The Ford Barn

pooch · 12-19-2010, 03:39 PM

I have read that .070 is the limit.

To get around the outer lip , I placed a 1/2 inch drill on outer drum and measured the total and subtracted the drill size.

Is this the best way to measure it?

If .070 is the limit, and the brakes are 60/40 rear/front, can the front have slightly more wear?

What is the end result of a too thin brake drum?

Does it break off at the flange and that wheel just continues turning with the broken band clamped stationary by the shoes, or does it shatter and seize the brakes up?

(BTW,After dismantling 4 brakes, I am over removing split pins (cotter pins to youse)..I might buy a box of internal star washers!

kenparker · 12-19-2010, 07:07 PM

Originally - as from the factory - the AR drum was the same thickness as the A, which was ( corrrect me someone if i am wrong) .144. I would never in my car or in a customers car ever use a drum that was less than .110 after turning. Even .110 is risky. That .034 of missing metal is 1/4 of the original thickness gone. The metal that is left gets hot easier and expands very easy, leaving you after a couple brakings or worse yet a panic stop with a "oops my brakse dont work anymore".

Jim Parker Toronto · 12-19-2010, 07:40 PM

Got to agree with Ken on this one, why use worn out parts for the most important part of your car. The end result of a too thin brake drum is NO brakes! Use bands or get some new drums from one of the suppliers, they have the Early drums in cast now as well!

Keith True · 12-19-2010, 08:21 PM

My old American garage quick reference manual says .110 minimum.I CAN tell you that at .110 the brakes fade quick.I had a set at .110 on my pickup years ago,the brakes were excellent,but for a very short period of time.The guy I worked for told me to band them,he still had dozens of bands.They were packed in wooden barrels.He had a lot of big machinery,and he told me to clean the outside of the drums on the big lathe.Not to remove any metal,but to get off any high spots caused by rust,paint,etc.His goal was to see if I could get away without turning the drums after the banding.It worked,the brakes are working fine to this day and they were done around 1975. .070 is way too thin.I never knew the early 28 drums are now available in cast.I have a set of early drums here to band for a customer,I will give him the option of the cast now if he wants.I doubt it will happen though.At $140.each,plus the work of pressing and turning,it may be a hard sell.The car just hit 500 miles since he took it over in 1970.

Jim Parker Toronto · 12-20-2010, 01:38 PM

"I will give him the option of the cast now if he wants.I doubt it will happen though.At $140.each,plus the work of pressing and turning,it may be a hard sell."

Isn't it funny how SAFETY is a hard sell, and CHROME and paint ain't?? Boggles my mind...

pooch · 12-20-2010, 04:15 PM

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So the banding is mainly for heat? These days, we have heat transfer paste to take any minor voids in mating surfaces. How thick and wide were the old bands.

Keith True · 12-20-2010, 05:46 PM

The bands keep the drums from expanding when they get hot.I have had real good luck with them.The fellow who owns the early 28 that is having me band his drums saved for a year to get the bands.Disabled,fixed income,just no money to maintain a toy car.His dad bought the car new and he claims it has never been over 40 MPH.I didn't think his brakes were bad at all.He has it in his mind that he should have the bands,it was known as a great improvement when he was a kid so he wants it done now.I know what you mean about paint and chrome though,a couple years ago I got a 28 or 29 Phaeton running for somebody.Nice looking car.They told me to take it for a ride,I got to the end of the driveway and refused to take it out on the road.That one was a family heirloom too,nice paint and original upholstery,but no steering or brakes.The kids that own it now thought that is just the way they were.

12-19-2010, 03:39 PM	#1
pooch Senior Member Join Date: Sep 2010 Location: South Coast NSW Australia Posts: 2,596	AR brake drum thickness. I have read that .070 is the limit. To get around the outer lip , I placed a 1/2 inch drill on outer drum and measured the total and subtracted the drill size. Is this the best way to measure it? If .070 is the limit, and the brakes are 60/40 rear/front, can the front have slightly more wear? What is the end result of a too thin brake drum? Does it break off at the flange and that wheel just continues turning with the broken band clamped stationary by the shoes, or does it shatter and seize the brakes up? (BTW,After dismantling 4 brakes, I am over removing split pins (cotter pins to youse)..I might buy a box of internal star washers!

