23.2 John’s Industries 9″ Ford Axle & CPP Leaf Spring Relocation Kit Expanded Install
When we started our 1955 4-Door Project, nicknamed Hela, one of the things we wanted to incorporate was a 3″ narrowed John’s Industries 9″ Ford rear axle assembly. These are bolt in, made for your Tri-Five axle assemblies that are virtually bulletproof. You have to move the leaf springs inboard to install one and we thought this would make for a good install article. We ran an abridged version in the newsletter. This is the in-depth version which goes into much more detail and has full-sized pics. Check it out. Special thanks to John’s Industries and Classic Performance Products for donating the parts for this article.
You will need:
Danchuk # 10235 CPP Leaf Spring Relocation Kit
Danchuk # 11290 Leaf Spring Relocation Rear Shock Mount**
John’s Industries 9″ Ford Axle Assembly 18405 – 18406 – 18407 – 18408
Electric or Air Grinder with Grinding Wheel and Cut Off Wheel or Plasma Cutter
Saber Saw & Blades
Ball Peen Hammer
Large Punch & Cold Chisel
Cardboard Stock, Sharpie & a Sharp Knife or Cutter
Click here to open a PDF copy of the Danchuk 10235 Rear Leaf Spring Drawing
** Shock support # 11290 is for relocated leaf springs. The shock mount angle is different than stock shock supports. You mush use the 11290 when installing the leaf spring location kit.
We are doing this on a bare 2-piece frame. If you are doing this job in the car then the first step is to remove the rear end, shocks and springs along with any items that will not be needed. You will also probably need to remove the spare tire well if you have one in your car. Also, we are using a John’s Industries 9″ that has already been set up for the relocated springs. We will not be covering the installation of the spring perches that come with the pocket kit that you will use if you are re-using your stock rear, but we do outline the procedure according to the installation instructions at the end of the article.
The spring relocation kit is designed for both a 1-piece and 2-piece frames but the section at the rear of a 2-piece is wider than a 1-piece. As a result, you have a roughly 1″ gap the inside of the frame between the pocket kit filler plate and the side of the frame. We made some calls to find out how to deal with the gap and got various answers; the best being to cut additional material out of some stock, fit it into the gap and then weld it up and grind it smooth. That seemed like a lot of extra work and fabrication that we felt most people would rather avoid, so we devised a method which is a lot easier to do and renders excellent results.
Note: We have numbered the pictures according to step and order. So, 1-01 means Step 1, Picture 1. 2-01 means Step 2, Picture 1 etc. This allows you to download and print each pic and put them together to they are in order according to the article. We have also included downloadable photo sheets and instructions in PDF form at the end of this post. You will need Adobe Reader to view the files. Corresponding photos follow each step. Click the thumbnail photo to enlarge it.
Let’s get started.
1. Begin by removing the stock leaf spring mounting brackets front and rear. Use your cutting wheel to cut the heads off the rear bracket rivets and with your punch and hammer drive the rivets out of the bracket and frame. It should come off clean. Use the cut off wheel to cut through the welds that hold the front spring bracket to the frame. With your hammer and cold chisel drive it loose. Grind the remaining weld material smooth.
2. Locate the 1-1/4” hole on the frame where the front of the spring was. Insert the supplied bolt into one of the holes in the pocket as shown and line the front pocket up on the side of the frame with one of the two holes of the pocket lined up with the center of the 1-1/4” hole on the frame where the front of the spring mounted. The center of the bolt head should be centered in the 1-1/4” hole so be sure to install the front spring bolt in the pocket kit as shown before you clamp it in place. If you can install this bolt with a large washer that is centered in the 1-1/4″ hole as shown you have the pocket positioned correctly. When it is clamped, take your square, line it up with the front of the pocket and scribe a mark on the frame. Do the same at the rear of the pocket.
3. Remove the pocket kit from the frame and move to a table. With a rolling motion starting at the deep part of the pocket trace the pocket kit onto your cardstock using your sharpie. You should end up with a rectangle that measures about 16” long and 3” wide. Cut it out of the cardstock. This is your template.
4. Starting at one of the scribed marks on the frame line up your template and run it down the frame to the other mark. Line it up between the sides of the frame so it is centered. When you are satisfied as to the fit scribe a mark down each side onto the frame. Repeat on the opposite frame rail. This is where you will cut the frame so you can install the pocket.
5. Using your cutting wheel cut the frame out around the scribed lines along the sides. Use your saber saw on the ends. Repeat on the other frame rail. When both frame rails have been cut using your grinding wheel clean up the areas where you cut the frame removing jagged areas and smoothing out the sides and ends.
6. Insert the pocket into the frame lining the front spring eye mounting hole in the pocket up with the 1-1/4″ hole in the frame. It should line up in the center as described in Step 2. When it is in place, clamp the pocket to the sides of the frame rail. At this time we installed the springs into the pocket mocking them up to check the fit. When we were sure everything was in the correct place we tack welded the front of the pocket to the frame. We then removed the springs and finished tacking the pocket on the sides and rear. You will finish welding once you have installed the rest of the kit.
7. Position the rear shackle mount in place on top of the frame, centered and parallel. To get a general idea as to where the shackle mount should be we re-installed the leafs into the front pocket laying the rear of the spring on the frame. We then took a round piece of doweling, you can use whatever is available, and mocked the mounts up on top of the frame lining the holes in the mounts up with the rear eyelet on the spring. Then, with our tape measure, we measured from the center of the 1-1/4” hole in the frame where the front spring bolt installs back 57” as shown. Re-position the rear spring bracket on top of the frame and center the mounting hole for the rear of the spring at the 57” mark on your tape. Tack weld the mount into place.
