GROUND CON­TROL

FRONT SUS­PEN­SION UP­GRADE WITH QA1 CON­TROL ARMS, AD­JUSTERS, AND DY­NAMIC STRUT BARS

Mopar Muscle - - Contents -

Front sus­pen­sion up­grade with QA1 con­trol arms, ad­justers, and dy­namic strut bars.

Dur­ing the pre­sea­son an­nual in­spec­tion of our ’69 Dodge Dart, we no­ticed that both of the lower con­trol arm bush­ings were torn. The drag race sea­son was ap­proach­ing rapidly, and, as a re­sult, our re­pair op­tions were quickly con­tem­plated. One thought was the con­trol arms could be re­built for a third time (the sec­ond time in the author’s 29 years of own­er­ship), but that con­sid­er­a­tion promptly de­parted as re­build­ing nearly 50-year-old con­trol arms seemed like an unat­trac­tive op­tion. A sec­ond, and more at­trac­tive, op­tion was to re­place the lower con­trol arms.

Two years pre­vi­ous, when the fac­tory up­per con­trol arms had be­come worn be­yond re­pair, a pair of QA1 tubu­lar up­per con­trol arms (PN 52301) and ec­cen­tric cam­ber bolt ad­justers (PN 52361) were in­stalled in place of the fac­tory con­trol arms. The qual­ity of con­struc­tion of the QA1 con­trol arms was ex­cep­tional, and be­cause of our sat­is­fac­tion with the con­struc­tion and per­for­mance of the up­per con­trol arms, QA1 was con­tacted for a pair of match­ing tubu­lar lower con­trol arms (PN 52307), tor­sion bar ad­justers (PN 52360), and dy­namic strut bars (strut rods) (PN 52311).

Although the fo­cus for the Dart was front end sus­pen­sion com­po­nents, for the last 25 years, QA1 has spe­cial­ized in per­for­mance shock ab­sorbers, car­bon-fiber drive­shafts, rod ends, front and rear sus­pen­sion, spher­i­cal bear­ings, and ball joints. QA1 pro­vides re­lated items to a va­ri­ety of mar­kets in­clud­ing: cir­cle track rac­ing, drag rac­ing, street per­for­mance, street rod­ding, con­struc­tion, fit­ness, agri­cul­ture and pack­ag­ing equip­ment, as well as sev­eral other in­dus­trial mar­kets.

Be­fore the parts swap­ping started, some rough front end mea­sure­ments of the Dart’s cam­ber (tilt­ing of the top of the wheels from the ver­ti­cal; when tilt is out­ward, cam­ber is pos­i­tive), caster (tilt­ing of the steer­ing axis for­ward or back­ward to pro­vide di­rec­tional steer­ing sta­bil­ity), and toe-in (the amount, in inches or mil­lime­ters, that the front of the wheels point in­ward) were per­formed. These mea­sure­ments would be the base­line when the new parts were in­stalled. Get­ting the ad­just­ments as close to the base­line dur­ing the in­stal­la­tion meant less work would have to be per­formed at the time of the align­ment on the Dart. The cam­ber mea­sure­ments on the Dart were: left front (LF) (-0.25 de­gree) and right front (RF) (-0.40 de­gree), caster was: LF (3.00 de­grees) and RF (3.25 de­grees), and the toe-in was 1/32 inch to­tal. The ride height of the Dart was also mea­sured. With all the ve­hi­cle weight on the four tires, ei­ther on the ground or on a drive-on lift, and the sus­pen­sion jounced sev­eral times, a mea­sure­ment from the floor to the wheel lip open­ing on the cen­ter­line of the spin­dle or axle at all four corners of the Dart was made. Ad­di­tion­ally, the tor­sion bar an­chor point heights were mea­sured to the ground. All the mea­sure­ments were noted for fu­ture ref­er­ence, so the ride height could be

re-es­tab­lished af­ter the in­stal­la­tion of the QA1 com­po­nents.

