Knocking while braking

I'm looking for advice from all of the TW members smarter than me out there. I have knocking/clicking noise coming from the front left side of the truck that correlates to the rotational speed of the wheels (maybe 2x per wheel rotation) when I brake and especially when I apply the brake firmly. It's not noticeable or present any other time. I can feel some slight feedback in the pedal and on the floor of the truck. It does not pull to either side when I brake. The dealership says they need to replace the CV axle but that doesn't line up with what I know about the normal symptoms of a bad CV.

Additional details: I recently had the dealership change the front diff fluid, replace the front brake pads, and resurface the rotors. I have 86,000 miles on the truck.

Main concerns: The dealership doesn't seem confident that the CV axle is the problem, but quick to tell me the price to replace it. The price they quoted me sounds outrageous at over $700 out the door. If I wait too long to get a second opinion I might do more damage to the differential/hub depending on what side might be causing the problem. The stealership is ripping me off.

Any advice will be greatly appreciated!

 

Can you get a vid of it? Is it louder that the normal Tacoma brake click?

 

I will try for a video in the morning. I've had the truck for months and it's definitely a new sound. The thing has lots of noises and rattles like I know most Tacomas do. This isn't normal. It seems to correlate to the rotational speed of the wheels as I'm slowing down so that might be the only thing that is consistent with a bad CV. @RacecarGuy

 

My 2 cents....


First Id try to be sure it's really what you think it is. I'd get a helper and find a long straight wall I can drive close next to - like the back side of a store/supermarket. I call these my troubleshooting walls as they echo the sounds back to the truck and driver. I'd drive slow close to the wall - right and left side closest to the wall and have the assistant outside the truck to use his ears as well. Find the noise and try to pinpoint the spot just to be sure. Also repeat driving in reverse. Also repeat while dragging your brake. Repeat while slightly tugging the steering wheel back and forth.

Did this Happen before they changed your brakes??

IF it is the wheel area. Jack up the wheel and hand spin it - tire on - then tire off.

I'd want to be sure that it's really where and what it is before I spend any moola on the issue.

I'd rule out - Bearing/races/cracks, bad bearing /ball, shake the wheel for bearing play, check any wear indicator/sound, Object in tire?, Bad tire/belt - try rotating tires. Caliper sticking closed/open and is clicking as it opens and closes when the disk rotates.

Well it's a place to start ....

 

Great advice, especially with the "long straight wall'...

I had same problem as the OP in a different vehicle and my local tire/brake shop, who I trust very much, diagnosed the problem that same way. He did it with me in the vehicle, took it back to the shop, pulled the back wheels and the rear brakes were literally falling apart.

The best thing you can do is to build a trusting relationship with a local guy and save yourself tons of cash in avoiding using the dealer. Local guys want to do right by you because word of mouth, either good or bad, is what they survive (or don't survive) by.

 

Well I couldn't get a video worth sharing of the noise, and tried the "long wall" technique with a friend. It is very slightly present when not braking, contrary to my original post. It's also certainly coming from the front left.

I jacked up the wheel as @Canufixit suggested. No signs that it's coming from the wheel/brake/hub area. Tires only have about 5k miles and have no debris that I can find on them or the brakes.

While I had it jacked up I found there was some play in the CV both perpendicular and parallel to the CV. The perpendicular play was coming from the center of the truck where the axle goes in the differential. So I compared that play to the front right and found this:

The play parallel to the CV was much greater on the front left than the front right, AND the play perpendicular to the CV was almost non existent on the front right.

My analysis at this point says it may be the CV, or the differential but I would have to take the CV out to know for sure. Either way I definitely need a second opinion.

Thanks for the advice TW!