Front Subframe Restoration Tips?

[jackm]

I recently pulled the engine in my '71 Roundie (with an eye toward converting this beloved heap into an EV) but my next challenge is dropping the front (and rear) subframe for disassembly, cleaning and restoration. I plan to follow the excellent overview on front subframe removal, and have also found this clip on YouTube very helpful

 

 

But I have a couple of practical questions for the 2002 braintrust.

 

• I will likely need to be able to roll the car in or out of the garage while getting the front suspension powder coated and rebuilt. What is the best way to do that with the front subframe (and next, rear) out? Dollies of some kind?
• Best way to organize all the hardware and fasteners ... maybe something like the tackle box approach in the video?
• Best source for a kit for all the new bushings and parts that should be replaced?

 

Of course, one of the first things I learned as a member of this great group is to do your homework in terms of searching for answers rather than just relying on the kindness of colleagues, and I am doing that as well. So more than asking for answers that I could just as easily look up, I wanted to get advice from people with experience on this next big step in my restoration, as a first timer. A thousand thank yous in advance.

 

 

[joysterm]

There are a few threads that are stored on the site that will help you immensely, just need to spend some time with the search tools to source them out.  As far as a dolly is concerned, you can make your own quite easily, just make sure to support the rear contact points for the rear frame and the front rails of the car,. I would  not rely on the jacking points that you find on the rockers. I made a frame using 2x6 lumber with 4x4 for the cross members to gain height and carry the weight. You will  to make sure you secure the body to the frame as well. It will move around on you if you don't. I used  3" ratcheted straps.

 

Get your self a couple of boxes of zip lock bags, and bag and tag EVERYTHING  as you go. Take pics as well to help identify the pieces as well. If you plan to refinish the mounting pieces it will help identify them as you will likely find that bulk plating will be cheaper.

 

good luck with the journey!

Edited April 20, 2023 by joysterm

[Mike Self]

And don't forget to doublecheck that you've disconnected everything from the subframe (steering shaft, brake hoses, clips holding wires or brake lines, etc) before you remove it...otherwise you'll damage/break something...

 

And while it's out, you can rebuild the front suspension easily--just don't torque down the suspension arm bolts 'till the car's back on the ground.

 

mike

[tech71]

10 hours ago, jackm said:

I will likely need to be able to roll the car in or out of the garage while getting the front suspension powder coated and rebuilt

I needed something fast to move Franzi around and this works pretty good:

About 6 ft of 2x6, 8 lag bolts and 2 Harbor freight HD swivel casters.

I used 10 in casters but the 8 in would be more level can save a few bucks.

Under 50 bucks, I'm doing the front subframe/engine bay first, will deal with the rear later.

Edited April 21, 2023 by tech71

[Themis]

My personal experience/opinions from doing this a couple of times:

1. Many photos and notes as you disassemble.

2. Strip of paint, inspect for cracks, weld if necessary

3. Prefer to rebuild with BMW brand rubber bushings; these have been tested in the field for many years, unless you require a harsher suspension

4. Do not plate and reuse the old bolts. An old fastener that’s been replated, although pretty golden, is significantly weaker than a new one. For suspension, use 8.8 / 10.9 fasteners throughout 

5. Use Loctite blue and a torque wrench tightening all when reassembling. Some require to be torqued with the weight of the car on the suspension

6. after a few miles, the suspension will settle, so revisit and make sure torque is in spec again

 

[Mort]

For my ‘76 I just used a 4x4 scrap piece of wood bolted to subframe captive nuts and a trailer jack with wheel. ($30 bucks at Harbor Freight) I could move it around easily and also change height. Not a great picture to show this but jack just attached to 4x4 with supplied u-bolts. 

[jackm]

On 4/20/2023 at 12:23 PM, tech71 said:

I needed something fast to move Franzi around and this works pretty good:

About 6 ft of 2x6, 8 lag bolts and 2 Harbor freight HD swivel casters.

I used 10 in casters but the 8 in would be more level can save a few bucks.

Under 50 bucks, I'm doing the front subframe/engine bay first, will deal with the rear later.

Is the car just resting on the board & casters? Seems like a smart solution, just wondering if it would work with the lip and slight incline out of my garage.

[jackm]

On 4/21/2023 at 7:32 PM, Mort said:

For my ‘76 I just used a 4x4 scrap piece of wood bolted to subframe captive nuts and a trailer jack with wheel. ($30 bucks at Harbor Freight) I could move it around easily and also change height. Not a great picture to show this but jack just attached to 4x4 with supplied u-bolts. 

Very clever.  What did you bolt the 4x4 to on in the engine bay?

[jackm]

I just had a bit of an epiphany from this clip:

 

 

The struts, hubs, & brakes are all in quite good condition. (I refreshed the calipers, rotors and brake lines to get the car drivable.)

 

Maybe I don't need to drop the whole front subframe but just take apart everything else: tie-rods, control arms and the rest, a bit like the way this guy did.

 

Is there anything that I can't do to rebuild the front suspension -- bushings, ball joints, new hardware -- if I leave the struts, hubs and subframe crossmember in place?

[AceAndrew]

On 4/20/2023 at 11:36 PM, Themis said:

 

4. Do not plate and reuse the old bolts. An old fastener that’s been replated, although pretty golden, is significantly weaker than a new one.

 

This is not true.  Where did you see this?.. so I can go slap them around a bit.

[Themis]

1 hour ago, AceAndrew said:

This is not true.  Where did you see this?.. so I can go slap them around a bit.

I worked in aerospace R&D for many years, personally I think it’s not good practice to take a bolt manufactured in the 60s and submitted to stress for decades, put through acid to replate it and then reuse it. You will not find any engineers following best practices that would do that. I understand many in automotive can say this is not an issue, that’s fine. I’d reuse bolts in many spots, but not in critical load components (engine, suspension).

Edited April 24, 2023 by Themis

[tech71]

3 hours ago, jackm said:

Is the car just resting on the board & casters? Seems like a smart solution, just wondering if it would work with the lip and slight incline out of my garage.

Of course not, drilled a couple of holes and  bolted to the frame rails at the subframe attach points. its not going anywhere😉

Edited April 24, 2023 by tech71

[jackm]

1 hour ago, tech71 said:

Of course not, drilled a couple of holes and  bolted to the frame rails at the subframe attach points. its not going anywhere😉

Ah, I get it: you used the same bolt holes that hold the subframe on. Duh.

[tech71]

4 minutes ago, jackm said:

Ah, I get it: you used the same bolt holes that hold the subframe on. Duh.

A bit longer bolts with large area washers, dug them out of the bolt can.

Edited April 24, 2023 by tech71

[2002iii]

2 hours ago, Themis said:

I worked in aerospace R&D for many years, personally I think it’s not good practice to take a bolt manufactured in the 60s and submitted to stress for decades, put through acid to replate it and then reuse it. You will not find any engineers following best practices that would do that. I understand many in automotive can say this is not an issue, that’s fine. I’d reuse bolts in many spots, but not in critical load components (engine, suspension).

It's not rocket science lol.

 

A lot of the time the metal used in modern bolts is not very good quality as compared to the original quality German steel.