Options for replacing rear struts needed.

[alchemist]

23 minutes ago, 89reattaWI said:

 Is this the right part?

 

Meaning is the picture included in your post the 73305 Insert?  If so, it *looks* like it but I cannot say for certain it is the 73305 just from a picture.  I have one 73305 strut and will work on the solid model of the retainer once I receive my 71801's.  I will then have the machining bid out by a few local machine shops who I work with on a regular basis.

[Ronnie]

2 hours ago, alchemist said:

I will then have the machining bid out by a few local machine shops who I work with on a regular basis.

I wonder how hard it would be to use a Regal strut that accepts that cartridge and graft it onto a Reatta rear strut by cutting off the top portion of both and welding the top part of the Regal strut onto the bottom of the Reatta strut? If so would be easier and cheaper than fabricating from scratch.

[alchemist]

2 hours ago, Ronnie said:

I wonder how hard it would be to use a Regal strut that accepts that cartridge and graft it onto a Reatta rear strut by cutting off the top portion of both and welding the top part of the Regal strut onto the bottom of the Reatta strut? If so would be easier and cheaper than fabricating from scratch.

Good question.  Not having seen what the 1996 strut housing looks like, uncertain how that would work.  If anyone has a 1996 Buick Regal front strut insert holder, it would be interesting to look at and pull some dimensions from it.

 

The design I am conjuring up would allow for the insert to be replaced and the adapter could be reused.

Edited March 3, 2023 by alchemist

[2seater]

I found this video which seems to indicate a wide range of GM models used this cartridge. In this video you never see the strut housing but they look pretty conventional.

 

The relevant video is really only seven minutes long

Edited March 4, 2023 by 2seater

[2seater]

I don't know if there is a difference in the various strut housings available for the wide range of years and models that the cartridge fits so there is some investigation required to see if melding them as suggested is possible.🤞

 

EDIT: A quick Rock Auto search shows no front strut housings available for any of these models except one for the Cutlass Supreme. Maybe something is available elsewhere but I suspect we are cut off at the pass on new housings which could potentially be modified. 

Edited March 4, 2023 by 2seater

[2seater]

It would appear if the strut cartridge is surrounded by oil, the housing must be a loose fit. That would lead me to believe it had some sort of socket at the bottom that fits the cartridge more tightly or it would flop around. My crude math for the cooling oil volume would seem to be about 2.125” id for the housing?

[alchemist]

8 hours ago, 2seater said:

It would appear if the strut cartridge is surrounded by oil, the housing must be a loose fit. That would lead me to believe it had some sort of socket at the bottom that fits the cartridge more tightly or it would flop around. My crude math for the cooling oil volume would seem to be about 2.125” id for the housing?

I am thinking that is the oil from inside the failed strut cartridge.

[2seater]

7 hours ago, alchemist said:

I am thinking that is the oil from inside the failed strut cartridge.

According to the video, in text form, it states he removed the old oil, whatever it may have been composed of, and then installed new motor or hydraulic oil to half the depth before installing the new cartridge. The reason given is for cooling or it would be enclosed in a chamber with insulating air around it. I would guess if the cartridge is exposed directly to the air, it would self cool? I was guessing on the size and volume of the housing based on the volume the strut cartridge would displace.

 

I wonder why GM would use such a system concurrently with the more common type like on the Reatta? It would seem to be much simpler to replace the worn unit and not require an alignment as well.

[DPS.01]

On 3/3/2023 at 1:46 PM, Ronnie said:

wonder how hard it would be to use a Regal strut that accepts that cartridge and graft it onto a Reatta rear strut by cutting off the top portion of both and welding the top part of the Regal strut onto the bottom of the Reatta strut?

It should work. 

1. A KYB 366004 strut insert was used.

2. Place absorbent material under the strut, and cut the Reatta strut just below the top weldment.

 

Drain any remaining hydraulic fluid. 

 

(If donor strut still has resistance, drill a small pilot hole to relieve pressure prior to cutting.)

3. Pull the inner workings out of the OEM strut. 

4. Insert KYB strut cartridge 

5. Fabrication is required for a top threaded interface to weld onto the strut that will accept the threaded gland (~51 mm).  Need to speak w/ machine shop. 

 

The gland nut supplied by KYB has a smaller OD than the ID of the Reatta strut and simply slips into the strut housing as shown below with no interference. 

6. Per KYB, do not add oil to strut housing during assembly (see comments later in this post). 

7. Install gland nut

8. Install on Reatta

 

 

Edited March 5, 2023 by DPS.01
Edited for clarity, added KYB part number to original post.

[alchemist]

4 minutes ago, DPS.01 said:

It should work. 

1. Using a KYB strut insert. 

2. Cut the Reatta strut just below the top weldment.

3. Pulled out the inner workings of OEM strut

4. Insert KYB strut insert

5. Need to fabricate top threaded interface to weld onto the strut and will accept the threaded gland…. Need talk to a machine shop. 

