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Farming in Michigan | Got an older IH Semi with floor-mounted pedal valve, occasionally could not pump up truck air as it had a gross leak out the bottom of the pedal valve. Pressing the brake pedal allowed air to build but would vent out the bottom of the brake pedal valve as soon as the pedal was released. Working the pedal up and down would sometimes solve the problem.
Figured the valve was old and needed to be replaced. Struggled getting all those old airline connections broken and lines removed but got the pedal valve replaced last fall. The new/reman Bendix valve worked fine at first but is doing the same thing now that it's nearing wheat season.
Did I get a bad valve, is it just sticking since the truck doesn't get used much, or do I need to look at some other system issue? Thanks for any help. |
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Southern Alberta Canada | That can be a bugger, chances are your treadle valve is good, it might be back feeding from another valve in the system. You have relay valves that the treadle valve operates, it's possible one of them is leaking, that may have been the problem to start with. One way to check is when it is happening remove the pilot line from the relay valve over the rear axles and see if air comes out of the pilot fitting and the treadle valve stops leaking.
R14 relay valve for truck/tractor in this picture http://home1.gte.net/res0f98n/airbrake.jpg
Or the R12 valve in this image http://ww2.justanswer.com/uploads/JANECZFJ/2012-02-12_212701_2-12-2...
How old is your truck?
Edited by Offroadnt 7/14/2014 08:07
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Wi | Did you clean the "plunger" in the pedal? This is all seperate from treadle valve. The "plunger" will often get corroded and can stick when you push on the brakes. Remove the pedal, disassemble and polish everything up, then put it back together and see how it works. |
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Leroy ks | I had this problem last week. On a 1995 international Valve was stilin to floor got it back up with pliers and used pb blaster worked it for 5 min ain't stuk since |
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Wi | ag6553 - 7/14/2014 09:57 I had this problem last week. On a 1995 international Valve was stilin to floor got it back up with pliers and used pb blaster worked it for 5 min ain't stuk since
PB can be a quick fix too if you don't mind the smell. |
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Farming in Michigan | This is a ~'77 Transtar II.
Thanks for the input, I'll check the relay valve and see it that solves the problem. |
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Farming in Michigan | The pedal plunger itself isn't sticking.....I cleaned that up when I replaced the valve last fall.
I usually keep that clean and lubricated with WD40. |
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Southern Alberta Canada | I never liked those under floor treadle valves, the ones mounted to the firewall are way better.
Transtar IIs were pretty neat trucks, it would be cool to restore one someday. I spent a bunch of time in a '79, it's in the boneyard now. |
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Semi Air Brake Pedal Valve problem
