View Full Version : Handling upgrades for leaf spring rear?

09-11-2015, 04:27 AM
Looking to decrease body roll greatly in my 85 c10. Currently the truck is lowered with a rear flip kit and cut coils roughly a 4/6 drop. Since my budget is very tight I'm trying to optimize what I have rather than spend more on components than the entire truck is worth currently. I plan to do this build in stages, with a end goal of a fun spirited daily driver, that's a beast on winding back roads.

Currently I have changed the ball joints and have a urethane control arm bushing kit to install. I also have a factory front sway bar with urethane bushings for the front as well to create a decent stock front end. Out back is where I'm struggling to develop a plan of attack. To stay in my budget I want to keep the rear leafs so I upgraded to poly bushings when I did the flip kit and that's where Im at now. Would it be better for me to find a stock rear sway to retrofit (any suggestions are appreciated ) or increase the spring rate with the addition of helper spring shocks. I'm leaning towards the helper spring shocks since I need to upgrade the shocks anyway and the fact that they will stiffen my rear up. Please help thanks

09-13-2015, 10:03 AM

09-13-2015, 11:36 AM
I would look at a factory bolt on rear bar from say a long bed truck with the "camper tow" package. Scourer some local junk yards if the budget is tight.

High Plains Mopars
09-13-2015, 02:30 PM
There is a lot more to making leaf springs handle well than simply reducing body roll. Body roll does not automatically mean poor grip. If you just want to reduce roll than a rear sway bar can handle that and be easily sourced from a salvage yard. However, adding a rear sway bar, or stepping up the leaf rates if you went that route, will make the already oversteer happy truck layout even worse, without a corresponding step up in rates at the front to offset the additional rate in the rear.

Avoid bolt on shock help springs. Those are the band aids band aid and the worst possible appraoch for this as it starts transfering suspension load into the shocks. Shocks are designed to dampen, not support loads.

09-13-2015, 05:46 PM
The factory rear bar isn't really a good choice. The whole setup is probably pushing 100lbs. They are on the back of most 73-87 duallys. I agree that a rear sway bar isn't the magic bullet for handling and could possibly make it worse. As for suggestions I think I would get rid of those poly leaf spring bushings. They are good for locations that work in one plane like control arm bushings, but can cause bind in a location the sees forces in all directions like a leaf spring. They probably won't last long there either. Hard to beat rubber there. As for the helper shocks, I'm thinking the coilover looking shock kits? I'd stay as far away from those as I could. The shock mounts aren't designed to carry weight and will break out of the frame.Go ahead and install the front bar and have fun. It'll handle pretty good with just that. Google search the " 73-87 Caster Mod" and the"Make it Handle" thread. Long read but well worth it........

09-14-2015, 05:24 AM
Thanks guys the caster mod is on my radar for a later date. But I think now I will just get some good shocks for the rear and see what the front sway bar does. As far as the poly bushings they are there until failure. I will probably be doing truck arms or link suspension by next year this time. Thanks again

10-02-2015, 09:46 PM
I just put in a sway bar i got from a friend in the rear of my 79 c10. It has a 8.5" 10 bolt from a caprice with custom shock mounts and the bar came from an f-150 and fits great!! I tried the factory rear bar but didnt like the way it mounted and how low it was. I use all junkyard parts when i can so buying a bar wasnt an option for me. I autocross mine and it is very nuetral handling. I have done the caster mod and got 8* caster out of it with -1* camber and it handles great

https://static1.pt-content.com/images/pt/2015/10/20150920_082809_zpsrfdan7bw-1.jpg (http://s134.photobucket.com/user/wells_329/media/Mobile%20Uploads/20150920_082809_zpsrfdan7bw.jpg.html)
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10-03-2015, 06:07 AM
cool lookin Square ya got Mtrhd. As to the OP, KO, a sway bar would help, but not a heavy bar. Look at a camaro rear bar, 3/4" to 7/8", '70 up to '92. Easy to find and fit. As for the springs, you want to go the other way. Soften them up to drop the spring rate. The key here is to 'Free' up the rear. Remove some of the short leafs so your down to the longest three or four leafs. Put Teflon spring liner between the leafs (Speedway or TCI). This may drop the truck some more - but that's OK, Another trick is to change the shackle position. This can be a big help for leaf suspended trucks. On a stock 'Truck' style leaf, the shackle runs from the frame mount UP to the spring. The spring then tries to PULL the shackle to a straight up position the more it is loaded. (Progressive rate) This works great for haulin hay, but not for haulin the mail. In a 'Car' style leaf set up, the shackle runs from the frame mount DOWN to the spring. The spring now tries to PUSH the shackle up, and in doing so, wants the spring to flex out to be longer so that the shackle can move up in an arc.(regressive rate). You can take your OE mounts, knock the rivits out, and flip them upside down on the chassis. Move them appx 1/2" forward on the frame, so that the shackle has a slight slope back to the spring eye (At loaded ride height) say 5* to 10*. this mod will raise the truck 1 1/2 to 2". some of that may be gained back with the spring mod. (or a small block if you want - I'm not a fan of blocks if you can avoid it.) These three changes could be done in a weekend for less than $100 bucks, and the difference would be huge. Please, try it and report back the improvements.

