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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 1598
Experience:  Owner at DJ Wilson
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2002 ud 1800cs brake alarm goes off when you release ebrake

Customer Question

2002 ud 1800cs brake alarm goes off when you release ebrake driving the customer crazy. has manual transmission. air over hydraulic brakes. need help w diag.
Submitted: 4 months ago.
Category: Medium and Heavy Trucks
Expert:  Pete replied 4 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

Have you had the fault codes checked at all with a fully compatible scan tool or computer that will plug into this model here and read out the codes?

Let me know so we can continue,thanks Pete.

Customer: replied 4 months ago.

well we have tried 3 scanners no communication... so with out chasing that problem, we checked the basics fuses ect. no go.

abs light and brake light where both previously on.

customer had issue with air pressure sensor leaking air though the sensor its self, changed them all good.

customer blew a brake line few months ago, we changed it and had a hard time bleeding it and getting a good pedal. after bleeding it 100 times it was good. so 2 month later now the customer blew another brake line in a different state, had it repaired and was on his way. this issue began after that. brakes seem to work fine.

truck has a single air tank, 2 gauges primary and secondary both read fine. I assume the tank is split on the inside, I changed both air pressure sensors when I took one out there was no air and the other one was full pressure, therefore I am thinking we have an air supply issue to one of the brake boosters. we have 2 boosters 2 masters next to the air tank on the passengers side.

my question is, how do I go about diagnosing an air supply issue, do I remove the line to see where I have pressure and where I don't? some of the air lines are very rusty so I would rather not go that path the whole way. I have sprayed everything down with pb blaster. there seems to be an air switching valve on the frame I am not sure if that could be bad or if I have a bad brake booster. if you have any diagrams or path of air flow that would help us out. thank you.

Expert:  Pete replied 4 months ago.

O.k.,unfortunately after looking through my info on this issue on this model here I dont have a diagnosis on this myself but someone else here might have this diagnosis info.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

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