TRW TAS85 Steering Gear Box Freeplay

[RichardEntrekin]

Thanks Geoff and I agree with you. However in this case the front is IFS.

I will check the back and the bushings in the Panhard bar.

[Geoff]

Thanks Geoff and I agree with you. However in this case the front is IFS.

I will check the back and the bushings in the Panhard bar.

I also have IFS.  The RTS used IFS until GM sold the manufacturing to TMC (I believe that is who bought it first, it has been sold a few times).  What I am warning you about has nothing to do with IFS.  That is part of the front end work-- I am warning you about the radius rod bushings in the rear, and that applies to all buses.

--Geoff

Oh, you have a Newell.  That isn't a bus chassis or a bus conversion.  Check your "Panhard bar", we have "dogbones".

[RichardEntrekin]

Sorry Geoff, I should have read your post more carefully. Yes, you clearly said rear.

Funny how the mind sees what it wants to see. My first Newell was straight axle in the front with radius rods. My head immediately went there.

The rear is a Ridewell suspension with radius arms and panhard.

So just how would one check for play in those bushings?

I suppose I could mount a dial indicator on them, point a remote camera, and go for drive.

I can't see wiggling the 50K lb coach by hand or pry bar.

[luvrbus]

I am at a complete loss here how does the rear radius or stabilizer bars bushings affect the free play in a steering wheel 

[Geoff]

Cliff--
You also missed the conversion.  What I've been saying is that if your front end and steering box is tight and your bus still wanders, it is probably from worn out radius rod bushings.  Richard-- I don't know any easy way to check for worn bushings, other than seeing if they are bulging out on the edges and just plain look old.  It is more of a process of elimination of having a tight box and tight front end and still having wandering problems (or loose steering).

I had this problem-- everything was new up front but I was constantly correcting the steering.  The rear end was dancing around from worn out radius rod bushings which kept me having to correct the steering to keep going straight.

--Geoff

[luvrbus]

I know about wander and radius rods bushings but Richard is working on steering wheel lash I thought.I never saw a heavy @$# Newell wonder my self like a bus will 

[RichardEntrekin]

Ahhh,

To get back on track, I never used the word wander in my original post. What I was trying to understand was some unwanted freeplay between turning the steering wheel and nothing moving at the pitman arm. It was a very disconcerting feeling to have deadband in the steering. It would feel the same as if the sector adjustment was too loose, but I was absolutely certain the sector gear was adjusted properly.

Did that result in wandering. Yes, most of the time on a dead flat road. The best driving was either on a heavily crowned road or a consistent side wind. Both conditions allowed me to just correct "one" side of the steering and let the crown or the wind move it back to center.

I think I found it when I discovered the bearing at the bottom of the steering column was worn out permitting the upper u joint in the intermediate steering shaft to wallow around. In my era coach, Newell used a tilt GM column.

A new bearing will be installed as soon as it gets here, and I will quantify and report the results.

I didn't mean to stir anything up, I just feel like that folks who post an issue should also post the resolution of the issue. Who knows when someone else may be dealing with a similar problem, and a search engine may find this post and help them.

I posted on this forum because I think a lot of it's members have tremendous knowledge about the systems which are common to commercial buses and to Newells.

Thank you for all your help.

[daddysgirl]

I cannot help but to repeat that if you have worn radius rod bushings it doesn't matter how tight you steering is up front your bus is going to wander and you will be constantly correcting the steering.  The radius rod bushings keep the rear and tag axles from moving side to side.  Up and down on the bushings is okay, but side to side play will make your bus wander.  I just got a call from a friend of mine that is in the same boat I was in years ago-- everything was tight in the steering components and steering box but the bus still wandered.  He is now having his radius rod bushings replaced.

--Geoff

Yep.
Not much like following a bus when the driver believes he's totally within his lane but his back end isn't.

But his setup must be totally different from mine. The procedure for determining the play is different, but one of the emphasized points is the cam groove adjustment.
I have a small wheel, but the book allows for  2" ( or 10 degrees) play. That would drive me crazy.

[Geoff]

I realize expanding steering box freeplay to radius rod bushings might be a jump for some people but people don't normally complain about freeplay unless they are fighting their bus wandering​.  As a 102" bus conversion driver I know first-hand that keeping a bus centered in your lane takes constant attention.  Loose steering and a wandering bus wears you out!

--Geoff

[luvrbus]

Yep I drove a few MCI 8 and 9 that had the old power assist steering they will wear you out trying to keep one between the lines and the ditch how the drivers could drive one every day was a marvel to me

[windtrader]

what year did the MC8 get upgraded steering from the factory?

[luvrbus]

The 8's were never upgrade from the factory the 9's were in about the mid 80's,the MCI have radius rods on the front axle also like all buses with a straight axle do.
Richard I am changing the mast bearings on my MCI too I have play there   

[buswarrior]

MC9 got a proper steering box for the 1982 models I was familiar with.

The older ones, it's all about properly set-up and everything the way it's supposed to be.

Set up wrong, you're rowing your way down the highway...

happy coaching!
buswarrior

[RichardEntrekin]

Woo Hoo!

I replaced the steering column lower bearing, replaced the u joints in the steering shaft, and tightened the pinch bolt where the upper u joint connects to the steering column.

I had 1 3/8 inches of play before the work. I now have 5/16.

I don't get to road test for two more days, but I am looking forward to the drive.

[windtrader]

Nice!