10-03-2015, 03:40 PM
Thanks Rob and mtrhd these are exactly the responses I wanted I will look for the sway bar this weekend since I broke a u joint and need a new drive shaft anyway. I will probably wait to do the shackle mod until I get a notch kit since my rear space really wont allow and lower after the flip right now. As far as the caster mod did you buy new cross beams for the control arms or have your stock arms re-drilled? Im really looking forward to getting my truck competition ready when I get home I'll post up a new pick of the truck yours looks real nice motrhd. BTW whats the gear ratio in that caprice rear is it a direct bolt in?

10-04-2015, 07:13 PM
Rob- funny you mention flipping the shackle mount i tried that out once and it rode great but when i added a steel floor to the stepside bed they wouldnt clear it so i swapped them back.

2ndroundko- i just flipped my shafts 180* and drilled them out. I clearance a few places to make sure i had good clearance during travel. Caprice rear runs a 4 link-ish type setup in the rear. I had planned weld new saddles for the axle flip so i just cut everything off and welded new ones on. I was going to intall a true trac in it so i swapped in some 3.73s at the same time. I think it came with 3.08s. Or something cant remember. The rear is narrower by i think 2" either side so i had to run spacers until i can get rims made.

Thanks for the compliments guys. I built the truck to be a sleeper. Unsuspecting even at the autocross.

10-04-2015, 07:29 PM
Oh ok cool I may drill mine this weekend while I'm replacing my control arm bushings. Do you have a build thread.

10-04-2015, 07:52 PM
Check out this thread if your doing the caster mod.
I have a build thread but i havent been updating it lately, been to busy working on the truck.

10-05-2015, 03:48 AM
Yeah I have that thread bookmarked. Just a little concerned about doing it at home.

10-05-2015, 10:21 AM
For handling dont look past air ride. I used parallel 4 link, welded plates too front mounts, bolted them in place of rear spring mount. to make it less expensive how about long lower control arms same as parallel 4 link, then add in a single third link on right side, making three link, add in either a simple panhard bar or watts link. Add in some decent ridetech single or double adjustable shocks at proper angle inward. Would have to make a shock mount bar, front cross member for upper arm and on drivers side you have to plate over the shock indent in frame but is easy enough.
My 78 C10 has air ride all around, and handles great. and it hasnt even seen good wheels and tire yet.

10-07-2015, 02:27 PM
I haven't counted air ride out, but I enjoy driving my truck and I know there is far more left in the stock setup. I'd rather optimize what I have than have truck down for months while fabricating and funding a four-link bagged rear and bagging the front.

11-07-2015, 04:19 PM
The easy stuff I have found for rear truck suspensions are adding a sway bar if it didn't come with one, adding a track bar and either buying or building a set of link style traction bars that tie into the front spring eye. Some people say a track bar isn't needed on leaf spring suspensions, but I can literally feel my rear step out over certain bumps. And it should only be about a $50 mod if you are creative. If your rear isnt positive, that makes a big difference too.

11-08-2015, 06:45 PM
Now the track bar is something I had not thought about! I will have to look into that. I recently got some decent tires for my 17 inch wheels and changed my control arm bushings to poly. so far the decreased side wall height and new bushings have made some nice changes to the way my truck drives.

07-27-2016, 07:38 AM
Long time no update. I got the control arm bushings in and the sway bar, but I left the back stock other than the bushings. That in itself made a considerable difference. As of now the truck is blown apart for bodywork. While the bed is off I'm going to flip the shackle mount and take out a couple leafs. while Im addressing the back I am also going to add some bracing to the frame in an A-shape to stiffen the frame a bit.