#1  
Old 11-02-2022, 11:28 AM
Hotrodjohn71 Hotrodjohn71 is offline
Senior Member
 
Join Date: Oct 2020
Location: Fair oaks Ca 95628
Posts: 223
Default Leaf spring question

Hi fellas, I have a question about the mounting of the leaf springs. I have seen two different styles. One style utilizes the u-bolts, two for each side, and one style utilizes four bolts to attach the retaining plate to the spring perch, four bolts on each side. What are the reasons for these differences?


Last edited by Hotrodjohn71; 11-02-2022 at 11:41 AM.
  #2  
Old 11-02-2022, 01:10 PM
JLMounce JLMounce is offline
Ultimate Warrior
 
Join Date: Sep 2005
Location: Greeley, Colorado
Posts: 3,679
Send a message via AIM to JLMounce
Default

The U bolts were used by the factory. With the U bolts you have a solid pipe that keeps the rear-end in position on the leafs. If you bolt directly from the mounting plate to the spring perch, you're relying on the welds at the spring perch. Considering how much the axle wants to move forward, backwards and side to side, it's not outside the realm of possibility that you could crack those welds.

If the car is nothing but a trailered show car with minimal driving at a leisurely pace, that's when I would personally think about bolting to the spring perch for aesthetic reasons. If the car is going to be used in any normal manner, or especially in a performance manner, I'd use U bolts.

__________________
-Jason
1969 Pontiac Firebird
The Following 2 Users Say Thank You to JLMounce For This Useful Post:
  #3  
Old 11-02-2022, 04:22 PM
Hotrodjohn71 Hotrodjohn71 is offline
Senior Member
 
Join Date: Oct 2020
Location: Fair oaks Ca 95628
Posts: 223
Default

Thank you JLMounce,
How necessary are the stock leaf spring cushions? One is supposed to go on top and one under the spring pac.
Mine does not seem to have them.

  #4  
Old 11-02-2022, 05:59 PM
JLMounce JLMounce is offline
Ultimate Warrior
 
Join Date: Sep 2005
Location: Greeley, Colorado
Posts: 3,679
Send a message via AIM to JLMounce
Default

For functionality, they are not necessary. In fact, there can be performance advantages of not using them and instead using solid spacers to take up and slack between the spring pack, perch and shock plate. It'll be harsh and noisy though.

If this is a street car, I'd recommend sourcing the upper and lower isolators.

__________________
-Jason
1969 Pontiac Firebird
The Following 2 Users Say Thank You to JLMounce For This Useful Post:
  #5  
Old 11-03-2022, 11:24 AM
Hotrodjohn71 Hotrodjohn71 is offline
Senior Member
 
Join Date: Oct 2020
Location: Fair oaks Ca 95628
Posts: 223
Default

Thank you JLMounce, I hope you dont mind one more question.
With the exception of no u-bolts and lack of cushions on this setup, can you see any other possible problems with the way this is setup?
This car is a stock 326 cruiser with a 2 bbl.
It's a 1967, probably originally mono spring, but a 4-spring pac installed.
Attached Thumbnails
Click image for larger version

Name:	20220911_163518.jpg
Views:	73
Size:	55.8 KB
ID:	601632   Click image for larger version

Name:	20220911_164025.jpg
Views:	69
Size:	56.8 KB
ID:	601633   Click image for larger version

Name:	20220911_163801.jpg
Views:	85
Size:	54.2 KB
ID:	601634  

  #6  
Old 11-03-2022, 04:27 PM
Hotrodjohn71 Hotrodjohn71 is offline
Senior Member
 
Join Date: Oct 2020
Location: Fair oaks Ca 95628
Posts: 223
Default

I have found the answers to my questions. Thank you for time.

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:44 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017