Rebuilding front end on Norm - Page 3 - PeachParts Mercedes-Benz Forum

Stretch · #31 02-18-2011, 02:53 PM

When you replaced the springs (on the front) did you compare the heights with the old ones?

Did you change the upper rubber shims? How many bumps - also called nubs - do you have on the shims that are fitted?

I think the best way to check the ride height is to follow the FSM - I've posted some information about this here:-

How I adjusted the toe in / out, camber and caster on my W123 300D

TylerH860 · #32 02-18-2011, 02:59 PM

Wow, new springs? Those will probably take longer to settle. Mine were in good shape so it wasn't nessicary. I imagine those would take a long time to settle.

The ride height on these things originally was pretty high in the nose.

colincoon · #33 02-18-2011, 03:00 PM

^I didn't have a chance to, the springs were going in while I was on the other end of the shop rebuilding the spindles. I do know that the rubber "top" was not replaced on the spring. We took the rubber piece off the old spring and put it on the new one.

I don't know what bumps/nubs you are speaking of.

TylerH860 · #34 02-18-2011, 03:01 PM

Have you had your alignment done yet?

colincoon · #35 02-18-2011, 03:12 PM

^Not yet, I had to do the drag link and steering damper today so I'll probably get the alignment tomorrow.

I'm just going to drive it. If it falls apart, it falls apart. It drives amazingly though.

Stretch · #36 02-19-2011, 05:40 AM

Quote:

Originally Posted by colincoon

^I didn't have a chance to, the springs were going in while I was on the other end of the shop rebuilding the spindles. I do know that the rubber "top" was not replaced on the spring. We took the rubber piece off the old spring and put it on the new one.

I don't know what bumps/nubs you are speaking of.

These nubs / bumps are visible on the underside of the rubber spacer that you fitted above the spring:- look at the top of the spring and you'll see them on the lip of rubber that comes out of the spring "socket" on the chassis.

There is loads of information on this forum concerning ride height

(Do a search in google => nubs spring spacer site:peachparts.com)

But here is one to start you off:-

http://www.peachparts.com/shopforum/sitemap/t-205709.html

Yak · #37 02-19-2011, 11:08 AM

It's very hard to tell but it does look like the springs are in wrong.

In the pic in post 30 is that the end of the coil sticking out next to the shock? If so, that part of the spring should be recessed into the lower plate. There's a scallopped out area for the spring to seat into. It appears that your spring needs to be rotated about 90 degrees and that may allow it to decompress a bit and drop maybe another half-inch to inch.

It is probably dangerous to drive in the current condition if that spring is not settled.

If I'm misinterpreting the pic and the end of the coil is settled, then disregard this.

Generally all the parts need to be tightened with weight-on-wheels. This includes the UCA/tower bolt, the LCA/eccentric bolt, the torsion bar bushings. This sets the "resting" position as the normal position. If they're tightened with the wheels in the air, the car has to fight the rotational "spring" of the rubber bushings from being torqued in a wheels-extended position. Yeah, it'll probably settle out over time.

The FSM covers this in a note on the front axle.

"Control arm bearings at front end and torsion bar at front wall, as well as supports of upper control arms on torsion bar may be tightened only when vehicle is ready for driving. When tightening these bearings with the wheels free of pertinent loads, wrong values for control arm position would result."

Ref: FSM 33.3-200 and 32.5-305

Yak · #38 02-19-2011, 11:20 AM

Regarding "right springs" vs. "wrong springs" and the rubber spring pads.

If you have the FSM, you can see there's a large range of springs available for the W123. Short or long versions, firm rate vs. soft rate. It's a combination of metal diameter and spring height.

Spring pads also need to be properly seated. They range from 8mm to 23mm. They'd only make much of a difference if you swapped from one extreme to another.

You can clearly see 4 bumps in this pic: http://www.peachparts.com/shopforum/attachments/diesel-discussion/41154d1171422989-write-up-ball-joints-lower-control-arm-bushings-tool-review-pics-small_klann.jpg

8, 13, 18, 23 for 1 thru 4 "bumps" respectively, I think.

colincoon · #39 02-19-2011, 06:10 PM

^The springs are seated in the plates fine, the final edge of the spring is in place against the indent.

As far as the nubs and bumps go I don't remember how thin they were, but they don't look like they were that thick. I'd say it was close to 8mm.

I'm just going to drive it and see what happens.

Yak · #40 02-20-2011, 07:55 PM

You may want to double check the spring length and compression rate. They look a bit more bowed then they ought to be. I checked an old thread and my research at the time showed 8 different types of W123 front springs.

I was also concerned after I rebuilt my front end on my 300CD. I reinstalled the factory springs though. Pics/measurements here: What is the stock w123 ride height?

After a year it hasn't settled much.

colincoon · #41 02-20-2011, 09:27 PM

^I have no way of getting the springs out myself, and Pierre has my old springs.

If it helps I bought these springs (the top one):

http://www.*********.com/catalog/1980/mercedes/300td/suspension/coil_spring.html

I'm going to give Pierre a ring, I really don't have the tools to dig in to this. I might even just install the old springs, if he still has them.

JamesDean · #42 02-20-2011, 09:41 PM

The EPC lists two spring part numbers for your TD..it has 4 different shims..

Yak · #43 02-21-2011, 09:32 AM

Cross referencing a few sources:

The upper ones (xx3354) say they're for chassis 011110 and up, the lower (xx1580) are 011109 and older.

EPC references chassis 011110 to p/n 123 321 2704, 011109 to p/n 123 321 3604.

The FSM says 2704 is the longer (463 mm) thinner (15 mm coil) softer (23.3 mm/1000 N) spring compared to 3604 shorter (453 mm) thicker (15.41 mm) stiffer (20.4 mm/ 1000 N)

So if you put more weight it may compress down, but (at least per the FSM, if the references are correct) you've got the tallest possible spring currently installed.

But...the FSM shows you can have a short (red coil) and a long (blue coil) spring with the same p/n. The difference is made up in the pad height. If you've got access to the FSM, check out section 32-220. It's almost as much fun as doing your taxes.

colincoon · #44 03-22-2011, 12:02 PM

One of my guide rod mounts is already bad. I guess I should have seen that coming when the Meyle box said "made in China" on it.

Looks like I need to replace them already. Does anyone know if this can be done without removing the spring?

JamesDean · #45 03-22-2011, 12:28 PM

Isnt the guide rod mount on the 123 just like the 126?

On the 126s it
1)remove cross member
2) remove two bolts that bolt support bearing bracket to chassis
3) unthread guide rod
4) take support bearing bracket to bench and do work..

As far as I can tell there is no need to remove a spring..