DPS.01 Posted March 18, 2023 Share Posted March 18, 2023 (edited) @alchemist: the threads were machined. Side by side assembly comparison: top: OEM fully extended (held extended by clamp.) Distance from top of sway bar mount to upper perch: 17.00” center: OEM body w/ Monroe insert. Distance from top of sway bar mount to upper perch: 16.125” bottom: OEM body w/ KYB insert. Distance from top of sway bar mount to upper perch: 15.75” the Monroe insert cartridge is approximately .125” taller than the KYB. Due to design differences, the KYB also has a shorter piston stroke for the identical application as the Monroe. as a side note, the Monroe gas charged unit comes compressed. The unit I received did not automatically extend once rotated to “unlock” from shipping state, and seems to have compression resistance similar to a hydraulic shock vs. substantial resistance on the KYB gas charged unit. Maybe the Monroe unit is faulty? the threaded height above the perch is a problem for assembly and there are two options to address: 1. Extend the thread with coupler and threaded rod which also raises the upper strut mounting perch. This also addresses the problem of enough piston length to extend through the upper rubber mount stack up. 2. Use a spacer under the insert cartridge as indicated by @alchemist and use the weld-on threaded adapter and threaded sleeve approach. The weld on adapter would be needed to extend the length of the shock body to allow for the 1.5” spacer insert. The OEM strut body is not long enough to accommodate. Edited March 18, 2023 by DPS.01 3 1 Link to comment Share on other sites More sharing options...
2seater Posted March 18, 2023 Share Posted March 18, 2023 (edited) At first blush it certainly looks like the original threaded extender would be a player when threading the OEM body. As it is shown, it really doesn't affect compression but will limit wheel drop, and that may not be an issue. I am sure a person schooled in CAD or similar programs could simulate the wheel travel from bottom to top and see what the strut is actually doing. Excellent visual aids😎 Edited March 18, 2023 by 2seater 2 1 1 Link to comment Share on other sites More sharing options...
sarookha Posted March 19, 2023 Share Posted March 19, 2023 Awesome work, guys! Another approach to the lack of OEM spec threaded height above perch, for those with access to a machine lathe, is to turn down the existing threads on the KYB or Monroe insert, and re-thread to a smaller size. Then fab a screw-on adapter with the desired overall length, thread, and OD for the OEM-style unthreaded part. NB, pad the lathe jaws so you don't scratch the shaft, and leave a clean fillet at the base of the smaller, newly threaded shaft so as to prevent cracking at its base. 1 Link to comment Share on other sites More sharing options...
DPS.01 Posted March 19, 2023 Share Posted March 19, 2023 (edited) like this? if this adapter is made to correct dimensions / thread sizes, it can be reused if cartridge requires replacement. Edited March 19, 2023 by DPS.01 Link to comment Share on other sites More sharing options...
alchemist Posted March 20, 2023 Share Posted March 20, 2023 (edited) Finally had a few minutes to sketch the basics up in Draftsight. This confirms the 2.5" differential, and somewhat amplifies the need for the weld adapter, bottom spacer, and sleeve nut to keep the stroke and overall length very similar. The upper comparison is with threading the existing body and the base of insert aligned with the base of the OEM housing. The lower comparison is with the top of the strut housings aligned, as they would be with the weld adapter and spacer. The sleeve nut would then bring everything together, and the Allen socket in the insert would allow for the sleeve to be tightened. Edited March 20, 2023 by alchemist 1 1 Link to comment Share on other sites More sharing options...
sarookha Posted March 20, 2023 Share Posted March 20, 2023 22 hours ago, DPS.01 said: like this? if this adapter is made to correct dimensions / thread sizes, it can be reused if cartridge requires replacement. Yes, that's what I had in mind. Pretty simple with a lathe. Link to comment Share on other sites More sharing options...
alchemist Posted March 20, 2023 Share Posted March 20, 2023 (edited) The 3D plastic printed adapter arrived today. it sides snugly over the Monroe 71801 Riviera struts that I have (which use the same body as the 71966, but with the addition of an air spring bladder). At the time, I made an assumption on the gland nut diameter being 48mm, however DPS.01 has since determined it is M51-1.5 diameter and thread pitch. I am going to have the top mount sleeve adapter printed in plastic for proof of concept of that so the stack up for the OEM bushings and retainers can be determined. Threaded end view (top) and slip end view (bottom). The resolution of the printing makes everything look threaded, but it is not. The threads are 1.5" deep which should allow for everything to come back to OEM suspension stroke, as the 73305 insert cartridge has 0.375" more stroke than the 71966. Edited March 20, 2023 by alchemist 5 Link to comment Share on other sites More sharing options...
alchemist Posted March 22, 2023 Share Posted March 22, 2023 (edited) The 3D printed plastic 'proof of concept' sleeve nut is complete. It will require the snout/bridge to be cut off the lower mount plate (far right in the picture below), the hole in the upper plate (second from left in picture below) will need to be made larger to allow the sleeve nut to pass through. The strut mount on the car will be left as-is, no modification necessary. The sleeve nut fits perfectly inside the plastic sleeve inside the lower rubber bushing. I have another set of mounts on order to modify as needed to confirm everything. Just waiting for the pricing on the sleeve nut. I will heat treat (austemper) the 4140 sleeve nut at our Oshkosh, WI facility. Again, soliciting for anyone who has a failed set of struts to donate to the cause and be the first one to receive prototypes. I have one Monroe insert strut already. Edited March 22, 2023 by alchemist 3 1 Link to comment Share on other sites More sharing options...
