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Options for replacing rear struts needed.


lukehemstreet

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That sway bar bracket acts as a locator and probably assists the strut clamp in keeping the control arm from "walking" up the strut.  There will be some finagling to install the Cardone pieces since the only things that are the same between the original and the Cardone is the diameter of the tube and the shaft.  I have a feeling the swap can be done.  The travel length does concern me but creative mounting may resolve that.  The longer travel may be because the correct strut hangs a couple of inches below the clamp and control arm.  I can't imagine that the suspension travel differed greatly between the 93 Allante and the earlier models.  The 93 went to a more conventional setup with coil springs and control arms albeit with speed dependent dampening built into the strut.  The 93 mounting didn't require the extra length.  When I realized Rock Auto had the listing incorrect I started a return but changed my mind since they were so inexpensive.  I thought it would be a worthwhile experiment for the price.

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I'm anxious to get into this.  I'm also going to attempt to eliminate the Bosch anti-locks with a vacuum booster and master cylinder from a 93.  Challenging cars these Buick and Cadillac "experiments".

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6 hours ago, 2seater said:

I really appreciate and applaud the effort to find a viable replacement. The loss of over 28% of the travel would be perfect for a lowered car with a stiffened suspension, but the Reatta is pretty soft, trading travel for a reasonable ride on a short wheelbase. Any strut with a bottom mount is going to take away from the available piston travel, unfortunately. The clamp on anti sway bar mount is a real plus, solving one of the fitment issues. 

Regarding your Supercharged Reatta.  I had a 95 Riviera with a bad engine and thought about buying a Reatta and attempting a conversion.  Did you do that or go with the post 1996 3800?

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10 hours ago, ErnieR said:

Regarding your Supercharged Reatta.  I had a 95 Riviera with a bad engine and thought about buying a Reatta and attempting a conversion.  Did you do that or go with the post 1996 3800?

My engine is a mutt made of parts from various LN3 model years, so it is all LN3. I guess an L27 from the 91 Reatta would have some advantages being a true Series 1 engine.

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Can see Reattas taking a hard corner and lifting the inside rear wheel off the ground.

 

BTW have often thought both the Allante and the Reatta could have done better with more common parts. Having both I think some of the Allante design was done by Japanese high school students. A surprising number of parts were made in Japan.

Edited by Padgett
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1 hour ago, Padgett said:

Can see Reattas taking a hard corner and lifting the inside rear wheel off the ground.

Below is a photo of me going into a curve really hard on the Tail of The Dragon. I was pushing it hard enough that I could feel the front tires walking toward the outside of the curve.   If you use some imagination you might think the rear tire is about to lift off the pavement. I wish my friend in his blue Cobra replica behind me had been a little closer going into that curve. He would have noticed it if the tire came off the ground and told me about it.

 

I think if I'd had the new Cardone struts on my Reatta with less extended length and less travel the inside rear wheel might've had daylight under it. In this situation I don't see that as being a problem. I don't think that inside rear tire was providing much grip anyway. 🙂

 

 

killboy - 3.jpg

IMG_20170923_123254966_HDR.jpg

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It looks like all 0f the Reatta owners have purchased a set of clamps, because they are sold out.

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" eliminate the Bosch anti-locks " Have been thinking about replacing with a much more common Teves. Block diagram and pressures are the same, has a larger accumulator. I like ABS.

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15 hours ago, ErnieR said:

assists the strut clamp in keeping the control arm from "walking" up the strut. 

Could it be possible to use the lower mounting on the ‘93 Allante strut to keep aligned vertically in the lower mount (in a higher location that the OEM strut) to make up for the shorter travel and lack of indent for the pinch bolt?
 

There are openings in the lower mount that may be adaptable for this purpose.

 

Just a thought… Need to take measurements ..,

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Keep in mind that those dimensions are all for aftermarket shocks. Do not know what the originals were.

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2 hours ago, jon L said:

It looks like all 0f the Reatta owners have purchased a set of clamps, because they are sold out.

They are already sent some over to the powder coater for painting and will ship in about a week. Just ordered the struts and and clamps. I figure if they don't work for me I can always give them to 2seater for a Christmas present...

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Think I'll hold off, I bought a pair for the Reatta a long time ago and Allante does not use the sway bar flange (no rear sway bar which was a surprise). Suspect GM got a deal on ones with the flange.

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1 hour ago, DPS.01 said:

Could it be possible to use the lower mounting on the ‘93 Allante strut to keep aligned vertically in the lower mount (in a higher location that the OEM strut) to make up for the shorter travel and lack of indent for the pinch bolt?
 

There are openings in the lower mount that may be adaptable for this purpose.

 

Just a thought… Need to take measurements ..,

That was my thought when I decided to keep them and experiment.  The indent for the bolt shouldn't take but a little grinding.  I found the clamps by searching "custom coil over suspension".  Could be something one of those vendor has.  Thinking a "u" shaped bracket that can be bolted to the control arm.

