Choosing Custom Pro Built 9-Inch Leaf Spring Fabricated Housings Part III

Wayne Scraba

29 Nov 2018

Click Here to Begin Slideshow In the last couple of issues, we’ve taken a detailed look at a leaf spring sheet metal or fabricated housing. We looked at the features of the basic housing from Jerry Bickel Race Cars and then we dug deep into housing end tech from Mark Williams. This time around, we’ll complete the housing overview with info on the back brace and, equally importantly, a new wave spring perch configuration from Kim Smith Race Cars. Check it out: We needed two more items to begin the build – a set of spring perches along with a back brace. Spring perches seem simple enough. For a Camaro-Nova-Firebird or other GM product, you can use multi-leaf or mono-leaf perches (depending upon your spring application). If you’re using a split mono-leaf of some sort, you can use a Ford or Mopar style perch on the rear end. Each of those setups makes use of conventional U-bolts to keep the rear end in check. So far so good, but for each of the above setups, it’s common to brace the perches. The reason is that most of those perch designs tend to fold up and bend when faced with big power. The more power you add, the more they fold up. There is a better idea, though, and that’s the Smith Racecraft perch. It’s an all-new design that allows for a large amount of contact area with the housing on four sides (welded where it attaches to the housing), plus it eliminates the U-bolts. Instead of U-bolts, the Smith Racecraft housing end incorporates four locked in studs to mount the lower traction bar plate (which in turn sandwiches the spring). The end result is a much stronger spring perch arrangement. Smith Racecraft offers these super cool perches for 3.00-inch, 3.250-inch and 3.500-inch diameter housing tubes. Each can be specified for stock ride height or one-inch-lower ride height. And finally, they can be used with split/mono leaf springs or multi-leaf springs (with a 1 1/2-inch overall spring stack height). The other very important piece of the puzzle is a back brace. In a typical Ford drag race application, the ends of the housing (tubes) tend to wander fore and aft (flex on the ends) under big power. The solution is a back brace of some sort. According to Mark Williams: “If it is a stock housing and you drag race, it needs to be braced. However, you need to reinstall the housing ends after all the welding is completed. It's impossible to do any amount of welding on the tube section of the housing without causing distortion.” Bickel and Smith concur. Kim Smith custom fabricates his back braces with 2.00-inch wide rectangular section tubing and forms it (beautifully, by the way) to precisely fit the contours of the housing. You’ll note the back brace ties into both the rear end cone and the axle tubes, ending just before the housing ends. Smith cut the axle tubes to length. He initially checked the housing for straightness, performed some corrections and then followed up with the back brace and finally the housing ends. Everything was carefully Tig welded and Smith, Bickel and Williams advise that for best results, all other welding must be done before the housing ends are installed. All the while, Kim used an alignment bar (and accompanying tooling) to maintain housing straightness. It is important to understand that the alignment bar is not used to prevent the housing from distorting while welding. Williams notes it is a tool to precisely position the housing end with a common center to the carrier. It does NOT restrain the distortion caused by welding. Ensuring the housing is straight while welding is tasked to the fabricator (which means they have to know what they’re doing). Something else (small) you’ll note in the photos is a pair of brake line tabs welded to the top of the housing. They’re six inches from the end. The idea here is simple: We like to run a short Teflon-lined brake hose from the wheel cylinder (or caliper) to a -3AN bulkhead fitting on the housing. The reason for the short length of brake hose on the housing is to make for much easier access at the wheel cylinder or caliper. From here, hard line goes over each end of the housing ending at a “T” on the top. By the way, Smith was also responsible for adding the tabs to the housing. In terms of dimensions, this housing measures 52.50 inches wide, axle flange to axle flange. That’s 2.00 inches narrower overall than a stock 10 or 12 bolt. In terms of weight, this is a rather long housing, and it tipped our home scale at 60 pounds. That’s approximately 17-20 pounds heavier than a stock 9-inch housing of a similar width, but the difference in strength between the two is significant. The following is a list of parts used for the assembly. FYI, the three manufacturers all have pieces in stock. It’s not that difficult to copy this setup: • Jerry Bickel Race Cars pro fabricated rear housing, 50-inch width: JBRC1109-50 • Mark Williams small GM housing ends, HD Timken unit bearing: 58560 • Smith Racecraft leaf spring perch, std. height; 3.25-inch axle: 04AZPERCH • Smith Racecraft back brace: Custom • Smith Racecraft brake line tabs: Custom Thanks to today’s technology, the 60+-year-old Ford 9-inch has marched ahead rapidly when it comes to strength as well as longevity (ring gear life improves dramatically too). With that said, the 9-inch Ford definitely has 9 Lives. It’s a great, enduring design, although in our case, not a single OEM Ford part was used in the housing. That’s a big testament to the manufacturers involved. For more info, along with a closer look at the fabricated leaf spring housing, check out the accompanying slideshow:

