Steering and Suspension: Design and parts

[jneely]

I've got my car mostly stripped down. I uncovered some issues with the front suspension, and wanted to make sure firstly that I understand how everything is supposed to work, as well as where to secure parts. This is a wordy post, but I want to make sure I can properly rebuild everything.

I am not used to trunnion based suspension. Not much by way of detail is given in the mechanic's manual. I've worked on plenty of old king-pin straight axle front suspensions and modern ball joint or McPherson types. Am I understanding correctly that the threaded joints are the articulating surfaces (wear surfaces) of the front suspension? The way it looks to me, A-arm spacing changes as the wheel turns left to right, as the knuckle threads in and out of the A-arm trunnions. Similarly, the A-arms move front to back through jounce as they thread into the support bar bushings? It seems foreign, especially given that modern style swaged ball joints were available, as indicated by the outer tie rod ends.

My trunnions, particularly the lower, are very much worn out. I've located the rareparts.com replacements for these, although they aren't cheap - especially for all 4.

Unfortunately, my lower control arm mount stud had rusted in the frame rail, and broke upon disassembly. Would anyone know where I might be able to find a replacement? I assume I would have to replace the entire shaft assembly.

As for steering, mine looks to be in pretty good shape. The pitman, idler and inner rods were tight and look good - except there isn't much left of the dust covers. There's just a sheet metal cover with a spring, and a couple were bent and broken. I'm not sure if there is supposed to be anything more than the sheet metal cover? Are ball and socket dust covers available, perhaps from a Jeep or other application?

The outer tie rod ends weren't horrible, but did have some slop. I would prefer to replace them, but haven't found any available for an Aero. Are they interchangeable with any of the 2wd Jeepster or Wagon or perhaps the Brazilian cars?

Lastly, the idler arm appears to be the same threaded working surface (reverse threaded, BTW, if you're struggling to get it apart), but I've seen bushings, including undersize service parts listed in the parts manual. Where would the bushing go? Is that the threaded portion which mounts to the idler arm? Perhaps mine is an older design?

As always, any help appreciated.

Thanks

[MarkH]

Check with Duane Hayes for the upper & lower trunnions. Rareparts upper trunnions are correct for you but the lowers are for early '52 and have a 2 1/2 degree "tilt" rather than a true 90 degree cross, although they will fit and work.
At one time Duane also had a variety of NOS control arms.

The idler arm bushing comes in diffeent undersizes, identified by the number of grooves in them, check parts book for that info.
There a seller on ebay that has the idler arm bracket with the bushing, listed as a jeep parts, along with other Aero part numbers always listed as "jeep".
http://www.ebay.com/itm/Antique-Jeep-Bracket-807761-Recovered-/250232173527?hash=item3a42fff3d7:m:m-cb8BmGQi9iJYAgJKy4nmg

I've seen kits for the cross tube that I think included flat rubber pads that go under the metal pads, haven't gotten that far yet on mine so don't have source info but the kits I saw also fit some jeeps so check out willys jeep parts suppliers.

I had a decent set of tie rod ends but didn't find new rubber boots. I ended up buying new ends from http://www.northwesternautosupply.com/ as well as motor mounts and the hard to find rear (trans) mount.

[Aeroman]

My usual warning about the lower trunnion bolts on the earlier Aeros: there are two bolts into each trunnion, securing them to the A-arm. These bolts tend to "gully-out" as John Parker put it years ago. Eventually, their threads will lose the grip in the trunnion, slide out and the wheel will collapse. Hopefully, you will be driving less than 5mph at the time.
MarkH may have a good lead on replacement bolts. Someone in California talked about making them up, but I've never heard of that project being completed. Needless to say, the bolts MUST be very hard steel.
When the 226 Kaiser engine arrived in March 1954, the suspension was beefed up and this problem was licked. If you wanted to, you could change out your suspension for newer, but it would require quite a few parts to be replaced.

[MarkH]

..................MarkH may have a good lead on replacement bolts. Someone in California talked about making them up, but I've never heard of that project being completed. Needless to say, the bolts MUST be very hard steel.
When the 226 Kaiser engine arrived in March 1954, the suspension was beefed up and this problem was licked. If you wanted to, you could change out your suspension for newer, but it would require quite a few parts to be replaced.

The small trunnion bolts (yours) are 1 1/4 long 5/8ths coarse thread. If you don't find them with the trunnions they can be bought in that length. Buy Grade 8, they can be drilled at low RPM (300 or below) with plenty of lube, then tapped for zerks.

If you do end up having to make them, look inside your trunnion, there's probably one or 2 pristine threads near the steering knuckle. A bolt closer to 1 3/8ths makes use of all the precious few usable threads inside the trunnion without bottoming on the steering knuckle. You'll have to cut down a 1 1/2 bolt to get those.

Rick is right about switching to large trunnions, lower control arms & steering knuckles at the minimum will need to be changed, unless you make custom trunnions, then just the control arms.

I believe the lube schedule is every 1K miles, which I doubt many cars got.

[edohan]

The idler arms and idler arm frame brackets are different between the earlier years with F head engines and the later years with 226 super hurricane engines similar to the different lower Trunnions and lower control arms.

The idler arm bracket  listed as a jeep parts and  Mark mentioned :

 http://www.ebay.com/itm/Antique-Jeep-Bracket-807761-Recovered-/250232173527?hash=item3a42fff3d7:m:m-cb8BmGQi9iJYAgJKy4nmg

probably is only good for 1954-1955 years with super hurricane engines unless you would be able to change the idler arm as well? . I include their  photos to compare:

[Aeroman]

Somewhere I have a service bulletin that says what needs to be replaced to convert older cars to the newer suspension. Jim Betts may have already scanned it.