6. Add oil?… or not?

7. Install gland nut

8. Install on Reatta

 

 

Excellent pictures, had not seen these before.  Fabricating the top adapter to be welded on should be straightforward.  Which KYB strut part number is this and is the diameter and pitch of the thread on the gland nut known?

[DPS.01]

15 minutes ago, alchemist said:

KYB strut part number

I think this is for a 1996 Regal… had these for awhile, waiting on donor struts. 
 

Gland Nut:

Not sure of the pitch, but the thread seems to be 51mm (reads 50.88 on my inexpensive caliper). 

 

Edited March 4, 2023 by DPS.01

[alchemist]

38 minutes ago, DPS.01 said:

I think this is for a 1996 Regal… had these for awhile, waiting on donor struts. 
 

Gland Nut:

Not sure of the pitch, but the thread seems to be 51mm (reads 50.88 on my inexpensive caliper). 

 

Oh good, I have the Monroe version of that same strut in my garage.  Will use that along with dimensions off the Riviera struts that will arrive tomorrow to build a weld adapter.  I should brush up on my welding skills, this might be a side hustle, rebuilding old shocks.

[Ronnie]

1 hour ago, alchemist said:

this might be a side hustle, rebuilding old shocks.

There is definitely a market for it right now.

[2seater]

DPS.01, Most excellent photos. From the look of it, our strut is actually an insert inside a welded casing? Is that the case? Was there fluid around the inner strut cartridge when disassembled? I noticed this style of strut was used on all the W body cars.

[DPS.01]

That depends on what you are referring to as an insert.
 

The original Reatta strut did not have a self contained insert, and was not designed to be rebuilt. 
 

It is hydraulic and uses oil to create resistance.  Most of the oil was expelled from the strut before it was cut open (it completely failed). 

 

Shown in the tear down photos are a piston, sleeve and other dampening components that are assembled and completely submerged in hydraulic oil. 
 

 

The Monroe 71966 was a direct replacement gas strut upgrade for the Reatta when it was available. 
 

The concept shown in the photos uses a self contained gas strut drop in cartridge designed for the front strut on a 1996 Buick Regal. 

[alchemist]

Based on DPS.01's pictures, it should be very possible to use the original strut housing as the new retainer housing for a strut insert.  Note, the original rear struts are NOT insert types, but the old housing should be readily usable as a retainer for an insert.  IF YOU HAVE BAD STRUTS, DO NOT THROW THEM OUT!

 

Does anyone have a donor failed Reatta rear strut they would be willing to send me? If so, I will do all of the solid modeling and work with a local machine shop on the weldable adapter.

 

Will also need a ring to pot the base of the insert and to keep it secure within the diameter of the original housing.  Definitely do not want it rattling around inside the housing.

Edited March 5, 2023 by alchemist

[2seater]

When installing a KYB strut cartridge do not put any water, oil or

Does any fluid need to be put into the strut housing when replacing a cartridge-style strut?

When installing a KYB strut cartridge do not put any water, oil or any other liquids inside of the strut housing. Any existing fluid should be removed from the housing before installing the new cartridge. KYB cartridges are designed and engineered to operate without any additional liquids.

 

This is what I found on the KYB site regarding fluid around the insert. It seems pretty emphatic😎

any other liquids inside of the strut housing. Any existing fluid should be removed from the housing before installing the new cartridge. KYB cartridges are designed and engineered to operate without any additional liquids.

Edited March 5, 2023 by 2seater

[DPS.01]

2 hours ago, alchemist said:

Will also need a ring to pot the base of the insert and to keep it secure within the diameter of the original housing.  Definitely do not want it rattling around inside the housing.

Originally thought of using a rubber bushing (think upper mount strut tower) compressed between the gland nut and the strut insert, and then drill  4 holes midway down the strut body opposite each other and use set screws to hold the insert centered to accomplish the same thing.

 

A combination of figure “a” bushing and figure “b” gland nut below. 
 

 

The strut wall should be strong enough and the set screws can keep the insert centered. 

I do like the ring idea, but tolerances may be a variable depending upon the insert cartridge used (OD) and the donor strut used (ID). There may  also be differences in the OEM hydraulic strut body and the aftermarket gas strut body. 

Edited March 5, 2023 by DPS.01

[DPS.01]

1 hour ago, 2seater said:

When installing a KYB strut cartridge do not put any water, oil or any other liquids inside of the strut housing.

2seater:

 

That answers the question about any fluid surrounding the KYB insert.  I updated the verbiage in the assembly pictures posting above. 

 

Thanks. 

Edited March 5, 2023 by DPS.01

[DPS.01]

2 hours ago, alchemist said:

IF YOU HAVE BAD STRUTS, DO NOT THROW THEM OUT!

alchemist:
 

Worth repeating… several times over.