Choosing Custom Pro Built 9-Inch Leaf Spring Fabricated Housings Part III — Click Here to Begin Slideshow In the last couple of issues, we’ve taken a detailed look at a leaf spring sheet metal or fabricated housing. We looked at the features of the basic housing from Jerry Bickel Race Cars and then we dug deep into housing end tech from Mark Williams. This time around, we’ll complete the housing overview with info on the back brace and, equally importantly, a new wave spring perch configuration from Kim Smith Race Cars. Check it out: We needed two more items to begin the build – a set of spring perches along with a back brace. Spring perches seem simple enough. For a Camaro-Nova-Firebird or other GM product, you can use multi-leaf or mono-leaf perches (depending upon your spring application). If you’re using a split mono-leaf of some sort, you can use a Ford or Mopar style perch on the rear end. Each of those setups makes use of conventional U-bolts to keep the rear end in check. So far so good, but for each of the above setups, it’s common to brace the perches. The reason is that most of those perch designs tend to fold up and bend when faced with big power. The more power you add, the more they fold up. There is a better idea, though, and that’s the Smith Racecraft perch. It’s an all-new design that allows for a large amount of contact area with the housing on four sides (welded where it attaches to the housing), plus it eliminates the U-bolts. Instead of U-bolts, the Smith Racecraft housing end incorporates four locked in studs to mount the lower traction bar plate (which in turn sandwiches the spring). The end result is a much stronger spring perch arrangement. Smith Racecraft offers these super cool perches for 3.00-inch, 3.250-inch and 3.500-inch diameter housing tubes. Each can be specified for stock ride height or one-inch-lower ride height. And finally, they can be used with split/mono leaf springs or multi-leaf springs (with a 1 1/2-inch overall spring stack height). The other very important piece of the puzzle is a back brace. In a typical Ford drag race application, the ends of the housing (tubes) tend to wander fore and aft (flex on the ends) under big power. The solution is a back brace of some sort. According to Mark Williams: “If it is a stock housing and you drag race, it needs to be braced. However, you need to reinstall the housing ends after all the welding is completed. It's impossible to do any amount of welding on the tube section of the housing without causing distortion.” Bickel and Smith concur. Kim Smith custom fabricates his back braces with 2.00-inch wide rectangular section tubing and forms it (beautifully, by the way) to precisely fit the contours of the housing. You’ll note the back brace ties into both the rear end cone and the axle tubes, ending just before the housing ends. Smith cut the axle tubes to length. He initially checked the housing for straightness, performed some corrections and then followed up with the back brace and finally the housing ends. Everything was carefully Tig welded and Smith, Bickel and Williams advise that for best results, all other welding must be done before the housing ends are installed. All the while, Kim used an alignment bar (and accompanying tooling) to maintain housing straightness. It is important to understand that the alignment bar is not used to prevent the housing from distorting while welding. Williams notes it is a tool to precisely position the housing end with a common center to the carrier. It does NOT restrain the distortion caused by welding. Ensuring the housing is straight while welding is tasked to the fabricator (which means they have to know what they’re doing). Something else (small) you’ll note in the photos is a pair of brake line tabs welded to the top of the housing. They’re six inches from the end. The idea here is simple: We like to run a short Teflon-lined brake hose from the wheel cylinder (or caliper) to a -3AN bulkhead fitting on the housing. The reason for the short length of brake hose on the housing is to make for much easier access at the wheel cylinder or caliper. From here, hard line goes over each end of the housing ending at a “T” on the top. By the way, Smith was also responsible for adding the tabs to the housing. In terms of dimensions, this housing measures 52.50 inches wide, axle flange to axle flange. That’s 2.00 inches narrower overall than a stock 10 or 12 bolt. In terms of weight, this is a rather long housing, and it tipped our home scale at 60 pounds. That’s approximately 17-20 pounds heavier than a stock 9-inch housing of a similar width, but the difference in strength between the two is significant. The following is a list of parts used for the assembly. FYI, the three manufacturers all have pieces in stock. It’s not that difficult to copy this setup: • Jerry Bickel Race Cars pro fabricated rear housing, 50-inch width: JBRC1109-50 • Mark Williams small GM housing ends, HD Timken unit bearing: 58560 • Smith Racecraft leaf spring perch, std. height; 3.25-inch axle: 04AZPERCH • Smith Racecraft back brace: Custom • Smith Racecraft brake line tabs: Custom Thanks to today’s technology, the 60+-year-old Ford 9-inch has marched ahead rapidly when it comes to strength as well as longevity (ring gear life improves dramatically too). With that said, the 9-inch Ford definitely has 9 Lives. It’s a great, enduring design, although in our case, not a single OEM Ford part was used in the housing. That’s a big testament to the manufacturers involved. For more info, along with a closer look at the fabricated leaf spring housing, check out the accompanying slideshow:

The back brace on this rear end was custom fabricated by Kim Smith at Smith Racecraft. It’s built from 2-inch wide rectangular section tubing.

Note how the back brace ties into the axle tubes at the housing cone. It’s not really possible to have a universal back brace. Each brace is custom formed by Smith for each application.

From here, the box brace goes almost right out to the end of the axle tubes, as shown in this photo. The fab work is fabulous.

This is an overall look at the unique leaf spring perch manufactured by Smith Racecraft. It does not incorporate U-bolts.

Instead, the lower spring/shock plate is held in place by way of four grade eight studs.

There’s a large amount of weld/contact area (to the housing) with the Smith Racecraft leaf spring perch. Smith offers them for 3-inch, 3.25-inch and 3.5-inch axle tubes.

The design of the perch is such that it cannot be folded over (like a stock perch with a high HP combination). They’re available for stock ride height along with 1-inch lower ride height combinations.

Here’s a look the brake line tab we mentioned in the text.

You can see a -3AN bulkhead fitting installed in the tab.

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