Options for replacing rear struts needed.

[1989reatta79106]

Maybe Im missing something here after reading the entire thread? Has this final product that Alchemist has worked so hard at and spent so graciously his own time and money (THANK YOU) to propose for our problem of a rear strut solution actually been installed on anyone's Reatta to see what the drive experience is like.  To harsh / ridgid, to soft, or is this our answer to our prayers, its just right. Hence your name could be 3 little bears struts.

[alchemist]

2 minutes ago, 1989reatta79106 said:

Maybe Im missing something here after reading the entire thread? Has this final product that Alchemist has worked so hard at and spent so graciously his own time and money (THANK YOU) to propose for our problem of a rear strut solution actually been installed on anyone's Reatta to see what the drive experience is like.  To harsh / ridgid, to soft, or is this our answer to our prayers, its just right. Hence your name could be 3 little bears struts.

It has not been tested, and to do so would take about $750, a donor set of failed struts and a new set of KYB inserts.  If anyone is willing to give a try, please advise.

 

DPS.01 has done something similar that machines threads on the inside of the existing strut tube and eliminating the weld adapter, but he is working on a solution for the upper mount as there is a difference that is fixed by the sleeve nut I am proposing.

 

I have both parts in 3D printed plastic, and geometrically they should work.  The dampening on the KYB insert is unknown at the current time, but there are few other options unfortunately.   Instead of the KYB insert (from the 1996 Buick Regal) a Koni dual adjustable racing insert could be used, and would allow for adjustment within the dampening parameters that it offers.

[DPS.01]

8 hours ago, alchemist said:

The price for a complete set of struts, including inserts, would be $485 plus shipping

@alchemist
 

Pricing for a ready to install strut is spot on in my opinion.  It is very fair and comparable to going the internal thread route. 
 

It will be a while until the internally threaded strut housings with KYB inserts are installed in my Reatta. 
 

I may not be a good judge of the ride quality as compared to OEM / OE replacements as the struts on my car were completely collapsed, but I will make an attempt once they are installed. 
 

Bottom line is that even a rough ride is better than one with worn struts. 

[DPS.01]

On 4/22/2023 at 12:39 PM, alchemist said:

DPS.01 has done something similar that machines threads on the inside of the existing strut tube and eliminating the weld adapter, but he is working on a solution for the upper mount as there is a difference that is fixed by the sleeve nut I am proposing.

Repost of some photos to show entire process of “Internal Thread Method”
 

Housing Modification:

Top of strut cut off

 

Housing internally threaded

 

Strut cartridge installed 

 

Gland nut installed 

 

Piston Extension Components:

*Coupling Union

*Upper Strut Mount Assembly 

*Bolt / Washer (may cut off bolt head and use nut for better compression control)(installation dependent). 

 

Assembled:

 

The Union raises the perch to approximately the same position as the OEM unit.  Using the bolt (or bolt /nut) allows the OEM upper mount assembly to be used without modification. 

[bobster99]

I just successfully installed rear struts on my 1988 Allante using Luke's Buick Reatta YouTube video as an inspiration.

 

The strange thing is that an Allante doesn't use a rear sway bar so for a Reatta you will need to figure out a Rear Sway Bar Mount.

The Strut I used has a location for a sway bar to mount though I don't know if it is even close to working for a Reatta.

If you search through this thread, someone did find a sway bar mount that could be retrofitted on a strut

 

Given that the Allante never came with a rear sway bar and the suspension is similar, i have no idea if it is truly required.

I guess if you want to join the SCCA and go racing around cones you would probably miss the sway bar

Then again, if you actually want to keep up with the Miata's and Civics, an Allante or a Reatta probably shouldn't be your first choice.

 

As to cost of this job.  I spent countless hours researching struts, about 3 hours engineering this solution for the first side.

The second side took me less than 2 hours start to finish.

Parts ran around $200 all in for both sides including 2 upper strut mounts that I didn't use.

 

 

1988 Cadillac Allante Rear Stut Replacement.pdf

Edited April 28, 2023 by bobster99
I can't spell to save my life.

[Ronnie]

Good write up. Thanks for posting the information. 

[AL C]

I just found this post Googling & thought this might help someone, I have a 90 Allante & modified a set of KYB #236003 / 1990 Regal rear struts. The upper stud/mounting and main tube diameter is Identical to original Allante struts & almost the same length. The valving should be close since they are similar size/weight cars, they ride like a new car in mine. You have to remove the lower mounting bracket and add the dimple for the pinch bolt & they bolt right in. You would have to make a mount for a sway bar if needed. I can post more pics of how I did it if anyone's interested.

