS kicking in at hard braking. If you feel it at lower speed, then check the pads and rotor run out to make sure it's not wear unevenly.

 

[Greasymechtech]

Inspect your brake system.

Have you ever used ABS before? Practice on a dirt road or wet/snow conditions when there is no traffic.

Sounds normal. If you're always driving like a fool, you might wear your brakes out earlier and inspect regularly.

 

[cam01speak]

Thanks for the replies. Will check out the pads and change them out with rotor resurfacing. Haven't noticed it during regular driving conditions.

 

[BUFFO]

Thanks for the replies. Will check out the pads and change them out with rotor resurfacing. Haven't noticed it during regular driving conditions.

Let us know if u get new brakes etc after 40K mi. Some last longer, some shorter, meaning Im aware how that works. Curious...on your hi speed slow down...did u pump brake pedal or just use steady pedal pressure? Tnx

btw....75 mph in my area or faster (& elsewhere) is common (for some/not all) Uphill, downhill & flat road makes no diff.

 

[cam01speak]

i did apply only steady pressure on the brakes.

 

[JohnGD]

before throwing parts at the problem I’d bleed the entire system (I use Valvoline Synthetic DOT 3/4 fluid). Make sure the anchor pins slide freely (use only JIS K2228 approved grease like CRC Silaramic). And inspect the pads and rotors for even wear, runout and thickness variation.

If the pulsation isn’t from rotor thickness variation I’d definitely bleed the system first. I’ve seen a little air in one corner causing ABS activation on hard braking.

Then afterwards if it still shakes also inspect control arm bushings an ball joints.

Thanks for the replies. Will check out the pads and change them out with rotor resurfacing. Haven't noticed it during regular driving conditions.

 

[cam01speak]

I will take out the front rotors and pads and start with pads replacement and rotors resurfacing first, since my brake fluid level dropped low also (wonder if it sucked some air in!). I will bleed the brake fluid also. For the grease for pins, I used Permatex 24129 Silicone Extreme Brake Parts Lubricant for my RAV4. I think that should work?
Control arm bushings/ball joints - for that, i may have to go to a mechanic; I can look around but not sure if I know what to look for. Do you have any pictures for those?

 

[Penzfan]

I will take out the front rotors and pads and start with pads replacement and rotors resurfacing first, since my brake fluid level dropped low also (wonder if it sucked some air in!). I will bleed the brake fluid also. For the grease for pins, I used Permatex 24129 Silicone Extreme Brake Parts Lubricant for my RAV4. I think that should work?
Control arm bushings/ball joints - for that, i may have to go to a mechanic; I can look around but not sure if I know what to look for. Do you have any pictures for those?

Question before you tear your vehicle apart: Are you familiar with the way an ABS system feels during use???

 

[cam01speak]

I think I know the basics - ABS modifies the brake fluid pressure, independent of the amount of pressure being applied on the brakes, to bring the speed of the wheel back to the minimum slip level. Why do you ask?

 

[Penzfan]

Just seems like what you described in your OP was the ABS working properly and not a brake system malfunction...

 

[Bobbolew]

Just seems like what you described in your OP was the ABS working properly and not a brake system malfunction...

Agree with this. Also, if you can possibly afford it don't "resurface" your rotors. It will make them thinner and, while possibly still within thickness limits, they will not have the heat capacity of new rotors. IMO new rotors is the way to go. You want your brakes to be 100%.

 

[cam01speak]

I replaced the front brake pads with Akebono pads and it is lot better now. The pads were almost gone.

 

[JohnGD]

Do also check the control arm bushings for cracks.