gumbiegumbie Posted September 18, 2011 Share Posted September 18, 2011 I bought a used jake brake to add to my 2001 E7-400 E-tech. I got the brakes, the spacer housings, and the longer bolts needed. One thing I'm not sure about is the exhaust yokes. Are the yokes the same and only the yoke adjusting screw different, adding the actuator pin, or is the whole yoke different? I added the switch to the dash and found the plug in there for it and I'm told if I add the fuse,breaker, or relay it will work without having to be plugged up at the mack place. I left the switch on by accident after adding it and the truck had a slight delay between mashing the go pedal and it actually going, which makes you look like you have never shifted a truck in your life, so the computer knows the switch is there and its doing something? I thought about running a wire from the jake brake plugs under the hood to an indicator light in the truck just to see if they were getting fire when they would normally be turning the brake on to answer if I would have to have the truck plugged up or not. Basically I just need to know if I need to buy the adjusting screws made for the jake brake or the whole yoke or both? And does anyone know if this thing is just gonna work without going to the mack place to be plugged up? Thanks! Quote Link to comment Share on other sites More sharing options...
rhasler Posted September 18, 2011 Share Posted September 18, 2011 You can make the Jake work by wiring it as you have said, you can make it work correctly by having a dealer make the necessary software changes and reprogram the ecu. The E-Tech exhaust yokes should be the same for Jake brake/non-brake pinned exhaust applications. Install the current yoke adjusting screws which are longer wearing than the original parts were.You need to check the valve yoke guide pins. If you have floating exhaust yokes and the heads aren't drilled for the guide pins (not likely to happen, but possible if a head has been replaced in the past) you'll be changing the head(s) so you can install the brake. If your heads do have pins installed in the cylinder head you'll need to make sure they are in good shape, I would suggest changing them out, if possible, with the Powerleash guide pins, which are more durable. Make sure that the yokes are balanced correctly, if not it can cause the guide pin to bend and eventually break. Also install replace the valve yoke adjusting screw jam nuts and the valve adjusting screw jam nuts with the flanged nuts. 1 Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
gumbiegumbie Posted September 19, 2011 Author Share Posted September 19, 2011 Thanks for the good info rhasler! When you say make it work correctly, what are you talking about? What will it do different? Im using all the factory wiring already on the truck. I just added a factory switch to the dash using the plug labeled engine brake, put a fuse in the spot for the brake and gonna use the factory plugs on the engine that are capped off right now. Mainly, is it gonna hurt anything. I think I also have to add a neutral switch to the transmission because I dont think the jake works unless the truck is in gear right? so something has to tell it that it's in gear. I found the spot on the transmission to put the neutral switch and there are a few plugs right there not being used so I figured one of them is for that. When the jake is on and your in gear and the clutch pedal is topped out and you let off the gas is it supposed to do anything besides energize the two wires going to the jake brakes? I dont want to tear anything up! Also am I right in thinking that when I add the yoke adjusting screws with the pins in the middle does that mean that the brake only opens one of the two exhaust valves in each cylinder, being the one under the pin? or is that not how it works? Thanks again rhasler !! Quote Link to comment Share on other sites More sharing options...
rhasler Posted September 19, 2011 Share Posted September 19, 2011 For a 2001 model you are probably at step 7 or 8 engine software, so it shouldn't need to see vehicle speed. I think step 10 is when they started adding restrictions for vehicle speed and oil/coolant temperature to engage the brake.To use the factory wiring you'll need to have the ecu programmed so that it knows an engine brake is installed, otherwise the engine ecu will not supply the current needed to pull in the brake solenoids. You could technically make the brake operate by hard wiring it to a switch, but the units would not disengage at the 1000 rpm drop out, nor when the clutch pedal or the accelerator are pushed.Another thing I would check is the rocker shaft plugs. The original rocker shafts had an expansion plug installed that would sometimes blow out, usually out of the front rocker shaft forward hole, when oil temperature was cold and more pressure was needed to pump the oil through the engine. Look at the valve spring arrangements on the heads. If the valve rotator is on top of the spring instead of on the bottom I would strongly advise replacing them with the lower valve rotators. The small coil springs in the rotators will eventually break due to bending loads applied to them during valve movement. The pieces will work out of the case of the rotator and wash down to the cam and contribute to cam failure. 1 Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
gumbiegumbie Posted September 20, 2011 Author Share Posted September 20, 2011 This is starting to get pretty involved!! As I read further in my service manual I see that im gonna need a different jam nut for the rocker arm adjusting screw. The manual calls it a "Spherical Jam Nut" and also an "oil supply screw" that I currently do not have since theres no jake brake there needing an oil supply. Unfortunately, the manual doesn't give the part numbers for the missing parts and since my truck doesnt have a brake, my vin# does no good at the mack dealer. Can someone give me the part numbers for the hollow yoke adjusting screws and the jam nuts for them if my current jam nuts wont work, and the actuator pins that go in the hollow adjusting screws, the "spherical jam nuts", and the "oil supply screws" and if theres anything else you know of that goes under the valve cover that is different between a brake equipped head and a non-equipped head, please chime in. I have the brake units, the spacer housings, and the longer bolts needed to bolt everything up. Mainly all the little parts that go between the brake units and the valve train is what I'm missing? If your up on your jake brakes and see that I'm missing something else please let me know and if at all possible throw in some part numbers or maybe someone could give me the last six of a truck that came with a brake so that the mack dealer will look the parts up for me. thanks again everyone! I had no idea this brake install was gonna get so complicated..... I guess nothing is simple anymore!! Quote Link to comment Share on other sites More sharing options...
