Porterbuilt Trailing arms, 5" drop spring, shock problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*vegaschevy* · 02-23-2010, 01:48 PM

I am having problems with my rear end of my 72 truck.

I have the porterbuilt 2" drop trailing arms with a 5" drop spring, drop shocks from KYB which are for the 5"-6" drop springs.

My problem is my rear end feels like all spring. no dampning or rebound and rides like HELL!!!

I have the spacer form porterbuilt to make my trailing arms 2" instead of 3". Im putting it in today!. So in the pics I am 7.5"-8" rear drop and should be around 7" after I install the spacer.

My problem is I am wondering if I need the ECE shock relocaters for the the top of my rear shocks. Im sure Nate will hopefully chime in here as well to give his two cents on the lowers as I am sure the trailing arms already relocate the shocks. anyone know?

Can anyone provide a pic of a rear end with stock height and one with lowered height with shock relocaters to see what the difference is and if my shocks are just laying so far over they are providing no dampening.
I bottom out over the smallest of bump and my rear end is all spring feeling.

hope all this makes sense.

**lolife99** · 02-23-2010, 02:56 PM

Those shocks aren't doing anything. They're layed over too far. They just pivot on the mounting bolts.
With your approximate 1" of travel, shown in the pics, I'm sure you are bottoming out alot. Your spacers will help that.
I'm sure you need some type of new upper mount.
Member SCOTI made his own out of the "stock" upper mounts.
He has a thread somewhere showing what he did.

**lolife99** · 02-23-2010, 02:58 PM

Look here:

http://67-72chevytrucks.com/vboard/s...d.php?t=359399

**lolife99** · 02-23-2010, 03:02 PM

Also,... which lower shock mounts do you have?
The ones for a 2" rear drop arm or a 3" rear drop trailing arm?

72BlckButy · 02-23-2010, 03:23 PM

Quote:

Originally Posted by lolife99

Those shocks aren't doing anything. They're layed over too far. They just pivot on the mounting bolts.
With your approximate 1" of travel, shown in the pics, I'm sure you are bottoming out alot. Your spacers will help that.
I'm sure you need some type of new upper mount.
Member SCOTI made his own out of the "stock" upper mounts.
He has a thread somewhere showing what he did.

Just from looking at the pics above, lolife99 is exactly right. Your shocks are laying to horizontal.

Here's a shot of my '69 with a 6" drop on the rear and you can definitely tell a difference in the position of the rear shocks when compared to yours.

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VA72C10 · 02-23-2010, 04:44 PM

I'd say the upper shock relocators or modded factory uppers plus the spacer should take care of the issues for you. The only other thing could be the shocks themselves...what is their extended/compressed measurements as compared to your current drop/drop with the spacer?

**lolife99** · 02-23-2010, 07:40 PM

I'm not sure the modded "stock" upper bracket will move it far enough to the rear.
(To help it stand more vertical)
Looks like you only gain 1/2" or so.

I think the ECE version will move it more.
Here's a pic,...

**lolife99** · 02-23-2010, 07:48 PM

I also think these could be fabbed from tube steel or channel,... if you had to.

SCOTI · 02-23-2010, 08:05 PM

Quote:

Originally Posted by lolife99

I'm not sure the modded "stock" upper bracket will move it far enough to the rear.
(To help it stand more vertical)
Looks like you only gain 1/2" or so.

I think the ECE version will move it more.
Here's a pic,...

If you look @ the pics, there's room to go further on the stock upper mounts as well. I just moved them over enough for my application.... they can prob go another .750" (but not as much as the aftermarket ones).

**lolife99** · 02-23-2010, 08:17 PM

Quote:

Originally Posted by SCOTI

If you look @ the pics, there's room to go further on the stock upper mounts as well. I just moved them over enough for my application.... they can prob go another .750" (but not as much as the aftermarket ones).

Thanks for the correction.
You were the only member that I knew of, that had done this mod.

*vegaschevy* · 02-23-2010, 08:34 PM

Hopefully ECE will sell me just the uppers as I do not need the lower mounts.

I added my spacer today, and I fixed a HUGE driveline issue I will cover in my build thread and hopefully my truck is a little more reliable

SCOTI · 02-23-2010, 08:39 PM

Quote:

Originally Posted by lolife99

Thanks for the correction.
Your were the only member that I knew of, that has done this mod.

I know N2billet did the same thing on 'Lucy' knowing they worked well on mine. We both used stock replacement gas shocks as well & they worked dimensionally (good ride & compressed heights).

**lolife99** · 02-23-2010, 09:03 PM

Did you raise the RH panhard bolt to the upper mounting hole after you added the spring spacer?
Keep it as horizontal as possible.

72 SUPER10 · 02-23-2010, 10:16 PM

looks like the reason its riding ruff is its bottoming out in the c notch,my 2.

