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Im­prove the han­dling of your vin­tage mus­cle car by in­stalling urethane body mount bush­ings

Chevy High Performance - - Contents - TEXT & PHO­TOS: Nick Li­cata

Im­prove the han­dling of your vin­tage mus­cle car by in­stalling urethane body mount bush­ings

When it comes to up­grad­ing the sus­pen­sion of your clas­sic Chevelle—or any mus­cle car for that mat­ter—the num­ber of op­tions is pretty much un­lim­ited. It can range from bolt­ing on a set of af­ter­mar­ket con­trol arms, spin­dles and low­er­ing springs to a per­for­mance coilover con­ver­sion kit, larger sway bars, or even go­ing all-in with a com­plete af­ter­mar­ket chas­sis.

But if you aren’t quite ready to jump into any of those sus­pen­sion up­grades, you can still get bet­ter han­dling per­for­mance by merely re­plac­ing the orig­i­nal rub­ber body mount bush­ings with a fresh set of urethane bush­ings. In fact, if you do plan on mak­ing sus­pen­sion up­grades, it makes even more sense to go the urethane route.

Brian Cox, a mem­ber of our team here at Chevy High Per­for­mance owns a ’67 Chevelle that has a stock­ish sus­pen­sion, sport­ing af­ter­mar­ket springs, shocks, and sway bars. Brian’s Chevelle was still out­fit­ted with the orig­i­nal 50-year-old rub­ber body mount bush­ings, which on their best day of­fered sloppy han­dling, un­de­sir­able vi­bra­tions dur­ing high­way driv­ing, and strange noises and squeaks when Brian pulled the car in or out of his drive­way—all com­mon symp­toms as­so­ci­ated with cracked and worn rub­ber body mount bush­ings. It was def­i­nitely time to up­grade.

We went to Prothane Mo­tion Con­trol in Pla­cen­tia, Cal­i­for­nia, for their 1965-’67 Chevelle, El Camino, Monte Carlo Urethane Body Mount Kit. Launched in 1991 with fewer than 100 prod­ucts, Prothane now makes more than 5,000 kits and parts rang­ing from en­gine mounts, trans­mis­sion mounts, leaf spring pads, con­trol arm bush­ings, strut arms, shocks, and more for do­mes­tic and im­port ve­hi­cles—all proudly made in the USA.

While rub­ber com­po­nents of­fer a soft ride for a lim­ited amount of time, they tend to de­te­ri­o­rate rather rapidly from the ex­tended ex­po­sure to the el­e­ments, which con­trib­utes to pre­ma­ture fail­ure, re­sult­ing in a “spongy” ride and a re­duc­tion of ride qual­ity and per­for­mance han­dling. Prothane’s urethane bush­ings are im­per­vi­ous to gas and oil, are stronger than rub­ber, and will of­fer a bet­ter over­all per­for­mance driv­ing ex­pe­ri­ence, es­pe­cially in a vin­tage 1960’s mus­cle car.

All these ben­e­fits are just what we were look­ing for, and the longevity is very ap­peal­ing, as we don’t plan on do­ing this ex­er­cise again any­time soon. As Prothane puts it, “Rub­ber will rot, urethane will not.”

So let’s dig into this ride and get rid of those vin­tage rub­ber bush­ings. CHP 02 | Prothane Mo­tion Con­trol’s 1965-’67 Chevelle body mount kit (PN 7-121) comes with all the new urethane body bush­ings, sleeves, and wash­ers and are a di­rect re­place­ment for the orig­i­nal, cracked, 50-year-old rub­ber bush­ings. They come in red or black; there is no dif­fer­ence in qual­ity be­tween the two col­ors—red just pho­to­graphs bet­ter.

03 | Ar­riero got started by hit­ting all the body mounts with good dose of spray lu­bri­cant to help loosen the stub­born nuts and bolts. Ev­ery bit helps when you are deal­ing with nuts that haven’t turned in over 50 years. Once done with the spray process, all of the body mount bolts were slightly loos­ened be­fore start­ing the re­place­ment process. 04 | Ar­riero got started at the core sup­port by re­mov­ing mount #1 (Prothane num­bers all the mount lo­ca­tions in the in­struc­tions to en­sure the cor­rect bush­ings are used) with a 5/8-inch socket. Note, this is the only mount with the slim bot­tom bush­ing. We re­moved and re­placed one mount at a time (one on each side) to keep the body square to the sub­frame. 05 | The stock bolts were a lit­tle too short for the new body mounts so we called an au­di­ble and went with Grade 8 bolts that were 1/4-inch longer to help make in­stal­la­tion eas­ier. 06 | We ap­plied a lit­tle an­ti­seize to each bolt for good mea­sure.

07 | At this point, with all the body mount bush­ings loose, Ar­riero used a pole jack and a length of 2x4 to care­fully raise the body on one side. You’ll have to fur­ther loosen the body mount bolts on the side you are work­ing on in or­der to raise the body enough to re­move the old bush­ings and slide the new ones into place. For safety pur­poses, be sure the chas­sis re­mains fully sup­ported, in our case with the lift.

08 | Due to the stock #2 body mount hav­ing the top washer and a por­tion of the sleeve in­te­grated as one piece, we had to raise the body a lit­tle higher in or­der to get it out over the top of the sub­frame. This photo il­lus­trates how long the orig­i­nal body mount sleeve is com­pared to the new Prothane bush­ing that will re­place it. Again, it’s im­por­tant you slowly lift the body to make sure the door gaps don’t tweak too much and that the frame is still fully sup­ported. 09 | As you can see here, the stock #2 bush­ing’s washer and rub­ber are in­te­grated to­gether (black ar­row), mak­ing it more dif­fi­cult to re­move. We yanked on it for a while be­fore re­al­iz­ing it wasn’t com­ing out with­out a fight and the help of a cut­ting disc. 10 | The new Prothane bush­ing slides in be­tween the body and sub­frame. It went in a whole lot eas­ier than get­ting the stock piece out.

01 | Chevy High Per­for­mance ac­count man­ager Brian Cox’s ’67 Chevelle was rocking the same body bush­ings it came with from the fac­tory so the car’s less-than-stel­lar ride was start­ing to wear on him. We brought the car into the Chevy High Per­for­mance tech cen­ter where in­stal­la­tion tech­ni­cian Chris Ar­riero han­dled the wrench­ing.

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