Advice on IE trailing arm mounts?

[dynoclimb]

Eccentric style adjusters use locking nuts (either nylock or deformed thread style) so there is no need for a jam nut.

The serrated style adjusters are just regular threaded on one side, so no locking feature. The jam nut keeps the bolt from unthreading from the serrated plate. You don't need 2 wrenches at the same time, only one on the bolt to tighten, then again on the opposite side for the jam nut.

They are also super fun to get to on the outer mounts....

[AndrewBird]

Why does it need a jam nut? I'd be tempted to just tack that nut on.

The eccentric bolt adjusters just have a nut on the other side, with the serrated plate on this one already being threaded it amounts to the same thing.

I like the idea of NOT needing a wrench on the other (difficult) side...

Eccentric style adjusters use locking nuts (either nylock or deformed thread style) so there is no need for a jam nut.

The serrated style adjusters are just regular threaded on one side, so no locking feature. The jam nut keeps the bolt from unthreading from the serrated plate. You don't need 2 wrenches at the same time, only one on the bolt to tighten, then again on the opposite side for the jam nut.

[dynoclimb]

Both sides are really tight... You might not need to take it all the way out. I wonder if you can leave it on the outer mounting studs and get it far enough out of the car to get to it. You'll need to the nuts all the way off and lower it with jacks, just don't let it the stud disengage from the bushing.

Good Luck....

[LateFan]

Test fit the Subframe back into the car before you reassemble it. I had some interference between the Chassis side and the Toe Adjusters. I needed the grind a 3/16" chamfer on the top side to the Toe brackets.

^^^ So here's some advice I missed or forgot.

We have a serious metallic clunk / rattle in the back, especially the right. Stripped the trunk to bare, re-fit the battery, checked the shock mounts, tightened the parking brake slack, tightened the subframe bolts just to make sure the studs had bottomed, checked every fitting underneath, and watched each trailing arm through its full travel.

With a light and a mirror, it looks like the upper corner of the outside flange of the toe bracket is just touching the chassis rail. Undercoating is carved up just a bit.

So if the subframe is mounted on bushings, it moves around and isolates the car from suspension vibration, and I think we may be transmitting all that directly into the floor.

Is there a way to get a die grinder or something up in there and nip off that corner? I DO NOT want to take off the subframe...again. We've had it down twice now.

On a positive note, it drives nice and tracks right down the road. Two several hundred miles trips so far.

<EDIT> - in Post #22 above, the 4th photo - his thumb is right at the point of the flange of the toe bracket. Both sides undercoating is cut, the right side is where the noise is coming from right now.

[LateFan]

School's out, time to get this thing back together! So fun to see him fixing his own car.



Cunifer brake pipes. So pretty until you actually maneuver them into place and connect fittings, then you get some wobbly bows here and there - and they're factory length.




We set them pretty close to the center of the slots and didn't torque them down hard. We'll take it to the shop that did the welding to align and set it up. IE sent us the missing lock nuts.


SO much easier job with two people!

[dynoclimb]

yeah, but vibrations and heat cycles could loosen the bolt to serrated plate threads, So the Jam nut is used to tension that threaded connection to keep it together. I would have preferred to safety wire the bolt head, and think I may look of a drilled bolt to replace it in the future.

[hoveringuy]

Why does it need a jam nut? I'd be tempted to just tack that nut on.

The eccentric bolt adjusters just have a nut on the other side, with the serrated plate on this one already being threaded it amounts to the same thing.

I like the idea of NOT needing a wrench on the other (difficult) side...

[dynoclimb]

Yeah, we made a spreadsheet, that I can't find, that we used to calculate the adjustments.
Used a String alignment rig, caliper's(measure),and a digital angle gauge.
Tracks straight and everything is within the BMW Spec window. its nice not to have massive amounts of rear camber now...

[LateFan]

Hoveringguy -

No, small nut is the jamb nut. he just sprayed the whole thing black so it didn't flash rust. It's skinny so you can get a wrench in there to get it off and adjust.

Dynoclimb above has more info on the adjustment increments. I thought IE said you have 1.5º range either direction if you centered the tab on the existing TA holes.

[LateFan]

I wondered about that, how big the jump is from tooth to tooth. The shop that welded it does alignments, so I think I'll have them do it. It's not a restored Duesenberg y'know, but they seem to like our project and let us bring it in.

We're waiting on hard brake lines and warmer weather in the garage, then we'll see about getting it back together.

[hoveringuy]

Is that nut welded on?
Is there any correlation between what each notch means for degrees of camber?

Those give a HUGE amount of adjustment compared to the eccentric bolts, almost too much.

Looks good!

[dynoclimb]

Looks good. the one thing we learned when aligning it was that .070 limit of the groove interval obviously limited our increment of adjustment and then the pivoting ratios of the mounts... So you get really fine adjustments in Camber and the opposite in Toe...
Although we're talking small amounts. We got it all close enough that I can't tell...

[LateFan]

Here's how mine turned out so far....

[LateFan]

Yep - the "nut" is actually a threaded square plate with the serrated teeth on the back face. The teeth fit into the teeth of the u-channel shape of the new tab. The bolt threads into that flat plate and holds it in the teeth. Then there's a skinny lock nut / jamb nut on the outside of that to keep it from loosening with movement or vibration.

[dynoclimb]

Poor mans safety wire. It s a jam nut, not a lock nut per say. I could see the confusion.