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[GMCnet] Gmc brake problem [message #270810] Fri, 30 January 2015 06:27 Go to next message
Advanced Concept Ener is currently offline  Advanced Concept Ener   United States
Messages: 112
Registered: December 2014
Karma: 0
Senior Member
For the record I would like to state that all the shops and individuals who dealt with this problem provided great service. Ken has gone way out of his way as well as Jim Bounds. The depth and quality of their work is not in question. This is the kind of problem that is not easily resolved no matter how much time and money is thrown at it. No one can make money fixing it or selling parts. This problem appears to have existed for many years as demonstrated by all the modifications previously made to the brake system.
The brakes locked up in the back only once , never to be duplicated again. At that time the wheels were showing 150 deg F on the TPS system. Bakes were readjusted soon after and found broken spring. Fronts never could be locked up. Shoes had 1300 miles when they were removed. They show very little or no wear. What wear there is appears to be at the center but it's hard to tell. The brakes never pulled. They never seemed to grab just slowed coach down. Maybe it is too much coach for brakes! From Kens explanation of how it brakes now seems that it's performance is better but he is not happy with it. At this point he is probably working for about $10 per hour because he doesn't feel he can charge me for all the time he has spent troubleshooting. I have 45 years of experience troubleshooting complex mechanical system problems and I understand the effort put in to resolve them. Sometimes you just bypass them because the answer stays elusive. I am very grateful for everyone's effor
ts on my behalf to solve the problem. When I get the coach back I will see how it is and go forward from there. Thinking about spraying foot powder on shoes to test contact point on drum. I really don't want to undo anything that Ken did. It went out there on a flatbed and I am driving it home!

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Re: [GMCnet] Gmc brake problem [message #271142 is a reply to message #270810] Tue, 03 February 2015 20:24 Go to previous message
Bob de Kruyff   United States
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
Senior Member
Advanced Concept Ener wrote on Fri, 30 January 2015 05:27
For the record I would like to state that all the shops and individuals who dealt with this problem provided great service. Ken has gone way out of his way as well as Jim Bounds. The depth and quality of their work is not in question. This is the kind of problem that is not easily resolved no matter how much time and money is thrown at it. No one can make money fixing it or selling parts. This problem appears to have existed for many years as demonstrated by all the modifications previously made to the brake system.
The brakes locked up in the back only once , never to be duplicated again. At that time the wheels were showing 150 deg F on the TPS system. Bakes were readjusted soon after and found broken spring. Fronts never could be locked up. Shoes had 1300 miles when they were removed. They show very little or no wear. What wear there is appears to be at the center but it's hard to tell. The brakes never pulled. They never seemed to grab just slowed coach down. Maybe it is too much coach for brakes! From Kens explanation of how it brakes now seems that it's performance is better but he is not happy with it. At this point he is probably working for about $10 per hour because he doesn't feel he can charge me for all the time he has spent troubleshooting. I have 45 years of experience troubleshooting complex mechanical system problems and I understand the effort put in to resolve them. Sometimes you just bypass them because the answer stays elusive. I am very grateful for everyone's effor
ts on my behalf to solve the problem. When I get the coach back I will see how it is and go forward from there. Thinking about spraying foot powder on shoes to test contact point on drum. I really don't want to undo anything that Ken did. It went out there on a flatbed and I am driving it home!

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I can't really determine what you are asking, but here goes anyway. When replacing rear shoes, you have to make sure they are "cam" ground. That means that the arc of the shoes is slightly less than the radius of the drum. As a result, the ends of the shoes will not contact the drums when first installed. If the ends of the shoes contact the drum, they will cause a lock=up condition and extreme dragging. Many Chinese sourced shoes are not cam ground-buy Dexter if you can. Over time the shoes will seat in and increase braking effectiveness. Properly seated drum/shoe temperatures will run about 450F max under hard braking. Try to use rivetted shoes if you can find them. Temperatures around 600F will cause the linings to come off. Disk shoes are another animal all together and another day's discussion.


Bob de Kruyff
78 Eleganza
Chandler, AZ
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