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Author Topic: Adjusting Steering & Leaks  (Read 2456 times)
DavidInWilmNC
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1978 MC-8 as I bought it May 2005




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« on: October 11, 2006, 07:19:12 AM »

Like I mentioned in an earlier post, the steering on my MC-8 has a lot of play. I know that the non-integrated steering has a fair amount of play, but this has a lot more than the repair manual indicates. I'm having a really hard time understanding how to adjust this. I've got good diagrams in both the parts and repair manuals, but I guess I'm just generally clueless about bus steering (which shouldn't come as a surprise). I assume it's related, but the steering wheel is way off center when the bus is being steered straight ahead.

I also have a leak in the power steering. It appears to be the valve part that bolts to the bottom of the steering box. Is there a seal or something that often fails here? I'm not sure if I should just remove this piece and examine it (for what, I'm not sure) or where to begin.

If anybody can shed some light on adjusting the steering box, straightening the wheel, or where to start with this leak, I'd love to hear any suggestions. Thanks, as always.

David
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Ross
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« Reply #1 on: October 11, 2006, 07:28:59 AM »

If it's like my MC9, the wheel can be positioned anywhere.  I can just remove the wheel and reposition it anywhere to make it straight when the bus is driving straight.  I can't help with the adjusting...yet...I'm sort of curious about that myself.

Ross
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kyle4501
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« Reply #2 on: October 11, 2006, 11:22:20 AM »

Before you take something apart, consult da' book.

I took apart a car's steering gearbox once, won't do that again as the little balls went everywhere... too many apples, not enough sack.  Embarrassed

First see if the bolts are loose.

Second, clean it as best you can & put something (paper towels?) on it to show where it is really leaking as the fluid really likes to cover everything once it's out.

Good luck
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NJT5047
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« Reply #3 on: October 11, 2006, 07:28:16 PM »

David, sounds like you have integral steering. Is there a slave cylinder on your drag-link? Integral steering doesn't have a "slave cylinder." The primary steering box adjustment is on the spare tire side of the box.
Believe it's a 5/8s or so nut on a screw. The screw will move the rack further into the pinion (relative terms). Don't "tighten" the screw. Slack off the locknut and see how far the center screw will turn in with a light touch...then remove any preload. Try the adjustment screw and see if it helps. Be sure to retighten the locknut.
If you have worn kingpins, drag link, tie rods, or worn steering box, you cannot remove the slop by adjustment only. Parts will have to be replaced to get the steering respectable.
Have someone move the steering a back and forth just enough to move the wheels and look for lost motion in the above locations. You'll see where the problem is located. May be everything.
The unit is designed to be adjusted with a torque wrench on the steering shaft with all linkages removed. But, you can take up a little bit and see if it helps. If the steering feels like it's binding at center steering it's too tight, and you'll damage the box if left tight.
As Ross describes, the MCI wheel can be pulled and replaced in any postion you wish. Do the steering adjustment before moving the steering wheel, as this will change the steering wheel orientation.
Regarding your leak, there are "O" rings that seal both ends of the steering box, I'd have to look at a breakdown, but you may be able to replace the lower end cap without anything falling out. You'll definitely loose some oil.
Clean the steering box off with contact or brake cleaner and be sure where the leak is coming from before removing anything. You may find something simple like a loose adjusting nut or line.
Add to the list of bad things on MCI steering: worn tag axles, worn tires, misaligned front end, link bushings (front and rear), low tire pressure, U joints in the steering shaft, and incorrect ride height due to leveling valve failure.
Most of the above appies to either type steering units...the slave cylinder control valve can wear and may need attention...if you have this cylinder. Some of the older style steering systems have been retrofitted with integral. The early slave-cylinder steering was quite acceptable if in good condition.
One other thing is that an air-ride coach has a "feel" and once you get used to it, you may find it easier to drive. Most people tend to "over drive" the bus, making too many tiny corrections. You probably have wear and tear issues, but the more you drive the bus, the easier it may be to keep between the lines.
Good Luck, JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.

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ChuckMC8
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« Reply #4 on: October 12, 2006, 03:36:03 AM »

David, unless its been changed to integral, like JR sez, it has the original slave cylinder model.
If thats the case.......If you keep this bus, you will wind up changing it to an integral box. I did, and it makes all the difference in the world.
  You can piddle with the OEM setup, but I doubt that you will get it to a satisfactory level. If its like miine (old and worn out) its just a WOT messing with it. Most leak and make a bad mess as well.
   A friend local here bought a new integral box on ebay for $278 and changed his out also.
 So , my advise is to work on something else and accumulate the parts that you need for the change and then fix it all at once.
Fred Hobe has good instructions and parts sources on his info page. If you need a link to that. I can find and post it.
I can also post pics of my steering box changeout (as can lots of others)
HTH, Chuck
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DavidInWilmNC
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« Reply #5 on: October 12, 2006, 05:34:57 AM »

Thanks guys. JR & Chuck, it is the original type of steering with the slave cylinder. The manual calls it 'semi-integral'. I can probably deal with the slop in the steering, but it would be nice to be able to tighten it up a bit. Mostly, though, leaking 2-3 quarts of steering fluid on a 130 mile trip is a real pain; the steering leaks a lot more fluid than the engine does. The bus is pretty much a shell with a generator, seats, and heat and air, so there is LOTS to work on. A bus that's mostly sitting in the yard under construction doesn't necessarily need integral steering, but it really can't be leaking like that! I'd love any info and links on converting to the updated steering. Pictures would be great, too. Is it really difficult to do? I've done everything else on the bus myself so far, so I imagine I can handle something like that. Does it require any changes to the steering pump on the engine? Thanks for the comments & suggestions.
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Stan
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« Reply #6 on: October 12, 2006, 05:42:56 AM »

Since you are having trouble understanding the manuals, I recommend that you take your bus to a bus garage or a truck alignment and steering shop. Have them do an estiimate of the parts required and the cost to replace them. At that point, you can decide if the job is a do-it-yourself thing or you can have them do it.

