Brakes - turn or replace?

[Secret Chimp]

Either my left front drum warped or I have an egg-shaped tire on there.

I'm not sure which is chicken or egg here, I'm guessing the tire since it spins freely then touches the floor in one spot when I have the car jacked at the right height. Either way the drum also grabs in one spot and I'm starting to get some light lurching while braking from it.

Should the original drums be OK to be turned? The factory shop manual is very adamant about not removing more than .065" of material to round the drums back out, but I can't tell if they mean "at a time" or "ever."

I also can't really tell if I buy new drums if they'll come with the appropriate hub castings for the wheel bearings. I've found reports from searching of people breaking their hubs and needing to find replacements separate from the drum. Is this the case for a 67 Coronet, or are my drums and hubs a single casting? I can't tell what I've be getting if I bought new drums that supposedly fit this car.

 

[Meep-Meep]

If your drums are within the limit turning is just fine. You could very well have an egg shaped tire but you will notice that while driving at about 30 MPH without hitting the brakes. The car will have a wobble sensation. I just went through this tire issue myself and had to have the tires ground to solve it. The tight spot on the brake is possibly another unrelated issue. A warped rim that causes the drum to warp when tightened will show up as a pedal pulsation when you step on the brakes. Loosen the wheel and see if the pads under the lug nut holes are flat against the hub, or check the rim with a flat plate from behind.

 

[MoparMitch]

Either my left front drum warped or I have an egg-shaped tire on there.

I'm not sure which is chicken or egg here, I'm guessing the tire since it spins freely then touches the floor in one spot when I have the car jacked at the right height. Either way the drum also grabs in one spot and I'm starting to get some light lurching while braking from it.

Should the original drums be OK to be turned? The factory shop manual is very adamant about not removing more than .065" of material to round the drums back out, but I can't tell if they mean "at a time" or "ever."

I also can't really tell if I buy new drums if they'll come with the appropriate hub castings for the wheel bearings. I've found reports from searching of people breaking their hubs and needing to find replacements separate from the drum. Is this the case for a 67 Coronet, or are my drums and hubs a single casting? I can't tell what I've be getting if I bought new drums that supposedly fit this car.

Im sure that the factory meant a total of .065 during the life of the drum. Also look to see if there is a limit of diameter cast into the drum somewhere . I t shouldnt take any more than around .010 to get it true. As always , if those drums are original , you will want to keep them.

 

[Secret Chimp]

Im sure that the factory meant a total of .065 during the life of the drum. Also look to see if there is a limit of diameter cast into the drum somewhere . I t shouldnt take any more than around .010 to get it true. As always , if those drums are original , you will want to keep them.

They are originals - I wasn't sure how much material is usually needed to get brakes rounded back out.

I doubt this car has had its brakes done more than once or twice in its whole life. The current drums have funny biscuit-shaped balancing weights on them, which I'm guessing are indicators of olde tyme casting & manufacturing processes.

Meep, who did you get to shave your tires? I asked around when I had someone slash a tire on my Miata and got a low-wear replacement, but most folks would only shave new tires. Of course this is assuming my tread is just worn unevenly and not slightly separated from the body of the tire...

 

[mobileparts]

Brake Drums Specs

Small block drums are 10" x 2 1/2" and NEW , their specs are 10.000"
You have .060 - .075 over the life of a drum, once you get past .060 and they are not true -- DISCARD -- you are pushing your wheel cylinders out too far -- and one can "explode" on you.... I have quality 10" x 2 1/2" drums BRAND NEW at 49.00 each...

Big Block Drums are 11" x 3" in the Front and 11" x 2 1/2" in the Rear. These drums start at 11.000" and their discard diameter is 11.090"... these drums have a life of .090 -- and again, don't get too close to the end..... for the end is the end......
I have quality 11" x 3" Front Drums at 139.00 each &
I have quality 11" x 2 1/2" Rear Drums at 65.00 each...

Will be at the Mopar Nationals, Columbus, Ohio in a couple weeks -- with all of these drums (( RESERVE -- can only carry so many!!!!!)) or

Call me -- Craig -- Mobile Parts --

 

[rlsbee]

If the tires are radials, you may have a broken belt in the tire. I had a similar issue with my Ram pickup. When spinning the tire, with my hand lightly dragging on the tread, it was easy to feel the lump. A friend told me that it's become a common problem in his shop.

 

[scotts74birds]

X2! Until the last ten years, I have never had a tire problem. But recently I have had a rash of tires with broken internal belts. I starts as an occilatition, or a wobble at low speeds. You cant see anything on the tire, but it can be bad. It may even pass a balance test. You just have to rotate it and see if the problem moves to a different corner of the car.

 

[Secret Chimp]

I ought to do the obvious and put a dial on the rims first... I have a definite high spot on one tire and both have some out-of-trueness when looking at the tread, but I honestly haven't checked for straightness right on the wheel rim. If those are true then these Les Schwab Coopers are crap. I think the tires are new enough still for a warranty (if it's transferrable) though I may just spring for decent tires from Tire Rack if two of them are buggered up already. Thanks for the tips.

The drums were turned without much material needed to get them trued up. One of my outside bearing races was messed up pretty badly. Phil at Action Auto Parts on Aurora will hook you up with a cash deal if it's a slow day, for those of you around my area - he installed my inner bearings and races and outer races for next to nothing over the turning!

 

[Meep-Meep]

Meep, who did you get to shave your tires? I asked around when I had someone slash a tire on my Miata and got a low-wear replacement, but most folks would only shave new tires. Of course this is assuming my tread is just worn unevenly and not slightly separated from the body of the tire...[/QUOTE]


There is a performance tire shop not far from me in NOR CAL and they grind new race tires, which I'm thinking is a good idea if you are going very high speeds. Most tire stores I called denied they know the machine exists.

 

[Secret Chimp]

Argh both of my flare nuts are completely stuck. The hoses look OK to drive for a bit. According to the internet I'll have to cut the lines above the nuts and re-flare them... hopefully that's hard to mess up.