8. At this point we mocked up the assembly completely to make sure that we had everything in the proper place. It is much easier to make adjustments now than after everything is welded up, so don’t omit this step.
9. Using your square as a guide scribe a mark on the side of the frame that is inline with the centerline of the rear spring mounting hole in the rear spring bracket. Then, using your square, extend that line across the bottom of the frame. From that point measure 4” from the scribed line to the rear of the frame and scribe another line on the frame.
10. Follow the instructions in this step depending on the type of frame you have. A 1-piece frame has no seams top and bottom and looks like box steel welded end to end to make a length of frame rail. 2-piece frames are basically two “C” channels put together open side to open side and welded together across the top and bottom.
10A. 1-piece frame –
Use the metal insert included in the kit on the side of the frame as a guide. Line the back end of the insert up with the scribed mark behind the centerline of the rear shackle bracket and trace the outline of the insert on the side of the frame. With your cut off wheel and saber saw, notch the frame along the outline on both sides and across the top. We cut the areas at the curves on the insert a little high and trimmed them after putting insert in place to assure a nice smooth fit in the curves. When you have the frame notched, fit the insert into the frame, line it up, clamp it into place and tack it to the frame. Then you can trim the portions of metal at the curves to fit the contour of the insert with your saber saw or grinding wheel. Repeat on the other side and proceed to Step 11. (There is no picture 10A-05)
10B. 2-piece frame –
Use the metal insert included in the kit on the side of the frame as a guide. Line the back end of the insert up with the scribed mark behind the centerline of the rear shackle bracket and trace the outline of the insert on the side of the frame. To compensate for the differences in width of the 2-piece frame you will leave about 1” of material on the inside of the frame at the rear as shown in the photos. We left material on the outside as well so we could get a nice fit in the radius of the insert. You will have to cut the frame on the bottom back to the scribed line behind the shackle support bracket made in Step 9. When you have the frame notched, fit the insert into the frame, line it up, clamp it into place and tack it to the frame. Repeat on the other side. When you are finished cutting the frame and have fit the insert you will see the gap on the inside of the frame. Once the insert is tacked into place you will work that additional material on the frame so you get a clean installation and no gaps to weld up.
Work the extra metal you left on the inside of the frame rail with your ball peen hammer and begin folding the extra material towards the pocket kit working it smoothly into the curve a little at a time. The idea is to get that extra material to become an extension of the frame rail past the curve in the insert and take up the gap. When the material is folded over cut the extra off with your cut off wheel so it is even with the side of the pocket insert and work the metal down beside the insert leaving a minimal gap that will need to be welded up. Use your grinding wheel to fine tune the radius both inside and outside. Repeat on the other frame rail and proceed to Step 11. (There is no picture 10B-06)
11. Now that everything is in place use your grinding wheel to clean up around both the pocket kit in the front and the metal insert in the rear. Finish welding the pocket and insert to the frame and grind everything smooth. Finish welding the rear spring brackets to the frame.
12. At this point we painted our frame and got it ready to install the John’s Industries 9″ Ford rear end. Begin by installing the rear leaf springs. Attach the rear shackles to the rear shackle brackets with the supplied bushings and hardware. Once they are installed in the brackets, bring the rear of the spring up to the bottom of the shackle, install the bushings and line it up with the bottom mounting holes. Install the lower bolt. Then, raise the front of the spring into the frame pocket. Line up the hole in the pocket with the front bushing of the spring and install the bolt. Using your 15/16″ socket and 1/2″ ratchet and and end wrench tighten everything up.
Once the springs are attached fit the rear end into place on top of the springs. The bolt in the center of the spring should center in the hole in the spring perches. Now we need to install the axle bumper. Place the bumper retainer over the bumper and fit it on top of the axle housing. The tab on the retainer should slide into the tab on the top of the housing. Tap it into place if it is tight. Place the u-bolts on top of the housing as shown and line up the spring plates with the u-bolts. The shock stud should be pointing towards the front of the car. Install the nuts and washers on the u-bolts and tighten them.
If you are reusing your original rear end you will have to cut the stock spring perches off the axle tubes and install the ones that come in the kit. The instructions say that these are installed to the bottom side of the axle at 38″ apart, centered between the backing plates and with the pinion shaft at and angle of 5 degrees. Sloping up towards the front. We did see in one article which was doing this pocket kit in the car and they took only one spring off of one side and supported the axle while they installed the kit. They they mocked the spring perch up on the side they worked on and tacked it to the housing. The other side that was still installed made sure the pinion angle was correct. So that is an option if you are not comfortable figuring out the correct pinion angle. We also read that the axle housing may need to be straightened as welding the perches on may warp the tubes. So be careful not to heat the tubes up too much.
We can’t wait until we have Hela farther along so we can install some monster meats in the rear. With the moved in leaf springs and the 3″ narrower housing we are sure we can go crazy back there and still have all the clearance you could want.
Please check out Hela’s progress on Instagram @1955chevyhela. We are planning to post photo updates so you can follow her progress from restorable car to, hopefully, street screamer.
Click here to open a PDF copy of the Blog Post 23.2 Pocket Kit Instructions
Click here to open a PDF of all the Johns Industries 9 Inch & Pocket Kit Install Photos