VA72C10 · 02-23-2010, 10:28 PM

Did you dent the bedfloor with it at 8"? Have you looked at the axle tube to see if it was hitting the bumpstop? Thinking of putting 1" blocks in the rear of mine (6" spring) and wondering if it would work with the stock bedfloor. Would do 3" drop springs in the front to be 5.5/7. Figure if you clear at 8" I'd be okay at 7...with a c-notch.

**lolife99** · 02-23-2010, 10:32 PM

Quote:

Originally Posted by VA72C10

Did you dent the bedfloor with it at 8"? Have you looked at the axle tube to see if it was hitting the bumpstop? Thinking of putting 1" blocks in the rear of mine (6" spring) and wondering if it would work with the stock bedfloor. Would do 3" drop springs in the front to be 5.5/7. Figure if you clear at 8" I'd be okay at 7...with a c-notch.

My '69 has a 6" rear spring and a 1.5" block and it works fine. (as long as you have a c-notch)

PBFAB.COM · 02-23-2010, 11:21 PM

I recommend the upper relocator bracket as several have mentioned. I will have my own available within the next few weeks.

VA72C10 · 02-23-2010, 11:21 PM

Quote:

Originally Posted by lolife99

My '69 has a 6" rear spring and a 1.5" block and it works fine. (as long as you have a c-notch)

I remember your "no life" now. My thing is the 4.5/6 drop on the shortbed chassis currently looked just as low as your 5.5/7.5 (when it had the cab, fenders, and a bed on it). Just goes to show no two trucks are alike or the drop springs don't change exactly as advertised every time. I know tires make a difference too, but I'm running I believe the same 15" tires as you in the rear (height wise) But shadows and picture angle could probably make up an inch difference in ride height appearance also.

*vegaschevy* · 02-24-2010, 10:12 AM

Quote:

Originally Posted by porterbuilt

I recommend the upper relocator bracket as several have mentioned. I will have my own available within the next few weeks.

Well get to welding

It actually rides 100 times better at about 7" of drop with the spring spacers put in versus 8" of drop. It will be even better once the shocks are relocated back a couple of inches.....
I can already here the bolt backing out of my driveshaft again I think. I might have to go have a one piece made or put a small tack weld on the bolt holding the yoke on

*vegaschevy* · 02-24-2010, 10:13 AM

Quote:

Originally Posted by VA72C10

Did you dent the bedfloor with it at 8"? Have you looked at the axle tube to see if it was hitting the bumpstop? Thinking of putting 1" blocks in the rear of mine (6" spring) and wondering if it would work with the stock bedfloor. Would do 3" drop springs in the front to be 5.5/7. Figure if you clear at 8" I'd be okay at 7...with a c-notch.

bed floor still has clearance when bottoming out in the cnotch.

I was at 8" and cleared, now at 7" and it rides way better and has more clearance.. LOL I might drop the front another 3/4' or so.

lowdownstar · 02-25-2010, 06:55 PM

I am running the same setup but i didn't feel there was enough clearence with our small c-notch. How does it ride? maybe i am asking to soon, as your just getting yours done. It looks great, and i really like the wheels. Thanks for all the pics as well they always help.

Ray

*vegaschevy* · 02-25-2010, 08:53 PM

Quote:

Originally Posted by lowdownstar

I am running the same setup but i didn't feel there was enough clearence with our small c-notch. How does it ride? maybe i am asking to soon, as your just getting yours done. It looks great, and i really like the wheels. Thanks for all the pics as well they always help.

Ray

I installed the spacer to make it a 7" drop in the rear, and with the Cnotch installed and virtually no shock action it has not bottomed out once since installing the spacer. the ride is a million times better. Once the shocks are moved back on top and I am using some shocks it will ride and handle even more better. Im not sure thats even a correct sentence LOL

lowdownstar · 02-25-2010, 10:50 PM

LOL it's ok i understood! Thanks for the feed back. Good luck getting it where you want it to be. i think your doing a great job with the truck!

Thanks Ray

02-23-2010, 01:48 PM	#1
vegaschevy Account Suspended Join Date: May 2009 Location: las vegas nv Posts: 1,493	Porterbuilt Trailing arms, 5" drop spring, shock problems I am having problems with my rear end of my 72 truck. I have the porterbuilt 2" drop trailing arms with a 5" drop spring, drop shocks from KYB which are for the 5"-6" drop springs. My problem is my rear end feels like all spring. no dampning or rebound and rides like HELL!!! I have the spacer form porterbuilt to make my trailing arms 2" instead of 3". Im putting it in today!. So in the pics I am 7.5"-8" rear drop and should be around 7" after I install the spacer. My problem is I am wondering if I need the ECE shock relocaters for the the top of my rear shocks. Im sure Nate will hopefully chime in here as well to give his two cents on the lowers as I am sure the trailing arms already relocate the shocks. anyone know? Can anyone provide a pic of a rear end with stock height and one with lowered height with shock relocaters to see what the difference is and if my shocks are just laying so far over they are providing no dampening. I bottom out over the smallest of bump and my rear end is all spring feeling. hope all this makes sense.

