Front Dropmember Install

Front Dropmember Installation

Front Dropmember Install

Overview:

There have been several updates and additions to the Dropmember product line over the past several years. We now offer three different variations of the Dropmember for the 60-87 C10 trucks. Although they are near identical in their installation procedures, there are a few differences that need to be noted. This set of instructions will serve all versions of the Dropmember for the 63-87 C10 trucks. We will point out the differences and variations of installation between the versions, so please pay close attention.

Dropmember Versions:

Dropmember Level 3 (formerly known as the “Extreme”)

The Dropmember Level 3 is the most commonly known version of the Dropmember. It is used when wanting to achieve an ultra-low ride height, run a large diameter tire, and allow the frame-rails to rest on the ground at full deflation with up to a 29” tall tire (when combined with Porterbuilt control arms and 2.5” drop spindles).

Benefits include a narrowed trac-width (1.25” per side compared to factory); wheel center-line moved forward to center in the wheel well opening; rack and pinion steering; and revised suspension geometry for an unbelievable ride quality and improved performance! This is the Dropmember that put us on the map!

Dropmember Level 2 (formerly known as the “Touring”)

The Dropmember Level 2 was developed to meet the demand of those looking for a C10 replacement cross-member that offered all the benefits of the Level 3 version, but not looking to plant the frame rails on the ground. So, we made it happen.

The Dropmember Level 2 is essentially the same assembly as the Level 3, but includes a different bag mount that acts as a bump-stop and keeps the frame rails 1” off the ground when fully deflated.

Benefits include a narrowed trac-width (1.25” per side compared to factory); wheel center-line moved forward to center in the wheel well opening; rack and pinion steering; and revised suspension geometry for an unbelievable ride quality and improved performance!

Dropmember Level 1 (formerly known as the “Mild”)

The Dropmember Level 1 was developed to meet the demand of those looking for a C10 replacement cross-member that offered the improved steering and performance of our other Dropmember system, but weren’t looking to cut up the factory sheet metal and achieve such an extreme drop.

There are a handful of differences in the design of the Level 1 version that sets it apart from its predecessor. First is the amount of drop built into the system. The Level 1 version raises the suspension 1” in the cross-member when compared to factory unit (while the Level 1 and Level 2 both raise the x-member 3” when compared to factory unit). Second, the trac-width is only narrowed .25” per side when compared to the factory suspension. With these changes in height and geometry, the frame rail does NOT need to be notched for rack and pinion clearance, and the motor sets much lower in the truck when compared to the Extreme version. This makes the Level 1 front kit 100% Bolt-in.

The Dropmember Touring and Mild versions are also offered in either airbag or coil-over configurations.

Special Notes:

When installing a Dropmember C30, please reference the “Level 1” procedures.

Frequently asked Questions:

Before we start with the actual installation procedures, I wanted to go over some of the most common questions and concerns.

Do I need to modify my floor or firewall?

On all Dropmember installations it is recommended to convert the transmission cover to a “Large Hump”. The “Large Hump” transmission cover is a factory bolt-in piece that came standard in many trucks, and can easily be acquired. It is a straight forward conversion that allows additional clearance at the floor to transmission. It is necessary on all Dropmember Level 2 and Level 3 installations, and is recommended for the Level 1 version as well.

How big of a tire can I run and still lay frame?

With the proper combination of spindle and control arms you can lay frame on up to a 29” tall tire with the Dropmember Level 3 (drop spindle and Porterbuilt Control Arms). We have customers laying frame on larger diameter tires, but some modifications may be needed.

What will my ride height be?

When running the Dropmember Level 3 and Level 2, the ride height will be right around 5” (we take this measurement from the bottom of the frame rail under the front cab mount to the ground) when combined with a 2.5” drop spindle and 28” tall tire. You can drive the truck much lower, but 5” is the “sweet spot”.

When running the Dropmember Level 1, the ride height will be 7” when combined with a 28” tall tire and 2.5” drop spindle.

What motor and transmission combo can I run?

We offer motor mounts for SBC, BBC, In-line 6, and LSX motors. The transmission cross-member supplied in the kit will work will all common transmissions with tail shaft style mount. We have had some fitment concerns with the 4L80-e transmission when running the Dropmember Level 2 and Level 3. The 4l80-e is HUGE and additional floor/trans tunnel modifications will be necessary.

Remove your factory suspension and steering components.