[rogold]

I think this the mount that was referred to earlier AA-484-A Clamp-on Shock Mount, Fits 2" Tubing (aa-mfg.com)

[Ronnie]

I'm happy to see so many people working on this and taking different approaches to finding a solution. Eventually the best solution will rise to the top and the problem of discontinued rear struts will be solved. Good work guys.

[bobster99]

12 hours ago, AL C said:

I just found this post Googling & thought this might help someone, I have a 90 Allante & modified a set of KYB #236003 / 1990 Regal rear struts. The upper stud/mounting and main tube diameter is Identical to original Allante struts & almost the same length. The valving should be close since they are similar size/weight cars, they ride like a new car in mine. You have to remove the lower mounting bracket and add the dimple for the pinch bolt & they bolt right in. You would have to make a mount for a sway bar if needed. I can post more pics of how I did it if anyone's interested.

This solution looks even easier than mine.   I didn't look too hard at struts with that type of lower mount since the ones that I saw had a full weld around the bottom plate and I figured it would never come off clean.

Edited April 28, 2023 by bobster99

[Ronnie]

12 hours ago, AL C said:

I can post more pics of how I did it if anyone's interested.

Feel free to post as much information and photos as you like about how you did it. I think all Reatta owners would be interested.

[2seater]

I looked up the equivalent standard Monroe gas strut, 71831, and the dimensions listed are hard to figure out. At least they are fairly different from the Reatta strut, like 10.3" body length?? I suspect they are measuring from the top of the bracket on the body rather than the total barrel length but I haven't been able to confirm. Even the Monroe site is lousy regarding engineering specs.

[bobster99]

2 hours ago, 2seater said:

I looked up the equivalent standard Monroe gas strut, 71831, and the dimensions listed are hard to figure out. At least they are fairly different from the Reatta strut, like 10.3" body length?? I suspect they are measuring from the top of the bracket on the body rather than the total barrel length but I haven't been able to confirm. Even the Monroe site is lousy regarding engineering specs.

I couldn't find that number on my list of Monroe Struts... likely why I didn't see that as an option.

I did find this and if this information is correct it is quite a bit shorter.

MONROE 801831 Part Description

Specifications

• Body Type :B1
• Body Length :10.000"
• Compressed Length :10.500"
• Extended Length :18.500"
• Travel Length :8.000"

Part No. Part Type Strut Type Strut Length Length Compressed Extension Travel 71966 Strut B8 14.25 15 22 7

[DPS.01]

23 hours ago, bobster99 said:

The second side took me less than 2 hours start to finish.

Parts ran around $200 all in for both sides including 2 upper strut mounts that I didn't use.

@bobster99:

 

I really like this approach. 
I have a 2014 Passat TDi that I am preparing to change out the front struts on…

 

Was curious if they could be modified for use on the Reatta.  Based on your write up, this is another viable option…

 

Well Done !

Edited April 29, 2023 by DPS.01

[AL C]

5 hours ago, 2seater said:

I looked up the equivalent standard Monroe gas strut, 71831, and the dimensions listed are hard to figure out. At least they are fairly different from the Reatta strut, like 10.3" body length?? I suspect they are measuring from the top of the bracket on the body rather than the total barrel length but I haven't been able to confirm. Even the Monroe site is lousy regarding engineering specs.

I checked cars at my local U-Pull-It looking for similar size ones that might be good donors & found a Regal that looked perfect. I contacted KYB for their specs to confirm they were close before ordering one to experiment on. Their specs are 2.13" tube OD and 14.19" from the base to the top of the body. The extended length from the base to the end of the main shaft where the mount washer seats is 21.27", I measured from here down the tube body to make the pinch bolt dimple the same distance as the original strut so the installed total travel would be the same.  It was fairly easy to remove the brackets, took about 30 minutes each, had to be careful not to cut the tube.  They're only welded around the bottom of the tube and some spot welds on sides of the brackets by the big holes. I can post more info on my install Sunday night, heading out of town until then.

Edited April 29, 2023 by AL C
more info

[DAVES89]

22 hours ago, AL C said:

I just found this post Googling & thought this might help someone, I have a 90 Allante & modified a set of KYB #236003 / 1990 Regal rear struts. The upper stud/mounting and main tube diameter is Identical to original Allante struts & almost the same length. The valving should be close since they are similar size/weight cars, they ride like a new car in mine. You have to remove the lower mounting bracket and add the dimple for the pinch bolt & they bolt right in. You would have to make a mount for a sway bar if needed. I can post more pics of how I did it if anyone's interested.

good work. Looks like you have old struts that could be used for cores if anyone is interested...

[2seater]

15 hours ago, bobster99 said:

I couldn't find that number on my list of Monroe Struts... likely why I didn't see that as an option.

