68 Cougar - Front Brake Shuddering after Replacing Drums and Shoes

Cougar Community Classic Cougar Maintenance Restoration and Repair
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Hi, everyone,

I’m brand new to the forum and this is my first post. I purchased my 68 Mercury Cougar back in February after a couple years of reading, researching and learning about the car. Its got a J-code 302, automatic and A/C. The paint and body are in really good shape, and mechanically it has just enough things that need work to make it interesting.

I had a noticeable shimmy in the steering wheel while braking, so assuming the front drums were at fault I set about purchasing and installing new shoes, hardware and drums (the old ones were out of spec and could not be resurfaced). I haven’t worked on drums in years so I of course read my repair manual and checked out some good online tutorials on drum replacement. Overall installation was fairly straightforward and I had no issues. I cleaned up and lightly dabbed caliper grease on the back plates before installation of the new shoes and I verified the shorter shoe is installed on the fronts of the backing plates. The wheel cylinders were not leaking and the rubber boots were in nice shape so I did not change them. I also cleaned up the spindles, hub assemblies, and inner and outer wheel bearings (installed new inner seals) and repacked everything with grease. I adjusted each drum until there was some slight drag when I spun the wheels by hand. I sprayed the insides of the new drums with brake cleaner to help remove the light oil coating on them and sprayed the surfaces of the new shoes to remove any greasy fingerprints I left during the installation process. The outer bearings were installed and seated and I torqued the nut on the spindle to spec according to procedure. I put my front wheels on and torqued the lug nuts to 80 ft-lbs.

Well, the shimmy in the steering wheel is gone, but it’s been replaced by a severe shuddering that I can both feel and see in the steering wheel & column (shudders up and down) and I can feel it in the pedal any time I apply the brakes. I can notice it at any speed above 25 mph when hitting the brakes, but seems worse when I brake from higher speeds.

I took off the drums this morning to double-check my work. Nothing looked amiss, but I went ahead and re-assembled the shoes and drums, and re-sprayed both with brake parts cleaner and wiped out the insides of the drums. I re-installed everything, put on my wheels, adjusted the shoes until there was some drag on the drums, set the car down on the ground and re-torqued the lug nuts. No change - I still have the bad shuddering while braking.

Does anyone have any suggestions of things I should check, or perhaps any steps I missed in the process that might cause such a bad shuddering? I’m puzzled and out of ideas, except for the idea of replacing the drums with discs, which I’m not quite ready to do yet. :slight_smile:

Thank you!

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It’s your anti gravity correction stabilizer!!!

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I have been there. My 70 convt did the same thing. I replaced drums at least 4 times, new shoes ect. Back when the cars we made the brake drums were swedged on to the hub and than turned so they were one complete unit.

What I did to fix my problem finally. I took the drums & hub to a local machine shop had the drill & tap threads into the hub and brake drum. I than had the drum & hub turned to make it round. There was no more shudder.

The shudder was very violent before this was done. I wrecked a couple of my wheels before I figured it out.

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Hi, Bill,

I’m not sure I understand your post??

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Your picture is upside-down; hence the anti-gravity comment.

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Aha - thanks for letting me know. It shows correctly on my iPad - bizarre!

Blake

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Randy - thanks for the suggestion - I didn’t think about needing to have the hubs swedged onto the drums. My hubs came off the old drums fairly easily with a block of wood and a few taps of a hammer, so I didn’t think about putting the new drums on without swedging the hubs to them.

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Kidding aside…

  1. Front suspension. Most likely something here unless all is new & double checked. IE: strut rod bushings tight, etc.
  2. Do the “back up/rev” thing to adjust brakes evenly & the check way they adjust automatically.
  3. Front bearings: loose or bad
  4. Backing plate grooves: caused by years of use, the side of the shoes cut grooves into the 6 “flats” per plate. Weld to fill & grind smooth. Lube & reassemble.
  5. Steering. Like #1 this “system” can also allow some issues-
  6. “New” drums & rotors. Out of the box the these can be out of spec. Have the drum turned to remove any issues.

Note for those doing rotors: Please put the races that came w/ the new bearings you are installing in your new rotors. The races in the “new” rotor is for machining the rotor surface, not for your brand new bearing!

Hope we got it your “vibe” figured!

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Some places can turn the drums w/ the hub!

More than likely your issue right there!

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Bill - thanks for the suggestions. It sounds like having the hub swedged on and/or turned or balanced as an assembly might be a good place to start. I didn’t think about the need for this since my old hubs came off relatively easily.

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Many choose to upgrade to disc brakes if possible due to those issues. Some side to side pulling is normal but not the shake rattle and roll thing.

