![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
'71 trailing arm questions
I have a '71 longbed that was made into a trailer. From the get-go, it was bouncy as a trampoline. I put some Monroe Gas Magnum shocks off a Suburban on, thinking the heavier truck had stiffer shocks. They weren't any better. Could have been bad to begin with as the Suburban was just sitting around. My Blazer has a 3/4 ton suspension kit on it, and when I replaced the Pro Comp shocks on it with Bilstien's I warrantied out the Pro Comps and put a new pair on the trailer. Still just a bouncy house on wheels. What gives? The original coil springs are on there, is that the problem? I wouldn't think so. Is it just too light? I wouldn't think that would be the problem either. Thoughts? Thanks in advance.
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#2 |
Senior Member
![]() Join Date: Dec 2013
Location: Gods country East,Tn
Posts: 8,545
|
Re: '71 trailing arm questions
Does it trail straight ? I would load a few hundred lbs in it as far forward as possible and see how it acts ? Are the tires balanced ? pick a point on each side of the axle and measure to the hitch and see if it measures the same ,Sometime home built trailers can be a little off center and wander
![]()
__________________
![]() 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
It pulls and tracks just fine. The problem is when crawling around inside it or loading it. It's like it has no shocks at all!
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#4 |
Registered User
Join Date: Aug 2012
Location: St. Croix River Valley, WI
Posts: 795
|
Re: '71 trailing arm questions
My truck was the same way (coil springs) even with new shocks. It didn't get better until I did the shock relocation kit. Now it's like a modern truck . The relocation kit has the shocks shooting toward the back, rather than the center of the truck. Much better geometry. No more bouncy-bouncy...
__________________
Meet "Old Roy": http://67-72chevytrucks.com/vboard/s...d.php?t=707801 |
![]() |
![]() |
![]() |
#5 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
surely these things didn't bounce like that new. Is it a spring problem more than a shock problem? Is there a 3/4 ton coil spring?
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#6 |
Registered User
Join Date: Jun 2005
Location: California
Posts: 521
|
Re: '71 trailing arm questions
It’s still a weight problem too. With no added weight, it’s always going to be bouncy
__________________
‘53 GMC COE stock ‘53 Chevy 3100 LSA/TR6060 http://67-72chevytrucks.com/vboard/s....php?t=805949‘ '70 Chevy C10 LWB 350/sm465 ‘74 Chevy C10 SWB 5.3/4L80e, Vintage Air, Dakota Digital, US Mags |
![]() |
![]() |
![]() |
#7 | |
Registered User
Join Date: Aug 2012
Location: St. Croix River Valley, WI
Posts: 795
|
Re: '71 trailing arm questions
Quote:
I agree with others that it will tow a lot better if you had a couple of hundred pounds in the back of it.
__________________
Meet "Old Roy": http://67-72chevytrucks.com/vboard/s...d.php?t=707801 |
|
![]() |
![]() |
![]() |
#8 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
I guess I just had more faith in what shocks can do.
Would it be worthwhile to convert to leaf springs? Could I do both, like the old squarebody HeavyHalf? Any stock-height springs laying around?
__________________
'72 K5, known as 'the Fox.' Last edited by mister.freeze; 06-11-2019 at 01:59 PM. |
![]() |
![]() |
![]() |
#9 | |
Registered User
Join Date: Aug 2016
Location: Lake Forest, CA
Posts: 2,177
|
Re: '71 trailing arm questions
Quote:
__________________
"Work hard, use your vacation days." 1970 C15 GMC Long Bed 1986 C20 Scottsdale 1983 K2500 Sierra Classic Suburban 6.2 Instagram: C10sofOC |
|
![]() |
![]() |
![]() |
#10 |
Registered User
Join Date: Nov 2017
Location: Leeds west yorkshire
Posts: 307
|
Re: '71 trailing arm questions
You think it needs the suspension? If it’s like a pogo stick it’s surely got to be a dampening issue
|
![]() |
![]() |
![]() |
#11 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
That was my thinking. I guess there's a big difference in when I'm loading and unloading vs going down the road. I'll have to drag it around and have the kids watch it. Maybe its just bouncing on the big tires when empty. I plan to camp in it and they way it rolls around on the suspension is no good. If anybody swapped out some c20 springs to lower theirs I'd be interested...
