39 P8 Rear Brake Drum

[Racerstev]

Now that a new drum is on the way there is one thing I want to try, plan D.

 

Silicon/Bronze brazing. Maybe I can save the old drum. From what I’m told you can’t weld cast iron, it will crack. You CAN braze it or in this case silicon/bronze with inert gas shielding.. The bronze melts at 1000F 

lower then steel so it will warp less and shouldn't crack. 

 

If it works there is a 30 day return window on the new drum..

 

Steve

[Los_Control]

I'll throw in my 2 cents ..... Uncle Tony you either like him or hate him, he explains pretty well his method of welding cast iron.

He gives some good examples here ..... He stresses that he uses a cheap 110V fluxcore welder.

In a different video where he actually shows welding up a freeze crack in a block he stresses the point he has tried all methods of welding, it was cheap 110V fluxcore that he has most success with .... it does not get too hot and not expand the cold metal around it forcing it to crack when it cools .... it just works when other methods do not.

 

 With all that said, everything he is welding is low stress no pressure. .... Although he mentions he did weld up a crank bearing saddle on a 426 hemi and it held up.

The motor was junk anyways and worth giving it a try .... at all cost you try to save 426 Hemi's

 

Your brake drum in that area that needs welded will be under extreme stress when you need your brakes the most and do a panic stop and stomp on them.

The shoes contact the drum and stops it from moving, the wheels have contact with the road and wants to still move ..... Your weld holding is very important here.

Just saying I'm not sure I would want to take that chance.

[Racerstev]

I’ll check out his video..

 

Two points, and I welcome any input on these. 
 

One, the way the factory holds the drum on is really pretty weak, just tabs  crimped into the drum. Hoping  a 360 degree braze will be at least as strong. 
 

Two, if the braze doesn't hold the drum will stay over the shoes. The hub and the backing plate holds it in place. So you will have 3 working brakes not four. 
 

Advice on this is well taken. Brakes are important!! 

[Los_Control]

There is a actual how to here from years ago, to remove the rivets and have removable drums without needing a puller for the tapered axles  ....

Just saying some may have intentionally made their drums like yours is  now ..... Not sure I see the value in it ....

 

I did have a 1961 D100 Dodge truck the rear drum was so thin it split in 2 and was interesting to drive it home. I still had brakes but pedal was to the floor.

 

If I was a 15 year old kid again, I would just cut the brake line and fold it over to pinch it off and not use that brake .... 3 is good enough .....

Word of advice there .... If cutting a front brake line, do mot cut the front passenger side .... you step on the brakes and it will pull you into oncoming traffic.

If you cut the drivers side, it will pull you into the ditch  .... please don't ask me how I know   🙄

[Racerstev]

Look closely at the pictures, the rivets are still there. The other end is what failed. 
 

Steve

[Los_Control]

2 minutes ago, Racerstev said:

Look closely at the pictures, the rivets are still there. The other end is what failed. 
 

Steve

I did before I ever replied ..... I took one look at how the 75 year old drum separated ..... I'm politely saying that drum is F'd up and I would not touch it with a 10' pole.

It was weak in one form or another to fail the way it did. ..... I get it was the wrong wheel, I just feel the wheel should have failed before the drum did.

Since the drum was the weak link ..... I simply would not be comfortable putting it back in service.

 

I have no idea what your car is, is it a show car .... a daily driver .... a trailer queen ..... This is where I would install a modern rear end with better gear ratio.

I could do that for the price of  1 replacement brake drum ..... plus the driveline needs to be modified ..... you may be able to weld it yourself.

 

Now I would be rid of the impossible to justify high priced brake drums, I would be rid of the poor tapered axle design with a woodruff key to apply power .... brake parts would be readily available at any parts store locally. .... The brakes would be self adjusting ...... Unless you are going for a 100 point show car .... I would kick that rear end to the curb in a heart beat.

Cheaper to update it and prevent future issues, it will be user friendly, more highway friendly ..... There is simply no bad points to updating the rear end and brakes.

