Front-end wheel adjustments and reduced drive/steering stability

Started by Jan S, 19 June 2021, 07:44 AM

Jan S

The car is a 1975 W116 450 SE US-version with a 6.9 (original is the 4.5)

- Do someone have access to the specs for the wheel adjustments on this car (caster, camber, toe-in/out), both front and rear? I would like to double check the current measures with specs.
- Is it possible to go a bit out of range to improve steering stability, e.g. with respect to toe-in/out? Anything I can do to improve stability?

Background
A few days ago a workshop replaced my 2 front ball joints and the 4 rear trailing-arm bushings. They also did a front-end wheel adjustment (measured also the rear end).
On my way home I noticed the car was not that stable anymore. The play in the steering was suddenly much more noticeable.

The workshop told me the "old" front toe-in/-out was way out of range. They had to do several test drives and adjustments to get it within range.

Prior to the workshop visit, I replaced several parts associated with the axles, steering and suspension (I did this work myself) – all contributing to a tighter and more stable drive feeling.
(Replacements include both front upper control arms, all shock absorbers, both flex discs, driveline center support incl. bearing, front steering damper, both rear subframe rubber mounts, power steering filter and complete flushing, center rubber bearing on diff housing).

Also, in 2019 a different workshop replaced my tie-rods and the drag link. They said they did the front-end wheel adjustments, but I guess they didn't (since toe-in/out was way out of range).

Does this problem sound familiar? Anything I can do to improve the steering/stability? Or do I have to check/tackle the steering gear box as next step?
1975-mod W116 450 SE with 6.9 engine

rumb

In the tech library:

https://www.w116.org/tech/wheel_alignment/

It's possible you have improved a lot and the steering gear box is more noticeable now.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

daantjie

I recall quite a few posts over the years on the forum where guys had a hell of a time time trying to align their cars.  Seems like the 116 can be tricky and the shop really needs to know what they are doing.
Daniel
1977 450 SEL 6.9 - Astralsilber

ptashek

You can't really align the W116 frontend properly without the fancy Bosch, or similar, preload tool. Another case of Daimler over-engineering the heck out of things.
See here for details: https://forum.w116.org/mechanicals/how-to-align-a-w116/
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

adamb

That's a good link. Not many of the contributors to that thread still contribute.

nathan

Jan,

I wonder how much of a problem having a 6.9 without hydropneumatic would influence your ability to get the front end right?

that motor is a lot heavier than an m117 450, so perhaps this is contributing to the woes as you are not using the suspension made to suit that motor?

regards
Nathan
1979 116 6.9 #6436
2018 213 e63
2011 212 e63
2011 463 g55
2007 211 e500 wagen
1995 124 e320 cabriolet
1983 460 300gd
1981 123 280te

Jan S

Thank you all for links, assessments and tips!

Rumb; nice link you provided. The figures correspond in part with some other specs I found the other day on www. I will try to summarize and compare later. Yes, I have improved a lot and the steering has improved as well, until the wheel adjustment (at least it feels that way). A lot of subjective feelings involved  :-\

daantjie; yeah, I'm not 100% convinced the workshop knows how to really adjust a W116 ......

ptashek; that's a very informative post, I need to study it and see how I can convey the important parts of the information to the workshop

nathan; good point, it has also struck my mind. I believe the M100 6.9 is about 75 kg heavier than the M117 4.5 - order of magnitude (you agree?). I do not have the mechanical climate control components installed (compressor, condensor, etc) that will offset the weight difference a few kilo  ;)

I will return to the workshop later, but first I need to replace all brakes (calipers, rotors, pads, hoses, fluid).

More later
1975-mod W116 450 SE with 6.9 engine