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Dvorak
Senior Member
United States
95 Posts |
 Posted - 10/04/2018 : 04:02:38 AM
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2018 IC, new style hydromax hydraulic brake system.
We took delivery of 2 of these buses over the summer. This past week, both of them started to have "low brake pressure" lights coming on intermittently. Service brakes operate normally when this is happening.
Also, when the key is shut off, occasionally the hydromax boost pump will run with no input from the brake pedal. While this was happening, I verified that the brake lights were not on and I tried disconnecting the switch at the brake pedal and that didn't change anything.
I called the dealership yesterday and they have one in their shop that is doing the same thing but they don't have an answer yet. He suggested disconnecting anything with GPS (cameras, Synovia) but that didn't fix the problem. Any ideas on these things?
Note: This problem seems to only be happening on 2018's. Our 2017's have not had any issues like this at all. |
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Thomasbus24
Administrator
USA
4544 Posts |
Posted - 10/04/2018 : 04:33:52 AM
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When you say disconnecting Synovia, do you mean just from it's plug that goes into the data port under the dash (option you may not have) or are you unplugging it entirely from it's taps to things like park brake, lights, etc (again, option you may not have)? Also from it's power sources? I could see how something could feed back and confuse the controllers. Same with camera if it taps into anything.
I like Synovia and their support, but the intallers (contracted) left a lot to be desired. I do my own installs on new buses now.
Please keep up updated and I'll ask if my dealer has heard anything like this, but to be fair there aren't many hyrdo brake buses in these parts. |
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Dvorak
Senior Member
United States
95 Posts |
Posted - 10/04/2018 : 06:44:34 AM
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quote:
Originally posted by Thomasbus24
When you say disconnecting Synovia, do you mean just from it's plug that goes into the data port under the dash (option you may not have) or are you unplugging it entirely from it's taps to things like park brake, lights, etc (again, option you may not have)? Also from it's power sources? I could see how something could feed back and confuse the controllers. Same with camera if it taps into anything.
I like Synovia and their support, but the intallers (contracted) left a lot to be desired. I do my own installs on new buses now.
Please keep up updated and I'll ask if my dealer has heard anything like this, but to be fair there aren't many hyrdo brake buses in these parts.
We don't have Synovia connected to the data port. By disconnecting it, I was referring to pulling the fuses. I will agree that the Synovia installs were less than desirable... |
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Thomasbus24
Administrator
USA
4544 Posts |
Posted - 10/04/2018 : 07:01:23 AM
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I'd unplug the harnesses from the Synovia LMU (wherever they stuck it) and ensure it cannot possibly ground out to anything while unplugged. Mine look at the warning lights, park brake, door and a "panic button" for example. A trickle back from the LMU through one of those could be enough to confuse a computer!
Also check how they grounded that system. I moved mine to the actual ground studs instead of how they did it. |
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Trailboss
Senior Member
United States
196 Posts |
Posted - 10/10/2018 : 12:02:50 PM
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| Our 2018 IC bus was doing the same thing took it to the dealer its still under warrenty. I Know toled them to replace the brake pedal switch, and it took care of the problem. |
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Trailboss
Senior Member
United States
196 Posts |
Posted - 10/12/2018 : 04:27:51 AM
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| Just curious did you get the brake issue fixed and what was the fix? |
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Dvorak
Senior Member
United States
95 Posts |
Posted - 10/12/2018 : 10:40:05 AM
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| The dealership still doesn't know what's wrong with it. They want to try putting in a new pressure switch (part number 4052584C1). This switch goes into one of the steel lines coming off the master cylinder. Unfortunately, there aren't any in stock anywhere and they don't know when the part will be available. I'll update this when I find out more about it. |
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exmod110
Senior Member
150 Posts |
Posted - 10/12/2018 : 1:51:15 PM
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| tell them to take one off a lot unit..... you have already paid for it and it sitting parked. |
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Dvorak
Senior Member
United States
95 Posts |
Posted - 10/24/2018 : 03:45:32 AM
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| UPDATE: The dealership replaced the pressure switch located in the rear brake line just inches away from the master cylinder and that seems to have taken care of the problem. Part number is 4052584C1. |
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Topic |
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IC new style hydromax issues
