Rear Suspension

This picture shows the rear spring hangers held in place with a piece of ¾ inch all thread holding them the correct distance apart (figured on the bench with the main leaf, spring shackle, and the spring pivots, all bolted together and in a straight line. Measure from the mounting flange of the spring pivot to the spring pivot on the other side. I use ¾ inch all thread because I make the spring pivot bolts from ¾ inch grade 8 bolts. If I only used 5/8^th inch bolts for the spring pivots, then I would use 5/8 in all thread) I then level the brackets with a magnetic level and support the whole apparatus with a small bottle jack. Then I center the apparatus on the housing, mock the spring in place to make sure the center section of the rear end will clear and then tack the brackets in place. I never fully weld anything because I may want or have to change something later. A tack is easier to cut and remove than a fully welded bracket.

This is just a side view to help show the set up. Notice the vertical strap that I placed on the frame to the rear end to keep it at the correct height and position.

This picture shows everything in place with the spring mounting cross member in place and the spring mounted to the rear end.

On this car, I decided to use stock rear wishbones and keep the trick end that bolts to the rear-end altogether. I made a bracket to mount the rear of the wishbone to the axle from 3/8th inch plate, a front mounting plate to the frame from 1/2 inch plate, the rod end bushing from 1 ¼ round stock with 5/8ths 18 threads for the rod bushing which I also made. This is shown in my DVD. I lined up and supported the assembly with stands made from 1 inch square tubing welded to 2x2x 1/8th inch angle. Then I used ¾ inch all thread with a nut for height adjustment and the all thread has a piece of 1/8th in 2 x 2 angle welded to it. I have several of these in the shop and use them for all kinds of set ups from what is shown here to setting up my exhaust system. There is another bracket not shown than is on the other side of the rear bracket and at approximately a 90-degree angle so that the rear force on the wishbone is spilt in two directions along the axle housing.

Notice the c-clamp holding the rear of the wishbone in place.

Here is a close up of the front wishbone bracket, urethane rod end and the homemade bung that goes into the wishbone and holds the rod end.

Another shot showing everything tacked in place.

Frame Front

On to the front section of the frame.  One of the reasons I built this in sections is the fact that small pieces of tubing are easier to handle than a ten foot section – especially when I am doing this as a one man project.  The other reason is that there is going to be a round tube front cross member and it is easier to use a hole saw to cut the tubing than a torch.  Although I have used that method in the past.  Notice that the hole is off set to the top.  This is to accommodate the taper in the lower part of the rail that I mentioned earlier.  The tube is heavy wall – schedule 80 pipe.  This piece was actually scrap from a welding yard and was used for boiler tubes at a power plant.  It is good to use heavy wall tubing as opposed to thin wall.  Years ago I saw a  T – bucket that hit a chuck hole and the force just peeled the spring perch back and tore the cross member to shreds.  I’m a quick learner!  Also notice how the rails are aligned and held in place for tacking.  Again , use the pins to measure the distance to the holes on each side.  I can’t tell you how important measuring is on a project like this. 

 

Here is the front cross member tacked and partially welded in place.  The frame is upside down – notice the difference in material from the cross member to the top of the rail.  Again – this is for the taper  that will be cut later.

 

Frame is right side up and measurements taken again this frame is within 1/32nd of an inch of being square.  Not bad for a table top frame jig.

Time to get down to setting the frame at ride height.  Notice the stands used to hold the rear end housing , rear of the frame and the front.  The rear end is set so that the center of the axle housing where the wheel bearings go is half the diameter of the tires to be run.  Ex.  If the tire diameter is 28 inches , then the center of the axle will be set at 14 inches and the stand height built accordingly.  The frame height is up to you.  I always allow at least 11/2 – 2 inches for the frame to settle ( loaded ) and at least 3 to 4 inches for axle to frame clearance.  The angle of the frame is also up to you.  This frame is going to have a greater forward rake than most cars I build. This is the affect that I am trying to achieve.  Remember – this car will have a suicide front end therefore; I can have a greater angle on the front.  If I were running a stock type suspension , the frame would be higher to accommodate the spring and axle under the frame.

Another view showing the set up.  Notice that the frame is leveled from side to side.  If this is not done, all of the brackets will be off and the car will ultimately sit awkward.

I make all of my brackets , spring perches, and other assorted needed accessories.  The spring perches along with a lot of other information is shown in detail in my DVD video from Streetrod 101.  The rear spring shackles on the bolt end are cut down so that the head of the bolt ( grade 8 ) will not turn.  I  make a lot of things for my cars and wind up saving a ton of money.  Rods on the cheap are great and just as much fun and look just as good!!

Mocking up the rear spring using bailing wire, masking tape and spacers to take the place of the actual spring leaves.  The spring perches and axle brackets along with the spring shackles are all necessary in order to arrive at the correct distance for the spring to be installed.  When all are in place, the spring shackles should be almost parallel to the ground when installed.  This way when the frame is fully loaded, the spring shackles will ride at about a 45 degree angle.  After this is figured, set up the brackets to the axle and tack in place.

