Rear Suspension help... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bhammer · 11-10-2009, 10:42 PM

So I have a 72 longbed 2WD with the trailing arm and spring combination on the rear suspension. I was loading my harley for the first time into the back and notice that the suspension was so shakey while I was standing in the back. I wiggled from side to side so bad that I nearly dropped the bike. Once I had it loaded and secured it felt fine driving. Same thing happened unloading it, wiggled so bad form side to side it was precarious unloading it to say the least. Anyone know what I can do to make it a little more stable? Thanks....

BAGNDRAGIT · 11-10-2009, 11:07 PM

i would check you track bar (panhard bar) bushings, and from there the trailing arm bushings.

also make sure everything is tight back there.

dan42 · 11-10-2009, 11:20 PM

Actually, these trucks normally are a little shakey when you get in the back of them, let alone with a 600 lb bike - especially the half tons.

69GMCLonghorn · 11-11-2009, 02:59 PM

Simple thing, but make sure your shocks are good. If you start crawling around under there, have someone else shake it around. Somethign should jump out at you (not literally) if it's broken or loose.

capev86 · 11-11-2009, 03:30 PM

new bushings (preferably poly) to tighten things up
modern shocks
rear sway bar will definitely help
3/4 ton rear coils if you plan to haul a lot.....stiffer makes for less sway

unclewatts · 11-12-2009, 05:12 AM

Betch'a it's the panhard bushings. They can be a pain to replace but it's worth it.

292farmer · 11-12-2009, 07:43 AM

hey uncle watts is the m20 the trannsmission? (in your vehicle list) because my glovebox says m20 4spdmanual for the option list i looked at it and it looks like a sm465 or np435 is the m20 a code for one of those or does it stand for a whole different transmission? thanks my trucks a 1972 c20 292i6

unclewatts · 11-13-2009, 04:01 AM

Quote:

Originally Posted by 292farmer

hey uncle watts is the m20 the trannsmission? (in your vehicle list) because my glovebox says m20 4spdmanual for the option list i looked at it and it looks like a sm465 or np435 is the m20 a code for one of those or does it stand for a whole different transmission? thanks my trucks a 1972 c20 292i6

That's an excellent question. Yes, it is on my SPID too and I'm not absolutely sure of what model transmission it refers to. It is a top loader with granny low and reverse is toward the passenger side and down. I believe it is a SM465 but I'm not positive. Maybe one of our more knowledgeable members could post an answer.

bhammer · 11-13-2009, 05:17 AM

Thanks for the input guys. I am not sure of the problem. I know the previous owner has lowered the truck. I am guessing a 2/4 drop. I just thought the suspension should have been a little stiffer even with it being lowered. I haven't really crawled around to see if anything is loose. I am planning on tearing it down anyhow. Hopefully putting in some poly bushings will help. I am probably going to end up putting bags on the rear to stabilize it a little more and keep the ability to tow. This is my daily driver now so it has to be able to tow a bike or something of equal weight. Is installing a panhard bar a huge undertaking or is it pretty simple?

Thanks again.

Brian

bhammer · 11-13-2009, 05:20 AM

Now that I have looked at it I don't think there is a stabilizer bar on it at all on the rear. When I unloaded the bike I had to put a scissor jack under the frame to keep it from wiggling so much.

ebfabman · 11-13-2009, 08:45 AM

bhammer, nice truck andVERYnice springer. It's unlikely your truck has no track bar but as others have said the bushing may be worn out. Post a pic of the rear suspension and you will get all the help you need.

btw here is my springy

11-10-2009, 10:42 PM	#1
bhammer Registered User Join Date: Jul 2009 Location: Las Vegas, NV Posts: 97	Rear Suspension help... So I have a 72 longbed 2WD with the trailing arm and spring combination on the rear suspension. I was loading my harley for the first time into the back and notice that the suspension was so shakey while I was standing in the back. I wiggled from side to side so bad that I nearly dropped the bike. Once I had it loaded and secured it felt fine driving. Same thing happened unloading it, wiggled so bad form side to side it was precarious unloading it to say the least. Anyone know what I can do to make it a little more stable? Thanks.... Attached Images

11-10-2009, 11:07 PM	#2
BAGNDRAGIT Just Not Low Enough! Join Date: Mar 2009 Location: Phoenix, AZ Posts: 525	Re: Rear Suspension help... i would check you track bar (panhard bar) bushings, and from there the trailing arm bushings. also make sure everything is tight back there. __________________ NEED ELECTRICAL HELP? ASK ME! 67-72 Full Wiring Diagrams Lots Of Info, TAKE A LOOK 1967 Chevy C-10 Shortbox Bagged 327 4spd Previous: 1971 Chevy C-10 Short Sep I6 Auto (Traded) 1973 Chevy C-20 THE REDNECK BATTLE TRUCK 2001 Chevy Silverado 2Dr 5.3L Shortbox. R.I.P. 1969 Volkswagen Bug This is my first meeting, I have a horsepower problem.

