Rear leaf spring replacement
Thread Starter
Pro
Joined: May 2013
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Rear leaf spring replacement
I would like to replace the rear leaf spring on my 69 bb coupe. The driver side sags slightly most likely from uneven wear on the original spring. One option I have seen at duntov is to get the original spring re-arced. Should I go that route or just purchase a new one? Should I also replace the rear shocks? What about going with a composite spring?
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
I would like to replace the rear leaf spring on my 69 bb coupe. The driver side sags slightly most likely from uneven wear on the original spring. One option I have seen at duntov is to get the original spring re-arced. Should I go that route or just purchase a new one? Should I also replace the rear shocks? What about going with a composite spring?
Instructor
Joined: Sep 2015
Posts: 216
Likes: 16
From: Haverfordwest Pembrokeshire
I would like to replace the rear leaf spring on my 69 bb coupe. The driver side sags slightly most likely from uneven wear on the original spring. One option I have seen at duntov is to get the original spring re-arced. Should I go that route or just purchase a new one? Should I also replace the rear shocks? What about going with a composite spring?
Graham
Le Mans Master
Joined: Dec 2006
Posts: 8,837
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I would like to replace the rear leaf spring on my 69 bb coupe. The driver side sags slightly most likely from uneven wear on the original spring. One option I have seen at duntov is to get the original spring re-arced. Should I go that route or just purchase a new one? Should I also replace the rear shocks? What about going with a composite spring?
Team Owner
Joined: Sep 2006
Posts: 31,202
Likes: 4,287
From: Westminster Maryland
Hi Bh,
Replacing the spring or even having it re-ached can be the start of problem with the rear ride height not being what you'd like it to be.
How much is "sags slightly" ?
What makes you think the spring is causing it"
Could the spring bolt bushings be more deteriorated on that side?
Normally the spring should appear to be nearly flat from side to side or even exhibit a slight negative arch.
The half shafts should appear to be nearly parallel with the ground.
Maybe a couple photos of the rear suspension.
Don't be too quick to replace the spring.
Regards,
Alan
Replacing the spring or even having it re-ached can be the start of problem with the rear ride height not being what you'd like it to be.
How much is "sags slightly" ?
What makes you think the spring is causing it"
Could the spring bolt bushings be more deteriorated on that side?
Normally the spring should appear to be nearly flat from side to side or even exhibit a slight negative arch.
The half shafts should appear to be nearly parallel with the ground.
Maybe a couple photos of the rear suspension.
Don't be too quick to replace the spring.
Regards,
Alan
Thread Starter
Pro
Joined: May 2013
Posts: 570
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I'll take some pics and post later today. I've already had the bushings replaced and attempted to level by adjusting the nuts. I'm pretty sure it's the original spring. The car sits about a half to 3/4 inch lower on the driver side rear and it is noticeable
Instructor
Joined: Sep 2015
Posts: 216
Likes: 16
From: Haverfordwest Pembrokeshire
Mine was a lot less than that but still noticeable and I couldn't ignore it, mine had air shocks fitted when it arrived and they were shot so I fitted new Bilsteins in case they were affecting things but it still had a lean to the drivers side, since fitting the replacement composite spring it's spot on now, just got to get the ride height correct so I can finalise the bolt length, I'm at 6" between the head and nuts will probably go to 6 1/2" and it should be just right.
Graham
Graham
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From: Tampa Florida
Racer
Joined: Nov 2013
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From: Colorado
You could rule the front springs out pretty easily by supporting the front level on jack stands by the frame not the control arms. Then you could see if the back was now level. You may want to pull the wheels off and lower the front to normal ride height to get a better visual and measure the same place you've been measuring the difference in the rear.
Thread Starter
Pro
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Yeah if I do replace, I will most likely go back with a steel spring. There are many sellers out there. Any idea which is the best quality to go with? What is the factory spec for a 1969 bb coupe?
Team Owner
Joined: Sep 2006
Posts: 31,202
Likes: 4,287
From: Westminster Maryland
Hi Bh,
?