With all the mea­sure­ments com­pleted, the Dart was moved to a two-post lift. The parts re­place­ment could’ve been per­formed on jack­stands, but we had an op­por­tu­nity to use the lift, and it’s al­ways nicer to work on a car while stand­ing. To re­move the lower con­trol arms and strut rods, we re­ferred to our fac­tory shop man­ual. Start­ing on the RF of the Dart, the wheel was re­moved and then the lower shock bolt. The shock was com­pressed to pro­vide ad­di­tional clear­ance to other sus­pen­sion com­po­nents and re­mained sus­pended by the up­per shock bush­ings and nut. If the Dart had still been equipped with the fac­tory disc or drum brakes, the disc brake assem­bly and the splash shield or the drum brake assem­bly would have to be re­moved to gain ac­cess to the lower ball joint, but the Dart was fit­ted with Wil­wood front disc brakes, con­se­quently this step was not nec­es­sary. If a sway bar had been on the Dart, the end link would have been re­moved. Mov­ing to the strut rod, the roll pin (cot­ter pin) was driven out fol­lowed by the re­moval of the nut, re­tainer, and front bush­ing with the sleeve from the for­ward end of the strut. The depth of the tor­sion bar an­chor bolt into the lower con­trol arm was mea­sured, and while un­wind­ing the tor­sion bar an­chor bolt, a count of the ro­ta­tions of the bolt was recorded for the re­in­stal­la­tion. The ball joint nut was loos­ened, and a pickle fork and ham­mer were used to break the con­trol arm free from the ball joint. The ball joint nut was re­moved, and the lower con­trol arm shaft nut was un­threaded. The tor­sion bar clip was freed from its re­tainer groove, and the tor­sion bar was slipped from the con­trol arm. The con­trol arm along with the strut rod assem­bly was re­moved from the Dart.

Once the con­trol arm and strut rod were out of the Dart, the strut rod was sep­a­rated from the con­trol arm. The length of the fac­tory strut rod was de­ter­mined by mea­sur­ing the dis­tance be­tween the mount­ing shoul­der on the strut rod at the lower con­trol arm and the bush­ing that con­tacted the K-frame near the ra­di­a­tor sup­port. This mea­sured length was trans­ferred to the new ad­justable QA1 dy­namic strut bar. Two jamb nuts (one on each end of the bar) were tight­ened to guar­an­tee the length would re­main sta­ble dur­ing the in­stal­la­tion and dur­ing the usage of the Dart in the fu­ture.

The assem­bly of the RF of the Dart was straight for­ward. The QA1 lower con­trol arm with the dy­namic strut bar loosely con­nected slid into place at the two fac­tory mount­ing points on the K-frame. The sup­plied washer and nut were lightly threaded onto the con­trol arm shaft, and a washer and bolt were run through the K-frame at the ra­di­a­tor

sup­port area to at­tach the dy­namic strut bar. The rod end of the dy­namic strut bar was ad­justed to line up per­pen­dic­u­lar with the floor, and the lower con­trol arm was moved through its en­tire range of mo­tion to con­firm the rod end would not bind at any point of the move­ment. If bind­ing had oc­curred, the rod end would have been ro­tated un­til a bind-free move­ment of the lower con­trol arm was achieved. Once the range of mo­tion was es­tab­lished, the lower con­trol arm nut, and the dy­namic strut bar fas­ten­ers were snugged to min­i­mize the play dur­ing the re­assem­bly. The lower ball joint was pushed through the lower con­trol arm, and the lower ball joint cas­tle nut was prop­erly torqued. A cot­ter pin slid through the ball joint stud and cas­tle nut. Af­ter the lower ball joint was in­stalled, the tor­sion bar was pushed into the lower con­trol arm and the tor­sion bar clip was re­in­stalled. The new QA1 tor­sion bar ad­juster was placed in the lower con­trol arm, the bolt lubed with a gen­er­ous coat­ing of an­ti­seize, and the bolt was threaded into the lower con­trol arm tor­sion bar ad­juster. An at­tempt was made to achieve a sim­i­lar ride height to our base­line, ac­cord­ingly the ad­juster bolt was twisted as nec­es­sary to achieve the pre­in­stal­la­tion mea­sure­ments. With the in­stal­la­tion fin­ish­ing up on the RF, we pulled the shock ab­sorber back into place, slipped the bolt through the lower con­trol arm shock mount and the ab­sorber, and we tight­ened the bolt. The RF sus­pen­sion was now re­assem­bled. We moved to the LF of the Dart and re­peated the pre­vi­ously de­scribed steps. Upon com­ple­tion of the LF, the Dart was low­ered onto its tires and was jounced sev­eral times to set­tle the sus­pen­sion. A few quick height mea­sure­ments were made and com­pared to the base­line mea­sure­ments. It was de­ter­mined the tor­sion bar ad­juster bolts needed to be twisted a few turns to reestab­lish the proper ride height. With the wheels and tires sup­port­ing the Dart’s weight, the dy­namic strut bars and the lower con­trol arm fas­ten­ers were torqued to the rec­om­men­da­tions of QA1.

