Shocks springs and more

[Crazyc]

I know this has been brought up several times, but I’m throwing in a new rear end in my GP. A 4.10 Richmond Posi. Anyways, while I’m back there, I’m changing the upper and lower arms with aftermarket ones with all new bushings etc. I’d also like to replace the rear springs and shocks. So bouncing back and forth on the rear springs. I was figuring just ordering the Ac Delco factory springs and new rear upper isolators and adding the Ac Delco spring assist rear shocks to firm up the cornering etc. I saw the post on spring rates and graph of the rear shock options, 5379 (wagon) the 6377 (Monza) and the 5659 (?) that got me thinking. I see a lot of guys using the 5379, but what’s the actual opinion of guys using the other ones on that chart. I don’t want to raise my rear up any, and I was intrigued by the little lower height of the 5659 with the higher spring rate as well.
(What are those off of anyways)
So just looking for some personal experience in the rear spring / shock department. Let me now your opinions!

 

[superbon54]

I can’t answer your spring question since I’ve never used AC Delco springs, but saw that you are replacing your control arms and thought I’d chime in. Do not use polyurethane bushings in all UCA and LCA locations - the suspension will bind horribly and the car will handle unpredictability. You need either rubber or a rotojoint style in one end, especially on the uppers.

 

[Crazyc]

I can’t answer your spring question since I’ve never used AC Delco springs, but saw that you are replacing your control arms and thought I’d chime in. Do not use polyurethane bushings in all UCA and LCA locations - the suspension will bind horribly and the car will handle unpredictability. You need either rubber or a rotojoint style in one end, especially on the uppers.

Ok so upper mounts use rubber !!!

 

[ssn696]

Or use spherical bushings on the differential ears to manage the conflicting control arm angles. UMI and Speedway offer them for widely differing prices.

 

[Doug Chahoy]

I just finished my rear suspension yesterday. I used UMI tubular control arms with the upper being adjustable with a rotojoint ( no bushing) $399.00 UMI 1 inch sway bar $160.00. That really opened up alot of space around my Pypes dual exhaust. I also used Moog 5660 coil springs, I had to get universal isolators due to GM and Moog discontinuing the actual ones for those springs, I finished with KYB gas shocks. I wasn’t intending to lower the back end but with those springs it brought it down so when you look straight at it the wheel lip is even with my 245/45X17 tires. I’m not a fan of lowered vehicles but it closed up the big gap there was with the original suspension

 

[pontiacgp]

Ok so upper mints use rubber !!!

the rubber is slightly softer than the poly and the poly lasts longer. The design of the upper control arms allow them to twist to prevent binding, not the bushing. If you box the uppers or use a solid upper then you need a spherical or roto joint at one end.

 

[Crazyc]

Or use spherical bushings on the differential ears to manage the conflicting control arm angles. UMI and Speedway offer them for widely differing prices.

Your saying only change the upper axle ear bushings to spherical

 

[Crazyc]

I just finished my rear suspension yesterday. I used UMI tubular control arms with the upper being adjustable with a rotojoint ( no bushing) $399.00 UMI 1 inch sway bar $160.00. That really opened up alot of space around my Pypes dual exhaust. I also used Moog 5660 coil springs, I had to get universal isolators due to GM and Moog discontinuing the actual ones for those springs, I finished with KYB gas shocks. I wasn’t intending to lower the back end but with those springs it brought it down so when you look straight at it the wheel lip is even with my 245/45X17 tires. I’m not a fan of lowered vehicles but it closed up the big gap there was with the original suspension

You used 5660 on the rear ? I thought those were for the front ?

 

[Doug Chahoy]

You used 5660 on the rear ? I thought those were for the front ?

My typo, I used 5665

 

[ssn696]

Your saying only change the upper axle ear bushings to spherical

That's what I did to reuse some Hotchkiss arms with poly bushings. I used Speedway, but the car's not on the road yet so I can't vouch for long-term durability. They press into the housing the same way as the rubber ones.