Jump to content

Rear Trailing Arm Installation


Recommended Posts

I finished assembling the front subframe of my 1970 BMW 1600 and moved on to the back.  During the disassembly of the rear subframe, I noticed that driver's side shaft threads for the M24 Crown Nut were damaged, so instead of sending out the original trailing arms for powder coating, I substituted a spare set of trailing arms from my stash, disassembled them, and sent them out instead.  In the process of trying to attach the rebuilt trailing arms to the rear axle carrier, it seems that they do not line up properly to get the bushing in.  They seem to be over 1/4 inch too narrow to slide into the rear axle carrier.  Were the 1600 rear axle carriers different than the 2002 models and I am trying to mix apples and oranges (2002 trailing arms on 1600 axle carriers), or did my trailing arms shrink during powder coating ;-)?

 

I really don't want to start over with the original trailing arms, but I will unless someone has a better idea.  Here are some pictures, (Original trailing arm fitment, new trailing arm with outboard side installed in axle carrier.

 

Thanks,

 

 

Mark92131

IMG_2956.jpg

IMG_2958.jpg

Link to comment
Share on other sites

The only difference in trailing arms that I know of is between long neck and short neck rear carriers and the miss by a lot more than that. Your not off by much in your picture, you can try to shoehorn that in using lube and a putty knife or bend the ear a bit and let the bolt bring it back in shape when you torque it down.

  • Like 1
Link to comment
Share on other sites

This may be a case of 1600 trailing arms vs 2002 trailing arms.  On closer inspection, the original trailing arms has a clip welded directly on the trailing arm to secure the hard brake line, the 2002? version has this clip on a structure on the lower spring pad.  Also, the bushing hole for the connection to the end of the sway bar is smaller in diameter on the original sway bar than on the 2002? version.

 

I don't know what would be easier, powder coating and rebuilding the original trailing arms or finding a rear axle carrier for a 2002 near me that I could powder coat to match the rebuilt 2002 trailing arms.

 

Mark92131

IMG_2962.jpg

IMG_2963.jpg

Link to comment
Share on other sites

Not sure that I really get this?  Why would you put a different set of trailing arms in for PC?   If it is the stub axle threads that were damaged, just get another stub axle.   You are taking everything out of the trailing arms when they are going out for PC, right?    There is no difference between 1600 and 2002 trailing arms  Sometimes the angle is just not right and as someone else suggested, slightly bend the tabs a bit so they start to slide in, they will go.  Did you put in new bearings and seals?  Good luck with the reassembly

 

Thanks, Rick

Link to comment
Share on other sites

2 hours ago, Son of Marty said:

 Your not off by much in your picture, you can try to shoehorn that in using lube and a putty knife or bend the ear a bit and let the bolt bring it back in shape when you torque it down.

+1

 

Mark, having done a fair amount of them .... this is fine.  Bend it and send it.  Won't take much, once you get it started you can slide a steel rod from the side and wiggle it in the rest of the way.  Having an extra set of hands is bueno.

 

Also, the tab for the brake hardline .... as mentioned, it isn't a 1600 vs 2002 thing.  I'm not %100 sure when the change happened though.... either part of the mid 71 cross over or the roundie to square change.

 

The bits sure look pretty though!

  • Like 1
Link to comment
Share on other sites

14 hours ago, stephers said:

Why would you put a different set of trailing arms in for PC?

 

In hindsight, I should have pulled the stub axles out of the spare trailing arms and used them in the original trailing arms, but I wanted to keep all the components together as a set.  Mostly because I was told that you needed to keep the inner sleeve and spacer together as a set for each trailing arm.  I didn't want to mix them up, but I should have checked the trailing arm fitment in the axle carrier before sending off to powder coat.  That would have probably changed my approach.

 

Mark92131

Link to comment
Share on other sites

3 hours ago, Buckeye said:

I am sure your bushing blocks orientation are correct

 

Yes, the bushings are installed as pictured in your illustration.  At least I got that right.  I'll do some measurements to see if the axle carrier is in spec.  Thanks for responding.

 

Mark92131

Link to comment
Share on other sites

14 hours ago, AceAndrew said:

 

Mark, having done a fair amount of them .... this is fine. 

 

It is hard to tell by my pictures, but the amount of bending required to get the bushing started will be significant and I am afraid my pretty bits won't be so pretty after installation.  I think an extra set of hands will help.  Thanks for the suggestions.

 

Mark92131

Link to comment
Share on other sites

There only 2 arms used in all 1602/2002 production. Buying new ones will result in getting the part you already have. What you have going is typical of a new rubber bushing install, put a c clamp with a washer covering about 1/2 the hole or a bit more and squeeze. Powder coating is great for parts but once you do it your stuck anything that hits or movers it will cause a nick or crack and your stuck with it. Use a heavy paint on them and you can touch it up, just my thought and preference.

Link to comment
Share on other sites

28 minutes ago, uai said:

The longneck rear subframe openings are narrower where the bushings go. 


100%
I sent a totaled 02 to the scrapyard with a ‘72 rear subframe and ‘68 1600 trailing arms. Since it was junk I just tightened the bolts until the brackets pulled into the narrower trailing arms. Not a functional solution in my opinion and the opposite  situation compared to the OP. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...