VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Front shock absorber/A-arm assembly challenge!!!

Well I've been pressing along on the 4T1 project. Got the tapered roller bearings installed and started buttoning up the front suspension. I'd had the front shock/A-arm assemblies exchanged for re-manufactured units from Apple Hydraulics.

The driver's side went together real smoothly considering that this was the first time I'd ever worked on this kind of suspension setup. The threaded eccentric connecting link is sure an interesting design!! I'd bought the seals from 'COTF' however my friend that helped me figure out the front seal solution had told me that they would not work well and would get torn up on installation. He had found that using either a big fat o-ring or a combo of two o-rings provides a good seal there and is A LOT easier to install!!

Here are some pictures of the driver side;




I was thinking that all went well with the first side and then I got over to the right side and found that it wasn't the same.

This picture shows just how much angle I'm fighting;


Another view without the allen wrench;


Here you can see the left side(facing the shock assembly) is touching;


Here on the right side you can see almost a 1/4" gap.


Here the shock has been removed to check for levelness of the upper A-arm/shock absorber assembly. Had to place it on three precision stand-offs to get the shock assembly to sit evenly on the precision table.


We used a dial height gauge in combination with the dial indicator to determine if the bores were horizonal with the big shaft in the shock absorber assembly.


Here is my machinist buddy checking for bore levelness.


Anyone had problems with the assembly of the front suspension.........in particular this threaded ecenteric?? Sure seems to be A LOT of angle, 1/4" in less than 3 inches!??? I don't know if there is something I can do with the lower A-arm that will help remove that angle as it will not go together correctly now. Sure wish the passenger side would hae went together as smoonthly as the driver's side did!!! Suggestions!!?????????

Have the upper shock absorber arms been Brazed or welded together incorrectly?

I don't remember them being joined originally ??

My suggestion is to return the shock to the rebuilder. The arms are welded together incorrectly.
When rebuilding the shock the arms are seperated and rewelded.
Did you try to follow the installation directions of the seals in the shop manual?....it works.

I was questioning the shock absorber/upper A-arm assembly as that was the only thing that has been changed out. After checking to see if the bore centers where the threaded eccentric is located were "level" I ruled that out. However now that I think about it there is no way of knowing about or checking the "lateral/fore-aft" positioning. Meaning in the long axis/wheelbase of the car how do I check the lateral positioning of shock absorber?? The U shape where the vertical kingpin suspension member with the threaded eccentric fits into the shock absorber A-arm?? Here is a picture from the driver's side where everything went together so well to illustrate what I'm questioning;

They were welded together originally - I have handled hundreds of them.

I am wondering about the shock re-manufacturing......it was Apple Hydraulics back in New York state and they are supposed to be the best of the lever arm shock rebuilders!?? I did not know that the arms are re-welded back together in the re-manufacturing process!??? I did see something on the mounting of the arms off the shock body shafts that concerned me. I'll find the pictures and detail what I'm questioning. Here they are;








I have an original 1941 shop manual that came with the car and the original seals that I took out of the car. The seals that 'COTF'(ChevsOfThe40's) sells are nothing like the originals. The seal installation procedure pictured in the original shop manual requires A LOT of stretching of the seal. I'll bring it home and scan the page and post it up. There is no way the seal that COTF sells would stretch that much.

I have no doubt that it is welded incorrectly. This is not the first "gooof" I have heard of. At least give them a call.

I just got off the phone after chatting with Lazar @ Apple Hydraulics for 1/2 an hour. No real resolution, he claims that the factory weld is still intact, which it is, and they add some extra welding on the bottom of the arms to reinforce the arms. He also mentioned that IF I were to dis-assemble the driver side shock and place the two shock absorber units back to back they should be mirror images of each other. I guess that would be a good check to figure out if the "A-arm" on the passenger side shock is incorrectly assembled.......however I'm NOT inclined to tear into that until I attempt to assemble the suspension on the passenger side with out the load of the coil spring. I will try that today and closely check out the lower "A-arm", the attachment of the kingpin casting to the lower "A-arm" and try to see if the top of the kingpin casting where the eccentric is located will fit in the upper shock "A-arm" when there is no loading from the coil spring.


The bore center-line of the threaded and smooth holes at the end of the "A-arm" is level/parallel with the shock shaft coming out of the shock body. The eccentric threaded shaft fits just fine into the two "cups" that mount in the holes on the end of the "A-arm". If the two halves of the "A-arm" could have been incorrectly welded together it seems that would throw off the straightness of the holes and not allow the eccentric threaded shaft to fit correctly!???