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#12 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
New springs. Much better, and taller! Settles down fster, but stillbouncy. How bad would it be to add limiting straps to add some preload?
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#13 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
Should this be straight?
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#14 |
Registered User
Join Date: Apr 2008
Location: Md
Posts: 2,475
|
Re: '71 trailing arm questions
Pan hard bar is usually strait, more important are the tires centered in the wheel well?
__________________
http://67-72chevytrucks.com/vboard/s...d.php?t=635605 |
![]() |
![]() |
![]() |
#15 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
Yes, pretty close. Should I try to straighten it? The passenger side is a touch more inboard than the driver side.
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#16 |
Registered User
Join Date: Aug 2012
Location: St. Croix River Valley, WI
Posts: 795
|
Re: '71 trailing arm questions
If you really want to cure the bouncy-bounce, do the rear shock relocate. Makes a WORLD of difference.
__________________
Meet "Old Roy": http://67-72chevytrucks.com/vboard/s...d.php?t=707801 |
![]() |
![]() |
![]() |
#17 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
Not family with that: is it easy to do?
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#18 |
Registered User
Join Date: Apr 2008
Location: Md
Posts: 2,475
|
Re: '71 trailing arm questions
Straitened panhard bar will help Center your tire better side to side.....Are those shocks intended to mounted that way, gas shocks can be mounted upside down I think...Oil filled not so much...Look for arrows pointing up?..mounting bracket for shock can be reworked to move the center back an inch or so.
__________________
http://67-72chevytrucks.com/vboard/s...d.php?t=635605 |
![]() |
![]() |
![]() |
#19 |
Senior Member
![]() Join Date: Jun 2009
Location: Portland - OR
Posts: 243
|
Re: '71 trailing arm questions
What springs did you use?
|
![]() |
![]() |
![]() |
#20 | |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
Quote:
Which shock mount can be reworked? Springs came off the front of a Lincoln Navigator. Bottom retainers worked just fine, had to fab the tops. They're 14" long, which is what I thought a C20 spring was, and for a 3/4 ton vehicle.
__________________
'72 K5, known as 'the Fox.' |
|
![]() |
![]() |
![]() |
#21 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
well crap. Won't fit the other way around. Not without some "adjustment."
EDIT- A quick call to tech support at Pro Comp said I can mount them either way...
__________________
'72 K5, known as 'the Fox.' Last edited by mister.freeze; 07-29-2019 at 01:08 PM. |
![]() |
![]() |
![]() |
#22 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,156
|
Re: '71 trailing arm questions
The springs are not right for what you seem to be doing. They are meant to have the weight of the front of the Navigator on them. The trailer has nowhere near the amount of weight that the front end of a 5,500 lb Navagator has. I would guess that they are so stiff that the tires are actually the suspension. I suggest finding a pair of used 1/2 ton springs and then the trailer should ride much better.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
![]() |
![]() |
![]() |
#23 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
You're probably right. But they were free and I figured I'd give them a go. I thought about the tire suspension thing too, and I assure you that is not the case. I have a feeling the original springs were just weak from time and maybe somebody trying to lower the truck by heating them. They are not as long as they should have been originally. I decided to try the current springs because of their stiffness. I can push down on the tailgate and it's still a lot softer than it should be. I suspect there just isn't enough preload weight to get the stiffness I want. That's why my question about limiting straps. The ride has improved with the current springs, but still bouncy. Perhaps the swingarm setup is just too independent for my needs. Unfortunately, I have neither the time nor resources to abandon it in favor of leaf springs.
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
#24 |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,337
|
Re: '71 trailing arm questions
I don't think the shock mod will help all that much. The rear suspension on a pickup was engineered to have the entire weight factored in how the rear springs work. Obviously the weight bias on a unloaded pickup is heavier in the front...
I am dismantling a LWB trailer I've had too long. It's a bounce house too. The spings have no compression on them Monroe used to sell shocks with springs on them, might help your deal...if they make them for that pickup... |
![]() |
![]() |
![]() |
#25 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
|
Re: '71 trailing arm questions
adding coilovers to the current setup might work, except for cost and clearance! I'm hoping adding some preload is all I need.
__________________
'72 K5, known as 'the Fox.' |
![]() |
![]() |
![]() |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|