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Eagle Suspension??? again...I know Lol

This is a public forum to discuss Eagle related technical issues. If you are having a problem with your Eagle, this is the place to find help.


Please help me members. I have searched and found info on the torsilastic suspension and adjusting it, cost to replace parts, re-indexing, not so ideal conversion to air bags, and checkout to see how many threads are left to see if you will have long enough for your plans....BUT I also read a post saying it was more about the rubber coming out of axle or maybe tube than the threads left.

I had an MCI and have never been under an Eagle and can't find any good pics of what he meant by this.

I really would love to see a diagram of how the suspension is mounted and how it works. I'm a picture or visual kind or guy. Lol

I know they use rubber and bond it to metal I assume and must compress because I assume if you were pulling like on a motor mount it would separate too easily.
The body needs pushed up off of the axles and there is an adjustment so must be a angle leverage sort of thing but I can't think in my head how it is arranged.

I understand certain 4wd trucks with torsion bars that the adjustment twists the bar under more pressure and that tries to turn the other end that it stuck into the lower control arm so it pushes the wheel down and lifts the frame up.

Help me understand..... Please
TobyU
 
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Joined: Tue Dec 15, 2020 1:01 pm




The torsilastics on an eagle are pretty much as you described on a 4wheel drive truck. There is an inner shaft and and outer housing and between the two is rubber that was pressed in with great pressure and the use of dry ice to shrink it. There is also a slit in the rubber that fits around a metal plate to help hold it from twisting. Also some sort of cement is use to bond it to the tube and the shaft. As far as the rubber bulging out the end of the tube that is a sigh that things are starting to unravel. Failure will happen when the tube fails or the rubber comes lose from the tube or the shaft.
Hope this helps and others will chime in with more info
Wayne
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rusty
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Hi Toby. Welcome to our forum.

The great thing about this forum is the wealth of information that is buried in all of the posts. Our search engine is less than perfect, but it does get you to many good posts most of the time. As a side note, the search tab leads you to two different search engines: Google and the search engine resident in our forum software. I tend to use the resident search engine.

I need to be careful here and not sound like a smart a**. While I suggest the search engine option, It is always a good idea to post a question if you don't find what you need. A few of us have read almost every post over the years and can possible lead you to a good answer.

Our thread on inspecting Eagles has a couple of good pictures/drawings: [url] viewtopic.php?f=5&t=4343&hilit=torsilastic
[/url]

The Technical Archive Forum has a ton of good information including adjusting the suspension.

Let us know if we can give you more help.

Jim
Jim Shepherd
Evergreen, CO
'85 Eagle 10 with Series 60 & Eaton AutoShift 10 speed transmission SOLD
2005 Dodge 2500 with 5.9 Cummins and 6 speed manual 2014 Passport 26 foot trailer
Bus Project pages: http://beltguy.com/Bus_Project/busproject.htm
Blog: http://beltguy.com/blog/
Email: jim@eaglesinternational.net NOTE this email box is only for general correspondence and not technical advice
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beltguy
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One of the better illustrations of the Torsilastic setup is one by Trailways Maintenance that was posted in the Facebook Vintage Bus Group in the files section on the opening page, posted by Tony Pascarella. The issues of adjustment and replacement have been covered fairly well in the files stored here.

The judgement of deciding when the Torsilastics need to be replaced needs more discussion, in my opinion. The mere sight of some aged rubber squishing out of the ends of the tubes does not necessarily mean that they are done for. I have the opinion that the effects of heat, time, and exposure to ozone degrade the rubber that is exposed in the outer extremities, but I doubt that it means that the inner rubber compound is totally shot. I think a more telling assessment of the Torsilastic is whether when it has been adjusted and/or reindexed, it stays in the same ride height, or quickly begins to lose height after being adjusted and used. I think in that case, we can conclude that the inner rubber has failed.

