3 Jake heads under a stock M809 hood!!!

[US6x4]

Looks good.
Might have some trapped air or a sticky solenoid. You could swap solenoids and see if it follows it.

I watched my short video again and the #5 was pumping out air bubbles from the control valve drain so there is still trapped air in there. I have yet to rev up and then engage that brake - I've only been playing with it at idle so I'll bleed it some more this afternoon and see if I can purge the remaining air out.

 

[Jakelc15]

The air is no big deal. The oil will drain from them if the truck sits for a long period. I notice mine will come on a few seconds apart after sitting for a month or so. Then they work as normal.
I was having trouble with my throttle returning to idle and initially thought it was because of the jake switch. So I adjusted it a little. I was wrong, got some flames from the exhaust on a drive! Pedal shaft was sticking. Fixed now.
I'm not sure how loud the stock exhaust will be with them but mine is 104db in cab with the windows up!
Are you using 24v solenoids?

 

[US6x4]

The air is no big deal. The oil will drain from them if the truck sits for a long period. I notice mine will come on a few seconds apart after sitting for a month or so. Then they work as normal.
I was having trouble with my throttle returning to idle and initially thought it was because of the jake switch. So I adjusted it a little. I was wrong, got some flames from the exhaust on a drive! Pedal shaft was sticking. Fixed now.
I'm not sure how loud the stock exhaust will be with them but mine is 104db in cab with the windows up!
Are you using 24v solenoids?

I'm using 12v solenoids powered from a drop wire? from the 12 volt post.

 

[US6x4]

The air is no big deal. The oil will drain from them if the truck sits for a long period. I notice mine will come on a few seconds apart after sitting for a month or so. Then they work as normal.

That's good to know. Do you tend to turn them on after sitting and get them primed so that they're ready when you really need them?

 

[Jakelc15]

I think I have a 12v solenoid around here somewhere if you want a spare.
I just pop it on at 2000 rpm to keep the rpm's in check. It comes right on. I tend to kick them on when I come up to a slow vehicle also. If your going slower than me then that's a problem!

 

[US6x4]

I would like to have a spare solenoid if you round one up sometime.

I was able to get the rest of the air purged out and now all 3 Jakes function as advertised All 3 valve covers are bolted on and I just need to reattach the draft tube, the filler cap chain, and the wiring brackets I made. I also need to finish the wiring from the firewall to the heads.

 

[Lonnie]

If you have the opportunity to road test each Jake individually, could you confirm each sounds the same? My center jake is quieter & I cannot figure out why. I thought it may be due to the firing order or the proximity to the turbo... I'm just guessing but wouldn't mind a second opinion.

 

[US6x4]

If you have the opportunity to road test each Jake individually, could you confirn each sounds the same? My center jake is quieter & I cannot figure out why. I thought is may be due to the firing order or the proximity to the turbo... I'm just guessing but wouldnt mind a second opinion.

Actually, when bleeding them I noticed the center one sounded different than the front or rear (higher pitched). I figured it was to do with the firing order but with 1-5-3-6-2-4 it looks like the 1st head (1 & 2) have three cylinders firing between them, the 2nd head (3 & 4) have two cylinders between and the 3rd head (5 & 6) have one cylinder between them so each one should sound unique.

When my wiring is done I'll have the choice of front & rear or all 3 but I could experiment with unplugging some of them to isolate the center head alone. Naturally I would want to experiment up on snob hill at 4 A.M. ....

 

[SCM35A2]

Awesome progress!

 

[Lonnie]

Actually, when bleeding them I noticed the center one sounded different than the front or rear (higher pitched). I figured it was to do with the firing order but with 1-5-3-6-2-4 it looks like the 1st head (1 & 2) have three cylinders firing between them, the 2nd head (3 & 4) have two cylinders between and the 3rd head (5 & 6) have one cylinder between them so each one should sound unique.

When my wiring is done I'll have the choice of front & rear or all 3 but I could experiment with unplugging some of them to isolate the center head alone. Naturally I would want to experiment up on snob hill at 4 A.M. ....

