s7ven

I have been trying to track down the cause of a weird brake creak/squeak for quite some time now. I posted on the general maintenance section thinking this was a brake issue but after lots of research I am thinking it may actually be caused by a bent axle. Here is my other thread:

https://ls1tech.com/forums/general-m...ak-cackle.html

The squeak I initially thought was coming from the front but after lifting the car and spinning the rear passenger side wheel I was able to replicate the squeak I hear when driving. I would describe the sound as a metal on metal creaking that seems to occur once per wheel revolution, increasing in frequency with vehicle speed. The sound is most audible under moderate braking and going by a divider or wall. I have not inspected the brake of the offending wheel really close but I can say the rotor doesn't have any obvious pitting or grooves, pins move freely, and there is plenty of brake pad life left.

Other symptoms include, the squeak seems to go away for a while everytime I take the brakes apart but always returns later. I have experienced some noticeable vibration at higher speeds, nothing in the steering wheel but the passenger seat will shake pretty violently.

So what is the easiest way to test for a bent axle? If I can buy the right tool at a local auto parts store then I can certainly do that.

Bob@BruteSpeed

iTrader: (16)

Put the rear up on jack stands and remove the wheel. With the car running in gear at idle, see if the axle has a wobble to it. Bob

ssvert99

iTrader: (26)

Chances are the rotor is warped which causes excessive side to side movement when the brakes are applied. This makes the caliper follow the warpage and the squeak comes from the pad moving around within the caliper, and/or the caliper is moving around on the backing plate with a dry surface.

If your wheel does not have excessive runout, you will probably find a fresh set of rotors, pads, hardware kit, and properly places high temp brake parts lube will take care of your noise.

s7ven

I did what you suggested, I put the car on jack stands and ran it at idle. I took both the wheel and brake hardware off, in my opinion there is a noticeable wobble but with my limited experience I wanted a second opinion so I made a video. My internet has decided to take a dump tonight so I'll post a link once I have it uploaded. Other things to note are the inner brake pad was almost completely worn down but the outer had significantly more life left. Also, the inner pad had uneven wear across the pad. Other than that, the pins move very smoothly, all bolts were tight and the rotor looked good from a quick visual inspection.

Update: Internet finally connected and I uploaded the video. Sorry for the shakey cam, I was trying to find the best angle.

ssvert99

iTrader: (26)

A steady video is a must to get help like that.... maybe find a tripod or something. A worn c-clip or axle could cause excessive run out that would give somewhat of the same effect as a bent axle in a video. With the brakes and rotors off check the axle end play first.

s7ven

How do I quantify the amount of run out and play? If I just need to buy a measuring device I can certainly do that. I think that might help determine if I'm within an acceptable range. Also just from previous testing, my axle has a decent amount of end play but without having a measurement I'm not sure.

ssvert99

iTrader: (26)

Good c-clip setup will have very little end play. The clips and the axle shaft wears at the button end that retains the clip.

Get a good magnetic base dial indicator to check the end play and flange runout numbers.

s7ven

Thank you, I'll buy what you said and I'll get some measurements. If my rear is fubar then I'll probably look at ordering my fab 9 earlier than expected.

ssvert99

iTrader: (26)

Now you're talking!

s7ven

Okay, I got a dial indicator from HF along with a few other goodies and I did my measurements this morning:

Axle end-play = .025 - .026"
Run-out at outter edge of hub flange (just beyond lug studs) = .028"
Run-out at inner-most flange around the hub = .018"

I took a video of me taking the measurement as well but I don't know if that will really provide any benefit to upload that.

Edit: I also decided to take a measurement of run-out along the outer diameter of the tire and I'm getting around .09-.1" inches of run-out. As for the other side, I didn't take all of the brake hardware and tire off but just for the hell of it I checked and I am getting about .05 inches of run-out on the other tire. So I'm not sure but there is a chance that both of my axles are bent but one much worse than the other.

s7ven

Can someone provide acceptable specs for axle flange runout and end play?

roastin240

iTrader: (13)

Bump for you and I....I have a shake coming from the rear and curious if it is a bent axle or bad wheel bearing. It is most noticeable at low speeds...and then at high speeds it resonates.....for example vibrates for about 1 second duration, then stops for 1 second, then repeats continuously, and gets worse as vehicle speed increases.

I am going to do the same runout and end play inspection as you. What are the specs experts? Mine is a 7.5 btw, is yours?

s7ven

Think I have it cured at least temporarily with some brake antisqueal on the offending wheels brake pads. I still am convinced the axle or axle flange is bent/uneven at least to a slight degree and I think the noise will eventually return. Won't be long I'll be putting the car into storage so come next spring I'll throw in a new fab 9 and almost all new rear suspension, if it is noisy after that I can blame it on the brakes without a doubt.

ssvert99

iTrader: (26)

This is direct from Strange Engineering, keep in mind these are the highest quality aftermarket axles:

"Axle shafts are under 0.015” TIR when they leave Strange. It’s possible for them to pick up another 0.005” when subjected to torque for a total of 0.020” TIR.

Flanges should stay under 0.005” axially and radially."



MWC can help on great deals on aftermarket replacement axles for the stock 10 bolt, or if you're ready to take that jump into the MWC fabricated 9" rearend or something like a Strange S60 or Moser 9" rearend, MWC offers the guaranteed lowest prices and absolute best tech help you can get!

s7ven

Thank you for following up with the specs.

Flanges should stay under 0.005” axially and radially

Given that I have stock axles I'm not sure if they would have been under .005" even from the factory but regardless....my questionable axle is at least 3-4 times the runout specified at the flange which I would think is unacceptable.

I hate to invest anymore money into the 10 bolt at this point. I'll be contacting MWC after I get my tax return and bonus next spring.

ssvert99

iTrader: (26)

Sounds like a great idea! Keep in mind most manufacturers will have price increase after the first of the new year. MWC offers a free payment plan with as little as 500.00 down to get you into the best f-body aftermarket rearend on the market. Get your order and down payment in and we can work with you on payments to work with your timeline and budget.

s7ven

Just following up, I got my hands on a GM service manual for the 2000 GM Fbody cars. It's a year off but I don't think a year is going to make a difference. I am going to say that my axle flange or axle is bent:

If the lateral runout cannot be corrected by
indexing the rear rotor, inspect the rear axle shaft
flange for excessive lateral runout. If the axle
flange lateral runout exceeds 0.040 mm (0.015 in),
replace the axle shaft. If lateral runout of the
axle flange hub is within specifications, refinish or
replace the rotor as necessary.

No Juice

iTrader: (11)

I've got that same vibration thing going on with my MWC 9". Any experts got any thoughts?

I bent all the 1/2" studs on one side of MWC 9" with 35 spline strange axles. More are probably bent on the other side. The wheel certainly wobbles, thinking the axle is bent as well. Haven't had a chance to check runout yet.

Car is an M6 making 525rwhp, on stock ws6 wheels, and 275/17 drag radials, only cutting 1.8 60'

ssvert99

iTrader: (26)

I listed the specs, we can't help you any more unless you get some accurate measurements. You can try to do it while mounted in the housing, but the best method is to have it checked in a lathe.

No Juice

iTrader: (11)

^^^ PM sent