Rear Coils

[selavia]

Two quick questions:

1. Do you really have to remove the drive axle to replace the spring?

2. How do you get the spring out? I am having difficulty pushing the hub and the whole assembly down far enough to get the spring to come out. The shock has been removed, but I cannot seem to get the coil out. Is the tension being cause by the drive axle?

 

[Big Daddy]

No you should not have to remove the axles, this from Pelican Parts Tech article, "Now, have a helper stand on the rear trailing arms, this will force the trailing arms down, and allow you to remove the rear springs. You should be able to simply pull them out "

http://www.pelicanparts.com/bmw/techarticles/E30-Rear_Suspen/E30-Rear_Suspen.htm

 

[Kirby]

They are definitely a tight fit, not easy to pull out from my experience. You do have to push down pretty hard. It is the TAB (trailing arm bushing) that is providing the resistance. As long as the resistance feels "soft" you are just twisting the TAB. If it stops and won't twist anymore at all, don't get too rough. That means you are at the limit of the axle free play. Forcing it (hammer, whatever) can damage the CV joints. That's why the "correct" (meaning safe) way involves removing the axle shaft.

 

[selavia]

Thanks. All right; I'll just put more force on it.

Kirby, did you have to take off the drive axles when you replaced yours?

 

[Big Daddy]

Sean make sure you have rotated the axle so that the CV joint is in the lowest position, in other words lined up with the u-joints so that the axle can hang to it's lowest point, than use some force but like Kirby said, if you feel you are pushing so as forcing metal rather than bushing...stop!

 

[selavia]

That's a very clever thought. I would have never though of that. I'll try that, and if I find I need more pressure, I'll either remove the axle or find a way to compress the spring.

 

[Kirby]

I already had the diff/subframe/axle shafts removed to install M3 subframe mounts when I put the springs in.

 

[echothreezero]

I'm suprised Pelican parts said that. Proper proceedure is to support the hub (not force it to lowest position) and use a spring compressor. It is possible to push the trailing arm down and pull it out but you run the risk of damaging the CV's.

 

[selavia]

I think I damaged the CVs or something isn't right.

The back end is lop-sided. The driver's side is approximately an inch lower than the passenger side. But I drove the car and there are no noises from the axles. I don't know what's wrong.

THe only two things I can think of are that (1) I dislodged the cv joint of one or both axles or (2) that I did not adjust the adjustable shocks equally in the back. I was fairly certain that they were equal, but maybe I'm wrong.

Also, when initially lowering the car, the ride hieght is equal on both sides, but after driving it, the driver's side is about an inch lower.

Any thoughts?

 

[Big Daddy]

Did you get the coils resting properly in their respective pads?

 

[selavia]

I'm pretty sure both are seated correctly. I'll check again today when I go home.

But I jacked the car up and check and them pretty hard and they were in place. I'll check again.

Besides that, what else could it be? Could it be the axles?

 

[Big Daddy]

I don't think the axles could account for an inch difference, however with a rear suspension like say in a VW bug years ago, when you jacked them up they usually sit at odd angles until you drove the car or rolled it, but that should correct itself in a few feet.

 

[Kirby]

Yeah, I agree with Dan, it's usually skewed when you let it down, and after driving it settles out, because the rear suspension is "pigeon toed" until it rolls out.

Make sure a shock isn't bottomed out. But that would be weird, because obviously you need free travel for the shock to work at all.

Does the suspension seem to have normal "springiness" in it on both sides? If not, maybe something is binding or jamming.

My only other thought is that the TAB (trailing arm bushing) rotated when you pressed down, and it is now supporting more weight. That could mean either the rubber in the bushing is separating from the metal, OR that the bushing rotated a bit in around the center mounting bolt. The picture below shows the TAB mount, the bolt is not visible.

Here is a link to some more info:
http://www.rogueengineering.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=RTAB

 

[selavia]

Followed the link. Okay; that actually makes some sense. I am going to look into that as soon as I get home. Thanks.

I think I got too rough with the passenger side, I began to use my foot to force pressure down, but the damn thing just held my weight and didn't go down any further. I ended up using 3 pry bars and 'springing' the spring out. (Very dangerous! I would not recomend anyone doing that.)

