740 GL: how much steering rod play?

Re: 89 740 GL sedan:

Once in a while the front end develops a strange shimmy/vibration. ON
very smooth roads, going straight, even at 70 MPH, the car has no
vibrations. But if you make a turn in the road, decelerating, and it
is not so smooth, often this "shake" will start. It lasts only about
4-6 seconds or so. Bad enough to sure get your attention! Its not the
road itself at all, it is something in the front suspension..but rough
roads are more prone to trigger this shimmy/shake/vibration. My first
impression was that I had a worn out tie-rod end. But I lifted the
front end and checked. At both tie rod ends there is NO play. BUT
both wheels can be moved back and forth about 1/4 inch, there is that
much play in the steering for each wheel. Each steering rod goes into
a boot, and it is the attachment at that inside end of the steering
control rods on each side, that has the play. It seems like this is
enough slop to cause an intmt. vibration, but I am not any expert. How
much play is allowable before this steering assembly has to be
replaced? Is 1/4 in. of play anything to worry about?

 

If you are saying that with the steering held still (no movement of
the steering column shaft) that there is 1/4" of play at each end of
the rack and pinion assembly, then yes, that would be excessive.

If the R+P has no adjustment (I do not think it is adjustable for
play) then hold one tie rod while someone else manipulates the other
wheel. If you can feel if then the rack and pinion sounds like it is
worn. If the wheels have 1/4 of play each, then the tie rod ends
(probably inner) and/or the rack needs replacing. When the R+P in the
960 wnet, there was excessive lateral lay at the end of the rack on
one side from a failed/worn bushing (the inner tie rod could be moved
fore and aft).

Sounds like it is time for a good shop to take a loook at it. Once a
steering component has excessive play, the subsequent wear accelerates
and will become worse in a hurry. It's not a good thing to lose
steering control.



__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"

 

I think you've found the problem - there should be no detectable play
(assuming you have one wheel off the ground and the other is on the ground).
I had to replace one tie rod because of vibration on braking, and the play
was about what you describe. The boot over the rack was torn and I guess
dirt got in there and attacked the joint.

Each tie rod is close to $100 US, and that probably depends on the version.
(Mine was a Cam Gear.) There is a ZF rack and a Cam Gear rack. The ZF rack
is boldly emblazoned "ZF." IIRC the ZF tie rod is staked onto the rack with
a dog washer and is easier to remove than the Cam Gear type, which has a
flattened collar or dimpled shoulder - something like that - to stake it.
Obviously, alignment is mandatory after replacing either tie rod. By all
means, replace the boot while replacing the tie rod.

If you take it to a shop, I'd expect about $400 US for the whole shootin'
match.

Mike

 

There's also the Koyo rack on the later 940s and 960s with similar
front-ends.

But.. um.. $100 for the tie rod? Aftermarket bits are available for about
$10 for the outter and $20-$25 for the inner bits (depending on rack).
The TRW branded bits for the Cam Gear/TRW racks run about $25, if you
really wanted to I'm sure you could find TRW or Moog branded bits for the
ZF or Koyo racks as well.

 

Yup... I had one replaced on the 960 when they were doing teh
alignment, and the part was about $25- a Moog..
__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"

 

That's good to know. The dealer only mentioned the entire tie rod (before I
had internet.)

Mike