rear coil springs on 412 Wagon
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d-Mag
- Posts: 15
- Joined: Sat Jul 29, 2006 11:52 am
rear coil springs on 412 Wagon
Does anyone have a tip on a replacement spring for the rear of this car ? What is the stock spring weight per inch ? A stiffer spring would probably not be to bad an idea but I don't know what we are starting with let alone it's length in original form. At present the bottom 4 coils are sqaushed together at rest. This gives a nice lowered stance to the rear but it can't be good (or is this normal for this car ???). I am familiar with the ford van KYB shock upgrade thanks to this board , but what about the springs??
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raygreenwood
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What you are seeing is 100% correct. The lower "squashed" section of coils is the load control section. It carries most of the weight. The upper section is teh ride control area. It is rare that anything is out of whack on 411/412's more than about 10% due to age. They also do not require larger springs for superb handling.
The problem is not teh springs. The problem was barely adequate sway control and barely adequat rebound and compression valving on the stock shocks. The KYB's take care of the shocks just fine.
There are a couple things you can do that to the sway bar assembly...ranging from getting a thicker one....which will not be calibrated as well as the progressive stock one.....or you can slave two stock ones together like I have....which keeps the stock calibration but exactly doubles the control rate.
Its actually rare that the rear of the vehicle is sagging. More precisely what is wrong...is that the front end is artificially high....which much has been written about here.
The rear springs are actually quite large and more than adequate if all else is set straight...which inludes better outer links for theexisting swaybar.
One upgrade that does help is to get the "blue" series springs from the rear of a 411/412 two or four door sedan. The coils on the yellow series on teh wagons were actually fatter....so they contorlled heavy loads better....but the tension rate was lower so they were not as responsive for handling. These are coded by blue or yellow paint marks near the top of each spring.
Also make sure the rubber spring perches at top and bottom are there and in good shape. Ray
The problem is not teh springs. The problem was barely adequate sway control and barely adequat rebound and compression valving on the stock shocks. The KYB's take care of the shocks just fine.
There are a couple things you can do that to the sway bar assembly...ranging from getting a thicker one....which will not be calibrated as well as the progressive stock one.....or you can slave two stock ones together like I have....which keeps the stock calibration but exactly doubles the control rate.
Its actually rare that the rear of the vehicle is sagging. More precisely what is wrong...is that the front end is artificially high....which much has been written about here.
The rear springs are actually quite large and more than adequate if all else is set straight...which inludes better outer links for theexisting swaybar.
One upgrade that does help is to get the "blue" series springs from the rear of a 411/412 two or four door sedan. The coils on the yellow series on teh wagons were actually fatter....so they contorlled heavy loads better....but the tension rate was lower so they were not as responsive for handling. These are coded by blue or yellow paint marks near the top of each spring.
Also make sure the rubber spring perches at top and bottom are there and in good shape. Ray
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raygreenwood
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- Joined: Wed Jan 22, 2003 12:01 am
Just be careful. There is not actually much room to lower in the rear..especially depending on tire width and spacing. Also, make sure that teh rotation of your sway bar has room with the design of the outer links. It should be little problem but its worth looking at. Also make very sure that whatever spring you find is of thesame pattern. It needs to be a two stage progressive type spring. The distance teh spring is mounted from the pivot point of the control arm makes for very large leverage. Add to that all of the drive train weight situated at or aft of the coil spring centerline and you very quickly have leverage that can kill springs of the wrong design.
Make sure the front end is sorted out before adjusting the rear. Also keep in mind that the rear rebound and bump stop extension ranges....are based upon the internal stops in the shock absorber itself. If you end up with a short spring to lower with....it can on rebound...unseat the spring itself. This almost always damages the shock tube when it happens. There is maybe 10mm of clearance at full trailing arm extension.Ray
Make sure the front end is sorted out before adjusting the rear. Also keep in mind that the rear rebound and bump stop extension ranges....are based upon the internal stops in the shock absorber itself. If you end up with a short spring to lower with....it can on rebound...unseat the spring itself. This almost always damages the shock tube when it happens. There is maybe 10mm of clearance at full trailing arm extension.Ray
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func412
- Posts: 506
- Joined: Sun Apr 03, 2005 10:55 am
When I get my 412 back in carage, I´m going to find out if it could be possible to lower car by modifying the mountigs of tranny/engine/rear control arm system. I mean if it would be possible to lift the entire rear system up some inches by modifying chassis mounting points.
