1997 N-14 Jake issues

[crane operator]

1997 n-14 460 e +

CPL 2025

C brake from Jacobs- Model 455B

New to us truck. KW t-800, came with the wiring cut off that went to the jakes. We've been trying to get the truck ready for the road and have some issues.

Sometimes when you start the truck, it will run rough, and I think I've got that isolated to the front jake. It seems like this jake will stick partially open, and stay stuck on. Its like there should be springs inside the jake pulling it off.

Its the only jake that will come on when you apply 12v to the solenoid, but then it seems like it won't go totally off. At times it will release all the way, and then the truck idles smooth, but if its stuck, it just kind of chuggs on the motor. Its not like the jake is totally on (which I can make it do with applying 12v), it just seems like something is slighly stuck. (maybe not totally releasing the valve?)

The middle and rear jakes, when you actuate the solenoid, will simply pump engine oil where the blue arrows are in the picture. I'm assuming there's seals inside the "pistons", that are bad, and so they won't build enough oil pressure to make the jakes come on. They won't even try to come on when you apply 12v, and I can see the solenoid actuating. It just seeps oil out the top.

Oil seeps out of the rear two where the blue arrows are, the front one does it a little bit, but not nearly as bad as the rear two.

Also- I have no clue how to set overhead on this motor, is it best to get a cummins book for these, I've read that using a dial indicator is the way to go, but I'd be lying if I said I knew what I was doing.

 

[funwithfuel]

I would definitely perform the overhaul on them. It's super easy. I used to set them running. It's not the right way, but the way I did em. Here's the right way.

 

[crane operator]

Looks like I need kit # 3871704 from my cummins man? From what I'm seeing online from cummins- its around $600.

And I'm guessing the jakes should come off- set overhead, then reinstall the jakes and set them after rebuilding?

 

[cfherrman]

Manual

https://issuu.com/heydownloads/docs/cummins_n14_engine_service_repair_manual___1_

 

[funwithfuel]

Good god almighty! Last time I did a set, the kit was about 225. Does the 600 kit include the little master valves and the solenoids or is that just for O-rings and snap rings?

 

[cuttin edge]

Wonder why the wires were cut off, because of them not working, and the previous owner not wanting to fix it. I worked for a guy that removed the jakes from a truck because he figured it was hard on the engine. I remember seeing them in their stock room.

 

[Tyler d4c]

Wonder why the wires were cut off, because of them not working, and the previous owner not wanting to fix it. I worked for a guy that removed the jakes from a truck because he figured it was hard on the engine. I remember seeing them in their stock room.[/QUOTE
Hard on brakes doing that I'd think

 

[crane operator]

 

[crane operator]

I worked for a guy that removed the jakes from a truck because he figured it was hard on the engine.

My dad told me about a local grain hauler/ farmer that removed all the jakes from all their trucks. His theory was that the jakes were hard on the rest of the driveline components, and he would rather buy brakes.

I need the jakes.

 

[92U 3406]

Truck drivers sure come up with some strange theories lol.

 

[Truck Shop]

Truck drivers sure come up with some strange theories lol.

It's the product of setting on their ass all day plus dreaming about what they would do if they were
president.

 

[fest777]

was always told the complete reversal happens, when using jakes coming down a hill it keep the heat in the motor, dont know if this is an old wives tale but heard the older 335's used to scorn liners after cresting a good long hard hill then when going down the other side is when you wanted those engine brakes mainly for slowing down and keeping a little heat in the engine .most engine makers ,let's say the last big 3 at least , recommended jakes . its not all about brake lining, bet you will find more million mile + engines with jakes on them that are kept in good condition. fest

 

[crane operator]

Do I need to remove the housings from the engine to install the kits, or does it all install from the top side?

 

[funwithfuel]

They have to come off.

 

[Truck Shop]

More than likely the control valves are bad, Do you have a solvent tank need to disassemble and flush
the oil circuits.
Once done setting valves and injectors which is easy-install jakes and you can set lash on any that
have closed exhaust valves, then just bar engine till you find the rest with closed valves. Normally
can set four then bar and get the last two.

 

[funwithfuel]

When you get the Jakes off, it would be a good time to re-torque the rocker box. Sometimes the common stud backs off a bit when removing and you wind up with a leak and improperly adjusted overhead

 

[Truck Shop]

Those C brakes don't use a rocker box stud, have their own 12 point bolt in center.

 

[funwithfuel]

Thanks for clarification. I wasn't sure , I remember they improved the water manifold/ rocker box. Thanks TS

 

[crane operator]

More than likely the control valves are bad, Do you have a solvent tank need to disassemble and flush
the oil circuits.
Once done setting valves and injectors which is easy-install jakes and you can set lash on any that
have closed exhaust valves, then just bar engine till you find the rest with closed valves. Normally
can set four then bar and get the last two.

I've got a parts washer tank, but we just run old diesel in it, and its filthy. I can clean them in a separate tub if I need to. I'll get the kit ordered and here first before I tear anything apart.

Is it likely that I need items that aren't in the rebuild kit?

 

[funwithfuel]

You said when you applied power, one hit and 2 slobbered oil. So your solenoids should be working. Besides, if you do need a solenoid, they're serviceable from the top iirc.