How to install ladder bars and a Ford 9-inch

There’s more than one way to figure out where a Ford 9-inch rearend will hang in a chassis but, for this story, the method started from the rear and worked forward. That’s because when the project began, the forward mounting point for the ladder bars was unknown because all the required parts weren’t available at build time.

But the stock Ford rear crossmember in the original 1934 frame was still in its factory location and, since the car this chassis will be going under will have a semi-traditional appearance, the frame and rear crossmember were not going to be altered. Adhering to that concept created some problems getting things to fit, but those stumbling blocks were addressed, modified, and all is well now.

An indispensable tool in doing any chassis work (from adding boxing plates or a dropped I-beam) is the chassis blueprint offered for free by Wescott’s Auto on their website that shows all the correct measurements (and location of body mount holes). It was used throughout this build and, since we’re using ladder bars from Pete & Jakes, we used their particular set of installation instructions, which have their own set of measurements to follow. Hot Rods & Custom Stuff in Escondido, California (a well-known parts and build shop that can do everything from blasting a body and chassis assembly to painting, wiring, and even upholstery), signed on to show how to properly hang a Ford 9-inch rearend.

Parts and pieces from several manufacturers were used in the build, from Pete & Jakes (ladder bars, ladder bar mount, and small assembly pieces) to Eaton Detroit Spring (for a custom side-bend transverse spring) to SO-CAL Speed Shop (rear spring U-bolt kit) to Walden Speed Shop (spring/shock brackets), as well as RideTech (for a pair of their tuned aluminum shocks).

Jeremy Shelton, the fabrication shop manager at Hot Rods & Custom Stuff, got the job started by leveling the chassis to his assembly table. Though we’ve radically changed the inner structure of the 1934 frame by adding an Ionia X-member and boxing plate kit, the stock Ford front and rear crossmembers are still in their factory locations, so all measurements will come off those points, along with the factory body and fender mount holes still in the frame.

Checking the Wescott Auto blueprints made a lot of the work go easier, but there were still portions where things had to be fabricated and configured to make it all work out in the end. Shelton worked from the center hole of the rear crossmember and worked forward to find the location of all the needed assembly points for hanging the rear.

One benefit in seeing how different shops do their job is checking out the tools they use to do the work. There’s always something cool to see, whether it’s simple like a spring-loaded center punch or a Roto-Bit for cutting holes in frames, but Hot Rods & Custom Stuff owns a Lincoln Electric Torchmate Classic 4×8 CNC plasma cutting machine that allows the operator to intricately design a complicated flat bracket or similar part on the computer and have it precisely and cleanly cut out from steel plate (up to 3/4-inch thick with a 105-amp plasma torch head) in just a couple of minutes. Yes, it’s pricey, but what a great shop tool and, with a little bit of imagination, the sky’s the limit for quickly fabricating needed parts.

For decades rodders relied on shocks that were the shortest ones available rather than ones built for the rodder’s application—basically shocks that took looks over comfort. But that has changed in recent years, and RideTech (the shock company originally called Air Ride Technologies) has been at the forefront of that change. Pioneers of the airbag suspension phenomenon and well-versed in the coilover shock market, they now also manufacture a line of mono-tube shocks specifically valved for street rod applications, designed by engineers with help from some of the country’s more well-known hot rod builders.

RideTech’s Hot Rod Shocks are made specifically for straight-axle applications. Made of polished billet aluminum, they come in covered- or exposed-shaft, and in two different overall lengths: 9.3 to 14.1 inches (with 4.75 inches of travel) and a shorter 7.9- to 11.2- inch shock (with 3.3 inches of travel). RideTech also manufactures two coilover versions (with optional polishing) of their mono-tube shocks for the rear. The HQ coilover has a rebound adjustment knob to allow adjustable ride quality and handling performance tuning, and the RQ coilover has the shock valving preset (and no rebound adjustment) for optimum ride quality. Basically if you tell RideTech the weight of your vehicle and the distance the shocks will travel, they can tune their shocks to your specific ride.

Since we won’t be looking to autocross our 1934, uncovered RQ Series shocks, overall measurements of 10.15 to 14.9 inches (with 4.75 inches of travel) will be used out back (and dialed in with a Hot Rod Shock valve coding), while the short-stroke uncovered Hot Rod Shock will go in up front. Hot Rods & Custom Stuff installs RideTech shocks on nearly every car they build, and they recommend them highly.

The only parts modification we found we needed to do on this build is alter the design of the Walden Speed Shop’s shock/spring bracket combo. Its designed use is for a straight tubular or aftermarket rear crossmember, which inherently offers more space between the housing and the crossmember for the shocks to be mounted. Since we’re using the factory Ford crossmember and curved spring, we’ll need to clearance the lip of the crossmember and the bottom of the Walden bracket so the shock can travel at its designed distance.

The angle of the shock is something most folks don’t think much about, but everything matters when talking about suspension travel. Fatman Fabrication’s Brent VanDervort literally wrote the book on the subject and, when considering locating the rear shock mount location, he suggests you should aim toward a 10-degree inboard inclination on the shock (0 degrees would be best, but due to body roll and depending on other chassis suspension parts and design, 10 degrees is the optimum measurement).

He explains the more a shock gets laid over, not only do you lose the effectiveness of the shock (i.e. 40 percent lost at 40 degrees), but there’s also added pressure on the bolt, brackets, and the welds. Most folks will eyeball the angle of the shock during assembly but keep in mind the more you lay it over, the more hardship you’ll be placing on your parts at the expense of your ride.

