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Rear suspension


jonlabree

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There are different things you can do to "lower" the rear, but most of them will affect the camber and unless you want to replace tires more often, then they are not the best option.

The most work, but probably the best overall method would be to reconstruct the rear mounting so the entire rear suspension unit could be moved up.

You could simply remove the rubber mounts, that would lower it over 1 in but there would be a substantial increase in road noise.

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the two ways i was looking at was narrow the spring by cutting off some off one side or attach a link to the center of the spring and hook it to the crossmember below. shortening the link will lower the car.in other words pull down on the center of the spring and cause the outer ends to rise.maybe use a shackle designed to use with lift blocks.

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Yes, Handmedown, That's what I was thinking. You might get a rough ride but it could work.

I also was going to try and shave the leaf down to 3" across just after the mounting and see if that would weaken it enough to lower it.

If I used a shackle type of pull down I am wondering if the spring ends would bottom out against the suspension?

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I had the same idea. Got my spare spring from J. Finn. Now I thinking of trying the shackle idea.

First Idea was to drill a hole thru the spring, put a plate on top and on the bottom of the cross member and use a piece of threaded stock thru.Then use a lock nut on the top and one on the bottom. (I am not sure of drilling a hole in the spring)

The only other way to do it would to make two L shaped pieces out of threaded stock and hook them over the spring, drill two holes in the cross member. Run a plate under the cross member with two 

holes lined up and put nuts on them .

What do you think?

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I think you may be taking the wrong approach to lowering the Reatta in the rear by modifying the spring. If it were me I would be looking at how to move part #7 up higher on part #6 in the diagram below. That way you avoid changing the geometry of the rear suspension and all the other problems that can pop up - like running out of shock travel, camber that can't be corrected, spring breaking and you name it..

 

If you take part #6 and #7 to a good machine shop and explain what you want to do, they could possibly make an adapter - or modify part #6 - so you could bolt the spindles on higher up which will drop the car. It would have to be done a way that would move both the spindle and the brake parts up to keep them in alignment. 

 

I've had dropped spindles on the front of my '99 S10 Blazer for 10 years. I've had no problems with alignment or otherwise. I was able to buy the drop spindles for my Blazer but with a little engineering and a good machinist I think something could be made for the Reatta that would drop it.

 

Going this route would be a lot less work for you than changing how the spring mounts although it might be more expensive. I don't like the idea of modifying a spring

 

58a86e4017ca9_suspensiondiagramrear.jpg.b8501c34c6d51e6faa12e77c4d4d208f.jpg

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Ronnie might be onto something....a steel plate between #6 & #7  could be made...

#6 bolts to #7 so if you could move the mounting holes up on the adaptor plate it would lower the rear to any amount you choose.

The only unknown is where and how the caliper mounts, if it mounts on #6 then you would need to make the adaptor plate have the needed holes to mount the caliper.

Lets say you used 1/2 thick steel plate (that should be strong enough) that would also move the rear wheels to the outside 1/2 inch on each side.....with stock rims and tires that should not be a clearance problem.

I don't have the higher math skills but moving the wheels out also changes the loading on the stock spring and that may also cause the rear to set a little lower.

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It looks like Barney has a point about the brakes and Viking about the ABS, so, part #6 either needs to be extended in length to where it bolts to #7 or alternatively, extend the lower mount of #6 where it bolts to the lower control arm. That would reduce the travel available in the strut by the same amount but I don't know how close it is to bottoming to start with.

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Here are a couple of ideas that may cause you to loose some sleep.

Neither would change the spring rate, they just raise the wheel location (or if you prefer...lower the body)

The left one puts a spacer on the lower "A" arm outer mount....since there would be two potential pivot points...one must be made so it cannot pivot.

The sketch on the left is the adaptor plate mentioned above.  The adaptor would need a big hole in the center for the ABS wheel and some way of attaching the ABS wheel sensor.

The plate would also need to have provisions for mounting the brake caliper etc.  This would move a stock wheel out the thickness of the adaptor, that could be corrected with aftermarket wheels with a different offset.