If you don’t have power brakes yet with vacuum, I’d do that first if it were mine.

Also check the obvious stuff.

Are your tires in good condition?

Did a previous owner correct a leaky tire by using that GREEN SLIME crap? It really stops leaks but rides like total and utter misery unless you have a truck even if you do both wheels on each side, in my opinion.

There’s really no way to check that with the tire on the wheel sadly enough. Are your wheels balanced?

Have you had a decent front end alignment lately?

Are your wheels the same size make and model side to side, not just real close but not quite.

I found out with my last one, a 1970 to far gone to save, that having the same lugnuts on both wheels on the same axle also makes a dramatic improvement.

Are all your tires the same brand and model? Are there any subtle kinks in any of the metallic brake lines?

It’s the little things that can cause the most havoc much of the time.

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This doesn’t sound like the same thing, as the problem I once had was only at higher speeds. Took my Cougar into the Merc dealer for something, maybe it was rear brakes. Pick up the car and start driving, get on the highway and the front end starts shaking, Slow down and it goes away. Cause, they had adjusted the front brakes too tight. With enough speed they would heat up and start grabbing. There excuse, I’d put bonded linings on the front rather than the Ford riveted linings. They didn’t pull the front drum just adjusted them. I’ve never had the problem again, I do my own brakes now, and I eventually upgraded to front discs.

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Thanks for the info, whitelightning. The tires are new and are the same size. The car has not had an alignment since I’ve owned it (February of this year).

I took the car to a shop today that has experience with drum brakes and I’ll update the thread with the diagnosis. Hopefully nothing too expensive!

The info on the same size lug nuts has got me thinking too because I have one mis-match on my driver side front wheel.

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I’m not surprised that it gets worse as the speed increases. There’s more kinetic energy the faster you go.

If you tighten up or replace one set of parts, many times older ones will react revealing their deficiencies. It’s like whack a mole but with a wrench.

With all the vehicles I’ve had with drum brakes (all rear however) those adjusters take quite some time to get synched. Finding a parking lot and simply going forwards and backwards literally 50 times or so speeds up the process, but they should only be pulling consistently to one side or the other until they balance out, not vibrating.

Setting them to tight is the main error that can occur. Ask me how I know…

One thing I forgot to mention before is to back them off a little and just spin the wheels by hand to see if they smoothly slow down. You can also see if there’s any noticable wobble.

Could the braking system in some way cause this? Maybe. Still, it seems like something else to me.

A loose transmission mount or bad motor mounts can also cause weirdness. The motor mounts are obvious, but the transmission mount is hard to see visually. If it’s old, it’s best to just go ahead and replace it anyway.

One of the things the appraiser caught when my car was getting a pre-purchase inspection was a cracked transmission mount, which the dealer replaced as a condition of sale. The bolts also weren’t torqued down evenly as well. He said it was shaking at 50 mph for no obvious reason, which led him to look at that.

Bad U-joints or a drive shaft out of balance can also do this. On my last cougar, a new set of heavy duty U-joints got rid of lots of annoying vibrations FWIW.

If it’s worse under strong acceleration, that’s important to notice. What happens if you just put it into neutral at highway speeds and just let it roll when it’s acting up?

Still, it’s a solvable problem unlikely to return.

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I mostly notice the shuddering while applying the brakes. I feel some other vibrations from time to time while driving, but the shuddering while braking definitely started after I replaced the drums and shoes. I replaced the u joints last month as they did seem a bit worn and had some excess play in them.

Once I get the brake problem solved I do plan to get the tires re-balanced (though they were just balanced in February) because I don’t think they were balanced properly. Good call on the transmission mount - I’ll check that out too because I’m not sure what condition it’s in.

Thanks!

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Hello all,

I just went through this last year. Wanted to replace brakes on my 69 all drum brakes. I was suspicious about the front drums and ordered new. Upon completion I had exactly your symptoms.

We have a nice manual lathe at work so I cut and turned a flanged axle into a hub that allowed me to turn drums. Fronts were way out and I turned them up. Back on the road and still the same thing. I then pulled the rear drums and turned them. One was pretty bad. Back on the road and still shaking.

With the aid of my heat gun after a test drive I discovered that the rears were set too loose. Upon cranking the rears tighter by about 4-6 clicks, the violent shaking was gone, and still is. Mine shook so bad that I decided to replace the LCA bushings over last winter to be safe.

While I don’t recall this kind of issue back in the day it did mess with me for a couple of weeks. Some day I will get disk brakes, at least on the front. But for now all is good.

Good luck.