Frame

Here is the plywood table with the body outline and the frame outline.  I set this up prior to building all of my frames – now.  Years ago , I just measured and laid things out on the floor and took my chances.  Now with everything up on the table, I can see and build with a lot more accuracy.  This frame will be built using 1 1/2 x 4 x  .188 wall rectangular tubing.  Most of the frames I build are 1 ½ x 3 x .188 wall rectangular tubing with the rounded edges.  This frame will be constructed in three parts: the middle or side rails, the rear section which contains the kick up , and the front section which I will taper from in front of the front wishbone brackets to the bottom of the round schedule 80 tube front cross member which will make it 3 inches.  So the taper will be from 4 inches to 3 inches which will give the frame some accent in the front and it will not look or be so boxy.

 Two things to notice with this picture:  One – I cut the angle for the kick in the rear ( 22 ½ degrees) before I started the bends in the frame ( it’s just easier when the tubing is straight and flat).  The second thing to notice is that there are two ¼ -20 holes with studs  on each end and are in the same location on each rail in the center @ ¾ of an inch. This is so that I can use them for reference points as I build and curve the frame.  The location is not important – what is important is that they are in the same place on each rail. These will stay and be used until all the brackets and measurements are in place and are right.  Then when I begin to finish weld and finish the frame, these will be welded up and will no longer be used.  There needs to be points of reference otherwise the end product can be off enough that it could affect the performance or outcome of the product.

 After deciding where the first bend will be, the cut is made and a disc and small 4 inch hard grinder are used to bevel the cut edges and open the cut if needed.  The come along is then used to pull the frame together (remember – I’m only cutting through three sides).  When the correct angle is obtained, tack the bend in place.

 The cut is made on the second rail ( in this case remember to turn it upside down because it is an opposite rail and also has the angle cut on the back).  Continue the same procedure with the beveling etc. and then use C – clamps and angle iron / flat bar with both pieces so that they will be the same - and tack them it in place also.

 Here is an inside shot with the rail to be tacked on the bottom and the clamps etc. in place.  This is the critical time and it may have to be undone  and  the cut opened up some more in order to make both sides match.

The next cut is on the outside because the frame is going to bend the opposite direction.  Here I have to be careful that the tacks are strong enough to allow the rail to be pulled in the opposite direction.  I weld the top and bottom and then put a short 1 inch tack/weld on the cut to ensure that the cut will not break loose and cause more problems.  If this happens, I’ll need go back and clean off the old tacks and re attach the come a long and then re – tack before I can pull the rail the opposite direction.

 Again I use the clamps, come a long, and metal to line up the rails.  Notice how the cut ends are opposite.  If I forget to do this,  I will have two of the same side rail and it just won’t work. Sorry.

The rails are set up aligned on the table and squared using the ¼ - 20 studs / pins and use a tape that has an end with a ¼ inch hole in the end – carpenters tape.  Do not use a tape that just has a 90 degree hook on the end.  The measurement will and can be off.  Measure corner to corner and adjust by moving one rail forward and backward.  Make sure that the width of the rails is what you want also.  When set, take a couple of 3/8ths pieces of flat bar and tack the rails and then double check before moving on.

 This is just another view showing the frame tacked and the two bends in the rail.  This frame is pretty simple.  I am not trying to follow the contour of the body real close.  Years ago , I built a Model A roadster and it took 29 cuts and bends on each rail to make the frame fit the body the way I wanted.  How close of a fit you want the frame is your decision.  Most highboys I build will have from 4 to 9 cuts per side depending on the body manufacturer.  This car is a highboy but it is also set over the frame about 3/4th of an inch and also is going to be built old school and won’t be as critical or showy as most of the cars I build.  This car will look good, run good, and just be fun to play with.

With the side rails squared and in position (  I am using 1 ½ in x 3 x .188 wall tubing for the rear section – the small 1 inch gap will be filled and then finished), I built the rear kick to be a 45 degree angle.  This means that each cut is 22 ½ degrees.  This is the same for the upper angle winding up with a 45 degree cut on the rear part of the cross member to give me a 90 degree rear frame member.  The two pieces that make up the rear frame were done on the bench and finish welded and then clamped to the side rails with flat bar and everything leveled.  The rear cross member is then figured and cut.  I do it this way because for some unknown reason , if the rear cross member is pre cut – it’s either too long or too short.  Too long is ok – too short is not good!

 The rear cross member is squared and held in place using c clamps and flat bar.  Use the tape and measure crosswise from the reference pins and adjust the cross member until they are as close to square (equal measurements) as possible and then tack in place.

 Another shot showing the alignment set up. 

 Now that the center and rear section of the frame are in place, it is time to set the body on and double check the fit and see if there needs to be some modifications.  Now is the time to make changes, not after all the brackets are in place.