Also, the reason I think my axle is broken is that before raising the trailing arm to attach it to the shock, I tried moving the axle around, toward the hub, toward the transaxle, and when I moved toward the transaxle, it moved a good .5 inch to 1 inch. And I could see the boot clearly expand and then go back in. The outer CV joint, I think is no longer 'locked' but now just kind of stuck in there. But when the car was lowered, it drove fine and I could not move that axle for the life of me. Is there any way to check without removing the boot? Or does it sound like I messed up the axle or am I getting overly concerned over nothing?

Thanks guys; as always, you are life savers!!

 

[Kirby]

By the way, the more I think about it the TAB might be the issue. There is a specific adjustment for the trailing arm to set the "static" adjustment of the TAB (in Bentley). It is actually under torque when the car is down on the wheels. If it rotated, it would be providing more lift torque, which would explain your ride height - the tab is carrying more weight on the high side, so the spring is not compressed as much.

if you decide to look at the TAB let us know before you do that. You will want to be prepared properly.

 

[Kirby]

The end play on the CV is fine, and necessary. Think about the geometry - the axle is part of a steel triangle. As the wheel moves up and down, the distance between the diff and wheel changes, something has to give, the end play gives the necessary freedom.

 

[selavia]

Kirby, thanks.


Okay, please educate me on the TAB. I reread the Rogue engineering article. The more I think about it, the more I agree with you. I am going to check the TAB tonight. I have bentley's and I'll read it before touching anything. But what else should I be looking for.

And I know that free play is nec on the axle, but sometimes when working on my car I tend to really doubt myself; even to the point where it defies logic.

Please, any information on the TAB would be helpful.

 

[Kirby]

I'm guessing that the static height is off, this is part of the TAB replacement procedure. The procedure is in the Bentley, follow the instructions about replacing TABS. Look specifically at the instructions regarding tightening the TAB center bolt to align the "console" to the hub. THIS PAGE has a detailed discussion on replacing the TABS, and also aligning them. Scroll down about halfway to see the alignment info, this picture. You can see that the BOTTOM of the console should project a line that is 8mm above the centerline of the axle. My guess is that yours is rotated lower due to the force of spring removal.

There are a couple of things to watch/plan for. I just know the pain of experience and can offer some tips and pointers!

- From the picture you can see that you will have to remove the "console" bracket. The 3 bolts might be rusty. Spray some PB Blaster, WD40, whatever. I had to replace one of mine, it was too rusty for my satisfaction.
- BE SURE to mark the exact position of the bracket before you loosen the 3 bolts. You want to get the bracket back in the same place to maintain alignment. (Of course, since you changed springs/struts, you need to get a 4 wheel alignment anyhow.) This will just help to keep it close.
- Loosen the center bolt and set the static angle. Do your best but don't worry about 1mm difference.
- Put some lube on the bolt threads before you tighten it, so you can get it good & tight.
- When you go to put the bracket back into the frame, it will be a biatch because you will have to force the bushing to twist into place. Remember how hard it was to push down? It's kinda the same. My trick is to use the floor jack to gently jack the bracket into place, enough to get the bolts engaged by 1/2" or so. Then turn each bolt 1 revolution at a time to line up the bracket and pull it into place.

This probably sounds confusing, but with the Bentley and the web site, you'll figure it out pretty easily. Good luck!!

 

[selavia]

All rightie, I think I got it. Thanks. Going to go do it right now. I'll let you guys knwo what I find. Thanks again!

 

[selavia]

Twas the TAB. It's perfect now. Thanks. Hopefully I won't have any problems when doing the fronts tommorrow. Any pointers on the front suspension?

And the TAB was not that off. All I really had to do was take the bracket off and apply pressure I heard it 'snap' into place. Put it back on as close to original as possible (the 3 screws) and she was matching height on both sides within a 1/10 of an inch. I think the vehicle is too low in the back; I may end up getting the 15 mm spring pads.

Dan (frolf), I remember you said you were getting rid of yours for the 10mm; I'll buy them from you (also, I have brand new 10mm from the dealer, if you want them)