Street rod rear suspension can take various forms. Transverse spring, parallel leaf springs, coil springs, coil-over shocks, quarter elliptic springs, etc. are all good, reliable street rod rear suspension choices. We’re glad to continue this series of blog posts that will give you a taste of what you’ll learn in detail in Bob Hamilton’s StreetRod 101 Hot Rod Frame and Chassis Construction DVD.
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). All thread, also called threaded rod, is a great street rod building tool for mock-ups because it’s cheap and versatile. But only used for mock-up purposes and not structural. Measure from the mounting flange of the spring pivot to the spring pivot on the other side.
Bob used ¾ inch all thread because he makes the spring pivot bolts from ¾ inch grade 8 bolts. (If he only used 5/8th inch bolts for the spring pivots, then he would use 5/8 in all thread). He then levels the brackets with a magnetic level and supports the whole apparatus with a small bottle jack. Then he centers the apparatus on the housing, mocks the spring in place to make sure the center section of the rear end will clear and then tacks the brackets in place.
Bob never fully welds anything at this stage because he 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 setup. Notice the vertical strap that Bob tacked on the frame to the rear end to keep it at the correct height and position.
This picture shows the 1927 T street rod rear suspension with everything in place. You’ll note the spring mounting crossmember in place and the spring mounted to the rear end.
On this ’27 T street rod build, Bob decided to use stock rear wishbones and keep the trick end that bolts to the rear-end altogether. He 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 he also made. This is shown in Bob’s StreetRod 101 Hot Rod Frame and Chassis Construction DVD.
You’ll note in the photo above that he lined up and supported the assembly with stands made from 1 inch square tubing welded to 2x2x 1/8th inch angle. Then he 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. He has several of these in his shop and uses them for all kinds of set ups, from what is shown here to setting up his exhaust system. There is another bracket not shown that 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 split 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 the complete street rod rear suspension with everything tacked in place.
We’ll continue Bob’s chassis build with some more street rod rear suspension how-to in our next blog installment. By now you’re probably ready to go ahead and order Bob’s informative how-to DVD on street rod frame and chassis building so you’ll have ALL the information you may ever need on how it’s done and how you can do it yourself in your home garage.
You’ll enjoy the experience of observing Bob show you how to build street rod frame variations in his home shop. Sit back and learn from Bob’s years of street rod chassis building experience. Here are just some of the things you’ll learn about how to build street rod frames the trouble free and easy way in this 4 1/2 hour video:
- The Ackerman steering principle
- How to taper your steering arms for a nice, finished look
- How to build Model-A type front frame horns to really enhance your chassis appearance
- How to make your own “Poor Man’s Flame Cutter” that will save you hundreds of dollars and hours of time
- The cheap and easy cutting barrel to go along with your flame cutter to keep your shop clean and prevent fires
- Build a super-clean looking spreader bar and license plate mount, with a hidden trailer tie-down as a bonus
- Make your own spring pivots using a special bracket to ensure proper weld alignment
- How to properly use a hole saw
- The best starting caster for your front suspension
- Understanding the critical height of spring-on-top-of-axle perches
- How to set the critically important scrub line (both front and rear) during your chassis construction for safe driving later and which is the better of two ways of measuring scrub line
- Determining the correct length for your tie rod and how to build it
- Building bat wing radius rod brackets
- How to fit radius rod brackets when they go on the S-curve of a dropped tube front axle
- How to make sure your tie rod doesn’t hit a radius rod bracket
Click here to order your own copy today!