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1 hour ago, Padgett said:

Keep in mind that those dimensions are all for aftermarket shocks. Do not know what the originals were.

Original NOS hydraulic strut with bump stop removed:


overall (top of piston to bottom of strut)

full extension:  ~25”

full compression: ~17.75”

 

top of piston to top of strut:

full extension: ~10.5”

full compression: ~3.375”


forgive the minor discrepancy…

 

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21 hours ago, DPS.01 said:

Original NOS hydraulic strut with bump stop removed:


overall (top of piston to bottom of strut)

full extension:  ~25”

full compression: ~17.75”

 

top of piston to top of strut:

full extension: ~10.5”

full compression: ~3.375”


forgive the minor discrepancy…

 

FYI:

 

There is a difference in the piston diameter:

 

OEM: 25 mm

Cardone for 1993 Allante:  20 mm

 

the threaded diameter is the same for the top mounting @ 15.9 mm, and the body is the same @ 54 mm. 
 

the upper mounting hardware from the OEM strut will fit on the Cardone replacement with some additional “play” when compared to OEM fitment. 
 

If the upper play is not an issue when installed, the lower mount weldment area could allow for the pinch bolt to be installed and prevent movements both vertically and rotationally to some extent. 

 

FYI:

the clamp on the OEM strut (Left) is to hold it fully extended for comparison. 

7E7F7531-A95F-4C5C-979E-465185AAB299.thumb.jpeg.7f820e98cfd97e0b965fde5ac64c7aac.jpeg

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42 minutes ago, DPS.01 said:

FYI:

 

There is a difference in the piston diameter:

 

OEM: 25 mm

Cardone for 1993 Allante:  20 mm

 

the threaded diameter is the same for the top mounting @ 15.9 mm, and the body is the same @ 54 mm. 
 

the upper mounting hardware from the OEM strut will fit on the Cardone replacement with some additional “play” when compared to OEM fitment. 
 

If the upper play is not an issue when installed, the lower mount weldment area could allow for the pinch bolt to be installed and prevent movements both vertically and rotationally to some extent. 7E7F7531-A95F-4C5C-979E-465185AAB299.thumb.jpeg.7f820e98cfd97e0b965fde5ac64c7aac.jpegFYI:

the clamp on the OEM strut (Left) is to hold it fully extended for comparison. 

Thanks for the picture comparison.  Makes me question whether the Cardone is a viable replacement.  I've been thinking this over more and more since my original post.  The key may be where the bottom ends up once the top is installed.  I purchased mounting hardware for the 93.  What I will be looking for is whether I have to push the strut up from the bottom to mount it or if I have to push the suspension up to mount.  If it's the latter I don't think they would work well.

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11 minutes ago, ErnieR said:

What I will be looking for is whether I have to push the strut up from the bottom to mount it

I was wondering about that. It looks like it might slide in from the top if the bushings and sleeve was removed from the eye mount on the bottom. Might need a little grinding on the eye mount as well but looks like that might allow it to slide in from the top.

 

On the other hand... if slid in from the bottom, the eye mount on the bottom might could be used in conjunction with a fabricated bracket to connect the strut to the pinch bolt to hold it in place so it doesn't want to slide through the knuckle if it bottoms out or tops out.

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1 hour ago, Ronnie said:

I was wondering about that. It looks like it might slide in from the top if the bushings and sleeve was removed from the eye mount on the bottom. Might need a little grinding on the eye mount as well but looks like that might allow it to slide in from the top.

 

On the other hand... if slid in from the bottom, the eye mount on the bottom might could be used in conjunction with a fabricated bracket to connect the strut to the pinch bolt to hold it in place so it doesn't want to slide through the knuckle if it bottoms out or tops out.

The widest point on the Cardone lower mount is the steel sleeve that accepts the mounting hardware. 
 

it measures 59 mm.  It may slide into the expanded lower knuckle, if not, grinding the metal sleeve flush with the rubber grommet brings it down to 50 mm, or just remove the rubber grommet completely. 

Edited by DPS.01
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15 minutes ago, DPS.01 said:

The widest point on the Cardone lower mount is the steel sleeve that accepts the mounting hardware. 
 

it measures 59 mm.  It may slide into the expanded lower knuckle, if not, grinding the metal sleeve flush with the rubber grommet brings it down to 50 mm, or just remove the rubber grommet completely. 

Actually, my concern is that the lower mounting point is higher than the suspension at full extension.  To me that would mean the strut would be fully extended before the suspension reached the end of it's travel.

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Just did a fast web search.  There are shock and strut extensions available,  for example only.

 

image.png.b2a45af0a2db049c06765da4b6d774c3.png

image.png

Edited by ErnieR
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