In both cases...the amount you can lower the car is controlled by the wheel diameter,   in both cases, as the wheel goes up in relationship to the lower "A" arm...the end of the "A" arm gets closer to the inside of the rim.

All of this would take some good layout, precision machining, and possibly trial and error.

REATTA REAR.jpg

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The spacer idea is pretty much what I meant and I like your sketch, something I sadly lack. My thought was to weld the extension to the bottom of the original part. Essentially material added to the bottom machined with the proper bolt holes. No worry of the extra pivot point. The point about wheel clearance is well taken. It will also raise the anti-sway bar mount since the mount on the strut will be higher, but I have no idea if that would need to be addressed as well.

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No... your idea of having a new spindle made is what J Leno would have done.....you get it engineered, designed, cast or machined from a big chunk of steel, drill, tap, etc  ...I try to think of solutions for the more average owner...someone that

might have a few less resources.

The adaptor plate would be the simplist solution from material availabity, but even then having a shop cut, add the holes etc could be expensive....unless you happen to have a mill in your shop.

I know a guy that just changed the steering on his '32 Ford (hot rod) from a Vega steering box to a rack...one custom made 90 degree 1/4 inch bracket cost $120 from a local machine shop...simple with little tolerance.

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John's silver 1990 factory supercharged car...

When a Reatta surfaces that is said to have a historic signifince within the Reatta community.......sure would like to see some documentation that verifies what the present owner is stating.

Who was the GM/Reatta employee that had the car made for his wife?

What is the vin number.....we have info on a good percentage of the cars that tells us where they went (dealer name, state, etc)

It is a strong possibility that the Eaton supercharger would have been in engineering in 1990 but the first production supercharged 3800 did not become available until 1992 on the Park Ave Ultra.

Maybe the words the owner used done at the factory could be confusing....sure engineering could have modified a car but the Craft Center did not build any 3800 supercharged Reattas

Edited by Barney Eaton (see edit history)
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1 hour ago, 63viking said:

But, I only have ONE Reatta.

Since Saturday several people have offered you suggestions, ideas and even drawings to try and help you find a way to lower your car. I'm surprised that this is your response to all that. I must be missing something.

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I was unaware that the Ultra had the supercharger in 1991........The 1991 product manual only shows one engine for all Park Ave. it could have been changed during the model year, does anyone have a product announcement

adding the supercharger?    I have a big 3 ring binder for 1991 that covers service information but will need to look for product changes.

 

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Couldn't we use a coil over set up and remove the leaf all together? 

 

Here is one for the Caddy side of the house.

http://www.streetbeatcustoms.com/Strutmasters/Coil-Overs/Cadillac-Eldorado-Strutmasters-Rear-Coil-Over-Shock-Conversion-Kit-_-CAD_R1/787315/

I am pretty sure these would be a bolt on. You may have to install the leveling kit for it, but that is easy enough and can be programmed in to the system.

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I am kind of wondering that also. 

I would assume that they are what the company says they are.

The rear suspension is the same as the Eldorado with the exception of the leveling option. 

I am hoping someone will bite the bullet on the rear suspension for us. If not I will eventually tackle it.

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9 hours ago, 89RedDarkGrey said:

What is so wrong with my earlier suggestion of at least trying the 2 companies I mentioned earlier in this thread- to have lowered spindles produced?

 

Remove what you have, clean them up, wrap up & ship. They don't destroy them, only use as a basis for CAD plot. They ship back to you, say yay or neigh, then you pay. (maybe small design fee?)

 

I don't have extra money- nor do I wish to lower my car. I just provided the (foreseeable) easiest method.

I certainly don't see anything wrong with the suggestion at all. I think many of us are making suggestions without the immediate desire to lower the car ourselves. There was a thread some years ago about either adapting or having a custom spring made but I do not remember the conclusion to that one? Wasn't RedRacer (or something like that?) working on a complete coil over setup in the recent past?

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