Hi guys,

I've just completed a brake conversion on my 1965 AP6 Valiant from drums to discs. New rotors (solid, dimpled and slotted), pbr calipers overhauled (cleaned, new seals, greased pins), new hub bearings, new bendix general ct pads, anti-squeal shims, brake grease, VH40 remote booster (new) set-up with reconditioned master cylinder and new brake fluid of course. Did the setup myself and got mechanic to check and rebleed system. Brakes work beautifully, but after a few km's there is a terrible squeal at low speed.

I suspect it is the pads as I had originally put the 3M self adhesive backing on the back of the pads for the 1st couple weeks. The squeal started, so replaced the stick on stuff (which looked completely stuffed) with stainless steel shims and brake grease. The squealling returned a few days later.

Suspension is new and brake conversion has been done properly. There is no shuddering or vibration at the steering wheel and the car stops straight and true.

I have a few sets of original old pads that are only 1/4 worn (have asbestos in them). If I can 't find a solution soon I will be cleaning the rotors (clean up any pad build up) with 120 grid sandpaper and brake cleaner and using the original pads.

Can any of you guys see something I've missed. I can replace the solid, dimpled and slotted rotors with standard ones is my only other alternative.

Any ideas/comments would be very appreciated.

Regrds,

Bare Metal Maz

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Love cruising in a bare metal Val!

I had that problem once on a stock 1973 set of discs that did what you are describing...ended up being the bearings had not seated correctly and they were singing/complaining about not being right with the bearing races...New set of bearings and races installed, everything went back to quiet again. I could also see an improper bearing grease packing, or using old bearings that don't like to be side loaded on turns or roads also whining as well.

I started to wonder if Timken bearings were the cause, but it wasn't them.

I always use the disc brake pad RTV type anti-squeal around the lip of the caliper piston where it contacts the pad and let it 'set' before using the brakes, grease has a tendency to wear away or flow when heated.

Thanks DI,

This is what happens sometimes when you replace everything with new gear, just for that little bit of piece of mind - it bites you! I'll get on top of it.

I have a set of standard discs/hubs/bearings and original pads/shims that I can throw on in pretty quick time.

I'd love to change one thing then drive to see if that pinpoints the issue, but time is a factor and I can't have the car off the road on too many occasions.

Did you have shims on the 73? I ask this as I have been told not to use the CRC disc brake quite RTV in conjunction with brake shims.

Also, did the squeal come from both side of the car? Mine definitely sound like its coming from both sides.

Bare Metal Maz

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Love cruising in a bare metal Val!

I have never used Brake Shims with any of my setups (nor have I ever seen anyone use them on the late setup), everything just fits fine without help. In that case, yes both sides of the car had issues...thus my original concern that the bearing quality had not been up to par (I also questioned whether the spindles were in good shape and were not adequately supporting the bearings once set).

-D.Idiot

I would like opinions on wheel bearing tightness procedures. My '69 has early '70's B body brakes on a '73 a body front end. The '69 FSM gives a different procedure for tightening wheel bearings from the '73 manual. It seems there is a bit more play than intuition wants when set up like the '69 manual. But, I do not want to make them too tight. I remember reading in the old Popular Mechanics MPG testing that they set the wheel bearings a bit loose for their MPG competitions. I would appreciate different opinions being expressed here. thanks.

Sam

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A recent addition of Australian Street Machine magazine had an article on fron brake upgrades. They detailed how the wheel bearing retaining nut should only be tightened with just the weight of a large adjusting spanner.
With my recent brake upgrade, the new bearings were placed into the freshly greased hub assembly and onto the impecably cleaned & lightly greased stub axle. Screwed the washer & nut on finger tight and then pushed and turned the assembly to initially seat the bearings whilst tightning the nut with my fingers. I tighten as descibed above with the weight of the spanner. So not too tight at all. A final check with th wheel bolted on. I know very scientific... I've done this on all me cars and never had an issue - until possibly now with this squealing brakes problem at very low speeds.

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Love cruising in a bare metal Val!

I've had problems with particular brands of pads on occasion.

For example, I had NAPA green box pads on a 300m that wouldn't stay quiet - squeals when cold, grinds when hot - right from day one.
After exhausting other options, I finally put a different brand on and had immediate silence.

I've had good results with Bendix in the past, but as they say, nobody's perfect! Maybe try a different brand or formulation?

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"A mechanic is Somebody."
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Thanks for the replies guys.


I will be (a) doing the rotor clean & pad change first off assuming the inspection of the bearings is ok. If that fails (b) replacing setup with used rotor/hub/bearings/pad combination.

Had a 2 hour drive down to Byro Bay on Easter Saturday after the car had sat around for a day or so. Brakes began to squeal after 3 or 4 kms. By the tim we reached Byron it was bumper to bumper for 20 mins going into the main town. The squealing was just so annoying, embarrasing , load and ear pearcing . The poor locals! The guys behind us in a convertible wished they had the top down!

Arrived back in Brisbane with squealing brakes and a slight split on the top tank of the radiator. At least the AP6 gpot us home safe and sound. Did find a fantastic radiator contact only 10 mins away (http://www.ftrs.com.au).

I forgot to mention I did a "pad break-in procedure" to try solve the problem (note these bendix ct pads do not require any break-in procedure). That is up to 60km/h, brake fairly hard back to 10km/h four or five times. Brakes faded pretty badly by the last attempt. Squeal went away all the way home (25mins). Next day squeal returned after 5 km.

I'm so looking forward to me getting this sorted and behind me. I hope plan (a) works.

Cross your fingers...

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Love cruising in a bare metal Val!

Finally!!! Managed to squeeze a couple hours on the brakes last week and got success to report.

I removed the old pads (Bendix CT) and installed a healthy set of original pads. I installed the shims and greased between the pad and the shim, and shim and piston. Greased the pins. Thoroughly cleaned the rotor with a scotchbrite and brake cleaner. Checked bearings were sound.

After a week and half of driving around on city and highway not a peep!

Thanks to all who passed on advice. Always appreciated!

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Love cruising in a bare metal Val!