Jake brakes 'sticking'

richard5933 · March 07, 2021, 04:22:07 PM

I noticed today that when I'm using Jakes there is a delay between pressing the pedal and the rack going to a 'fuel' position. The engine will not react for a second or two when pressing the pedal, and then it will sort of surge as it gets revved up.

The throttle feels perfectly fine when the Jakes are off, so I don't think it's got anything to do with the air throttle.

Any clues? Buffer switch maybe? Or is there something else that might need attention?

windtrader · March 07, 2021, 05:12:14 PM

Sigh. first trip out of hibernation. bummer. have no clue what's up but just another instance where these old beasts are too damn temperamental

richard5933 · March 07, 2021, 05:31:18 PM

Yeah - I have no clue either, but it sure feels like the Jakes are not getting the message that the throttle is coming out of the no-fuel position for a few seconds, which is why I'm wondering if the micro-switch is sticking/dirty/out of adjustment.

luvrbus · March 07, 2021, 05:35:35 PM

The combo fast and Jake do that till the oil gets hot most of the time if it keeps doing it and if you have the combo switch check and be sure the red protection rubber cap on the switch is not falling to pieces and causing binding of the pin

richard5933 · March 07, 2021, 07:21:46 PM

Quote from: luvrbus on March 07, 2021, 05:35:35 PM
The combo fast and Jake do that till the oil gets hot most of the time if it keeps doing it and if you have the combo switch check and be sure the red protection rubber cap on the switch is not falling to pieces and causing binding of the pin

That's the micro switch visible from the outside of the combo buffer switch? I've got the fast idle combo - if this is what I'm thinking it is I can check it without removing anything, correct?

HB of CJ · March 08, 2021, 10:46:47 AM

Cold oil. Cold water? Low oil pressure? Let the engine warm up more? What works fine at 180F and 210F in the summer might not work so well during the cold winter.

richard5933 · March 08, 2021, 01:22:23 PM

Quote from: HB of CJ on March 08, 2021, 10:46:47 AM
Cold oil. Cold water? Low oil pressure? Let the engine warm up more? What works fine at 180F and 210F in the summer might not work so well during the cold winter.

Engine temps got to about 180 during the 1-1/2 hour drive, with good oil pressure.

The way it felt when I pressed the accelerator pedal was as if the micro switch didn't know I'd move the pedal from the no-fuel position right away, and suddenly it would figure it out and the engine would surge to where it should be.

I tried to get eyes on the red rubber boot of the micro switch today but of course it's hidden under the mounting bracket.

luvrbus · March 08, 2021, 04:00:37 PM

There is nylon roller on the switch that will detartrate over time that will make the switch stick too sometime the pin falls out for roller to

richard5933 · March 08, 2021, 06:04:26 PM

Quote from: luvrbus on March 08, 2021, 04:00:37 PM
There is nylon roller on the switch that will detartrate over time that will make the switch stick too sometime the pin falls out for roller to

Any idea where I can find parts for this if I need? Took a while to find the combo Jakes/fast idle buffer switch the first time around, and not sure where to look for parts on this right now. Even if I don't need the whole thing and just need the roller...

luvrbus · March 09, 2021, 05:55:17 AM

When I get time I will check I have parts for those if you know what you need.Right now with 4 engines waiting and repairing a cooler problem on 1 that went out last week, like the saying I am as busy as a 1 legged person as a @$# kicking contest

richard5933 · March 09, 2021, 06:03:00 AM

Quote from: luvrbus on March 09, 2021, 05:55:17 AM
When I get time I will check I have parts for those if you know what you need.Right now with 4 engines waiting and repairing a cooler problem on 1 that went out last week, like the saying I am as busy as a 1 legged person as a @$# kicking contest

Thanks. I'll take a look and see what I can spot.

luvrbus · March 09, 2021, 06:12:22 AM

The electronic Jake control has less parts and give no problems but you lose the fast idle,the mirco switches give you problems because the are a click style and a bear to get adjusted sometimes

richard5933 · March 09, 2021, 07:12:58 AM

Quote from: luvrbus on March 09, 2021, 06:12:22 AM
The electronic Jake control has less parts and give no problems but you lose the fast idle,the mirco switches give you problems because the are a click style and a bear to get adjusted sometimes

Any advice on looking for the specific problem without disturbing the buffer switch settings? I can see the micro switch and a part of the orange rubber boot, but I cannot see much more in there due to the way it's mounted.

richard5933 · March 09, 2021, 11:29:06 AM

So I think I've identified a potential problem. There is a small pivoting piece that pushes against the micro switch button as the governor opens/closes. It pivots on a shaft in mounting assembly.

This piece seems to be very stiff. I was able to use a little light spray lube to free it up somewhat. Hope that makes a difference, but not really sure. There seems to be a little free play on the pivoting piece with the engine off, and when I started it was holding the button on the micro switch in the pushed-in position. Now it doesn't.

Don't really know the specifics of how this all works, but it seems that not binding is better than binding.

Coach_and_Crown_Guy · March 09, 2021, 04:57:06 PM

At the risk of sounding like a Debbie downer, or a lazy driver. I've experienced this many times in my driving career and on many types of Jake equipped Coaches, Crowns, and Tractors. I've developed a keen mistrust of the very finicky adjustment tolerances, and timing of the switch(s) involved, either on the governor housing, or on the actual throttle linkages.

Whenever I sense the Jakes not coming on, or going off, which I feel is even worse, Valves hitting pistons and such, I default to the tried and true driver overide and simply turn off the Jakes at the dash until I need them on a downhill grade. I know it removes the fun of having everyone around hearing the Jakes, which is great sport indeed, but from a strictly operational point of view we really don't need them to be turned on at the dash until we need them, if you know what I mean.

I've become truly mistrustful of all the engine/throttle linkage switch setups and have become a manual Jake switch myself, and only turn on the dash switch when I'm engaging in a downgrade and I've fully removed my foot from the throttle. I've even thought of moving the dash switch to a much easier to reach location so I can turn it on and off without reaching or being distracted and having to look at it. But that's just me not trusting the nice little automatic switching feature, and doing it myself. Kind of like I prefer to have a stick shift and control my vehicle myself instead of trusting an automatic to do it, and downshift without lugging the engine, if you know what I mean, and I'm sure you all do. Simpler is better, and I can learn to handle my vehicle better than any automation.