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8 & 10 cyl Bristol cars Type 407 onwards - restoration, repair, maintenance etc

409 frt springs

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Old 22-03-16, 04:57 PM
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Default 409 frt springs

Does anybody have the specs for the frt springs as when new? Typically this would include free height and load in lbs under a specified compressed height.
If unavailable maybe someone would be kindly give me a height from the road to say the frt edge of the body panel at the center point in line with the hood emblem.
The car is definitely low in the front but I want to have a reference point before doing any work in that area.
Regards,
Anne
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Old 22-03-16, 11:03 PM
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Anne ,
I have had no direct experience with a 409 but expect it will be the same as the 411 .
The top of the 411 front coil springs are located in a tubular sleeve of the front cross member. Between the cross member and the spring there is polyurethane type spring pad which I assume softens the ride .

When I bought my 411 I though the springs had sagged but found the polyurethane spring pad had started to disintegrate which lowered the front of the car . I replaced the spring pad with aluminium which raised the car to the original height and did not effect the softness of the ride .
This was done about 25 years ago and the car is still sitting at the correct height , with the original springs .
It is worth checking it out before considering new or retempered springs

Geoff D
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Old 23-03-16, 02:10 AM
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Anne, see this post for what should be there http://www.bristolcars.info/forums/8...on.html#post83

My view is that you should replace the original parts, rather than using an aluminium spacer, assuming of course that they are still available from Bristol.

I have the full spring specs somewhere, because I had new ones made. I will dig them out as soon as I have some time.

Whatever you do, don't be tempted to just install longer springs!
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Old 23-03-16, 02:14 AM
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Anne, also see this post for ride height 409 ride height and front suspension
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Old 23-03-16, 03:12 AM
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Smile

Thank you both for the good info. We now know what to look for starting with a nominal 5" cross member to ground distance and I will factor in a 3.25% bugger factor for wheel size LOL.
Once I have one side apart I will probably come across broken/deteriorated rings as per the pictures. If so I can then get new ones from Bristol or see what is available from another car.
Thanks again,

Anne
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Old 26-03-16, 12:47 PM
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For what it's worth my 410 looks right at a ride height of 6 1/4 inches between the underneath of the front cross member and the floor, measured underneath the suspension arm mountings. The bottom suspension arms are to all intents and purposes level.

I had the opposite problem, in that the torsion bars had sagged. Resetting the rear arms on the splines to achieve a level stance improved the handing considerably.
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Old 28-03-16, 02:09 PM
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Thanks...So far I am at 4", so definitely at least 1" off spec. Will see when I get around to taking a spring out. I have considered the torsion bars but at this time will work at the frt and bring it to factory specs and see how level it is.

Anne
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Old 28-03-16, 05:39 PM
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A contemporary road test on the 409 quotes ground clearance at 6.5 inches so I guess that's the number to aim for. My comment regarding a level stance improving handling was only intended as a "useful to know". Good luck, it will be interesting to hear what you discover.
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Old 28-03-16, 09:49 PM
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Anne, please bear in mind that my experience relates to a 411, which will similar to a 409/410 may not be exactly the same, (the 411 used many suspension parts from earlier cars). So I don't think you should view 5" as a definitive figure for ground clearance.

Also wheel and tyre size will make a different to ground clearance. The 409 was originally shod with full height profile cross ply tyres, which have a taller side wall than modern reduced profile tyres.

I think you should focus on making sure that the front suspension has all the correct parts and then see what ground clearance you end up with rather than working to achieve a particular ground clearance.
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Old 28-03-16, 10:14 PM
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Quote:
Originally Posted by PEU186F View Post
The bottom suspension arms are to all intents and purposes level.
Ultimately I believe this is what you should aim for, after which the ground clearance will be determined by wheel and tyre size.
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Old 29-03-16, 02:44 PM
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Thank you all. By the end of May I plan to have the suspension apart and will see and advise accordingly. A holiday and also the car is now in the body shop having some work done that precludes any work that would make it hard/impossible to move.
A quick way to check will be to jack the car up so it's level and see how many inches i'm missing.....probably 2". After I get the springs off I can measure them and see how the rubber /plastic rings are.

Anne
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Old 29-03-16, 09:29 PM
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Anne, while you have the springs out would be a perfect time to check the condition of the wishbone bushes, because it's very difficult to check them when the wishbones are under load from the spring.

And of course while you're at it you should also check the upper and lower stub axle joints

See Resources - Bristol Cars - Owners and Enthusiasts Forum

When the time comes, there is quite a bit of information on this site about dismantling the front suspension. It may also be worth contacting Bristol in advance to check that all the parts are available and the cost.
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Old 29-03-16, 11:06 PM
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Thank you.. I have new joints that came with the car. Something I forgot is that with A arms a 1" spacer = 2.5" in height gain....about what I may be out.
The ratio changes to over double. 1" spacer on leaf springs gives you 1" so it's a direct one to one but not with a Arms.

Anne
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Old 27-06-16, 06:05 PM
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Default 409 frt springs

With lots of fun I now have a spring out and it measures 15" so on spec, and it also stands straight, another bonus.
There is no rubber or? spacer material left of any consequence. The bits left I scraped and torched out.
Now for the help / advice.
With the spring held in place and holding it straight 1/2 the coil shows under the upper retaining lip. I realize the center sleeve keeps it in place, but any spacer I put in on top will have a full coil or more showing at the frt...side facing the brakes.
Is this assumption correct?
If it is...how much coil is showing at the frt.? This will give me a thickness to work on and then make up a tapered spacer to allow for the back.....assuming this is not available from Bristol.
I also realize there is some sort of rubber spacer at the bottom...if I work on 1/2" for that one, does it sound right?
Any thoughts on shocks?

Thanks,
Anne

Last edited by Anne; 27-06-16 at 11:38 PM.
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Old 28-06-16, 11:42 AM
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Quote:
Originally Posted by Anne View Post
With the spring held in place and holding it straight 1/2 the coil shows under the upper retaining lip. I realize the center sleeve keeps it in place, but any spacer I put in on top will have a full coil or more showing at the frt...side facing the brakes.
Is this assumption correct?
This is what it should look like
http://www.bristolcars.info/forums/a...ccessories.jpg

Quote:
If it is...how much coil is showing at the frt.? This will give me a thickness to work on and then make up a tapered spacer to allow for the back.....assuming this is not available from Bristol.
I suggest you contact Bristol first, and see if the parts are available. Given that they are used on many of the V8s, they probably will be. That will save you the trouble of making your own and guessing dimensions.

Quote:
I also realize there is some sort of rubber spacer at the bottom...if I work on 1/2" for that one, does it sound right?
Did you read this thread that I linked to earlier?
http://www.bristolcars.info/forums/8...uspension.html it shows all the parts you need

Quote:
Any thoughts on shocks?
Spax G712
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Old 28-06-16, 03:44 PM
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Default 409 Sprongs

Thanks...I've ordered the parts from Bristol.
The Spax shocks may be a problem...may have to find an alternate.
Anne
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