Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks



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#224946 11/18/11 01:15 AM
Joined: Mar 2011
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Backyard Mechanic
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Ok I may have been a bit hasty with glowing report of uni joint modification, I had hells trouble getting the torque tube to sit right when bolting up the uni joint it was pulling to the Aussie drivers side, had to use a clamp to pull it across, any thoughts as to why the car was on flat level ground and if any thing the joints at the spring shackles are worn and a bit loose so should have been easy to manipulate? RAY

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Ray
Go back to my previous posting re this problem. Short version is one of the back has sagged more than the other which drags the torque tube to one side
Chris

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Ah so if my tool box on the back left side was full it would push one spring more than the other? The springs were re tempered and set a while ago . RAY

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Also check the frame for squareness by measuring the diagonals. That can be hard to do on a complete vehicle. It's easiest to do it by parking the vehicle on a flat and level surface (garage floor), and using a plumb bob or something similar to transfer fixed points of the frame down to the garage floor. If you can transfer a point from each corner of the frame to the floor, you can then measure diagonally between the LF/RR and RF/LR, and compare those two measurements. If they differ more than about a 1/4" (6mm), your frame has been pushed out of perfectly square and is now more of a diamond shape.

This is common with old Chevs as they do not have a "K" or "X" member in the center of the frame to keep it rigid, but rather riveted in straight cross members. If the vehicle has been hit in any of the four corners fairly hard, straight on, or has been pulled on any corner hard (think tractor pulling a stuck car out of the mud using a chain), the frame can be pulled into a diamond shape. At that point, the cross members and axles are not square to the center line of the frame, and the front of the torque tube will not want to center up on the transmission.

If your measurements show this, it is usually easy to push it back to square using a Porto-Power (hydraulic) or something similar that can push or pull (or both) on the frame diagonally from solid points. I have even welded small gusset plates into a couple of my old trucks where the cross members meet the frame rails to hold the frame square. Once it's back to square, the torque tube will line up perfectly with the transmission without having to use force.

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Hi Ray

Before you start pulling stuff apart do some simple quick checks. First is to measure the wheelbase and if it is the same both sides you are ok. Which really means that your springs etc are pretty much alright.
This drama is a problem that I have seen before and on that car it was a bent torque tube. The best way to see it is to get the car up on a 4 post hoist and view it from underneath when you release the uni it is easy to see the bent tube. Very easy to fix by just heating the opposite side at the bend and watch it move by it self or you can quench it with a wet rag but be careful it doesn't shrink it too much. This should then line up without pulling the tube across to bolt up the uni. Should not be a big drama so don't turn it into one. Good luck
Twin4

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The frame is pretty straight I checked it a while ago to get the wheel alignment right. I think the main problem was I have a big tool box on 1 side of the ute and it was full of tools. I dont think the torque tube itself is bent I placed a long straight edge i use for work down its length and all seems good, will park ona good level surface and take a few measurements tomorrow, its 37 Deg C ( approx 98F) here today and I couldn;t be assed. RAY

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Grease Monkey
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Ray I had the same problem on my 28 roadster. I fought it for years.I did everything you have tried and I was told to check the torque tube because it was probably off center. When I checked it it was over one half inch off. I had another tube whitch measure perpect and put it in with a new drive shaft and the car runs smoother than it has in 53 years and is also quieter. I measured the tube on both sides out of the car from the top on one side to the lip of the differential housing to find this. Lewis McFadden


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There is another thing you need to be aware of. If one rear wheel is lower or higher than the other rear wheel The geometry of the 90 degree angle that the axle houseing to the centerline of the car will change the alignment of the torque tube away from the centerline of the car and put the joint of the long torque tube and it's driveshaft in a slight angle away from a straight line. If you don't believe me just jack up one rear wheel with the ujoint disconnected from the rear of the transmission and notice the miss alignment of the driveshaft and the transmission.


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Thanks guys Will check that as well, next week end now! was out and about yesterday and lost all vacuum in my vacuum tank so had to limp home filling the vacuum tank 2 liters at a time, put in a new gasket on the top and replaced the line to the inlet manifold, seems fine now, RAY


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