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valleybusman
Top Member
USA
813 Posts |
Posted - 03/29/2024 : 06:06:22 AM
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I have a 2004 Thomas saftyliner rear engine. In our state patrol inspection, they require. The bus to stop within 50 feet at 15 MPH. After the park brake is applied Bus took 56 feet to stop. So it was placed out of service. In the past it was always a broken spring in the air can. We replaced both air cans and didn't change a thing. The trooper thought the brake was coming on to slow. Could this be the valve that releases the air to the brakes? Could it be the park brake hand valve the test is made up with 2 cones. As soon as the front of the bus gets to the first cone at 15 MPH. The driver pulls the brake and bus must not go past the second cone.Sorry so long. |
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Bluenozer
Top Member
Canada
650 Posts |
Posted - 04/02/2024 : 07:38:26 AM
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could be a bad slack, wore pin holes in the slack itself , s-cam bushings slowing it down |
OEM trained in wiring and all engine platforms for over 20 years
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CISDbusman
Advanced Member
306 Posts |
Posted - 04/18/2024 : 10:00:24 AM
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quote: Originally posted by valleybusman
I have a 2004 Thomas saftyliner rear engine. In our state patrol inspection, they require. The bus to stop within 50 feet at 15 MPH. After the park brake is applied Bus took 56 feet to stop. So it was placed out of service. In the past it was always a broken spring in the air can. We replaced both air cans and didn't change a thing. The trooper thought the brake was coming on to slow. Could this be the valve that releases the air to the brakes? Could it be the park brake hand valve the test is made up with 2 cones. As soon as the front of the bus gets to the first cone at 15 MPH. The driver pulls the brake and bus must not go past the second cone.Sorry so long.
Did ya get it figured out? This one interests me. Thanks!! |
Edited by - CISDbusman on 04/18/2024 10:01:02 AM |
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tigger2
Advanced Member
USA
470 Posts |
Posted - 04/19/2024 : 11:50:50 AM
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Make sure all of the pins in the slack adjusters spin freely, with brake applied slack should be 90* to the shaft of the brake chamber, adjust the brakes and only back off 1/4 turn. Make sure there are no kinks in the brake hoses to the parking brake chambers. Double check the operation of the quick release valve for the parking brake. And lastly make sure the driver takes his foot off of the throttle |
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valleybusman
Top Member
USA
813 Posts |
Posted - 04/19/2024 : 2:45:33 PM
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Still working on this issue. Right now there are some electrical issues. So maybe next week |
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valleybusman
Top Member
USA
813 Posts |
Posted - 05/07/2024 : 06:59:26 AM
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Got rid of the electrical gremlins. We thought maybe the brakes weren't coming on fast enough and replaced the relay valve. Didn't change anything. So, I think maybe somewhere with the shoes and drums. There is still a lot of shoes left and I have had buses with less work fine.Maybe S cam's |
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Bluenozer
Top Member
Canada
650 Posts |
Posted - 05/09/2024 : 08:52:07 AM
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do the test in gear 2 instead of drive and get help from transmission , I find these brake tests useless ,best case Ontario, has to be dry and sunny , not a real world test , when greasing the s-cam do it while applied then again with brakes off her in NS Canada we go 35kmp then hammer the foot , and then go 20kmp and pull maxi and take readings off a brake meter dry or wet pavement conditions (50% of our fleet operates on dirt roads) but test will no pass if we do it on dirt or snow covered roads again not a real world test , we do brake jobs once a year on every bus as per law |
OEM trained in wiring and all engine platforms for over 20 years
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Edited by - Bluenozer on 05/09/2024 08:55:52 AM |
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