Joined: Aug 2017 Posts: 1,808 Threads: 99
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ive not seen linings brake up like that before.
as the brake is fresh and new, id suggest the piece of linning has trapped and the force has broken the shoe.
if it happend over time from a crack, you would expect to see a dirty area forming over time.
tony.
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Location: Scottish Borders
I had 2 break like that on my 1930 fabric saloon in the 60s. They went with a very loud bang and the pedal went hard.
Jim
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Location: On a hill in Wiltshire
I think you are correct, Tony.
There was a time when one rear wheel locked on the first application of the day, about 50 yards off the drive.
Reversing a little freed it, I thought no more about it - the brakes often need an application or two to settle down.
We've done probably 300 miles since then, the brakes as good/bad as they ever were.
When re-lining from some I had in stock, I found two similar with cracks starting from a mid rivet hole.
I think I have the same linings on the other three wheels, they all look ok.
I thought they were supplied new about three years ago, but maybe not.
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I had this happen to a lot of moulded linings. I now use woven with no issues
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Location: Auckland, NZ
30-03-2022, 07:24 PM
(This post was last modified: 31-03-2022, 02:00 AM by Bob Culver.)
I suspect was relatively common as little else would explain the number of obvious replacement (and welded) shoes encountered. If the bedding is not reasonable from the outset can be a mighty leverage on the casting.
When it is considered that the cam and pivot are all that stops stop the wheel rotating, and experience about 4 times leverage, components seem modest. Little wonder cam spinles often bent
.
If the fulcrum end makes heavy conatct tends to fracture the shoe. But t is hard to imagine how the rivet face could be very stressed.
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For what it worth, this is what happened on my 31 12/6:
After going on a pleasant VAR (NZ) run, and a lovely picnic, I went to move off to go home. The moment I used the brakes BANG, the front axle locked up. The effect was such that it was hard to believe that the wheels did not break off. It was one wheel that kept on locking up on braking, so I got home by slackening off that brake
Investigating, I found that oil was on the lining. I assume that it got sticky when warm and decided to really stick as it cooled down a bit.
New linings fixed it, and I was lucky that the shoes did'nt break.
Slowly rebuilding a '34 RP
Joined: Aug 2017 Posts: 389 Threads: 33
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Location: Garden of England
Car type: ARQ Ruby July 1936
Bob, just speculating on your comment re the rivet face of the brake shoe being stressed……
I had braking issues at first running after fitting new linings etc but on re-assembly the shoes were not held vertical by the lugs on the back plates, my error, I wrongly assumed that once the drums were fitted the shoes would sit square, they didn’t. They sat skewed at an angle and stayed that way unbeknown to me until I had to strip the rear axle for other reasons after a period of running. When I removed the drums, which took some effort, the linings were quite worn on the inner side with no wear at all on the outer edge.
I guess uneven loading of this nature could cause this sort of failure.
I now know to ensure the brake shoes sit square and the tabs should not allow the shoes to sit lopsided.
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Location: Auckland, NZ
31-03-2022, 09:27 PM
(This post was last modified: 31-03-2022, 09:28 PM by Bob Culver.)
Hi Denis
On other makes I have encountered shoes which do not sit square. Takes years for a firm pedal to develop and then shoes worn out on one side. I made up threaded grubscrews thru the backplate.