I have yet to see a diagram or pictures of the inner workings of the Torsilastic tube, which I would guess is due to their being a patented item. I have seen a video of the inner tube being inserted in the outer tube at the Eagle Plant using a hydraulic press with a long stroke. Wayne's description of using exterior heating and internal cooling to facilitate the insertion may be a factor in making the process go smoother. No where have I seen the interior details of the inner tube and how it is constructed. The only company that provides these tubes now is Sulastic Corp. in Texas, but apparently, they do not actually do the work of making the inner tube, they are manufactured in Mexico. So, only a few people somewhere in Mexico know the details of making them (and the people who used to do it for B.F. Goodrich).

I have a strong desire to cut apart a failed Torsilastic to do a post mortem to find out just what happens when they get tired and old. I know that there exists two part rubber/neoprene compounds in various formulas that could come close to duplicating the original material, the question is, how did they achieve the assembly in the first place? I am wondering if the compound was simply poured in the tube, after using coatings or bonding agents, and molds? Looking at new tubes from Sulastic, it appears that the rubber was liquid at one time, and was wiped or scraped with a tool at the ends that are exposed. I suspect it is not rocket science, and that there might be a way to rebuild these cylinders without spending $2500 per tube, plus shipping from Texas.

The alternative that has been used by many is to add two airbags by welding connections to the Torsilastic outer tube, which, while it may work, is a crude adaptation to a wonderful original system. The support framing for the airbags interfere with various things such as the fuel filler piping. The cost of materials and paying someone to add airbags seems to get close to replacing the Torsilasics (not counting labor). The alternative is finding good used tubes from salvage buses, but that won't work forever. I believe we need to keep the suspension original, and find a less expensive way to do it.
Attachments
Eagle drive axle torsion bar 001 (4).jpg
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740
1994 Eagle Model 15-45, Series 60 w/Jacobs, Allison HT746
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DoubleEagle
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I agree with Walter just because the rubber is bulging out the end doesn't mean the rest of the rubber is bad but the rubber is starting to deteriorate.
This is what I know for sure because I saw it at Jefferson shop and he assembled these springs. They were assembled using a press. Dry ice was used ( Jeff told me ). From now on is conjecture. I am pretty sure the parts came with the rubber bonded to the inner tube. That is what Walter was talking about the poured look on the ends. I was then forced into the outer shell. The outer shell does have a plate that sticks inside the shell. This plate ends up in a slot in the rubber that holds the rubber from twisting. You can see where the plate was welded in a slot in the outer shell. I never was there when Jeff assembled the spings but I heard him talk about it. I did see the press. I think I remembered seeing an inner tube with the rubber attached but am not sure. Wish I would have paid more attention. It would have been nice to see him assemble one of the springs.
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rusty
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Walter, you have outdone yourself this time :D Great info.

What we think of as rubber (natural rubber, neoprene, buna N, etc) is never in a liquid by the time they reach the manufacturing plant. Those rubber materials are made pliable with heat and mechanical mixing and then cured with heat using sulfur (vulcanizing).

However, you triggered a thought that a company might use a form of urethane. Urethane is used for all kinds of suspension parts and can be compounded to give a large range of mechanical properties. As an FYI the famous PolyChain belt by Gates (think Harley Davidson and blower belt drives) is an urethane product. It has tremendous mechanical properties in compression (not so good in tension). In the 60s and into the 70s Gates made polyurethane snowmobile tracks that the industry loved. The lugs were about 1 inch tall and the track lasted forever. When folks started wanting 2 inch tall lugs, the poor tension properties of the urethane resulted in cracking at the base of the lugs. Ozone and other contamination has almost no affect on urethane. However, it does not do well at high temperatures (should not be a problem with the suspension parts).

