Options for replacing rear struts needed.

[Ronnie]

26 minutes ago, Padgett said:

Might be easier to machine a mount bracket for the knuckle/sway bar and use a standard shock. Just a thought.

Did you read my previous post? I don't think a standard shock can be used unless you mean to keep the original strut and add a external shock to it.

 

 

18 hours ago, Ronnie said:

The strut on the Reatta not only acts as a damper it is an integral part of the suspension. It holds the knuckle so the camber is in correct alignment as the knuckle goes up and down. The knuckle pivots on one bolt in the lower control arm.  Without a strut to keep the knuckle aligned vertically, it will just flop over as can be seen in the photo below. The blocks of wood you see are to keep the knuckle from flopping over and putting a strain on the ABS sensors. Because of the side load on the strut, the rod is a larger diameter than a shock.

 

[Philbo]

3 hours ago, Padgett said:

Might be easier to machine a mount bracket for the knuckle/sway bar and use a standard shock. Just a thought.

That's an idea too! Maybe machine a piece that fits into the stock knuckle that would have the mount for a standard damper of some kind.

 

Which is kind of what Jon L is trying to do.

Edited October 12, 2022 by Philbo

[Philbo]

Sorry for jumping around between ideas so much, but I did confirm that the housing diameter and shaft diameter of the 2010 ford tuarus (part number 335611) front strut matches that of the Reatta's rear. 

 

I think that could be a candidate for relatively easy modification. You would need to cut this hardware off, which I think you could make quick work of with a portable band saw and a file

I think some pitfalls (aside from the sway bar mount) might be the difference in machining at the top of the rod and I am worried this small notch at the bottom is to let the bolt for the clamp through. 

[Philbo]

3 hours ago, Ronnie said:

Did you read my previous post? I don't think a standard shock can be used unless you mean to keep the original strut and add a external shock to it.

 

 

Standard shock, no, but maybe a standard strut. There are universal struts out there like the konis that maybe could be retrofit in a similar way.

[Ronnie]

1 hour ago, Philbo said:

Standard shock, no, but maybe a standard strut. There are universal struts out there like the konis that maybe could be retrofit in a similar way.

Thanks for all the work you doing on this. Maybe it will lead to finding a stock strut that will work will little modification.

[Philbo]

SYNOPSIS

 

So I wanted to kind of summarize everything, since I have kind of been all over the place on this topic.

 

Right now, to me anyway, there are 3 main avenues of interest.

 

1. Finding a similar strut for a different car that is close enough in dimensions and could be modified to fit the Reatta suspension.  I will call this the Luke method, since it seems that this has been successfully pioneered by @lukehemstreet.  The only difference is I am interested in finding a strut that maybe needs less modification than the one he chose.

Currently I found the strut for a 2010-2012 Ford Taurus is a pretty close fit and at least has a similar lower mounting style to the Reatta's.  Pros of this method are relatively low cost, availability, and it has been successfully done before.  The cons, I think, are labor intensive and unsure about if the damping is right.

 

2. Using an aftermarket Strutt Insert like the Koni adjustable inserts.  Here is a video by Koni that shows the installation procedure, to give an idea. I think this is currently the most appealing option for me right now.  I plan to contact Koni to try and ask them a few questions, but I see no reason why this would not work, and you would have a performance strut that is adjustable. What I am not sure of is if the inserts will fit inside the stock Reatta rear strut housing.  Long term, at least, I am going to pursue this.  My plan would be to try to use the original strut housings, but if they are not dimensioned properly, I will explore fabricating my own custom housing.  Really all you need is a tube that has the right ID for the Koni insert, and the right OD for the clamp at the knuckle.  The pros of this are you would get a high quality performance adjustable strut that is also rebuildable.  The cons are significantly higher cost ($200+ each ), might also be labor intensive depending on how difficult the retrofit turns out to be. 

