Back on her wheels.

January 3rd, 2013

I had a very frustrating time trying to get the diff set up in the end. I spent days on it. Every time I assembled it the adjusters would lock up tight. Eventually I worked out the problem. The bushes I had reamed were very off centre. Enough that the half shafts would lock on the adjusters. Since I couldn’t assemble it all properly I simply hand filed the bushes for now so nothing binds and threw the axle together enough so the car can be on it’s wheels and I can start finishing off the body.

I did make the pointer needed to set up the backlash from some aluminium and I also found that I could get a much more accurate run-out reading with the carrier stuck in half of the axle housing held on it’s bearing. Using that method there is only about 2 thou run-out.

IMG_3301_1 IMG_3303_1

The backlash is measured as 1/16th of an inch 7 inches from the centre of the shaft. I made the pointer twice as long to increase the movement to 1/8th which should be easier to see.

I’ll order new bushes for the carrier as well as new oil seals for the axle housing. In the meantime the diff and torque tubeĀ  are on the car and the car can be wheeled around. The torque tube is at the right angle so all the oil won’t leak out of it. If you lower the springs too far you can end up with all the oil in the diff going down the tube and onto the road!

I also ended up rebuilding the steering box. I took it all apart and cleaned out the old grease from it (you’re supposed to use heavy oil not grease anyway). The worm and gear didn’t seem worn at all. The thrust button was though. I needed a lot of shimming to get the end float down to nothing. I made my own shims. I cut little squares of shim steel then clamp them between two little pieces of steel with a suitably sized hole drilled in one. Then you just run a drill through the holes. It gives nice, tidy holes in the shim stock. I drill a whole stack at one that way so I have plenty to choose from. I simply put the button through the hole and trace around the outside with a Sharpie marker then cut out the circle with ordinary scissors.

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I also cleaned up the column and painted it. With the box on the car I was able to fit the drag link but I found the end of the link fouled the chassis when you turned the wheels to the right. This is because I’d shifted the box over to the left a little to get more room in the cockpit foot well. The 1/4 inch gained there was enough to cause the drop arm to be too hit the chassis. I ended up heating and bending the arm which is not really an ideal thing to do! Hopefully it hasn’t weakened it in any way. It is definitely something you don’t do with the steering arm at the other end of the drag link as they are knowing to break but that has a tight radius bend that take a lot of stress. The drop arm shouldn’t be so much of an issue. I heated it carefully just enough to bend it then let it cool slowly so it shouldn’t be brittle.

With that all done I tweaked the cut-out in the valance that the drag link passes through.

IMG_3328_1 Drag link cut-out.

I also had another go at sealing the top of the stub axles. This time I machined down the plugs on the lathe. I drilled a 1/2 inch depression in the head of a bolt and was able to clamp the plug between that and the live centre with enough friction I was able to take very small, high speed cuts (0.0005 of an inch at a time) to make the plug fit the axle. I then glued them in place using Loctite 3805 steel epoxy and hammered them home. I am hoping that now does the trick.

IMG_3321_1 IMG_3327_1 Stub axle grease caps.

With all that done I then found I needed more shims in the steering box to eliminate some end float. Lucky I had made extra! With the valance unbolted it was easy enough to get into the box without removing it.

I was then finally able to roll out the car.

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Car outside again.

The other thing I did was modify the front shock to lock one arm to the axle to reduce the swinging you normally get on an Austin 7 front end. Instead of using a shackle on one side you modify the arm by welding in a tube into which you press a rubber bush. This mounts directly to the axle mounting stud. This then means the axle can’t swing sideways and it will only move up and down. Unfortunately I found once I had done this that the arm was now actually 1/4 inch or so too short due to the slight change in geometry. I will fix this by making two new, slightly longer arms form some 2mm thick steel. I will need to order some tomorrow.

 

One Response to “Back on her wheels.”

  1. Nigel Hamlin Wright Says:

    Simon,
    It looks great and very vintage – a great effort. If you haven’t already done so, check the drag link cut-out for clearance by jacking up as far as it will go that side’s wheel and turn lock to lock. It tripped me up on mine and I had to do a roadside mod the first time I went up the verge to let a tractor past on a single track road. Similarly, I set the rear mudguards too low and had to get help to lift the car back on the road after a trip up the verge. The axles move about a lot more than we might imagine!
    All the best,
    Nigel

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