I did find this and if this information is correct it is quite a bit shorter.

MONROE 801831 Part Description

Specifications

• Body Type :B1
• Body Length :10.000"
• Compressed Length :10.500"
• Extended Length :18.500"
• Travel Length :8.000"

Part No. Part Type Strut Type Strut Length Length Compressed Extension Travel 71966 Strut B8 14.25 15 22 7

That part number is for a quick strut including the top mount I believe. They may only offer the complete setup from Monroe today?? But if you look at those dimensions in comparison to the installed photo, it sure doesn't look 10" long? Edit: must be why the plain strut is on closeout on RA?

Edited April 29, 2023 by 2seater

[bobster99]

25 minutes ago, 2seater said:

That part number is for a quick strut including the top mount I believe. They may only offer the complete setup from Monroe today?? But if you look at those dimensions in comparison to the installed photo, it sure doesn't look 10" long? Edit: must be why the plain strut is on closeout on RA?

My main concern when it came to a solution was for it to be something that was repeatable.   Back in the late 80's/early 90's the W Body (Lumina,  Cutlass, Regal) used cartridges inside the front struts.  That made it really easy to change the struts, just a specialty tool and you could change both struts in less than an hour.  In theory these could be used as a replacement insert into the OEM Struts.   The problem I ran into is that I found low or no stock so even though they made 100's of 1000's W Bodies.  Just do to the age, it is likely that we would be back in the same situation as we are now really soon.   Beyond that... Earlier in this thread someone purchased a couple of NOS struts and found 50% dead out of the box.   I just figured something that was in production within the last few years will have a longer life span.

 

 There are other sources that supply just the bare strut.   KYB has one that looks like it will work but I don't have the specs and since my car is done I my motivation is just to be helpful.  I did see that Amazon listed the KYB strut but as of yesterday, they only had one in stock.   I have no idea if the KYB strut will still be available in 6 months. 

 

The process I outlined is really not hard to do.  A $20 Harbor Freight Cut off tool and a  couple of spare cut off wheels and your strut will be ready to be installed in 30 minutes or less.   Getting the old one out... well, that takes a bit longer.

[bobster99]

13 hours ago, DPS.01 said:

@bobster99:

 

I really like this approach. 
I have a 2014 Passat TDi that I am preparing to change out the front struts on…

 

Was curious if they could be modified for use on the Reatta.  Based on your write up, this is another viable option…

 

Well Done !

It worked for me.  The idea of putting in an insert is a bit cleaner but sure looks like a lot more work.  When Allante's get invited to Pebble Beach in 2055, well, I will loose some points but I am pretty sure that Allante's will never be recognized as Full Classics by the Antique Automobile Club of America anyway.  😛

[AL C]

Here's some pics of how I modified The 1990 Regal rear struts for my 1990 Allante.

1)  Original 1990 Regal strut with bracket, the only welds are around the 
      bottom of the tube and 5 spot welds on the brackets around the large
       bolt holes, none on the tube sides.

2)  cutting off the side bracket parts at an angle with cut-off wheel, saw would work also.
      Cut carefully so you don't cut into strut body.

3)  One bracket cut off

4)  Both brackets cut off, you can see the lower weld bead in the gap, you will have to cut 
       just above it  to remove the rest of the bracket

5,6,7)  I used a cut-off wheel to cut just above the weld around the base of the strut, the 
        bottom of the tube is slightly tapered so there is a VERY SMALL gap between the 
        bracket and the tube at the bottom above the weld. 
         BE CAREFUL TO NOT CUT INTO THE TUBE! 
         I slowly cut into the piece between the previously cut- off parts & bent it up until it 
         came off, then I  could see how deep I could cut around the bottom for the rest of the 
         mount.
        It might be easier & safer to just use an angle grinder to slowly grind off the bracket 
         at the weld around the base of the strut.

😎   removing the rest of the bracket, carefully cutting the slot deeper to peel it off

9)     main bracket removed, now have to remove the remaining welded on piece

 
10, 11)    grind off the welded on piece 

12)    finished strut end

13)    measuring from end of strut rod where the upper mount washer seats to the 
          dimple in the strut tube for the pinch bolt - mine is 19 3/4"

14)     transfer measurement to new strut

15)     strut mounted in vise to make dimple with a chisel rounded off on the end

16)     align dimple with bolt hole & test fit the bolt,  make dimple deeper if it doesn't fit
           I used a small chisel to spread the spindle apart to make it easier to slide the strut in

17)    tighten the bolt, strut is ready to install, uses the original upper mount parts - no modifications needed.

 

 

Edited May 1, 2023 by AL C
more info