Loud howling when turning left

[Yadkin]

This started after I installed a front disc brake kit.

I was busy so had my buddy Joe at Classic Metal in Mocksville do the conversion. Joe has 40 years experience and is a professional mechanic.

Symptoms are, when I turn left only, a low frequency howl. It's not a tire rubbing. It happens at any speed. Joe tried to diagnose it while I drove. He discovered that when I apply the brake the noise goes away. The noise is from the right side. Joe (passenger seat) and I (driver) think its from the right front wheel. When Mike rode in back he thought it was from the right rear.

There is no tell-tale contact areas from tires making contact. It doesn't sound like rubber on steel anyway.

Joe and I took the left front wheel off and checked the brakes. The pads were new and were not making complete contact with the rotor. The bracket (part of the kit) was very close to the ID of the rotor so Joe ground down a small area for additional clearance. This had no effect.

I've driven the car a bit to fully break in the pads. I removed pads (both pads, both right and left sides of the car) and applied a generous coat of squeal stop, and followed the directions to the letter. During disassembly of the right side I did find a lot of slack between the inboard pad and the rotor. No effect on the noise.

Both front springs are new, installed along with the brake modification. I inspected those; all rubber seats are in place.

I cleaned and adjusted the rear brakes. The E-brake works better now. No effect on the noise.

I replaced the rubbers on both front shocks, as I had a rattle on the right side. No effect.

Any thoughts?

[OX1]

Did kit replace spindles? (thinking maybe alignment, but that would be tire scrub/screech noises). Do brake pads have "anti-squeal" spray, goop, or small pads between them and calipers?

[simplyconnected]

Are you using backing/air deflector plates behind the rotors?

Robin says you may be hearing from a great number of wolf spirits in your area that may have died at the hands of murderous Thunderbird drivers. A shaman can save you, Steve. - Dave

[Yadkin]

Shaman on you Dave!

The spindles are original. Alignment done after the conversion. No backing plates. I applied a generous amount of CRC Disc Brake Quiet applied to the pad backing plates before my last test drive- no effect.

[simplyconnected]

If all that is true, something is flexing. I put my money on loose spindle nuts IF your bearings are good. Pull the wheel off and check it. - Dave

[Yadkin]

I checked the bearing pre-load with Joe when checked the assembly clearances the first time. I fact I remember quizzing Joe on his method of applying pre-load, to see if was how I book-learned how to do it 30 years ago.

[JJbird]

Howling is usually a bearing

[MLZ]

I had a similar situation. It turned out to be my sway bar would rub against the vibration damper when turning left. The left front spring was sagging slightly. The short term fix was to space the sway bar bushings down about a half inch. I'm sure this will correct itself when the springs are charged.

[Yadkin]

Well, both my sway bar, links and bushings are new, springs are new. I'll check this today or tommorow when I visit the shop.

The wheel bearings are also new, part of the disc brake kit.

Everything so far is pointing to the excessive play in the new caliper that I found during disassembly. The piston self-retracts, leaving a significant play between the inboard pad and the rotor.

Last night I took my bride on a short drive and she cut it short because of the noise.

[scumdog]

How sharp a turn are you making when the noise occurs?
It might give us all a clue!

[MLZ]

It would start with the steering wheel about 90 degrees left of center.

[Yadkin]

How sharp a turn are you making when the noise occurs?
It might give us all a clue!

It will happen on a curve in the road as well as a sharp turn, regardless of speed, no difference in volume or frequency.

[bird 60]

Just for the fun of it, even though it would be more of a growl, check the power steering fluid to see if it's low. Mainly because of you making a turn it would do it.

Chris......From OZ.

[Yadkin]

The fluid was about 1/4" low, so I filled it: no change.

Here's a video of the noise, maybe this will help in diagnosis.

https://www.youtube.com/watch?v=EBaB8tzIwUg

[Yadkin]

I took both front wheels off and inspected the brakes on both sides, using the left side as "normal". Based on the wear on the rotor, the right side inboard pad is definitely not making as much contact at the outboard pad. Here's a video of my inspection of the front caliper and rotor.

https://www.youtube.com/watch?v=Btl7yaWZQkQ

I then took the caliper off and "reset" it, then drove the car, and the noise had gone away until the first time I applied the brakes. Then the noise reappeared at every left turn as before.