I don't know what else to do except dig in and try to figure out what the problem is. Thinking about it now it almost makes sense to remove the driver side shock/"A-arm" assembly from the start and do the mirror comparison to see if there is any variance!?? Well I've got to get rolling as there is a lot of work ahead of me any way I go about it!!

I think also that you may have to check the straightness of your axle spindle, it looks very thin at the top mounting hole neck for the upper eccentric pivot. Is it possible to cold press the upper end to gain the correct alignment with the upper a arms.

This must be very frustrating as you have pulled all these components off your car and now they don't go back together, which makes me think that the rebuilder may have exchange items in stock , and these have come from a different vehicle or vehicles.

The other possible explanation for the difference in the A arms height is that this is due to the caster angles of the front suspension geometry , and either the top or bottom of your spindle is bent, and not lining up .

If the rebuilders have lined them up( the A arms) the same side to side ( next to each other) and not mirror fashion that would mean that the caster is going the opposite dirrection on your right hand wheel.

Did you also measure the centre heights of the pivots for the a arms at the shock absorber end?, because they may be at an angle to the mounting face aswell.

Another thing to try would be to assemble the upper pin into the the outer A arm and physically see if the whole assembly can be installed without the spindle.

I also checked the 2 front end assemblies in my shed , and the A arms are all welded.

It may only be the angle the pics are taken at but I dont think the arms are a mirror image of each other.
A quick check is to hold the loose unit upside down over the unit you have fitted.
Tony

Some good thoughts here Jack!! I am a bit confused on what your calling the spindle. I have always thought that the spindle was what the wheel bearings were mounted on!?? However I don't know what the official terminology would be of the vertical casting that attaches to the lower "A-arm", the upper shock absorber/"A-arm" and the kingpin hole is machined into that casting!!??? For now I'm going to to call it the VKPC or Vertical King Pin Casting.

After figuring out that the shock absorber/"A-arm" is not the problem then I had to dig in deeper. Here are some pictures to show what I found;

This is my quickie "alignment" jig made up from some precision spacers and blocks. I figured that bolting to the machined top of the VKPC would show if the hole the eccentric threaded bolt goes through was in alignment with the VKPC.


The next two pictures are of the driver side VKPC and you can see that the precision ground flat stock pieces of the alignment jig look centered over the VKPC.




These two pictures show the alignment jig veering off in a direction that would correlate with the threaded eccentric bolt angle issue that was illustrated in earlier pictures




Soooo any suggestions from folks that have had bent VKPC parts before!!?? It appears that the bend is right below the threaded hole as that is the thinnest/weakest part of the casting. I'm presuming that I'll have to remove the VKPC which we know what kind of work that entails. Removing the hub/brake drum assembly, removing the backing plate, removing the tierod and removing the VTRC from the loweer A-arm assembly. I'm certainly NOT looking forward to that teardown and then I have to figure out if it(VKPC)is something that can be pressed out and how to do that.

Suggestions anyone!!???? Anybody have a straight VTRC available for a 91 year old WWII veteran 'Battle Of The Buldge' survivor to purchase for his car!!??? It's my GF's dad's car and I'm trying as hard as possible to get it up and operational before it gets into the hot season here. We've got maybe 1.5 good months of great weather for him to enjoy driving his car before it gets too warm for him to enjoy it. Here's a few pictures of this remarkable man and his car!!

Yes, that vertical member was what i was talking about ,
The correct terminology on a 39 to 48 IFS is KNUCKLE SUPPORT.
with the wheel spindle( wheel knuckle) then attached to the Knuckle support.

I think on ball jointed IFS it is called the spindle again.!!

http://cgi.ebay.com/ebaymotors/NOS-...ck_Parts_Accessories?hash=item48396753d7

This knuckle is listed as a LH one.

The knuckle support is also a steel forging and not a casting, if it were a casting it would be fractured or broken instead of being bent. They were forged so that they could withstand things like gutters etc without breaking causing a complete failure. This is probably what has happened, with your passenger side being bent.

Here is another pair for sale by a member here on the chat site.
ChevyB
http://cgi.ebay.com/ebaymotors/1939...ck_Parts_Accessories?hash=item3a5480a4be

Thanks, Jack, we truly appreciate the info you provided on the availability of parts that we need to get the 4T1 up and fun-ctional!! I've established contact with ChevyB/Bruce and should have the parts I need soon!! He is a wealth of knowledge and I'm sure we'll be communicating with him about more parts in the future!!

What a great and helpful asset this forum has been!! I've never worked on this old of a vehicle before so it's been fun learning curve about how cars were built 69+ years ago!!