vivi Posted March 25, 2023 Share Posted March 25, 2023 Hey all, Great work with all of this. Been looking for solutions myself and it's amazing what some of us can come up with. In the meantime though, I went ahead and took a gamble on these from earlier; https://www.universalairride.com/product/1988-1991-buick-reatta-rear-electronic-to-passive-suspension-air-shocks-conversion-kit/ I'll update here if they ever show up/fit fine. 1 Link to comment Share on other sites More sharing options...
DAVES89 Posted March 25, 2023 Share Posted March 25, 2023 That's really not that bad a price as I bought some of the last NOS from a local Buick dealer who sourced them out across the country. I believe I paid about $130.00 each and didn't get the air lines. I got three Riv struts and one Reatta strut. Link to comment Share on other sites More sharing options...
DPS.01 Posted March 26, 2023 Share Posted March 26, 2023 23 hours ago, DAVES89 said: That's really not that bad a price as I bought some of the last NOS from a local Buick dealer who sourced them out across the country. I believe I paid about $130.00 each and didn't get the air lines. I got three Riv struts and one Reatta strut. agree. they are $$$, however the options for rear strut modifications may approach that level to get to the finished product… Link to comment Share on other sites More sharing options...
alchemist Posted March 26, 2023 Share Posted March 26, 2023 (edited) 7 hours ago, DPS.01 said: agree. they are $$$, however the options for rear strut modifications may approach that level to get to the finished product… And the options are depleted and it appears there are no NOS OEM or Monroe units for sale. I am thinking it will be about $200 per strut when all is said and done for adapters and labor, assuming the old struts are sent along with new inserts. Edited March 26, 2023 by alchemist Clarified estimated cost. Link to comment Share on other sites More sharing options...
Ronnie Posted March 26, 2023 Share Posted March 26, 2023 1 hour ago, alchemist said: I am thinking it will be about $200 per strut when all is said and done, Is that what you could sell them for or just the cost of parts and labor if someone wanted to do it themselves? Link to comment Share on other sites More sharing options...
alchemist Posted March 26, 2023 Share Posted March 26, 2023 15 minutes ago, Ronnie said: Is that what you could sell them for or just the cost of parts and labor if someone wanted to do it themselves? Sorry, I should have been more explicit. That would be adapters plus labor. Assumes the customer would provide usable old struts for cutting down, and the insert struts (KYB or Monroe). Link to comment Share on other sites More sharing options...
Ronnie Posted March 26, 2023 Share Posted March 26, 2023 I'm hoping once a solution is found someone will offer them for sale on an exchange basis. I made the mistake of throwing my old struts away. Although I don't think my Monroe replacements will be worn out by me, it might just take one pothole to ruin one and I would be out of luck. Link to comment Share on other sites More sharing options...
alchemist Posted March 26, 2023 Share Posted March 26, 2023 7 minutes ago, Ronnie said: I'm hoping once a solution is found someone will offer them for sale on an exchange basis. I made the mistake of throwing my old struts away. Although I don't think my Monroe replacements will be worn out by me, it might just take one pothole to ruin one and I would be out of luck. I am thinking about doing just that, but would need a bank of old struts to start with. Even the cartridges that are proposed appear to be on their way out as many are on closeout. Link to comment Share on other sites More sharing options...
Ronnie Posted March 26, 2023 Share Posted March 26, 2023 I hope you do. Seems like there are Reattas in the salvage yard up north that might be a source of used rear struts but here in the south Reattas in a salvage yard are scarce. I've never personally seen one here. Maybe some of the guys up north can help you get started by finding old struts for you. I fear front struts my go the same route as the rears before long. Link to comment Share on other sites More sharing options...
vivi Posted April 3, 2023 Share Posted April 3, 2023 Update on the universalairride.com shock kit, these are also unobtanium. Called to get a status and was told they're on backorder and was sent a refund, so looks like that's another dead end. 1 1 Link to comment Share on other sites More sharing options...
DPS.01 Posted April 3, 2023 Share Posted April 3, 2023 That is unfortunate, however not surprising… had it happen to me more times than I can count. Link to comment Share on other sites More sharing options...
DPS.01 Posted April 3, 2023 Share Posted April 3, 2023 On 3/26/2023 at 5:02 PM, alchemist said: That would be adapters plus labor. Assumes the customer would provide usable old struts for cutting down, and the insert struts (KYB or Monroe). Just some additional information regarding required adapters / sleeve nut retrofit… The thread size of the pistons are different between Monroe and KYB. Monroe thread size is 16mm; 2.0mm pitch. KYB thread size is 16mm; 1.5mm pitch. For reference, OEM is 16mm; 2.0mm pitch. Not sure what the thread size is for others that are out there. Looking like there is not a one size fits all retrofit solution. 1 Link to comment Share on other sites More sharing options...
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