New Rear Disk Install with Groan

[BMosely]

68’ Coronet 440 with Right Stuff 4 wheel disk conversion. We just got the car rolling and the right rear is giving me fits. All of the brakes work great but the right rear has a very low frequency groan while driving. Apply the brakes and it goes away so it is in the brake assembly. I thought maybe caliper grease was needed so I even swapped pads left to right to eliminate them and applied the grease. No change. Visually everything looks good and the caliper bracket appears square. I backed off the parking brake adjustment to take it out of the game also. A left hand turn putting pressure on that right rear makes it worse. My temp gauge says a pad is dragging as it is running hotter than the other side but I can’t figure it out. Any thoughts would be appreciated. The groan vibrates the entire right rear.

 

[BeatersRus]

hows the end play in that axle shaft??..do you have the Adjuster properly set?
did you change the rear axle bearings before the brake install?
a groan is usually a bearing,in my experience.....shrieking or dragging would be the shoes.

 

[Big Bad Dad]

8-3/4 axle end play adjustment is on the passenger side. Sounds like it is loose...

 

[Jerry Hall]

Don't most rear disc brake conversions require green bearings to eliminate end play?

 

[dadsbee]

Bearing... you put Greens in I bet too....

 

[themechanic]

Residual valve in the master cylinder or rear brake line?

 

[BMosely]

Yes, green bearings for the conversion. I will check end play in the morning.

 

[BMosely]

New master cylinder for the conversion so no residual valve but I did use the original distribution block and I don’t think it has any valves in it.

 

[ruffcut]

My money is on the bearing! ruffcut

 

[BMosely]

My money is on the bearing! ruffcut

Brand new with about 20 miles on them. I know that does not mean it could not be bad. Other than end play, what is the check? Pull the axle and feel the bearing out by hand?

 

[MoparLeo]

Pull the axle and closely inspect for play, damage, color changes...
Also swap the rear rotors side to side. This will eliminate the bearing.
The brake rotor may be the groaning sound. If it is , it may require either re machining or replacement. I have found that sometimes rotors and even drums will have "grain" to them and will make noise in one direction of rotation.
Most common on non ventilated rotors.

 

[BMosely]

At install several months back.

 

[steve340]

Is the calliper bracket causing some kind of alignment issue?

 

[BMosely]

I could not take it. Summit Racing in McDonough had a green bearing in stock so I rode early and tore the axle out at lunch. No visible signs or rotating indicators but after replacing the bearing we appear back in order. The old races and balls looked good, but obviously there was a spot somewhere.

 

[RemCharger]

Did you remove the thrust buttons with the green bearing install. I see no mention of it.

 

[beanhead]

Yes, green bearings for the conversion. I will check end play in the morning.

The end play adjustment is eliminated with green bearings..