| Author | Message | ||
| jj-mc9 Rating: N/A |
Hi all. I just committed to buy a nice Eagle conversion. I plan to take delivery of it in a couple weeks. It has some equipment with which I'm not familiar, as they're not on my MC9. There's a jake brake on the 8V71, a Stone-Bennet shifter on the Allison and a Williams air throttle and modulator. If I could get some input as to how this stuff works, it would sure help me when I drive the coach home. Also, are the start batteries 24V? The son of the owner (who passed away) was not sure. I question my sanity for buying it, but no one is guaranteed tomorrow. Thanks for the info to my questions. | ||
| RJ Long (Rjlong)
Rating: N/A |
OK, here goes: Williams air throttle: Takes the place of a cable. MUCH LESS pressure is needed to operate, almost "featherlike" in it's operation, reduces driver's foot/leg fatigue. More difficult to modulate with a stick shift, not a problem with an Allison automatic. Find out if there's a spare diaphragm for the engine-mounted modulater cylinder, as that's the weakest link. If not, get one from Luke before you go. Stone Bennett shifter: Instead of a mechanical cable actuating the transmission's "R-N-D-3-2-1" shift pattern, it's done with an electric solenoid, controlled by a switch on the dashboard. Click one way or the other, depending on what gear you want to select. Usually the gear selected is noted on the dash by a light or similar next to the switch. Later models could be a push-button pad, altho those are more common with an ATEC (computer-controlled) Allison. Jake Brake: On the engine, is used to supplement the coach's service brakes. Turned on/off by another dash switch. When adjusted properly, will allow you to maintain a safe speed down most mountain grades without having to use your service brakes, or use them very, very sparingly. Electrical system: MOST Eagles are 12vdc, altho I think the NJT models were set up as 24. Take a look at the way the start batteries are wired - if parallel, it's 12vdc; if series, it's 24vdc. As for actually driving the Eagle, you'll find that it "feels" a lot different than your MCI. Major reason, of course, is the Torsilastic suspension - no air bags. If the shocks are weak, it will have a tendency to "porpoise" on highway undulations. Nothing serious, but be aware of the possibility. An Eagle in good condition is a great coach, highly coveted by the entertainer industry back when they were in production. Enjoy!!  HTH, RJ PD4106-2784 Fresno CA | ||
| jj-mc9 Rating: N/A |
Thanks for the helpful info, RJ. | ||
| Bob Oakman (Bobsbus)
Rating: N/A |
On my Eagle, the switch on the dash says, "Jacobs Brake" on it. It works, but from the sound, or rather the lack of, I suspect it is, as some have suggested, a transmission brake. Any such thing? Is that common on Eagles? If so, do these things wear out or need adjustment? Too many questions? Sorry... It's a 5 speed Allison automatic. Thanks. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Jacobs Brake is a registered trademark I believe and I do not think it would be a transmission brake. There are a few adjustments to make to it that will generally make it work perfectly. You will definitely know it is working when it is working properly. Do a web search and download the Jake manual to find out how it works and adjustments to make. Generally it is only a matter of adjusting the buffer switch to get it working properly. Richard | ||
| RJ Long (Rjlong)
Rating: N/A |
Bob - The Jacobs Brake is the official name of the Jake Brake, as Jacobs Manufacturing is the company that makes them. They are an engine brake, NOT a transmission brake. Richard's right, sometimes the buffer switch needs adjustment, but, as Tom Caffery found out at Southern Oregon Diesel last week, it can also be some little things under the valve covers that need attention. Here's a copy of his post on the Yahoo GMC busnuts group: ~~~~~~~~~~ "We were able to stop into Southern Oregon Diesel and ask them to take a look at the Jakes. I had already bypassed the buffer switch, so I knew that had made no difference. Dwayne started on the job a little after 8. He found some different things while troubleshooting the Jakes. He took all the valves out after removing both valve covers, which meant that the air horn had to come off. One problem was that an o-ring had been installed on top of another one. The bottom ring was as hard as a rock. Another o-ring had some damage, but he didn't seem to think that it played much of a role. Another was that the tangs that the wires connected to were bent so that the screw's tips were almost touching the Jake bridges. He straightened the tangs. Another problem was one of the connecting wires was flopping around because the screw was very loose. And into the bargain, he found that the air horn bellows type hose had an air induction leak on the back side, a pretty bad one. He said that if there was going to be a leak in that hose, it would likely be in the back, where you couldn't see it when installing it. He cleaned up everything and reassembled it before morning coffee, and I was out of there, a happy camper. It's worked perfectly ever since. I gave all the detail, partly because some people had offered suggestions of how to fix the Jakes, and I tried some of them. I've done a lot of mechanic work before, but never on Jakes. Between the suggestions, a complete manual and Southern Oregon Diesel's help, I know a lot more about them now. Thanks for the help. Tom Caffrey PD4106-2576 Suncatcher" ~~~~~~~~~~ Unless it's outdated or has been moved, here's the URL for the Jake Brake troubleshooting manual: http://www.jakebrake.com/pdf/tsman.pdf Finally, Bob - what does the shifter say on your Allison? HTH, RJ PD4106-2784 Fresno CA | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Thanks for the adeed info RJ. One quick and dirty test for the electrical portion of the system is to bypass the buffer switch with a jumper wire. Then with someone in front to turn on the ignition switch and then flip the Jake brake switch thru its high and low positions. If everything is ok in the electrical portion then someone in the rear can hear the electrical solenoids under the valve covers click on and off. Richard | ||
| bartggggggggg Rating: N/A |
Bob, Check the wiring as in your work it probably has been disconected. Your bus does have Jakes and not a trans retarder. also it is a 4 speed Bart | ||
| bart g Rating: N/A |
Bob, Maggie, You don't want to see what I have in now!! it is not on the site yet. Bart | ||
| Bob Oakman (Bobsbus)
Rating: N/A |
Hi Bart! What do have in now? Don't tempt me. I need to finish the bus I have before I buy another. I guess the transmission break info I got was wrong. The wiring should be OK. I inadvertently cut the wires during the conversion and ran new ones. After testing it out the Jake seemed to work like it did before, which is weak. Perhaps it just needs adjusting. Judging by RJ's experience, I'll bet that the entire system could use some attention. Thanks for the post RJ. Bart, I'll probably be calling about a steering wheel soon. |