rhasler Posted September 20, 2011 Share Posted September 20, 2011 Jam nut- 142GC33MOil supply screw- 4559-25132RD688S 59572 was built 10.23.00 and has a Jake Brake. 2 Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
gumbiegumbie Posted September 20, 2011 Author Share Posted September 20, 2011 rhasler,you're extremely helpful! What does the 59572 part mean? Any chance you know the numbers to the hollow yoke screws and the pins that go in the middle of them? I think I've about got everything on the way. This good deal on ebay is turning out to be not so good of a deal since the guy that took it off didnt know what all he needed to take off to make it an add on jake brake like it was advertized. I guess I would have thought all the rest of it was the same to. To the un-trained eye it all looks the same! Thanks for all the help! Quote Link to comment Share on other sites More sharing options...
rhasler Posted September 20, 2011 Share Posted September 20, 2011 59572 is the chassis serial number of an RD690S that was built with a Jake Brake. Why your dealer won't/can't look something like that up when asked is beyond me, but it seems like a lot of dealers are like that anymore.The adjusting screw you refer to is part number 421GC41CM. 1 Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
hog611 Posted October 21, 2011 Share Posted October 21, 2011 I found that a jake brake on a 2000 model 400 hp Mack is useless, it don't work Quote Link to comment Share on other sites More sharing options...
Frydchkn Posted July 21, 2020 Share Posted July 21, 2020 How do you remove a broken valve yoke guide pin from the head? Quote Link to comment Share on other sites More sharing options...
tractor Posted March 23, 2022 Share Posted March 23, 2022 (edited) have a 99 mack e7-400 no power going to jake but power at switch and clutch switch works Edited March 23, 2022 by tractor Quote Link to comment Share on other sites More sharing options...
tractor Posted March 23, 2022 Share Posted March 23, 2022 jake Quote Link to comment Share on other sites More sharing options...
Onyx610 Posted March 23, 2022 Share Posted March 23, 2022 Wires connected at the head? Do you have power there? Quote Link to comment Share on other sites More sharing options...
tractor Posted March 23, 2022 Share Posted March 23, 2022 no powerat head Quote Link to comment Share on other sites More sharing options...
tractor Posted March 23, 2022 Share Posted March 23, 2022 No power to head Quote Link to comment Share on other sites More sharing options...
Onyx610 Posted March 23, 2022 Share Posted March 23, 2022 Should be a relay/relays. I’m not sure with out looking. Did you check them? 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 23, 2022 Share Posted March 23, 2022 see if this diagram helps. its for 'r' models.. you didnt post the chassis model..jojo 1 Quote Link to comment Share on other sites More sharing options...
tractor Posted March 23, 2022 Share Posted March 23, 2022 R model switch has power. Clutch switch works Quote Link to comment Share on other sites More sharing options...
tractor Posted March 23, 2022 Share Posted March 23, 2022 Does anybody have wiring diagram Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 23, 2022 Share Posted March 23, 2022 ok, an easy test is to warm the engine above 125 degree's take a test light and probe the plug and ground it to the engine. place it so you can see it from the big seat... switch the eng brake to high, rev, it up high and let off, it should light. do it to both plugs. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 23, 2022 Share Posted March 23, 2022 I do, but it is too big to photograph, then post.. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 23, 2022 Share Posted March 23, 2022 this issue, should be a simple repair,, I dont want to post too many pics and info, and turn this into a 'Sh!tshow'.. jojo Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 23, 2022 Share Posted March 23, 2022 (edited) you said power is at the clutch switch.. do you hear the clutch switch click when you work it by hand, did you probe for power on the output side to see if power is going through the switch? when you cycle it by hand... jojo Edited March 23, 2022 by Joey Mack More content needed Quote Link to comment Share on other sites More sharing options...
tractor Posted March 24, 2022 Share Posted March 24, 2022 Switch works tested it by hand and it clicks Quote Link to comment Share on other sites More sharing options...
tractor Posted March 24, 2022 Share Posted March 24, 2022 Probed it and ohms it also Quote Link to comment Share on other sites More sharing options...
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