Ok, so now how about the rear suspension?

Posted By: dodge41

Ok, so now how about the rear suspension? - 05/26/08 10:57 AM

So, now that you gurus have cleared up the front susp for me (and others) how about the rear? I had planned on flipping the rear and c-notching the frame, but I was told that it is possible to build a 4 link or 4 bar set up your self. I'm a machinist and welder, so that part of it is no problem, it's just the geometry I'd have to learn. There is a guy on ebay that sells plans right down to the spring cradles, has anyone used these? Or other plans?
I love this forum!

Matt

Posted By: moparx

Re: Ok, so now how about the rear suspension? - 05/26/08 01:08 PM

the rear suspension is a piece of cake compared to the front. there are several styles to chose from, and that may be your most difficult decision to make. as to making the 4-bar, or 4 link yourself, you have the skills necessary, so it wouldn't be hard for you at all. the main concern is to keep the bars parallel, and to set the pinion angle up properly. spring rate would also be of concern, dictated on the weight distribution front/rear. don't skimp on the quality of the related hardware [ bolts, heims, bushings, etc.] and make sure everything is square / parallel to the chassis & front suspension when welded up and you will have no problem.

Posted By: RodStRace

Re: Ok, so now how about the rear suspension? - 05/26/08 01:53 PM

Since Ma didn't mess with the cross spring, you can ignore that.
You can use good ol' parallel leafs. If you have a tight front, you may want to add a sway bar.
Pros: strong, easy, already there, clearance for exhaust, cheap.
Cons: while it can be tuned pretty well, it's still pretty basic. not easy to air bag (if that's in the plans)
Multilink solid axle. Requires time and effort or money. If set up right, is better for drags or handling. Can run coilovers , coil springs or air bags. You will have to snake the exhaust through the area if you are going out back. About the best a solid axle can be for handling or drags.
IRS. Lots of choices. Main thing is to find a setup that fits and can handle the power and weight. Then try to engineer the proper mounting to the frame. This is the highest difficulty, and if any part of the design or build is off, can drive worse than the first, or be dangerous.
Since you didn't finish the first rod projct, and (AFAIK) you don't have a bunch under your belt like Ron, I'd stick to the easy path. There is a LOT to do, and sucess is the goal. You can change what you don't like AFTER it's running and driving..

Posted By: dodge41

Re: Ok, so now how about the rear suspension? - 05/26/08 02:24 PM

That's a good point about doing it later, especially with a pick up, it's not too hard to take the box off and redo the rear susp. after it's on the road. And you're right, this is my first rod project.
Matt

Posted By: RUMBLON

Re: Ok, so now how about the rear suspension? - 05/26/08 04:49 PM

Quote:

Since Ma didn't mess with the cross spring, you can ignore that.
You can use good ol' parallel leafs. If you have a tight front, you may want to add a sway bar.
Pros: strong, easy, already there, clearance for exhaust, cheap.
Cons: while it can be tuned pretty well, it's still pretty basic. not easy to air bag (if that's in the plans)
Multilink solid axle. Requires time and effort or money. If set up right, is better for drags or handling. Can run coilovers , coil springs or air bags. You will have to snake the exhaust through the area if you are going out back. About the best a solid axle can be for handling or drags.
IRS. Lots of choices. Main thing is to find a setup that fits and can handle the power and weight. Then try to engineer the proper mounting to the frame. This is the highest difficulty, and if any part of the design or build is off, can drive worse than the first, or be dangerous.
Since you didn't finish the first rod projct, and (AFAIK) you don't have a bunch under your belt like Ron, I'd stick to the easy path. There is a LOT to do, and sucess is the goal. You can change what you don't like AFTER it's running and driving..

So anythign wrong with an 8 3/4 and leaf springs?

and

how about the frame? Does it need to be boxed?
cross supports, ect?
Dave

Posted By: Mopar Ron

Re: Ok, so now how about the rear suspension? - 05/26/08 06:07 PM

I like the leaf springs for a non prostreet car or daily driver, I had stock 1936 leaf springs on my humpback and drove that truck for over 130,000 mi. in 12 years amd my wifes sedan was pro street and I used the stock leaf springs that were on the 80 datsun frame that I used. that car also had about 12 years on it and over 120,000 mi.
she even drove out here when we moved to CA in 1993

I am running a triangulated 4 bar on my roadster PU and ladderbars on my racetruck, the roadster PU will have air bags and the racetruck will have coilovers.

for a cheap reliable rear setup, good old leaf spring work very good but I like to upgrade to a newer mini truck springs instead of 70 year old stock springs.

but 4 bar or ladderbars work good as well but you have the added cost of air bags or coilovers.

and Dave your frame has a X frame in it and you will not need to do any boxing

Ron....

Posted By: RodStRace

Re: Ok, so now how about the rear suspension? - 05/26/08 10:58 PM

Quote:

So anythign wrong with an 8 3/4 and leaf springs?

and

how about the frame? Does it need to be boxed?
cross supports, ect?
Dave

Dave, I was thinking about you when I wrote this (the mention of an earlier project), and crossed wires with the original poster.

I'd go with the original springs and an 8 3/4 or a later model rear (donor car/truck) unless you plan on some HP. Then I'd consider using some later springs (60s-up short front section), but that means new mounts.
If you are thinking about BIG HP, go with SS springs or a ladder bar/4 link.

Posted By: mopowertim

Re: Ok, so now how about the rear suspension? - 05/27/08 12:06 AM

Really cool article in this months Hot Rod Deluxe mag on how to build a proper "poor mans" 4 link using a 8.75 rear. Check it out, lots of good info, pics, and parts resources listed.