11-10-2009, 11:20 PM	#3
dan42 Registered User Join Date: Feb 2007 Location: Cali Central Coast Posts: 5,191	Re: Rear Suspension help... Actually, these trucks normally are a little shakey when you get in the back of them, let alone with a 600 lb bike - especially the half tons. __________________ '67 SWB Fleetside ZZ4/350/Tremec 5-speed/4link/Scott's IFS - and fun as heck! SOLD Click here to support the board Philippians 4: 6-7

11-11-2009, 02:59 PM	#4
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	Re: Rear Suspension help... Simple thing, but make sure your shocks are good. If you start crawling around under there, have someone else shake it around. Somethign should jump out at you (not literally) if it's broken or loose.

11-11-2009, 03:30 PM	#5
capev86 Registered User Join Date: May 2009 Location: Eliot, Maine Posts: 1,314	Re: Rear Suspension help... new bushings (preferably poly) to tighten things up modern shocks rear sway bar will definitely help 3/4 ton rear coils if you plan to haul a lot.....stiffer makes for less sway

11-12-2009, 05:12 AM	#6
unclewatts 70 Chevrolet=Obsession Join Date: Jun 2009 Location: nice ca Posts: 1,067	Re: Rear Suspension help... Betch'a it's the panhard bushings. They can be a pain to replace but it's worth it. __________________ I'm Just like my truck. Old, Ugly and Grouchy. Except my truck starts easily in the morning and doesn't smoke! IT'S NOT EASY BEING GREEN! -Kermit the frog 1970 Chevrolet C-10 Longbed Stepside : 350, Muncie M20, 3.08 GM corp. positraction Forest green exterior/light green interior(Where all my money goes) 1996 Toyota Corolla (Parts runner)

11-12-2009, 07:43 AM	#7
292farmer Registered User Join Date: Nov 2009 Location: stoddard nh Posts: 693	Re: Rear Suspension help... hey uncle watts is the m20 the trannsmission? (in your vehicle list) because my glovebox says m20 4spdmanual for the option list i looked at it and it looks like a sm465 or np435 is the m20 a code for one of those or does it stand for a whole different transmission? thanks my trucks a 1972 c20 292i6 Last edited by 292farmer; 11-12-2009 at 07:44 AM.

11-13-2009, 05:17 AM	#9
bhammer Registered User Join Date: Jul 2009 Location: Las Vegas, NV Posts: 97	Re: Rear Suspension help... Thanks for the input guys. I am not sure of the problem. I know the previous owner has lowered the truck. I am guessing a 2/4 drop. I just thought the suspension should have been a little stiffer even with it being lowered. I haven't really crawled around to see if anything is loose. I am planning on tearing it down anyhow. Hopefully putting in some poly bushings will help. I am probably going to end up putting bags on the rear to stabilize it a little more and keep the ability to tow. This is my daily driver now so it has to be able to tow a bike or something of equal weight. Is installing a panhard bar a huge undertaking or is it pretty simple? Thanks again. Brian

11-13-2009, 05:20 AM	#10
bhammer Registered User Join Date: Jul 2009 Location: Las Vegas, NV Posts: 97	Re: Rear Suspension help... Now that I have looked at it I don't think there is a stabilizer bar on it at all on the rear. When I unloaded the bike I had to put a scissor jack under the frame to keep it from wiggling so much.

11-13-2009, 08:45 AM	#11
ebfabman Registered User Join Date: Nov 2001 Location: Concord, NC Posts: 2,489	Re: Rear Suspension help... bhammer, nice truck andVERYnice springer. It's unlikely your truck has no track bar but as others have said the bushing may be worn out. Post a pic of the rear suspension and you will get all the help you need. btw here is my springy Attached Images



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