Yes, it means a lot of welding and modification, but I would get original wheel alligments as well as engine height (which is definitely needed with external wet oil sump)
Yes, it means a lot of welding and modification, but I would get original wheel alligments as well as engine height (which is definitely needed with external wet oil sump)
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raygreenwood
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- Joined: Wed Jan 22, 2003 12:01 am
Sounds interesting. But incredibly difficult.
Personnally I would only attempt that route if the chassis is rusted out and you are having to remove the rear undercarriage beam to weld the body. It will take a lot of cutting and welding. Also, that mount area is part of the rear accident crumple zone the car was built with. I'm not sure how much you can cut out and still have room to move the beam upward. For sure it will be under the back seat area.
There is no pan on this car. Ray
Personnally I would only attempt that route if the chassis is rusted out and you are having to remove the rear undercarriage beam to weld the body. It will take a lot of cutting and welding. Also, that mount area is part of the rear accident crumple zone the car was built with. I'm not sure how much you can cut out and still have room to move the beam upward. For sure it will be under the back seat area.
There is no pan on this car. Ray
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Wally
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Because of what was described above on the 3 or 4 spring windings sitting on top of each other when mounted on the car, it should be very possible to just cut off one spring ring and not have to worry about not seating right. The original last part of the rear spring is not flattend after allfunc412 wrote:I have the same question.
I`m just about to look after lowering springs of some other car, that would fit in place of originals.
(top ring is)T4T: 2,4ltr Type 4 Turbo engine, 10.58 1/4 mi in a streetlegal 1303
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
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raygreenwood
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- Joined: Wed Jan 22, 2003 12:01 am
Been there and done that. It can be done but you must be careful.
You can cut off 1/2 of a coil at the top before you begin to have problems. It will not be a load control issue. All of that is at the bottom.
Depending upon wether you have the type of spring that has the flat ground top coil or the round wire end on the top coil......just cutting off 1/2 of the top most coil can lower you about 5/8" to 3/4".
Problem is this.......the stroke extension length of the rear end...and the compression length stop...are all built into the shock.
This method of lowering puts the inside stop part of the shock piston....3/4" closer to being bottomed out....without adding any extra ability to arrest downward compression movement any quicker.
This means that if you hit a bump.....it bottoms out much faster. I destroyed a pair of KYB's this way.
By the way...just cutting off the 1/2 top coil is not what killed them. I liked what I saw...and then proceeded to remove the other 1/2 coil to make it one whole top coil removed. That is what killed the shocks. It causes about 1" of lowering. I later achieved that much just with lower profile tires.
But what both of these moves did...first cutting 1/2 coil then later another 1/2 coil.....is that they altered the ability of the spring to stay under tension between the upper perch on the body and the lower perch on the trailing wishbone.
You go over a tight bump like a speed bump (sleeping policeman to you Brits).....and on the rebound...up rebound...the spring unseats from the body.
You hear a "jangling" sound....the spring slams back into its seat.
But since the clearance is but 10mm to the side of the shock...it has a tendency to dent the shock body when this happens. I trashed another pair of shocks this way.
Mind you...removing a full top coil is a good way to lower. The spring is so well sized that it still has plenty of control.
What is needed to use this method.....is a shock with a correspondingly shorter extended stroke length.
Or........if you can add a spacer onto the top side of the body under the rubber bushing...to put more of the shock rod farther up into the cavity near the heater area...you can manage. Just be careful and plan what you do. Its way easy to make a car very unmanageable. Ray
You can cut off 1/2 of a coil at the top before you begin to have problems. It will not be a load control issue. All of that is at the bottom.
Depending upon wether you have the type of spring that has the flat ground top coil or the round wire end on the top coil......just cutting off 1/2 of the top most coil can lower you about 5/8" to 3/4".
Problem is this.......the stroke extension length of the rear end...and the compression length stop...are all built into the shock.