02-23-2010, 02:56 PM	#2
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems Those shocks aren't doing anything. They're layed over too far. They just pivot on the mounting bolts. With your approximate 1" of travel, shown in the pics, I'm sure you are bottoming out alot. Your spacers will help that. I'm sure you need some type of new upper mount. Member SCOTI made his own out of the "stock" upper mounts. He has a thread somewhere showing what he did. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

02-23-2010, 02:58 PM	#3
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems Look here: http://67-72chevytrucks.com/vboard/s...d.php?t=359399 Attached Images __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 Last edited by lolife99; 02-23-2010 at 02:59 PM.

02-23-2010, 03:02 PM	#4
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems Also,... which lower shock mounts do you have? The ones for a 2" rear drop arm or a 3" rear drop trailing arm? __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

02-23-2010, 04:44 PM	#6
VA72C10 VA72C10 Join Date: Mar 2008 Location: Midlothian, VA Posts: 25,267	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems I'd say the upper shock relocators or modded factory uppers plus the spacer should take care of the issues for you. The only other thing could be the shocks themselves...what is their extended/compressed measurements as compared to your current drop/drop with the spacer? __________________ Looking for a 67-72 swb or blazer project in or around VA.

02-23-2010, 07:40 PM	#7
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems I'm not sure the modded "stock" upper bracket will move it far enough to the rear. (To help it stand more vertical) Looks like you only gain 1/2" or so. I think the ECE version will move it more. Here's a pic,... Attached Images __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 Last edited by lolife99; 02-23-2010 at 07:44 PM.

02-23-2010, 07:48 PM	#8
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems I also think these could be fabbed from tube steel or channel,... if you had to. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

02-23-2010, 08:34 PM	#11
vegaschevy Account Suspended Join Date: May 2009 Location: las vegas nv Posts: 1,493	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems Hopefully ECE will sell me just the uppers as I do not need the lower mounts. I added my spacer today, and I fixed a HUGE driveline issue I will cover in my build thread and hopefully my truck is a little more reliable

02-23-2010, 09:03 PM	#13
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems Did you raise the RH panhard bolt to the upper mounting hole after you added the spring spacer? Keep it as horizontal as possible. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

02-23-2010, 10:16 PM	#14
72 SUPER10 Registered User Join Date: Nov 2008 Location: LUCEDALE MS. Posts: 157	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems looks like the reason its riding ruff is its bottoming out in the c notch,my 2. __________________ http://i648.photobucket.com/albums/u...Picture008.jpg

02-23-2010, 10:28 PM	#15
VA72C10 VA72C10 Join Date: Mar 2008 Location: Midlothian, VA Posts: 25,267	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems Did you dent the bedfloor with it at 8"? Have you looked at the axle tube to see if it was hitting the bumpstop? Thinking of putting 1" blocks in the rear of mine (6" spring) and wondering if it would work with the stock bedfloor. Would do 3" drop springs in the front to be 5.5/7. Figure if you clear at 8" I'd be okay at 7...with a c-notch. __________________ Looking for a 67-72 swb or blazer project in or around VA.

02-23-2010, 11:21 PM	#17
PBFAB.COM Senior Member Join Date: Dec 2003 Location: Mesa,Az Posts: 3,981	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems I recommend the upper relocator bracket as several have mentioned. I will have my own available within the next few weeks. __________________ www.PorterbuiltFabrication.com Phone: 480-297-2621 E-mail: sales@pbfab.com Find us on FaceBook under Porterbuilt Fabrication Specializing in Chassis and Suspension Components for your Classic Chevrolet Truck. We offer components from the following manufacturers: Porterbuilt Accuair Ridetech (Air Ride Technologies) Air Lift Wilwood Intro Unisteer ECE Gotta Show Air Lift Borgeson CPP Supporting this forum since 2003!

02-25-2010, 06:55 PM	#21
lowdownstar big guy Join Date: Jun 2008 Location: mass Posts: 824	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems I am running the same setup but i didn't feel there was enough clearence with our small c-notch. How does it ride? maybe i am asking to soon, as your just getting yours done. It looks great, and i really like the wheels. Thanks for all the pics as well they always help. Ray

02-25-2010, 10:50 PM	#23
lowdownstar big guy Join Date: Jun 2008 Location: mass Posts: 824	Re: Porterbuilt Trailing arms, 5" drop spring, shock problems LOL it's ok i understood! Thanks for the feed back. Good luck getting it where you want it to be. i think your doing a great job with the truck! Thanks Ray



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