 

If you are going for a show car, I think you might get dinged on welding the brake drum together.

 

You already ordered the drum and is on it's way .... it is the easiest way to fix your problem ....

Me being the cheapest guy here on the forum, I think for a little extra work I could have done a rear end swap for the same price as a new drum.

I would be money ahead and troubles behind. ...... Your car do what you want.

 

[Frank Gooz]

Just a thought What about a early Dodge Dart maybe 1963 ish. I think the V8 car had a five on 4 1/2 bolt pattern and were 10 inches.

I THINK MAYBE.

Good luck

Frank

[Racerstev]

Just looked on Rock, they have rear with 9” drum but don’t list rear with 10”….

 

I think I need to walk around Hersey this year with a tape measure! 
 

Steve

[Los_Control]

10 hours ago, Frank Gooz said:

Just a thought What about a early Dodge Dart maybe 1963 ish. I think the V8 car had a five on 4 1/2 bolt pattern and were 10 inches.

I THINK MAYBE.

Good luck

Frank

Most common is to use a early 90's, jeep cherokee or Ford explorer .... I know 1996 Ford had rear disk, you need to get older to stay drums. They have correct bolt pattern, width, variety of gear ratio available. 

Generally you have to remove the spring perches & weld new ones on in correct location .... some report that the existing perches were fine.

You can get new perches from tractor supply in the trailer section for $20 .... before existing inflated economy.

The cost of the rear end varies depending where you buy it.

 

Then there is the issue of the u-joints wont match ... your existing drive line needs to be modified with a new yoke to match the rear end.

Typically I think the cars use the ball & trunion u-joints ....  What a pita.

If I was doing the rear end swap I would also change the yoke on the transmission and update both ends to modern u-joints.

Just eliminating one more future problem when it is time to replace them.

 

If you need to buy 2 new drums when you do brakes that would be over $800 just for drums and not including brakes.

My Cleveland u-joints on my truck were $85 each when you can find them .... there was only one supplier then they quit selling them, A few years ago another supplier popped up .... no idea if they are available today. .... I just imagine Ball & trunnion are available and cost even more then my truck.

 

I'm all for keeping them stock, personally I'm medically retired in my 60's, I do not want to deal with these issues in my 70's.

The ones that can afford to keep them stock have my support. ..... Simply cheaper to swap out all the future problems then it is to do a brake job.

 

I'm greatly saddened that the previous owner did a new brake job before they parked it .... all new drums on 4 corners ....

 

[Ivan_B]

Have you already googled the available drums by size specs (both standard and metric)? Even if the bolt holes do not match, I suspect that if you can find the correct size there should be a way to make it work 🤔

[Sniper]

18 hours ago, Frank Gooz said:

Just a thought What about a early Dodge Dart maybe 1963 ish. I think the V8 car had a five on 4 1/2 bolt pattern and were 10 inches.

 

A bodies (Dart, Valiant, Duster, Demon) were ALL 5 on 4" bolt pattern till 73.  I have a 65 Cuda, V8 car, that had that pattern. 

 

 

[Racerstev]

The new drum has arrived, standard for Mopar Pro the packaging was sub par. Holes in the box..

 

I do have to say the drum looks good, all cast in one piece. No ID numbers of any kind so no idea the source. Still IMHO the price is about double what it should be, clearly a only game in town thing.

[Racerstev]

[Racerstev]

And the old drum ready for brazing.

 

A note on the failure. No clue to my cars history but I do know the drum was stuck pretty badly. The right puller got it off but what if the PO used a sledge on it. This could have started the failure. All you need to do is break one tab, the rest will follow.

[Sniper]

10 minutes ago, Racerstev said:

Still IMHO the price is about double what it should be, clearly a only game in town thing.

 

Oh he's that way even if he's not the only game in town.

