cutdown Posted June 22, 2023 Share Posted June 22, 2023 After spending time getting my brakes working really well I finally got the chance to remove the left rear wheel and inspect the drum thickness. Ages ago, I could not get the left rear hub loose, so I left it alone and jut drove the car. More recently i had another go at getting the hub off and found it loose. I measured the drum thickness and it was between 25 thou and 50 thou thick. Also, I noticed the hub was further into the diff housing so that the axle protruded about 20 thou. No wonder it was loose. [ Doesn't explain why it was so tight in the first place thou ]. I managed to track down a used drum and a 20 inch wheel fitted to a Dodge rear hub. Got the lot home and set about removing the thick rust on the inside and outside of both drums. In the mean time, I checked the used hub and found it cracked along the keyway. I had a quick look at my original drum and found it was ok. After making a few measurements, I made up a 5 thou shim to go between hub and axle and fitted the used drum I had emeryed the rust off.. On the road test, the left rear kept locking up under harder braking. Thought I had cleaned the drum up satisfactorily but obviously not. [ quite badly pitted, buy as it was 125 thou thick, think it better to not machine it. Then the weather turned shitty so spent the time having another go with the emery tape. Still pissing down and some flooding around the country, so decided to remove the sump as per the other thread. Will have to wait for the weather to clear before putting it back on the road again. Link to comment Share on other sites More sharing options...
MikeC5 Posted June 22, 2023 Share Posted June 22, 2023 I wish there were repro drums available or a tried and true repair. I've heard flame spraying metal to build up the thickness is possible but haven't heard of anyone succsessfully having it done. 1 Link to comment Share on other sites More sharing options...
22touring Posted June 22, 2023 Share Posted June 22, 2023 Also, I asked the question of Open AI Chat, and it said you can flame-spray thick-ish, up to 3 mm. or over 1/10 of an inch, if you use a low-expansion feedstock. 1 Link to comment Share on other sites More sharing options...
cutdown Posted June 23, 2023 Author Share Posted June 23, 2023 Does anyone know what the original thickness of these drums was. Metal spraying could be an option but I suspect it would be very expensive. I think a qualified boiler maker would be able to weld on a new band better that spraying. After all. Steam boilers are just bombs waiting to explode. I remember watching a video on running steam engines and the driver mentioned that the engine is just a big bomb running on rails and 80 mph. Link to comment Share on other sites More sharing options...
JFranklin Posted June 23, 2023 Share Posted June 23, 2023 What is the size of your drum? Link to comment Share on other sites More sharing options...
cutdown Posted June 24, 2023 Author Share Posted June 24, 2023 On 6/23/2023 at 4:29 PM, JFranklin said: What is the size of your drum? 14 inch O D Link to comment Share on other sites More sharing options...
JFranklin Posted June 24, 2023 Share Posted June 24, 2023 (edited) On 6/22/2023 at 9:09 PM, cutdown said: Does anyone know what the original thickness of these drums was. I was asking about the size of the braking surface. If it is 14" you need to measure with a precision instrument to see how much it is off 14" to determine the amount of wear (loss) to the original thickness. Edited June 24, 2023 by JFranklin (see edit history) Link to comment Share on other sites More sharing options...
cutdown Posted June 25, 2023 Author Share Posted June 25, 2023 Understand. Dodge did work to inches and fractions of inches except in 2 places that I have found so far.. the 0.2 inch size of the pin through the front of the crank and the 0.4 inch square on the rear sump bolts. Not sure how accurately I can measure the inside and outside diam of the drum though. I don't know of a 14 inch micrometer so it will have to be a gestimation. Link to comment Share on other sites More sharing options...
JFranklin Posted June 26, 2023 Share Posted June 26, 2023 I took some drums I needed miked to my friendly tire/brake shop and they gave me the answer I was needing, and for free! Link to comment Share on other sites More sharing options...
cutdown Posted June 27, 2023 Author Share Posted June 27, 2023 (edited) 20 hours ago, JFranklin said: I took some drums I needed miked to my friendly tire/brake shop and they gave me the answer I was needing, and for free! JF You must live in an area with a very big population. The nearest brake specialist to me is 0ver 50 miles away. If I am right, the drums were 14 inch OD and there has been 1/16th inch wear, bringing them down to 13 7/8 inch OD. Near enough for me. Still no guarantee what the original thickness or OD might have been though. When the weather cleared again, the road test showed a great improvement in brake performance. I had to really step on the brakes to even get a feeling the the l/rear was about to lock up. Need to do plenty of driving now to bed it all in. Edited June 27, 2023 by cutdown (see edit history) Link to comment Share on other sites More sharing options...
JFranklin Posted June 27, 2023 Share Posted June 27, 2023 So the brake drums you have are for external contracting bands? Is there an area where the bands did not wear on the drum and form a ledge of unworn material? If so you can measure the original thickness. My town has had a tire shop since the '70 when the population was under 2,000. Link to comment Share on other sites More sharing options...
Minibago Posted June 27, 2023 Share Posted June 27, 2023 In my experience the outer band has a tendency to squeeze the drum face inwards over the years so the resulting measurement of the outer diameter will include this as well as the wear. I have not found a nice ledge on any that I have seen. Link to comment Share on other sites More sharing options...
cutdown Posted June 28, 2023 Author Share Posted June 28, 2023 Hi JF. I have a variety of drums, some worn with a huge ridge and others that have been machined , and having very little ridge. Yes they have external contracting bands as well a a full shoe inside for the hand brake. The hand brake would probably not wear the inside of the drum so much. I was just hoping someone would have information on what the original spec for the drums were. Not a problem though. I should have mentioned that we are talking about a 1923 Dodge here. We have tyre shops here but they are not brake specialists. Estimation of our greater population is approx 16,000. Hard to know how much the drum would compress, but I suspect it would be minimal otherwise that would be no good. I am a retired mechanic that used to own my own business way down south of here. Link to comment Share on other sites More sharing options...
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