Is there a final say - w123 with limited slip? - Page 4 - PeachParts Mercedes-Benz Forum

t walgamuth · #46 02-16-2008, 01:36 PM

OK, today we assembled the diff with the new one sided friction plates.

It has excessive free play in the pinion as MBDOC and GSX said it would have. So we will be ordering a spacer to be made next week, either 4.9 or 5 mm. We will meet back at his shop this afternoon and attempt to measure it so we know how thick to have it made.

It is pretty sticky with the new friction plate in it. We don't have the equipment necessary to measure the resistance of the clutches so it is a bit of a guessing game. I think we can adjust the resistance some with the lube additives.

comments are welcome.

Tom W

gsxr · #47 02-16-2008, 04:35 PM

Yep, due to the ratio difference, I figured you'd need a spacer. But it should work with the correct spacer installed (and longer bolts).

The resistance is measured in lb-ft of rotation torque, on the workbench (clamped in a vise). From my experience, you basically have to make it as tight as possible, while still being able to rotate it at all. If it's too tight, it won't rotate... that's not good. The weird part is how touchy it is, a few hundredths of a millimeter can be the difference between just right, and too tight. It's trial and error, and it took me a dozen attempts. If it's too loose, you won't get as much lockup.

I'd be really careful messing with additives to adjust the friction, if the plates get messed up from the wrong lube, you'll have to take it all apart again to replace them. I used OE LSD lube from the dealer. BTW - did you replace all the discs, or just the end disc?

t walgamuth · #48 02-16-2008, 04:37 PM

We replaced the end only. The spacer needs to be 4 mm. We just got done measuring it.

Tom W

gsxr · #49 02-16-2008, 04:47 PM

Quote:

Originally Posted by t walgamuth

We replaced the end only. The spacer needs to be 4 mm. We just got done measuring it.

What was the thickness of the old, double-sided discs? Does the surface at all look 'patchy' or spotty, like in the photo below?

t walgamuth · #50 02-17-2008, 08:12 PM

My discs were smoother than those in the pictures. Our measurement of the one sided discs was 3.13. The total wear on the two sided discs plus the wear on the plain discs totalled .025 for a total of 3.155 so we figured that we could use the 3.2 one sided disc and compensate for all of the wear and then some. I bought two of the two sided discs so we have that flexibility and we can take material off the one sided disc if needed. Also there is some adjustment available with the friction modifying additive, I believe.

Does this sound OK to you?

Tom W

gsxr · #51 02-17-2008, 08:55 PM

That might work, assuming both one-sided discs measured 3.13mm. On my diff, there was 0.10mm difference from right to left, and you need to install different thicknesses on each side. Otherwise the left may be tighter than the right, or vice-versa. Just make sure you can get it to rotate on the bench, before installing in the car. I would avoid liquid additives if at all possible, I'd only try that as a last resort before re-opening the diff.

gsxr · #52 03-06-2008, 10:12 AM

Any update, Tom?

t walgamuth · #53 03-06-2008, 10:19 AM

The 24 mm bolts are supposed to be in today to bolt on the ring gear with the cusom made 4 mm spacer.

I hope to have it finished and ready to wrestle into the car by noon saturday.

Tom W

mbdoc · #54 03-06-2008, 11:26 AM

Use flywheel bolts!
Have used them on 25+ custom differentials!
I have several of those ring gear spacers & all of the different sized adjustment snap-rings if you need some!

t walgamuth · #55 03-06-2008, 11:39 AM

Whoah! Great idea! Thanks for the tip and thanks for the offer on the snap riings! We may need some for sure!

Thanks to both of you fellows for your kind assistance in this matter. I would probably not have had the courage to embark on this adventure if not for your encouraging information!

Tom W

t walgamuth · #56 03-15-2008, 12:22 PM

We installed the 24mm bolts today and put the cover on the diff. New seals and it is ready to install. He set the play (?) in the ring and pinion at 5 thousanths, IIRC.

Now I will need to figure out if I have enough skill tools and energy to install it myself or if I have to find the money to pay my indie to do it.

Tom W

t walgamuth · #57 07-07-2008, 11:18 PM

With some financial breakthroughs, I have the autocrosser now at the indie getting the LSD installed along with some other things. I hope to have it ready to compete really soon!

Tom W

t walgamuth · #58 07-19-2008, 03:07 PM

I got the limited slip diff installed last week, the battery moved to the rear and the rear spring shim removed. They also installed my sport seat and a very light front pass seat. I just changed out the thermostat....a 92 for a 79 degree, and I am trying to install a power steering filter. It doesn't seem to have one. It appears I can just install one in the housing and shorten the spring inside.

Oh yeah, I also have the slicks installed on my 240d lightweight al wheels. Unfortunately my 30mm spacers won't work because they are made for a newer benz with bigger wheel openings.

So tomorrow I am headed up to South Bend to an autocross at the tire rack test track.

Wooo hooooo!

Oh, yeah, I got a cortesone shot in my knee on Thrusday and my energy is trememdous!

I feel like I'm forty again.

Tom W

POS · #59 07-19-2008, 04:51 PM

Sounds like fun - no pics of this thing coming together? Or better yet, pics on the track? Congrats!

t walgamuth · #60 07-19-2008, 11:22 PM

Yeah, I thought about taking pics today with the autocrosser next to the diesel to show how low it sits, but never go around to doing it.

(Its so low I can't get my floor jack under the crossmember).

But the car is loaded and ready for an early departure.

Unfortunately I jambed my left pinky catching my wayward bunny today (yes again) and I'm typing with my pinky taped to my ring finger and am hoping I can drive tomorrow with the proper vigor with it this way.

Wish me luck.

Tom W