[9 foot box]

   There is a vendor, Old Parts Source, that sells on eBay as old.parts. They sell a BD1976 brake drum for $95, but almost $60 delivery. The ad has a Kanter banner on it. The eBay item #312278878867. I don't understand how the Rockauto drum didn't fit, if you didn't use the hub from the broken drum.

[Racerstev]

I measured on the Ford drum. I didn’t want to take the old one apart until I was sure it would fit. 
 

Kanter lists that drum as out if stock, called and they hadn't had it for years. 
 

I’m really confused about the years, Kanter lists both “40-54” and “37-56”

 

Old parts lists it as “46-56” then another spot “37-56. 
 

Can anyone clear this up? 
 

Steve

[Racerstev]

The pic shows the differance in height between the Ford drum and the Mopar Pro drum. 
 

Took a screen shot of Kanters site showing the year difference. 
 

Kanters drum look right but the year difference bothers me. 

[9 foot box]

   If you’re not familiar with a Tod Fitch web site, you should be, it’s “ply33”. In group 22, it shows brake drums from 1936-48 used the same front and rear brake drums. Evidently the same drums with 10” brakes were used until 1956. 

[TodFitch]

32 minutes ago, 9 foot box said:

   If you’re not familiar with a Tod Fitch web site, you should be, it’s “ply33”. In group 22, it shows brake drums from 1936-48 used the same front and rear brake drums. Evidently the same drums with 10” brakes were used until 1956. 

https://www.ply33.com/Parts/numeric should get you to the top of my parts cross reference information.

[Racerstev]

Thanks guys, going to give Old Parts a call on Monday. 
 

When I called Kanter the salesman was really confused when it came to drums. Told me he would call back, 2 hours later I called back. He said he was waiting on a answer… 6 hours later he called and said something about “when they changed hands” the brake catalog got messed up.. and it’s been years since they had these. 
 

Maybe Old Parts took the brake stuff with them? I sure am learning nothing is easy on these old cars! 

[Racerstev]

Update, seems Old Parts dosn't list a phone number so E Mail. The reply to does it fit a 39 is “yes it does” from Dan. So this sounds like the best option so far. Seems to be a few posts on E Bay for this drum, one as low as $95 plus 20 to ship. Not cheap but reasonable. 
 

Did a test fit on the Mopar Pro drum, fits perfectly. Waiting for the welder at work to braze the old drum, should be tomorrow. 
 

Steve
 

 

[keithb7]

For anyone reading this, keep an eye out for hot-rodders who are replacing the drivetrain. Pick up a complete front and rear axle assy for nearly nothing. I did, and parted them out. I have 4 spare 10” drums for my ‘38 Plymouth. Another 4 spare 11” drums for my Chrysler. I threw out another 4 spares. Too many to keep. Nobody wants to pay freight charges from Canada for these heavy parts.  
 

Edited May 13 by keithb7

[Los_Control]

53 minutes ago, keithb7 said:

I’ll die happy some day, knowing I will have never sent Mopar Pro another cent. 😁

I'm with you brother .... Pretty dirty what they did to you ..... same time it has been going on since the industrial revolution a 100 years ago. .... Legally.

Not saying I agree with it ..... I simply will not deal with them either.

 

Spare parts are great to have, and it takes time or years to collect them as they become available. Then you still need to store them.

I bought a home made utility trailer for parts .... I assume I may have a decent rear end or spare drums, I have spare original wheels .... the sheet metal, tailgate is much better than what my truck has ..... So far I have taken the fill plug off of it and replaced it with my crappy one.

 

Just not easy to have a parts car or a 1/2 a truck trailer around ..... at least my trailer doubles as a bin for scrap metal and call up a scrapper from time to time to empty it.

Not everyone wants this stuff lying around or a HOA will not allow it.

[Eneto-55]

re: welding cast iron:

I've mentioned this here on the forum before, but a friend of mine in Brazil, a Swiss-Argentine guy, welded his exhaust manifold with a common stick welder by heating the entire piece to cherry red in a home-made forge, then quick welded it while it was still red hot.  (His dad taught him how to do it.)