Front Dropmember Install

The factory cross-member and factory steering components will no longer be needed. Remove them and set them aside. The only factory steering component that will be maintained is the steering column. All other linkage and components may be discarded. It is not necessary, but recommended that you also remove your engine and transmission when installing the Dropmember.

Install the frame notch for rack and pinion clearance (continue reading before you do this).

When running a Dropmember Level 1 you WILL NOT need the frame notch for rack and pinion clearance. So do NOT cut your frame.

When running a Dropmember Level 2 and Level 3, the center-line of the rack notch will be located 4.25” forward of the front most mounting hole of the lower cross-member assembly (this is on the BOTTOM of the frame rail… see picture below)

Front Dropmember Install
Front Dropmember Install

Install Main Cross-Member Assembly

Front Dropmember Install

Level 1 Version Shown

Front Dropmember Install

 

When installing main x-member assembly, do not fully tighten the bolts, as the inner frame support plate will slide under the washer. Make sure to use the lock washer included, but not shown in the pic. (We typically drill the x-member mounting holes in the frame to 9/16” to make installation a little easier). The front two mounting holes have a blind nut welded to the bottom of the mounting flange, make sure the bolts threads in easily before attempting to install the cross-member. It may be necessary to run a tap down the hole after paint or powder coat is applied.

Front Dropmember Install

(Driver Side Shown)

Front Dropmember Install

(Passenger Side Shown)

The inner frame support brackets will slide in place between the frame-rails. Remember that the inner braces are side specific (also, the 63-72 inner frame support bracket is not as tall as the 73-87 bracket). Make sure the inner plate slides UNDER the washers on the bolt head.

Front Dropmember Install

Snug the main cross-member assembly mounting hardware. Do not fully tighten the bolts yet

Front Dropmember Install

 


Install Inner Support / Truss Tabs

Front Dropmember Install

(Pass. Side Level 1 shown)

The truss tabs will vary depending on the Dropmember version. The truss tab pictured above is the passenger side of a Level 1 Dropmember. The Level 2 and Level 3 variations are similar, but different heights… they will install in the same manner.

Front Dropmember Install

Level 2 and Level 3 style truss tabs shown (driver side).

The front and rear tabs are not identical, and a notch will indicate the front tab.

Front Dropmember Install

 

Use the supplied hardware to install the truss tabs, but do not fully tighten.

Front Dropmember Install

 

Front Dropmember Install

Driver side Level 1 shown

This is the Driver side truss tab for a Level 1 Dropmember. (The Level 2 and Level 3 driver side truss tab will look identical to the passenger side shown previously)

Front Dropmember Install

 

Front Dropmember Install

 

There are two machined spacers that will be installed on the driver side truss tabs on the Level 1 version to add additional strength/rigidity to the truss. The inserts are the same as the crush sleeve used in the motor mount isolator bushing. (See picture below for reference). Do not fully tighten the truss tab hardware at this time. It will be fully tightened once the motor mount perches are in place.

Front Dropmember Install

 

Install Upper Hat

The mounting holes on the side of the hats will line up with the existing holes on the side of the frame where the factory cross-member was secured (if they do not… please contact us to ensure you have the correct year application). It is recommended to open up the existing holes to ½” to aid in installation.

On the 63-72 chassis, the mounting holes on the top of the frame will all line up. It is recommended to open them up to ½” to ease installation. On the 73-87 chassis, it will be necessary to drill some new upper mounting holes, as not all holes will properly line up.

Use the provided 7/16 grade 8 hardware and snug it up. Do not fully tighten at this time.

Front Dropmember Install

 

Once fitment is confirmed, fully tighten the upper hat, inner support bracket (not the truss tabs yet), and lower cross-member hardware, torqueing the 7/16 hardware to 65lbs. and the ½” hardware to 75lbs.

Install Lower Control Arms (Older version of Coil-over arm shown)

Front Dropmember Install

(Older version of Coil-over arm shown)

Front Dropmember Install

(Older version of Coil-over arm shown)

 

Use the supplied locking sleeves and 5/8 grade 8 hardware to complete installation. The locking sleeve assembly will lock in place in the Dropmember’s control arm mounting shaft, preventing the hardware from loosening or backing out over time. It is recommended that anti-seaze be applied to the area where the sleeve and the shaft contact. Once installed, torque to 80 lbs. If running a factory lower control arm from 73-87 C10 or Air Ride Technologies Strong Arm, it will be necessary to first remove the lower cross-shaft from the arm.