This method of lowering puts the inside stop part of the shock piston....3/4" closer to being bottomed out....without adding any extra ability to arrest downward compression movement any quicker.
This means that if you hit a bump.....it bottoms out much faster. I destroyed a pair of KYB's this way.
By the way...just cutting off the 1/2 top coil is not what killed them. I liked what I saw...and then proceeded to remove the other 1/2 coil to make it one whole top coil removed. That is what killed the shocks. It causes about 1" of lowering. I later achieved that much just with lower profile tires.
But what both of these moves did...first cutting 1/2 coil then later another 1/2 coil.....is that they altered the ability of the spring to stay under tension between the upper perch on the body and the lower perch on the trailing wishbone.
You go over a tight bump like a speed bump (sleeping policeman to you Brits).....and on the rebound...up rebound...the spring unseats from the body.
You hear a "jangling" sound....the spring slams back into its seat.
But since the clearance is but 10mm to the side of the shock...it has a tendency to dent the shock body when this happens. I trashed another pair of shocks this way.
Mind you...removing a full top coil is a good way to lower. The spring is so well sized that it still has plenty of control.
What is needed to use this method.....is a shock with a correspondingly shorter extended stroke length.
Or........if you can add a spacer onto the top side of the body under the rubber bushing...to put more of the shock rod farther up into the cavity near the heater area...you can manage. Just be careful and plan what you do. Its way easy to make a car very unmanageable. Ray
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Jadewombat
- Posts: 1447
- Joined: Sat Jun 22, 2002 12:01 am
Instead of remaking springs and all that, why not just take the shock out and insert coilspring airbags like we do here in the states? My friend had some on her Ford F-250 inside the spring. You can then control the height and ride.vonkr wrote:there are several factorys in my country (so probably in every country)where they can made custom made springs. Maybe it is interesting to go to one, bring along the original spring and ask what they can do.
Suc6, Ronald
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raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
I guess it really depends on what you want to do with teh car. Airbags are lousey for handling. They are made for weight support and height control....and are good at that.....but are terrible at modulating shock frequencies off of a road at high speed and are very "marshmellow" like at handling.
Thats also bearing mind...that without the vertical "tie" point of the shock absorber on the rear end of teh trailing wishbones.....the traing wishbone will get very very twisty on teh bushings. It will wallow through curves.
If you are just for cruising and looks...cool. If you want to handle well....this is not a great car for that. The type 3 would do air bags well...but not the type 4. Ray
Thats also bearing mind...that without the vertical "tie" point of the shock absorber on the rear end of teh trailing wishbones.....the traing wishbone will get very very twisty on teh bushings. It will wallow through curves.
If you are just for cruising and looks...cool. If you want to handle well....this is not a great car for that. The type 3 would do air bags well...but not the type 4. Ray
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vonkr
- Posts: 127
- Joined: Sun Aug 21, 2005 12:43 pm
Would adjustable or stiffer (is that word correctMind you...removing a full top coil is a good way to lower. The spring is so well sized that it still has plenty of control.
What is needed to use this method.....is a shock with a correspondingly shorter extended stroke length.
) shocks also decrease the chance of "loosing control"?-
raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
The problem with shocks is this. The adjustability must be very precise. Its not enough just to be able to adjust the basic hardness or compressability. You must be able to adjust the rebound and compression rates seperately. Basic adjustable ones will get destroyed quick.
It took me a little bit to understand why I destroyed a set of rancho RS-9000 5 way adjustables in 3 months. Its because the shocks are so far from the pivot point of the arc of the trailing wishbone. The leverage is huge...and the entire drivetrain weight is right over the axle and the bottom shock mounting point is just off center of the axle line.
This is why for instance....the cross match KYB shock that matches the valving of the rear of our cars....is from the front end of a V-8 powered cargo van,,,,the ford econoline 1/2 ton
Adjustables are always nice to have....but are not the main issue. If you lower by using a shorter spring.....wether you cut the stock one or have one made.....AND you plan to retain teh stock shock.....you will need to find a way to shorten the stroke of the rod.