 

3. Rebuilding factory Struts.  So in my research, rebuilding struts, is a thing.  Most of the youtube videos I find on the topic are similar to this one and seem to be from foreign countries.  I guess here in the USA, when stuff wears out we just throw it out and get a new one , until Monroe discontinues the part and you can't .  I question some of the methods here, but I think it is an indication that they do come apart, and can be serviced.  I think the hurdles would be sourcing replacement seals and such, and also figuring out how to get apart and re-assemble, since the Reatta struts are welded shut and do not have a nut like you see in the video.  My thought was that you could cut the top off and then cut threads for that nut on the inside and then close them up with one of those nuts (seem to be pretty standard on a lot of struts).  I think for a lot of reasons this is the least appealing solution due to the uncertainty, expertise needed, and no obvious way to source the replacement parts, seals, etc. (although I am sure they are likely standard parts).  This solution does interest me personally though for two reasons.  First, I just kind of find satisfaction in figuring out how to fix things that would normally be thrown away. And second, there is the element of keeping the car as original as possible (less of a concern for me personally).  It is entirely possible that this would be relatively easy and inexpensive to do and could be something that, if figured out, could be reliably proliferated.

Just trying to get all my thoughts in one post. As I said, I think ideally I will pursue #2, but cost may end up being a roadblock.  It is hard for me to dump $500 into a project like that right now, especially when there is a potential $100 alternative 

 

[ErnieR]

Good morning, I don't own a Reatta but I have a 92 Allante.  Because RockAuto mistakenly listed 93 Allante rear struts as a fit for a '92 I decided to attempt adapting them for use in the '92.  Part of my decision is that they are CHEAP.  Less than $100 with tax and shipping for a PAIR.  The dimensions are the same but lack the sway bar mount.  The Allante doesn't have a rear sway bar but I thought that extra piece also helped keep the strut in place so I also purchased some adapters used in building custom coil-over suspensions to mimic the sway bar mount.  I haven't begun the actual work but I wanted to share this with this group.  While I never owned a Reatta I ran a Buick dealership from 1988 - 1996 and had both Riviera and Reattas at my disposal as demonstrators.  BTW, the notch that was referenced in a previous post is probably for locating the strut in the bottom mount with the bolt acting as the locator.  The metal on these feels heavy and thick enough to take some careful grinding in the appropriate spot to accommodate the bolt.  Also, the bottom mount on the strut is there since the 93 Allante went from leaf to coil springs.  It looks like it can easily be removed.  There is a wire harness included with this kit to bypass the active suspension on the Allante.  It has no actual connection to the strut. 

 

 

 

 

Edited October 17, 2022 by ErnieR

[Ronnie]

Looks like a good prospect for replacing the rear struts on a Reatta. Do you know if the diameter of the body of that strut where it would slide into the clamp is the same as the body of the Reatta strut? The adapter for the sway bar looks like it would work great. Thanks for sharing!

 

[Philbo]

Oh man @ErnieR thank you, this could be a game changer. So you are saying from the top of the housing to the top of the bottom mount is the same as the reatta strut? And also the housing diameter is correct (55mm)? The rod looks the same. I measured 25mm shaft diam on my reatta.

Edited October 17, 2022 by Philbo

[ErnieR]

The diameter is the same.  I'm thinking the length of the body may be shorter with overall length including the standard style shock mount being the same.  That nay not be an issue though.  I did compare extended and compressed lengths and the are virtually the same.   My main concerns with this adaptation are the locating tab and the sway bar mount.  Even with no sway bar as is on the Allante I think it would further strengthen the resistance for the control arm to move upward on the strut itself.  So while I didn't need a sway bar mount I am hoping the extra clamp would be enough on its own or I would be able to secure it to the control arm in some way.

 

Edited October 17, 2022 by ErnieR

[Philbo]

Hmm, a quick check of the part on Rock auto states the stroke length as 5" where the reatta's is stated as "7.  Not sure how much wiggle room there is on that. I do know the stroke length on the Koni inserts I was looking at is only just over 6". 

