TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Suspension, Steering, Brakes & Wheels
  New Posts New Posts RSS Feed - Isoclamp - what is this madness you speak of
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Isoclamp - what is this madness you speak of
 Post Reply Post Reply Page  123>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
Regamble1969 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Dec/01/2021
Location: Boise Idaho
Status: Offline
Points: 204 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Regamble1969 Quote  Post ReplyReply Direct Link To This Post Topic: Isoclamp - what is this madness you speak of
    Posted: May/22/2022 at 1:57am
I have read several posts on here about isoclamp vs non-isoclamp rear axle spring perches. In my quest to root out and abolish my own personal ignorance, i tried to find out what this isoclamp mystic beast is and have found no helpful information. Could someone enlighten me in the isoclamp and the difference between a standard leaf spring perch? Preferably with pictures because... well pictures make me feel warm and fuzzy. Thanks.
Back to Top
6PakBee View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Charter Member

Joined: Jul/01/2007
Location: North Dakota
Status: Offline
Points: 5457 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2022 at 7:38am
I couldn't find a drawing of the AMC version but here is Mopar's version.  It's nothing more than a cushion on both sides of the spring.
Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.

Forum Cockroach
Back to Top
Regamble1969 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Dec/01/2021
Location: Boise Idaho
Status: Offline
Points: 204 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Regamble1969 Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2022 at 10:05am
Originally posted by 6PakBee 6PakBee wrote:

I couldn't find a drawing of the AMC version but here is Mopar's version.  It's nothing more than a cushion on both sides of the spring.


Interesting... thank you for the education.
Back to Top
Red Devil View Drop Down
AMC Addicted
AMC Addicted


Joined: Jul/10/2007
Location: Canada
Status: Offline
Points: 1743 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Red Devil Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2022 at 9:11pm
"Madness" may be a good description.  They were intended to help reduce noise/vibration/harshness (NVH), but had a bad side-effect of trapping moisture and the salt applied to snowy winter roads between the rubber and the spring.   Leaf springs cracked through the centre of the clamp were a common result.  

The iso-clamp arrangement generally kept the leaves from fully separating - unless you went over a particularly nasty bump/dip or were jacking the car at the stock jack locations to change a tire.  A sagging rear end was a tell-tale sign. Replaced several sets of rear springs on iso-clamp cars where earlier ones without clamps lasted much longer.
Back to Top
Regamble1969 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Dec/01/2021
Location: Boise Idaho
Status: Offline
Points: 204 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Regamble1969 Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2022 at 9:31pm
I can definitely see how it was seemingly a good idea on paper and yet problematic in practice. Funny how a few years of road (or off-road for that matter) can so easily trump all the "best engineering" in the world. I really appreciate the added info and experience.
Back to Top
Heavy 488 View Drop Down
AMC Addicted
AMC Addicted


Joined: Apr/27/2019
Location: In the
Status: Offline
Points: 3552 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: May/23/2022 at 8:57am
Its only problematic in practice when people think a rubber suspension part should be forever. These are 40+ year old vehicles.
Back to Top
pacerman View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum


Joined: Jul/03/2007
Location: United States
Status: Offline
Points: 9057 		Post Options Post Options   Thanks (0) Thanks(0)   Quote pacerman Quote  Post ReplyReply Direct Link To This Post Posted: May/23/2022 at 12:43pm
It was part of making the Hornet generation body into the quieter and better riding Concord series.  Also used on the Pacers.  Joe
Happiness is making something out of nothing.
Back to Top
danleym View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Oct/17/2009
Location: Colorado Spring
Status: Offline
Points: 850 		Post Options Post Options   Thanks (0) Thanks(0)   Quote danleym Quote  Post ReplyReply Direct Link To This Post Posted: May/23/2022 at 3:41pm
A lot of those posts have probably been mine. I've been learning along the way. I have a 1980 Spirit, which had an Isoclamp AMC 15 in it. The drawing linked above is very similar to the AMC version. I didn't even realize there was any other mounting system until I started dropping a normal AMC 20 in, then realized the parts didn't all match up. Hasn't been a big deal, but I did have to get some new shock plates and shorten my leaf spring centering pins. I suppose I could have swapped the perches from the 15 to the 20 and kept the isoclamp, but that sounded like more work. I don't know much about performance or longevity of the setups side by side, I only switched because I was changing to a 20 and the one I found was not set up for the isoclamp stuff.
Hollis Danley
1980 Spirit, 258
2000 VW Jetta TDI
2002 Jeep Wrangler, 4.0
2015 Subaru XV Crosstrek
Back to Top
Red Devil View Drop Down
AMC Addicted
AMC Addicted


Joined: Jul/10/2007
Location: Canada
Status: Offline
Points: 1743 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Red Devil Quote  Post ReplyReply Direct Link To This Post Posted: May/23/2022 at 5:07pm
Originally posted by Heavy 488 Heavy 488 wrote:

Its only problematic in practice when people think a rubber suspension part should be forever. These are 40+ year old vehicles.


Within my family, we had close to a dozen Spirits and Concords.  I can assure you issues appeared within 5-6 years of ownership.  Some lasted longer, some not.  I converted a '78 Concord to a non iso-clamp arrangement after replacing rear springs a second time.  It was fine after that.

Of course, few of the AMCs lasted much more than 10 years in the rust belt without some significant body and chassis rust, unless religiously washed and oil-sprayed.   In a small town with no local car wash, there were no opportunities to wash the car until warmer weather.

I also suspect aged rubber flexing concentrated loading near the centre, contributing to breaking the leafs through the middle, compared to the more rigid support of the typical steel perch arrangement.  

Not sure if the Concord/Spirit arrangement was worse than others or if replacement parts are available new if rebuilding one?   

YMMV
Back to Top
70BBOAMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Sep/30/2008
Location: South Carolina
Status: Offline
Points: 568 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 70BBOAMX Quote  Post ReplyReply Direct Link To This Post Posted: May/23/2022 at 5:19pm
Snow, Ice and Salt  - What is this madness you speak of....LOL
Back to Top
 Post Reply Post Reply Page  123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.078 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or