To start with....think about finding a shock that has a shorter stroke in teh range you need...and make sure it comes from something that has considerable weight....then buy it in an adjustable version (Koni, Bilstein, Fox, Spatz, Tokico etc)
This is where the problem will come in. Satisfying teh first two parameters of your search....stroke length, adjustability.....will be easy. Getting a "shock" that fits a front engined v-8 vehicle from one of tehse quality aftermarket adjustable companies...will be hard.
Most of what they make is for relatively modern cars...and mostly European and Japanese cars. That will pretty much leave you with struts only.
Yes...you could find a shock that fits the rear of these newer cars....but since they are all fron't engined...the valving will be way off.
By the way...you can also use teh shock from teh Ford econoline 3/4 ton van and it is the correct valving an a little stiffer....and is an exactfit.
I would do that and then simply put a stroke limiting spacer at the top. With better sway control in the rea....these high pressure gas shocks handle very well. Ray
It took me a little bit to understand why I destroyed a set of rancho RS-9000 5 way adjustables in 3 months. Its because the shocks are so far from the pivot point of the arc of the trailing wishbone. The leverage is huge...and the entire drivetrain weight is right over the axle and the bottom shock mounting point is just off center of the axle line.
This is why for instance....the cross match KYB shock that matches the valving of the rear of our cars....is from the front end of a V-8 powered cargo van,,,,the ford econoline 1/2 ton
Adjustables are always nice to have....but are not the main issue. If you lower by using a shorter spring.....wether you cut the stock one or have one made.....AND you plan to retain teh stock shock.....you will need to find a way to shorten the stroke of the rod.
To start with....think about finding a shock that has a shorter stroke in teh range you need...and make sure it comes from something that has considerable weight....then buy it in an adjustable version (Koni, Bilstein, Fox, Spatz, Tokico etc)
This is where the problem will come in. Satisfying teh first two parameters of your search....stroke length, adjustability.....will be easy. Getting a "shock" that fits a front engined v-8 vehicle from one of tehse quality aftermarket adjustable companies...will be hard.
Most of what they make is for relatively modern cars...and mostly European and Japanese cars. That will pretty much leave you with struts only.
Yes...you could find a shock that fits the rear of these newer cars....but since they are all fron't engined...the valving will be way off.
By the way...you can also use teh shock from teh Ford econoline 3/4 ton van and it is the correct valving an a little stiffer....and is an exactfit.
I would do that and then simply put a stroke limiting spacer at the top. With better sway control in the rea....these high pressure gas shocks handle very well. Ray
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Wally
- Posts: 4567
- Joined: Mon Oct 28, 2002 12:01 am
'We' should have an online order link for these in this forumraygreenwood wrote: .you can also use teh shock from teh Ford econoline 3/4 ton van ..
as we in Europe don't have your typical local friendly autoparts or FLAPS store
T4T: 2,4ltr Type 4 Turbo engine, 10.58 1/4 mi in a streetlegal 1303
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
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raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
The part #'s go like this:
Stock KYB gas-a-just shocks #KG5531....obsolete and no longer available
Ford Econoline 1/2 ton: #KG 5410....
Ford Econoline 3/4 ton: #KG 5406.
The 1/2 ton models are exact cross match for the stock KYB 5531 taken from a KYB dealers books. Same valving. The only difference is that the bushing on the bottom is different. You will need two small rings of Urethane or rubber and you are done. When you see it you will know instantly
The 3/4 tons are just slightly stiffer.
The KYB gas-a-just 5531's (411/412).....are roughly 15% stiffer than stock. They are actually pretty good. The 5410's are exactly the same as the 5531. The 5406's are roughly another 10% stiffer than those. Ray
Stock KYB gas-a-just shocks #KG5531....obsolete and no longer available
Ford Econoline 1/2 ton: #KG 5410....
Ford Econoline 3/4 ton: #KG 5406.
The 1/2 ton models are exact cross match for the stock KYB 5531 taken from a KYB dealers books. Same valving. The only difference is that the bushing on the bottom is different. You will need two small rings of Urethane or rubber and you are done. When you see it you will know instantly
The 3/4 tons are just slightly stiffer.
The KYB gas-a-just 5531's (411/412).....are roughly 15% stiffer than stock. They are actually pretty good. The 5410's are exactly the same as the 5531. The 5406's are roughly another 10% stiffer than those. Ray