12-19-2010, 07:07 PM	#2
kenparker Senior Member Join Date: May 2010 Location: Van, Texas Posts: 1,122	Re: AR brake drum thickness. Originally - as from the factory - the AR drum was the same thickness as the A, which was ( corrrect me someone if i am wrong) .144. I would never in my car or in a customers car ever use a drum that was less than .110 after turning. Even .110 is risky. That .034 of missing metal is 1/4 of the original thickness gone. The metal that is left gets hot easier and expands very easy, leaving you after a couple brakings or worse yet a panic stop with a "oops my brakse dont work anymore".

12-19-2010, 07:40 PM	#3
Jim Parker Toronto Senior Member Join Date: May 2010 Location: Toronto, Ontario, Canada Posts: 1,289	Re: AR brake drum thickness. Got to agree with Ken on this one, why use worn out parts for the most important part of your car. The end result of a too thin brake drum is NO brakes! Use bands or get some new drums from one of the suppliers, they have the Early drums in cast now as well!

12-19-2010, 08:21 PM	#4
Keith True Senior Member Join Date: May 2010 Location: Epping N.H. Posts: 2,989	Re: AR brake drum thickness. My old American garage quick reference manual says .110 minimum.I CAN tell you that at .110 the brakes fade quick.I had a set at .110 on my pickup years ago,the brakes were excellent,but for a very short period of time.The guy I worked for told me to band them,he still had dozens of bands.They were packed in wooden barrels.He had a lot of big machinery,and he told me to clean the outside of the drums on the big lathe.Not to remove any metal,but to get off any high spots caused by rust,paint,etc.His goal was to see if I could get away without turning the drums after the banding.It worked,the brakes are working fine to this day and they were done around 1975. .070 is way too thin.I never knew the early 28 drums are now available in cast.I have a set of early drums here to band for a customer,I will give him the option of the cast now if he wants.I doubt it will happen though.At $140.each,plus the work of pressing and turning,it may be a hard sell.The car just hit 500 miles since he took it over in 1970.

12-20-2010, 01:38 PM	#5
Jim Parker Toronto Senior Member Join Date: May 2010 Location: Toronto, Ontario, Canada Posts: 1,289	Re: AR brake drum thickness. "I will give him the option of the cast now if he wants.I doubt it will happen though.At $140.each,plus the work of pressing and turning,it may be a hard sell." Isn't it funny how SAFETY is a hard sell, and CHROME and paint ain't?? Boggles my mind...

12-20-2010, 04:15 PM	#6
pooch Senior Member Join Date: Sep 2010 Location: South Coast NSW Australia Posts: 2,596	Re: AR brake drum thickness. Sponsored Links (Register now to hide all advertisements) So the banding is mainly for heat? These days, we have heat transfer paste to take any minor voids in mating surfaces. How thick and wide were the old bands.

12-20-2010, 05:46 PM	#7
Keith True Senior Member Join Date: May 2010 Location: Epping N.H. Posts: 2,989	Re: AR brake drum thickness. The bands keep the drums from expanding when they get hot.I have had real good luck with them.The fellow who owns the early 28 that is having me band his drums saved for a year to get the bands.Disabled,fixed income,just no money to maintain a toy car.His dad bought the car new and he claims it has never been over 40 MPH.I didn't think his brakes were bad at all.He has it in his mind that he should have the bands,it was known as a great improvement when he was a kid so he wants it done now.I know what you mean about paint and chrome though,a couple years ago I got a 28 or 29 Phaeton running for somebody.Nice looking car.They told me to take it for a ride,I got to the end of the driveway and refused to take it out on the road.That one was a family heirloom too,nice paint and original upholstery,but no steering or brakes.The kids that own it now thought that is just the way they were.