Lower control arms are a popular rear suspension upgrade to eliminate tire hop and help out with traction. I thought I would make a little guide of after market lower control arms to help out anyone looking at this type of upgrade.
First off let me start off with my setup; I have UPR rear upper and lower control arms (nonadjustable) with UPR rear spherical axle bushings on the upper. My UPRs are very light but also very strong and are also tubular, keep in mind the stock control arms are stamped. The spherical bushings keep things in the rear fairly tight, and take hard launches at the track much better than their rubber counterparts.
here is a thread that discusses bushings, it mentions control arms:
control arm links
Rear control arms
here is info on rear control arms and their duties
taken from: Late Model Mustang Suspension Basics
The upper and lower rear control arms constitute the four links in this rear suspension. The upper arms locate the axle side-to-side and prevent pinion angle changes (axle wind-up). The lower arms locate the axle front-to-back and and transmit the wheels' thrust to the chassis. Note that the control arms are not parallel to each other.
When the car leans (rolls) in a turn, one side of the chassis moves upward relative to the rear axle, the other side moves downward, and these non-parallel control arms must twist and change length axially to allow the axle to articulate. This causes the control arm bushings to bind. If this bind becomes excessive, it can raise the rear wheel rate and produce sudden, undesireable changes in handling (e.g., snap oversteer).
Ford minimizes this suspension bind by using compliant rubber bushings in both the upper and lower control arms. These relatively "soft" bushings acommodate the necessary motion of the control arms during body roll. However, they also permit wheel hop on hard launches and horizontal axle deflection in aggressive turns. Axle dampers (quad shocks) were installed on V8 Mustangs to eliminate this wheel hop, but nothing was done by Ford to cure the horizontal axle deflection. That deflection is responsible for the "tail-wagging" sensation well known to anyone who has driven a late model Mustang aggressively.
If improved straight-line (dragstrip) performance is your primary goal, the stock rubber upper & lower control arm bushings can be replaced with solid polyurethane bushings or spherical bearings. Hard bushings/bearings eliminate wheel hop, reduce axle deflection, and improve rear end grip. The downside of solid poly bushings is that they prevent the necessary movement of control arms during body roll, which in turn produces significant suspension bind in turns. Spherical bearings do a better (but still imperfect) job of handling control arm motion during turns. And they also tend to transmit a lot of road noise and vibration into the car.
If you use your car in open track or autocross competition, you'll probably want to leave the stock upper control arms alone and install only new lower control arms. The stock rubber bushings in the upper arms continue to allow the axle to articulate through its full range of motion in turns, while the new lower arms improve axle location. One popular lower arm design (illustrated below) uses segmented poly bushings on the chassis end and spherical bearings on the axle end. This combination has been found to improve rear axle location without any significant increase in suspension bind.
a few aftermarket control arms that are available.
hotchkiss rear lower control arms
link discussing hotchkiss
hotchkis upper ad lower control arm? - Mustang Forums at StangNet
maximum motorsports rear control arms
Heavy Duty Rear Lower Control Arms, with Spring Perch and Swaybar Mount, 1999-04
HD Rear Lower Control Arms, 1999-04, with perch, swaybar [MMRLCA-5] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
Heavy Duty Adjustable Rear Lower Control Arms, with Swaybar Mount, 1999-04
HD Adj. Rear Lower Control Arms, 1999-04, with swaybar mount [MMRLCA-6] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
several links discussing
Replacing Upper/Lower Control Arms
taken from-Griggs Racing Products MCA 4500 N
which is used with coil overs shocks, and utilizes a Urethane minimal compliant bushing at one end and Teflon lined spherical bearing at the other.
MCA 4000 N
is a street/ strip control arm for use with coil overs. Bushed at both ends it provides a degree of anti-roll to aid in launch of drag cars.
MCA 6000 WC
are extended length control arms designed for serious competition vehicles such Autocrossers, American Iron and World Challenge cars and are very light weight but strong aluminum tubular arms. They also work well on Drag cars up to about 1000 Hp.
MCA 4000 D
is designed for competition vehicles where rules and /or budgets require the stock lower control arm chassis location to be retained. They are usable on the street and are fitted with friction free rattle free ball type rod ends at both ends and allow for easy alignment of rear axle. They are light and strong. Deletes rear OEM anti-roll bar in Mustangs and T birds prior to 05.
allows for adjustment of rear ride height by turning a bolt. They utilize a stock style spring or Flat wound springs common in the oval track market.
lower control arms? - Mustang Forums at StangNet
J&M control arms
1979-2004 Mustang Rear Lower Control Arms Street Performance
- 1979-2004 Mustang Rear Lower Street Control Arms Weight Jack Adjustable
1979-2004 Mustang Rear Lower Control Arms Street Performance - Weight Jack - Ride Height Adjustable
3 Piece Poly-Ball Bushing on Chassis & Axle Side
1979-1998 & 1999-2004 Mustang Street/Race Rear Lower Control Arms W/ Weight Jack Spring Perch
J&M Rear Control Arms. Yes or No??? - Mustang Forums
J&M Mustang Rear Upper Control Arms (79-04) - Corral.net : Ford Mustang Forums
J&M control arms. - Mustang Forums at StangNet
steeda control arms
Steeda Steel Upper & Lower Control Arm Combo - 79-04
steeda weight jackers
steeda adjustable uppers
here are a few to get everyone started, so lets get some more info on rear control arms posted