My brake light switch leaks around the terminals when I release the parking brake. This is the switch that engages the brake lights when the parking brake is on. It is a N.C switch. I took it apart and the little rubber washer is old and is what is leaking. I flipped the washer 180 deg. and it slowed the air leak some, but still can feel air blowing on my hand.
I went to NAPA and a standard 60 psi switch is $47. Wow, a lot of $$ because of a .60c washer. Unfortunately, there is no brand name on the switch. Anyone know of a better source to replace the switch?
David
David,
Go to your local wallyworld and buy yourself a $5 silicone baking/cutting mat in the household section. Make yourself a new diapragm/gasket with that. It should last another 50 or 60 years, if you don't abuse it.
Dallas
I'm just amazed at the amount of usefull information dallas has stored in the dismal swamp, I had heard at one point that useless trivia that gets remembered outnumbers all other thoughts by a ratio of 10 to 1, and that really scares me because it doesn't seem to matter what the topic or question is, the right answer or at least a version that will help seems to pop out, now if only he could remember where he left the remote. lol The silicon baking mat does work tho, I've cut gaskets, washers etc out of them and they do hold up well lol.
Brilliant.
The best minds in the world dwell in this bus-nuthouse. ;D ;D ;D
This is an air pressure regulator I rebuilt as an exercise to show how to make a quick roadside repair
In Progress
Rats, it didn't work. I cannot cut a perfect circle on the pad and this washer has to be perfect to hold that air. It is a bit smaller than a dime in diameter. Back to searching for a switch. Anyone know of one less than the $47 at Napa?
David
David,
Try a leather shop, and ask them to punch one out for you with a hole punch (not the plier kind) and hammer.
A parachute rigger should be able to do the same.
Jay
87 SaftLiner
David, Are we talking about the one below the driver in the lower access?
I got mine from Hector at CHF some years ago. I think it was less than $20. I could probably look up the receipt for it or you could just call his son. He tried to talk me out of by suggesting I jus tgo to a truck parts store and get one but I wanted his Eagle one.
Have you tried Jefferson or Eagle?
Quote from: akroyaleagle on November 28, 2007, 08:30:17 PM
David, Are we talking about the one below the driver in the lower access?
I got mine from Hector at CHF some years ago. I think it was less than $20. I could probably look up the receipt for it or you could just call his son. He tried to talk me out of by suggesting I jus tgo to a truck parts store and get one but I wanted his Eagle one.
Have you tried Jefferson or Eagle?
No I haven't tried them.
Yes it is below the Eagle wiring panel where all the air switches are. It is a NC switch that sends 12v to the brake light relay coil when the parking brake is engaged. When the parking brake is released the air line is loaded and disconnects the switch. This is when it leaks which would make it leak all the time the bus is rolling down the road.
David
I know that I had one of these switches purchased for an 4104 and was the wrong pressure, I am almost sure it is a 60 psi normally closed
THE SEARCH IS ON ..........when I find it i'll let you know
chris
On our MC-8 we installed a brake application pressure gauge. Normal braking is 10-20 PSI. A 60 PSI switch not not activate the brake lights except in a hard panic stop. We do have a 60 PSI N.C. switch for the LOW AIR warning. Our brake light switch is about 3-5 PSI N.O. (confirmed by watching brake application pressure gaue and brake light telltale). Hope this helps, Jack
Quote from: JackConrad on November 30, 2007, 04:35:08 AM
On our MC-8 we installed a brake application pressure gauge. Normal braking is 10-20 PSI. A 60 PSI switch not not activate the brake lights except in a hard panic stop. We do have a 60 PSI N.C. switch for the LOW AIR warning. Our brake light switch is about 3-5 PSI N.O. (confirmed by watching brake application pressure gaue and brake light telltale). Hope this helps, Jack
You kind of have me thinking now. This is on the parking brake circuit and I think when the parking brake is disengaged it blows full tank pressure on the switch. I'm not sure if the brake pedal actuation while driving affects this switch. However, I'm not sure. I think I will put a pressure gauge on the circuit and see what happens with a service brake application, so I can find out what pressure this switch really is.
Thanks for the heads up Jack.
David
David,
Different bus, but same problem.
Your post reminded me that I need a diaphram for a small, but annoying air leak on mine.
Called Mike at US coach and after a little research, he found me the rebulid parts, $5.00 for my 4905's.
If anybody can get you yours, I bet Mike or Luke can!
He told me most just order a new one(not as cheap as me ;D) but I like to tear things apart.
Best of luck on your fix
Cliff
I put a gauge on it and it is 100+/-psi when the parking brake is off and 0 psi when the brake is engaged. No proportional change when the service brake pedal is pushed. So, it is just an on/off switch.
David
David,
Sounds like any N.C. pressure switch will work. Might check at a truck parts supply place for an air brake switch. Should be reasonably priced. Should have contacts that are closed until air pressure reaches approx. 60-65 PSI. Jack
Dave, If your switch is like on my Eagle it should be a Bendix SL-4 stop light switch that you can pick up at any truck parts place. Do a Google on that part and you should get a picture.
Tom Hamrick
1984 Eagle 10S
Hello precision speed phoenix 602 973 1055
Part no. pts 721014 pressure sw nc 2/30 psi adjustable $19.85
make sure they set and test the switch before shipping..
The no versoin is pts 721010
I have bought several over the years. the latest 2 I just received did not work and are going back. Hopefully to be replaced but before this no problem.
Datcon also makes one part no 100450 C form contacts set at 4psi dont know if its available anymore
Happy bussin mike