My center one sounded more muffled similar to the pop from an air compressor, whereas the rear one had the more obnoxioius typical Jake brake sound.

 

[US6x4]

Well, the jake brakes are now wired up and ready to get tested. To see the full wiring details go to my other thread here: https://www.steelsoldiers.com/threa...ke-grenade-shifter.189934/page-3#post-2274120

For now, here are some finished pics!

 

[Jakelc15]

That looks awsome!
Now lets hear her sing!

 

[US6x4]

I took my Jake-equipped M813 out for a test run yesterday and it was sweet! The LO and HI work very well and it's not too loud with my H-161 headset on

My issue with the rear head not shutting off immediately has returned so I'm going to look at the inner springs on the control valves for cylinders 5&6. I was testing the throttle switch to shut off the brakes with the rear brake still fading out & got a good pop out of that! My other issue is the throttle wanted to rev the engine to a 1700 rpm idle so I'll need to check the throttle switch for interference and my pedal linkage for lubricity as @Jakelc15 suggested.

My daughter filmed a 15 minute bouncy video so once I figure out how edit out all the fluff I'll post the meat & potatoes portion for everyone.

 

[Hammer]

Why only High and Low? Why not medium to have two working?
I know in my M920, and other commercial semi tractor and wrecker trucks, I would use the different settings for different grades. Makes it nice to have a little more control,

 

[US6x4]

So on my setup LO is front and rear heads and HI is all 3 heads. Since I wanted to use a rotary switch that limited me to 2 circuits versus the 3 circuits that a jake specific toggle switch would give you. Since others have said 1 jake head doesn't do much I didn't feel bad skipping that one and giving myself the option of either 2 or 3 jake heads operating.

 

[Hammer]

So on my setup LO is front and rear heads and HI is all 3 heads. Since I wanted to use a rotary switch that limited me to 2 circuits versus the 3 circuits that a jake specific toggle switch would give you. Since others have said 1 jake head doesn't do much I didn't feel bad skipping that one and giving myself the option of either 2 or 3 jake heads operating.

Ok, two and three is better than one and three.
And I definitely like the look you have on the switch, no arguements there!
Btw, really nice job getting these in under the hood. I can see other people doing this now! I know if I get back around to messing with my M818, I will copy what you have done for clearancing, etc.

 

[US6x4]

Ok, two and three is better than one and three.
And I definitely like the look you have on the switch, no arguements there!
Btw, really nice job getting these in under the hood. I can see other people doing this now! I know if I get back around to messing with my M818, I will copy what you have done for clearancing, etc.

Thanks for the compliments - much appreciated. I know before the surgery on the hood was a big deterrent to quite a few folks but the hack & whack on a valve cover is far less scary. I imagine M818s are more likely to need jakes than cargo variants like mine, but my jakes are mostly for fun and also a little bit of redundancy in the stopping department.

 

[Hammer]

Thanks for the compliments - much appreciated. I know before the surgery on the hood was a big deterrent to quite a few folks but the hack & whack on a valve cover is far less scary. I imagine M818s are more likely to need jakes than cargo variants like mine, but my jakes are mostly for fun and also a little bit of redundancy in the stopping department.

Yeah, any extra braking on these trucks is always a good thing.
And I will use my M920 for any big hauls, but the M818 is still more maneuverable in tight places.

 

[US6x4]

I've been reviewing the video of my test trip and I notice that the jakes shut off properly when the RPMs are 1500 or above, but when the RPMs are less than 1500 I get the hesitation for the rear head to shut off. The manual button on the solenoid never stuck in the down position so I'm leaning toward control valve inner springs being the cuplrit and they are in the mail so I'm hoping that fixes it.

 

[US6x4]

Found the culprit to the rear head not shutting off right away; broken inner control valve spring on cylinder 6.

New spring | old spring (cyl. 5) | outer spring


Cylinder 5 spring | cylinder 6 spring