Jim
Jim Shepherd
Evergreen, CO
'85 Eagle 10 with Series 60 & Eaton AutoShift 10 speed transmission SOLD
2005 Dodge 2500 with 5.9 Cummins and 6 speed manual 2014 Passport 26 foot trailer
Bus Project pages: http://beltguy.com/Bus_Project/busproject.htm
Blog: http://beltguy.com/blog/
Email: jim@eaglesinternational.net NOTE this email box is only for general correspondence and not technical advice
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beltguy
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Thanks Wayne and Jim, the whole issue of keeping the Torsilastics going is important. I really think some type of compound can be found to work. No doubt about it though, we should have paid more attention to Jeff, Norris, and Ed. I deeply regret not going out to Oklahoma for that final auction, there were piles of Torsilastic tubes there, and lots of other parts. I have a particularly hefty log splitter on a I-beam that I would like to try out with a Torsilastic tube to see if I can disassemble one that is no longer useful. If the internal layout of the inner tube becomes apparent, and the formula for the rubber compound can be duplicated, maybe, just maybe, a homespun rebuilding can be done. We just need someone with Eagles to spare to test the result :!:

As far as the deteriorating rubber at the ends of the tubes go, what about performing Torsilastic Dentistry by gouging out the soft rubber as far as possible, and pouring or packing in some new rubber compound to seal the ends? That might buy time for the rest of the tube that would be worthwhile. What about a metal cap on the ends to seal the rubber compound from road spatter and ozone? When they developed the Torsilastics they might not have thinking about keeping them going into the next century, but here we are, twenty years into it. Save your old Torsilastics, they might come in handy.
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740
1994 Eagle Model 15-45, Series 60 w/Jacobs, Allison HT746
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DoubleEagle
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Location: Dayton, Ohio




Marty Golden showed me how to reindex the spring which he has successfully done. In figure 2 it shows the spring fixing arm in its removed position. You slide it off the torsion spring which is splined on each end You adjust the nuts on the adjusting arm to the angle measurement shown in figure 4 and drive it back on the splines. The assembly angles should resemble the illustration. Reinstall the whole assembly and you have started over again with a new (old) spring with all its adjustment left for the future. Yes, the caveat is that if it holds and doesn't slip it's good. If it slips it is time to replace.
Marty told me that just because it is cracking out the ends of the tube doesn't mean it has failed.

My hesitation is the removal of the torsalastic assembly from the coach drive axle. That would be a brutal job.

David
davida
 
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Joined: Tue Jun 02, 2009 7:43 pm




David, that is good information, it certainly can work for some torsilastics, but it sure would be nice if there was a way to test the suspension to determine if re-indexing would be of benefit. The work of getting everything off is indeed brutal, but that applies whether re-indexing or replacing with a rebuilt. I still hope there is a way in-between where the torsilastic can be improved on the spot. It is aggravating to go through all that work only to find out that the tube is shot. We need to know what is happening inside that tube.
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740
1994 Eagle Model 15-45, Series 60 w/Jacobs, Allison HT746
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DoubleEagle
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Posts: 220
Joined: Wed Feb 14, 2018 9:26 pm
Location: Dayton, Ohio




davida wrote:Marty Golden showed me how to reindex the spring which he has successfully done. In figure 2 it shows the spring fixing arm in its removed position. You slide it off the torsion spring which is splined on each end You adjust the nuts on the adjusting arm to the angle measurement shown in figure 4 and drive it back on the splines. The assembly angles should resemble the illustration. Reinstall the whole assembly and you have started over again with a new (old) spring with all its adjustment left for the future. Yes, the caveat is that if it holds and doesn't slip it's good. If it slips it is time to replace.
Marty told me that just because it is cracking out the ends of the tube doesn't mean it has failed.

My hesitation is the removal of the torsalastic assembly from the coach drive axle. That would be a brutal job.

David

Walter, I misinformed you about the torsion tube being splined. I has a bolt through it on each end, no spline I am pretty sure. I remember Marty saying he drilled a new hole in the outer tube to re index it. Marty showed me this at the rally in Branson last October and my memory is slipping a bit. Regardless,
reindexing can be accomplished. I can't imagine the shear pressure against those two bolts.

David
davida
 
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Joined: Tue Jun 02, 2009 7:43 pm


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