Sat­is­fied with the in­stal­la­tion of the QA1 sus­pen­sion com­po­nents, the Dart was loaded on to a trailer and trans­ported to Penn­syl­va­nia Col­lege of Tech­nol­ogy (Penn Col­lege) to have the align­ment per­formed. Penn Col­lege has the lat­est Hunter Align­ment ma­chines and equip­ment, hence it was a per­fect plat­form for the per­for­mance align­ment. Once at the col­lege, the re­quired pro­ce­dures to es­tab­lish the Dart’s align­ment an­gles were per­formed, and based upon the com­puter read­out, some ad­just­ments were re­quired. The dy­namic strut bars were short­ened 1/8 inch (a slight change of caster), and the ride height was read­justed. The pro­ce­dures to de­ter­mine the align­ment an­gles were re­peated. The up­per con­trol arm ec­centrics were ad­justed to pro­vide cam­ber mea­sure­ments of: LF (-0.20 de­gree) and RF (-0.30 de­gree) and caster mea­sure­ments of: LF (4.6 de­grees) and RF (4.3 de­grees). The toe ad­juster sleeves were ro­tated to con­firm a toe-in of 1/32 inch. Af­ter all the ad­just­ments were com­pleted, the ride height was checked for the last time, and all of the fas­ten­ers that had been loos­ened or re­moved dur­ing the QA1 sus­pen­sion com­po­nent swap were fi­nal checked for proper torque.

The de­ci­sion to in­stall the QA1 parts on the Dart was the cor­rect choice. Un­less an en­thu­si­ast’s ride is a qual­ity restora­tion, why re­build 50-plus-year-old com­po­nents when QA1 pro­vides qual­ity after­mar­ket prod­ucts? If the plan of a Mopar afi­cionado is to run their ride on the street or, bet­ter yet, run their ride hard at the track, QA1 parts will pro­vide piece of mind when the owner’s safety is on the line. In our case, with the new QA1 parts in­stalled, the Dart has in­creased front-end travel, the lower con­trol arms and dy­namic strut bars are a slightly lighter weight com­pared to the fac­tory parts, the com­po­nents fit per­fectly, and the QA1 com­po­nents look great. Is it time to up­date your Mopar? Get in touch with QA1 to see what they can do to bring your Mopar into the 21st cen­tury.

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Be­fore the QA1 com­po­nents were in­stalled onto the Dart, we made a few mea­sure­ments. These mea­sure­ments would be our tar­get when we re­assem­bled the sus­pen­sion. Luck­ily, we had an align­ment bub­ble gauge, which al­lowed us to mea­sure the cam­ber an­gle of each front wheel. With turn ta­bles un­der the front (and rear) tires, we were able to per­form caster sweeps (as seen here) of the front sus­pen­sion to ac­quire the caster an­gle at each front wheel. We noted the cam­ber and caster mea­sure­ments for later re­view.

An ad­di­tional ride height mea­sure­ment was made from each tor­sion bar an­chor point to the ground. These two mea­sure­ments plus the wheel open­ing mea­sure­ments as­sured us that we could re­turn the Dart to the base­line ride height af­ter all the assem­bly was com­pleted. Dur­ing the re­assem­bly of the sus­pen­sion, fine-tun­ing the tor­sion bar ad­justers would al­low us to at­tain the base­line set­tings.

QA1 sup­plied a pair of dy­namic strut bars (PN 52311), a pair of tubu­lar lower con­trol arms (PN 52307), and a pair of tor­sion bar ad­justers (PN 52360). The lower con­trol arms have pro­vi­sions for sway bar endlinks, but our ’69 Dodge Dart does not have a sway bar. The dy­namic strut bars can be ad­justed to fine tune the ve­hi­cle’s align­ment.

We mea­sured the ve­hi­cle at each wheel open­ing to es­tab­lish a base­line ride height. The mea­sure­ment was taken from the floor to the fender open­ing while lined up with the cen­ter­line of the spin­dle or axle. Again, we recorded our find­ings for later use.

The last base­line mea­sure­ment we made was the toe mea­sure­ment. An old me­chan­i­cal toe bar was used to mea­sure the dis­tance be­tween the front of each front tire (mea­sured 8 inches off the ground at a tread bar on the tire) and mea­sure the dis­tance be­tween the same two tread bars on the back of each front tire. The use of the toe bar made the mea­sure­ments eas­ier to at­tain when com­pared to us­ing a string.

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