 

I have not found many car struts with a stroke length as high as 7" so I wonder how much of it the reatta suspension actually uses. Summit Racing had a how-to for figuring out your suspension max travel. I might explore that further.

Edited October 17, 2022 by Philbo

[ErnieR]

I went to Monroe's site and looked up 71966 specs.  See the notes on travel length.  Not sure how this affects use on the Reatta.

 

[2seater]

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. 

[Ronnie]

That Cardone strut appears to have a top that might screw off. I wonder if it could be rebuilt if needed? Or is there possibly an insert inside that could be changed?

[Padgett]

What is the part number of the clamp & how to order please ?

 

$74 is a closeout so just ordered what is hopefully a pair. (pictures show two but does not seem to say anywhere)

 

Does say for 91-92 Allante.

 

ps just looked on my 89 Allante and does have the sway bar flange but nothing is bolted tuit.

Edited October 17, 2022 by Padgett

[ErnieR]

It is for a pair but the fit info is wrong, really 93 only.  92 is just like the Reatta.  No sway bar on the Allante, I don't know why.  That may be my next endeavor.  I understand the travel length issue.  I'm going to try it any way since no harm will be done to any original pieces.  It will be awhile since I have something else on my QuickJack that needs to be completed.  Nothing fancy just a new engine for my 89 Cherokee.  I measured the body of the Cardone units and it is 11" not including the mount piece on the bottom.  I verified the 5" travel.  I'm curious what the extended piece on the Reatta strut measures.  I took a measurement from the top of the body to the spot where the mounting bushings obviously sit.  Clamps sre available lots of Places but this vendor was the least expensive.  Fast ship no problems.

[ErnieR]

Interesting.  5" travel may work.  I'm more concerned about over extension than bottoming.  

 

How much shock travel does a street car need?

This depends on what type of suspension you have. It differs between straight axle suspensions and independent suspensions.

On straight axle suspension systems, there is a 1 to 1 ratio between the movement of your shock and your wheel. That means if your wheel moves one inch, your shock extends or compresses one inch. In these applications 2.5 inches of shock travel in both directions (compression and extension) should generally be enough.

Depending on the way your suspension is set up, you may need more. If you want to limit body roll for stiffer handling, you may want less travel than that. But even in these cases, your shock should not be thing limiting your suspension—ie being fully extended to keep the car from experiencing body roll.

For independent suspension systems, shocks do not require as much travel. That’s because the control arm acts as a lever. So, while your shock may only be moving an inch, your wheel could be traveling two inches. It could be moving three inches.  It all depends on where your lower shock is located. The closer your shock is to your wheel, the closer to 1:1 that motion ratio will be.

When measuring for shock travel on an independent suspension system, start with wheel travel. Make sure it can move 2.5” in both directions. To check this, measure between your upper and lower shock mount when your suspension is fully compressed and at full droop. This will tell you how much overall stroke you’ll need to keep from bottoming out or topping out your shock.

Edited October 18, 2022 by ErnieR

[Padgett]

" really 93 only" my 89 Allante has the sway bar bracket but is not used for anything, & doubt is necessary. Is there any other difference ?

 

[2seater]

I suspect the present unknown is the actual travel being used in normal driving. There does need to be some amount of wheel drop but perhaps it is possible to bias the position of the strut up or perhaps just split the travel evenly? The math wizards or cad engineers maybe could help us out with a diagram of the wheel movement and where the strut might fit in that. I am more of an empirical type, which would work if there was an easy way to take the spring out, but there isn't that I am aware of. 

[Ronnie]

I think running out of travel when extended is a much less of a problem than the strut bottoming out. When it bottoms out the weight of the car comes into play.  If it over extends just the weight of the wheel and suspension parts are pulling on it, and even that downward movement of the suspension is being controlled by the dampening of the strut. If it is over extended there might be a problem with the strut being pulled out of the clamp unless there is the notch in the side of the strut body for the bolt.