So follow along to see how the work is done—the only thing left to make it a rolling chassis is to figure out which rearend gearing is best for the motor, assembling the axles and new rear drum brakes, adding the front suspension, and getting the chassis up on all fours with the addition of the factory 17-inch wire wheels.

Here’s where we started: with the original 1934 Ford frame with an Ionia X-member and boxing plate kit added. The frame has been tack-welded to an assembly table (which is level at the top/middle section of the framerail), and the centerline of the frame has been marked with string from the middle of the front crossmember to the middle of the rear crossmember.

Referencing the Pete & Jakes installation instructions, Shelton finds the center of the axle tubes by measuring 17-3/4 inches back from the factory fender hole on the side of the frame, then notes the location of the measurement with a piece of masking tape to the outside of the framerail for future use.

At this point the custom Eaton Detroit side-bend spring is set in place with the SO-CAL Speed Shop U-bolt kit, PN 62811.

Since the custom Eaton spring has one less leaf than the factory spring, spacers were made to compensate before the spring’s U-bolt assembly was bolted up.

C-clamps are required on each end of the spring in order to compress (flatten) it before attaching it to the rearend.

The Pete & Jakes shackles are assembled using white lithium bearing grease, noting the threaded section should point to the rear of the frame.

More grease is used to assemble the shackle bushings in the spring hanger bracket.

When the spring and shackle are fully assembled, the shackles should look like this, with a 45-degree angle to the spring hanger bracket.

The tape on ’rail indicates both the 112-inch wheelbase measurement and the centerline of the axle tube. Using large C-clamps, the rearend is suspended 3 inches from the bottom edge of the framerail.

The 9-inch housing is set in place on the table, and its face placed at 90 degrees.

Using a straightedge to come down from the tape on the framerail (that marks the correct 112-inch wheelbase) to the center of the axle tube. The rear is then centered side-to-side in the frame, with the outside flange edge being (for this particular vehicle) about 2-5/16 inches away from the edge of the frame.

To double-check the wheelbase, with the leading edge of the tape measure at the center of the front crossmember (in the middle of the spring’s pinhole), the center of the rear housing measures 112 inches, the factory-indicated wheelbase for a 1934 Ford coupe.

Once everything is centered and measured, the spring brackets are tacked in place.

With the housing rotated, you can see the spring brackets are set at an outboard angle from the center of the housing because the spring’s eyelets are at an angle, too.

More white lithium grease is used on the ladder bar bushings.

With both bushings in, the bolt spacer is pushed in place.

To put a sufficient amount of threads into the ladder bar, each adjustable clevis joint is assembled in the end of the ladder bar with the mount hole 2-1/2 inches from the locknut.

Walden uses 3/8-inch holes in their ladder bar mount while Pete & Jakes requires a 1/2 inch for their ladder bars, so the boltholes on the Walden bracket needed to be opened up.

Note the triangular brace (arrow) in the middle of each ladder bar. The correct orientation is that the wider end of the brace is on the lower ladder tube. If you have it at the top, it’s upside-down.

In order to aid the exhaust routing, the decision is made to attach the tubular Pete & Jakes ladder bar mount (PN 3511) to just the center portion of the X-member rather than continue it out to the framerail. FYI: the P&J 3511 mount is made for 1932 Fords, but we’re only using the center portion of it for this application.

The Lincoln Electric Torchmate Classic plasma cutter is a fantastic tool that, after Shelton designed then input the measurements for an inner mounting plate into the design program . . .

. . . the machine quickly cut the pattern out of 0.125-inch steel plate.

With some bracing behind the plate so the edge steps into the X-member’s C-channel 1/4 inch, Shelton can then weld the plate in place.

After noting where the assembled ladder bars end, Shelton configures where the tubular forward ladder bar mount should go by measuring back 16 inches from the center of a factory body mount hole on each framerail.

With the mount centered in the frame using the same string centerline as before, Shelton notes where the diagonal cut marks will need to be made on the tubular mount.

With the ladder bar attached to the forward mount, the mount’s location is determined after level is located on the top of the ladder bar. (Note the mount is slightly rotated to add clearance between the ground and the ladder bar mount).

Knowing everything is true, Shelton then tack welds the mount in place.

After the X-member plates and ladder bar mount have been tacked in place, double check all the measurements before final welding.

The Walden shock/ladder bar bracket was designed to work with an aftermarket (straight) crossmember, not a curved factory unit, so the lower section had to be modified. It was also lengthened for the longer shock travel, and moved forward so the shocks will clear the factory crossmember.

With the location of the lower shock mounts set, the location of the upper shock mount brackets are located after noting the mid-point of the shock’s travel on the shaft and leaning the shock inward (toward the pumpkin) at a roughly 10-degree angle. The lip of the factory crossmember is also cut back so the shock can travel without any interference.

Once the upper shock mount is tacked in place, the shock assembly should look like this.

Once everything has been measured, checked, and tacked in place, the whole assembly is blown apart and final welding can occur.

Since brackets were added after the initial straightening of the rearend, it had to go back to Walden’s Speed Shop to get rechecked with their precision-ground tooling. As it turned out, one side was unaffected by the new welding, the other side was only off 0.015 inch (see arrow), but needs to be corrected.

Walden’s Matt Bryant applies a little bit of torch heat on the housing tube to shrink the material, which causes the housing tube to pull slightly toward the hot spot and, after an immediate cold water quenching, allows the bearing ends to become perfectly aligned with each other.

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