Install Rack and Pinion

Front Dropmember Install

 

Front Dropmember Install

 

Use the supplied rack mounting bushings and 9/16 grade 8 hardware. Insert the mounting bushing from the front side of the rack. Torque to 65 lbs.

Install Upper Control Arms

Front Dropmember Install

(Older version of upper control arm shown)





Use the supplied 9/16 hardware to install the upper control arms (you can run factory upper control arms from 63-87 C10 on the Level 1, Level 2 and Level 3 versions, however some trimming may be necessary). The short tube will face the front of the vehicle, and the long tube towards the rear. Do not yet torque the hardware, as it may be necessary to add alignment shims once installation is complete, just snug it up for now. When installing the bushings, make sure they slide into the arm without forcing them. If they bind when tightening down the hardware, it will bend the arm. Take your time and make sure the bushings do not bind. The bushings are a machined fit and it is important that no paint or powder coat be on the inside of the bushing sleeve of the control arms.

Install Ball Joints and Spindles

The upper ball joint will bolt into the control arm from the top side. The lower ball joint will be pressed into place. The rubber boot will be installed on the top side of the ball joint after it is pressed in place.

Note: There are a few different ball joint tapers available for the C10 spindles depending on the year. 63-70 lower ball joint has its own taper, as does 71-87 lower ball joint. There are 3 upper ball joint tapers as well: 63-70; 71-71; 73-87. It can complicate things a little if the actual spindle year is unknown. Test fit the ball joints in the spindle before pressing them into the lower arm.

It will be necessary to ream the hole in the steering arm to 5/8” for tie-rod installation. We have found that a heavy duty reamer works best, but a 5/8 drill bit will also get the job done. (see pic below)

Front Dropmember Install

 

Install Tie Rod Assembly

Front Dropmember Install

 

Front Dropmember Install

(Level 1 version mounts on bottom side of steering arm)

Front Dropmember Install

(Level 3 version mounts on top side of steering arm)

Use the supplied hardware to install the tie rod assembly. On the Level 1 version of the Dropmember, the tie rod will be installed on the BOTTOM side of the steering arm. When running the Level 1 and Level 2 version of the Dropmember, the tie rod will be installed on the TOP side of the steering arm.

Note: It may be necessary to trim the length of the threaded part of the rack and pinion to achieve proper length for alignment. On the Level 2 and Level 3 version we have had to trim just over one inch in some cases (and an additional inch when running a narrowed arm). This is one of those steps where it is best to remove a small amount at a time until you get the correct length.

Install Air Spring

Use the supplied 3/8 x .75” grade 8 bolt and locknut to install the air bag. The bag will utilize two bolts on the top, and one bolt in the center on the bottom of the bag.

When using Ridetech (Air Ride Technologies) lower control arms on an Level 2 and Level 3 versions, it will be necessary to re-drill the lower bag mounting hole 1.25” outboard from its current location.

Install Shock Relocation Bracket

Slide the shock bracket forward on the frame until the front edge contacts the raised portion where the original shock stud was located. (see picture below)

(Mock up the shock and bracket before drilling any holes, to confirm fitment and clearance) Once fitment is confirmed, mark and drill holes to 7/16”. Secure bracket using supplied 7/16 x 1.25” long grade 8 hardware.

Front Dropmember Install

 

Install Shock Mounting Studs and Shocks (see pic below)

Front Dropmember Install

 

Install motor mount perches

The motor mount perches will bolt directly to the block of the engine, and the end with the poly bushings will bolt to the inner truss tabs as pictured below. The driver side mount is recessed for the steering linkage to clear. When installing the mounts, do not fully tighten until engine installation is complete.

Front Dropmember Install

(LS mount shown Level 2 and 3 pass. side)

Front Dropmember Install

(Level 1 pass. side perch SBC)

Front Dropmember Install

(Level 1 driver side SBC)

Front Dropmember Install

(Level 1 driver side SBC)

 




Install Transmission Cross-Member

There is no specific locating hole in the factory frame-rails for the transmission cross-member. It will be necessary to set the proper pinion angle, ensure the transmission cross-member is squared in the chassis, mark the mounting holes of the transmission cross-member, and then drill. Typically the trans will set at a 5* down slope towards the rear on the Level 2 and Level 3. While the Level 1 will typically be 3*.

Front Dropmember Install

 

Driveline Angles and Set-Up:

Please review the 2-piece drive-shaft tutorial to gain an understanding in regards to proper two-piece drive-shaft set-up. Also, please feel free to call or email with any and all technical questions.
480-297-2621
tech@pbfab.com