BTW: Changing to an integral steering box requires welding of critical components in an awkward location. A steering box coming loose from the frame at 75 MPH really makes for a bad day.
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DavidInWilmNC
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« Reply #7 on: October 12, 2006, 06:47:48 AM »

Since you are having trouble understanding the manuals, I recommend that you take your bus to a bus garage or a truck alignment and steering shop. Have them do an estiimate of the parts required and the cost to replace them. At that point, you can decide if the job is a do-it-yourself thing or you can have them do it.

BTW: Changing to an integral steering box requires welding of critical components in an awkward location. A steering box coming loose from the frame at 75 MPH really makes for a bad day.

Stan, maybe I should modify my not understanding the manuals. The steering box in the manuals does not really look like what I have. I'm sure it is, or is very similar, but some of the pictures and diagrams in my reproduction manual, though mostly very clear, are fairly dark and lack contrast. Thanks for the input.

David
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ChuckMC8
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« Reply #8 on: October 12, 2006, 07:13:50 AM »

David, here's the link to Fred's page with the steering box info.
I feel your pain with the reprint manual. I had one of those and the photos are useless.
If you'll email me I can scan the steering page out of my manual and send it to you.
chuck

I am adding the link that Chuck apparently forgot to attach. LOL
I found this on page 2:
Integral power steering in your MCI 5, 6, 7, 8,and early 9s for around $1000

http://users.cwnet.com/~thall/fredhobe.htm

Richard
« Last Edit: October 12, 2006, 08:13:49 AM by DrivingMissLazy » Logged

Far better is it to dare mighty things,to win glorious triumphs,even though they may be checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much,because they live in the gray twilight that knows neither victory nor defeat.  Theodore Roosevelt (1858-1919)
DavidInWilmNC
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« Reply #9 on: October 12, 2006, 10:25:18 AM »

Chuck, or anybody else who's switched their steering boxes... what would I need to replace my box from a MC-9?  I assume that this would be an easier swap than from a truck.  Thanks!

David
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NJT5047
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« Reply #10 on: October 12, 2006, 10:29:19 AM »

David, have you looked at your drag link (long bar that connects tie rod to pittman arm) and see if there's a cylinder attached to it?  You may have an integral conversion.  If no cylinder, you have integral steering. That may be why your box doesn't look like the  manual pix.
JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.

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DavidInWilmNC
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« Reply #11 on: October 12, 2006, 11:31:56 AM »

Yep, there's a great big cylinder there. The only part that's actually power that connects to the steering box is where the two hoses from the pump and the two hoses that lead to the cylinder connect. It's this valve that's leaking. I'll mess with it some and see if it can be tightened up, but if I can locate an integral unit, it would be a nice improvement. Then all I have to complain about driving the bus is that HEAVY clutch!

David
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Ross
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« Reply #12 on: October 12, 2006, 01:00:11 PM »

If you have the manual on CD from Coachinfo, then you don't have the right year manual for the bus, unless they have recently aquired the 1979 manual.  The MC9 manual he sends out is a 1989 manual, which would be the integral steering.  That one threw me for a little while as well until someone here suggested I check the year of the manual.  From what I can gather, Coachinfo does not have the 1979 MC9 manual on CD.

I agree with JR.  These slave cylinder systems work fine and are quite acceptable as long as everything is in good shape.  Just take a good look at the system and fix what is loose.  I would consider upgrading if the steering box was bad, but if you have loose kingpins, tie rods or drag link, those will still have to be fixed...even after you spend $1000+ to upgrade the steering.  I like this bus, but it's an old bus.  I'd rather take that $1000 and apply it towards a newer shell.  I think it's cheaper in the long run to just upgrade to a newer shell than to keep spending thousands to upgrade systems on an older model bus.

Ross
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gus
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« Reply #13 on: October 12, 2006, 01:19:43 PM »

David,

I agree with Kyle. I'm a GMC guy so what I say might not apply completely to an MCI.

It sounds as if your steering box is mechanical and there is a hyd boost cyl on the tie rod, just like a GMC.

The adjustment in the box is basically a pin going down into a worm gear, when you screw the pin down it fits tighter into the gear so you want to do it a small bit at a time and then check it for looseness.

The grooves in the worm gear are smaller in the center for wear purposes since the wheel is centered most of the time, this is where the "Highway slop" problem usually exists.

I made this simple adjustment on my 4104 in two increments and it is like I have new steering. Amazing!

I solved my gear box oil leaking by using grease instead of oil. It made the steering much easier also. Don't do this if your box is part of the hydraulic system!!
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PD4107-152
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buswarrior
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« Reply #14 on: October 12, 2006, 04:57:43 PM »

Remember, experience is not neccessarily a good teacher...

Who would change out a good steering system?

Not entirely fair comparing worn out system to a new system?
How many bunuts have driven a slave system that is in proper condition and can give a fair comparison?

And in other news, never under-estimate what worn tag axle bushings or radius rods will do to the coach as it travels down the road. You want wander? that worn tag axle will drag you all over the place.

Until you have checked all the other suspension points for play, you may be fixing something that isn't broken.

happy coaching!
buswarrior
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