Trying to diagnose Jake brakes.

RickB · June 21, 2015, 01:24:27 PM

Hey all,

I pulled the valve cover today and there was a small cut in the insulation on one of the wires inside the valve cover but I don't believe it was touching anything to cause a short. Nevertheless, I pulled the wires and ran new ones into the head and reconnected everything. In order to get to the valve cover I had to pull the air filter housing and after blowing a ridiculous amount of dirt out of the filter I just decided to buy a new one when the shops open tomorrow. I have my doubts about whether this will fix the jakes or not so if it doesn't what exactly do these solenoids do? Is there an easily replaceable part in each of these? Do these fail a lot?

Leaving for Colorado and I want both banks of my jakes working before I leave.

Rick

luvrbus · June 21, 2015, 02:13:44 PM

The solenoids lets the oil pressure apply pressure to the slave piston holding the 2 valves open.You should have tested the solenoids with the covers off a hot wire to the solenoid or a meter will tell you , opening manual by pushing in the middle where the tag is by hand will tell if you have a bad oil control valve .

They are not hard to change just be sure to replace the 2 o-rings every time if you lose the o-rings or they are broken it will self engage without power,the solenoids do go bad over time like all electric control stuff and are a little pricey for their size

.

RickB · June 21, 2015, 03:58:00 PM

Clifford,

I can pull the valve cover off in about 5 minutes. So, keeping it very simple for the non-electrical among us...how do I test these? I'm thinking I should turn the key on, turn on the jakes and touch the leads to their respective connection points and I should hear a click. Is that pretty much it?

Also, when you say spend what are we talking dollar wise?

Thanks

Rick

luvrbus · June 21, 2015, 04:36:59 PM

Yep that is all there is to it if the lead has power,the solenoids cost 125 to 140 bucks ea from DD the after market from PacBrake are cheaper like around 75 bucks ea and are just as good IMO

RickB · June 21, 2015, 04:42:31 PM

Are they hard to change out?

luvrbus · June 21, 2015, 04:45:28 PM

No just watch the 2 o-rings but best if you have a spanner wrench installing the new ones

RickB · June 22, 2015, 06:38:55 PM

Well it's not the wiring. I took it for a test run and it blew the 15 amp fuse in a second. I don't know if I have it in me to pull that damn air cleaner again. It's absolutely mandatory that I remove it but getting it back in is such a tough job for someone working alone. I think this one is gonna be fixed by JD and the boys at C&J.

RB