I'm surprised to see how much the rubber bushings are compressed already and also by the number of washers being used between the spring bolt's nut and lower bushing.
Were those washers added to try to level the car?
When the bushings were replaced what did the arch of the spring look like with no weight on it?
Has the spring been taken off the car and disassembled to see if it's damaged in some way?
Another spring is one answer, but so often that avenue seems to lead to car's needing longer spring bolts.
What is the dimension from the ground to the center of the wheel arch on each side? (The size of the tires affect this dimension.)
Regards,
Alan
?
I'm surprised to see how much the rubber bushings are compressed already and also by the number of washers being used between the spring bolt's nut and lower bushing.
Were those washers added to try to level the car?
When the bushings were replaced what did the arch of the spring look like with no weight on it?
Has the spring been taken off the car and disassembled to see if it's damaged in some way?
Another spring is one answer, but so often that avenue seems to lead to car's needing longer spring bolts.
What is the dimension from the ground to the center of the wheel arch on each side? (The size of the tires affect this dimension.)
Regards,
Alan
Thread Starter
Pro
Joined: May 2013
Posts: 570
Likes: 22
Hi Bh,
?
I'm surprised to see how much the rubber bushings are compressed already and also by the number of washers being used between the spring bolt's nut and lower bushing.
Were those washers added to try to level the car?
When the bushings were replaced what did the arch of the spring look like with no weight on it?
Has the spring been taken off the car and disassembled to see if it's damaged in some way?
Another spring is one answer, but so often that avenue seems to lead to car's needing longer spring bolts.
What is the dimension from the ground to the center of the wheel arch on each side? (The size of the tires affect this dimension.)
Regards,
Alan
?
I'm surprised to see how much the rubber bushings are compressed already and also by the number of washers being used between the spring bolt's nut and lower bushing.
Were those washers added to try to level the car?
When the bushings were replaced what did the arch of the spring look like with no weight on it?
Has the spring been taken off the car and disassembled to see if it's damaged in some way?
Another spring is one answer, but so often that avenue seems to lead to car's needing longer spring bolts.
What is the dimension from the ground to the center of the wheel arch on each side? (The size of the tires affect this dimension.)
Regards,
Alan
Team Owner
Joined: Sep 2006
Posts: 31,202
Likes: 4,287
From: Westminster Maryland
Hi Bh,
The composition of the rubber determines how much the bushings compress immediately.
It 'appears' just the left side bushings were replaced (the right side look 'aged'). Is that so?
What are the ground to wheel arch dimensions at all 4 corners?
From the photo it 'appears' that wheel/tire has a lot of negative camber. Does it?
Could this be coming into play on the ride height dimension?
Regards,
Alan
The composition of the rubber determines how much the bushings compress immediately.
It 'appears' just the left side bushings were replaced (the right side look 'aged'). Is that so?
What are the ground to wheel arch dimensions at all 4 corners?
From the photo it 'appears' that wheel/tire has a lot of negative camber. Does it?
Could this be coming into play on the ride height dimension?
Regards,
Alan
Last edited by Alan 71; Mar 30, 2017 at 09:44 AM.
Thread Starter
Pro
Joined: May 2013
Posts: 570
Likes: 22
Hi Bh,
The composition of the rubber determines how much the bushings compress immediately.
It 'appears' just the left side bushings were replaced (the right side look 'aged'). Is that so?
What are the ground to wheel arch dimensions at all 4 corners?
From the photo it 'appears' that wheel/tire has a lot of negative camber. Does it?
Could this be coming into play on the ride height dimension?
Regards,
Alan
The composition of the rubber determines how much the bushings compress immediately.
It 'appears' just the left side bushings were replaced (the right side look 'aged'). Is that so?
What are the ground to wheel arch dimensions at all 4 corners?
From the photo it 'appears' that wheel/tire has a lot of negative camber. Does it?
Could this be coming into play on the ride height dimension?
Regards,
Alan
Driver rear 27 1/8"
Pass rear 28"
so almost 1" difference
The tire is not out of line that is just the angle of the pic.