Suspension similarities

Whether it's up high or draggin', this is the place to discuss anything related to body and suspension modifications for street or offroad use.
2zuzus
Regular Member
Posts: 31
Joined: Thu Nov 16, 2017 5:36 pm
Location: N.J. U.S.A.
Isuzu vehicle(s): P'up Friendly Trooper Owner

Suspension similarities

Postby 2zuzus » Tue Nov 21, 2017 7:00 pm

Greetings Folks, This is my first post to this site after my intro. First of all, Thanks to you for the great info you have collectively put together here. Great stuff. I actually own a Trooper and have a question in that regard. How much similarity is there in the suspensions of a 1986( and '85, '84) Trooper and any year of P'up that may apply? If there is any, I dug up some info this summer that may be helpful regarding torsion bars and shocks. If there isn't, so be it, but I hope it could be useful. The early troopers '84 to '86 used "half" a wishbone (rear) and a rod (front) on the bottom at the front axle, with a torsion bar for springing as well as a bottom eye, upper post, type shock. Will check back to see what's what. Thanks, Chris.

2zuzus
Regular Member
Posts: 31
Joined: Thu Nov 16, 2017 5:36 pm
Location: N.J. U.S.A.
Isuzu vehicle(s): P'up Friendly Trooper Owner

Re:More About Suspension Similarities

Postby 2zuzus » Wed Nov 22, 2017 8:15 pm

Hello Again, Had some time so I thought I would add to this. Didn't mean to be so cryptic, I didn't have time to look up info #'s during that first post and didn't know if anyone could use them, so I just put the question out in the meantime. I'll fill in some gaps now.
This past summer from May to Sept. I was trying to get my Trooper suspension squared away as the springs/bushings and shocks were shot. I have known about Old Man Emu/ ARB components since the early 80's and the generally favorable reputation those parts have. Isuzu aftermarket suspension parts buyers don't have a lot of manufacturers to choose from, and I was glad to see that O.M.E./ARB was one of them.
As I navigated through a fair amount of information, I made some choices and placed an order. I ordered a complete OME suspension kit for a pre'92 Trooper. There were only two kits listed for Troopers, '92 and above being the other application. The kit arrived, and as the rear springs were my first and most major concern, I verified their fitment and set about acquiring the shackles and hardware to finish that phase of the installation. I put the rest of the install on the backburner.
First note: Apparently anything that has to be ordered out of the U.S. by one of the OEM ( careful, that's NOT OME ) suppliers online for Isuzu will wait until they have a sufficient quantity of orders before they actually put an order in to the Japanese warehousing. I was told OEM spring shackles would take a minimum of 6 weeks to reach me, and that was a best case delivery date. It would most likely take longer because of the reason already given. 8 to 12 weeks was more likely according to 2 different suppliers. Too long for me.
I didn't want a shackle lift as the OME springs give a 3/4" lift over stock. Anything over 1" and you have to start adjusting the driveline angle with shims as per various reliable sources, including OME. Also, the stock sized bushing (replacements being the same size as OEM) have an 18mm bore. The OEM shackle pin has an 18mm diameter, but the necked down "bolt" part of the pin is threaded for a 14mm socket driven nut, so is probably around 10mm threaded diameter. This gives a lot of metal in the shackle width where the "bolt hole" is bored. I wanted to retain both that and the height features. My original shackles were worn on that 18mm area and needed replacement. In the end I had to fab shackles and use 18mm bolts with a sufficient smooth shank area for the bushings to ride on. I threaded two 18mm bolt holes on one of shackles and bored two 18 mm holes in the other shackle in each of the two sets. This allows setting the "crush" on the bushings at the OEM spec. Too much is not good. A nut on the bolt projection locks the assembly as a jam nut. The rear spring parts were collected and now ready.
In the meantime I had cleaned up one of the torsion bars including the splines and rear socket. I got an overall length through various parts and pieces and a somewhat maddening spline count. (Those splines are SMALL, especially under a vehicle with older eyes. Thank goodness for reading glasses.) My overall length was within 1mm of factory spec as it turned out. I opened the torsion bar package to spec them out and found a major problem. Then another. The OME torsion rods were 1 meter/ 39+" long with a 43 spline count. My '86 trooper has a 36" length (NG) with a 40 spline count (another NG). This is a no doggone way situation. All applications pre '92 ? BOLONEY!
Come to find out the rear shocks were wrong also. '86 Troopers have eye and eye shocks, holes on each end. What I received had eyes on the bottom and posts on the top, (or a threaded bolt type arrangement if you will). NG again.
I called the vendor, multiple times, who also placed calls to the OME/ARB main office in Australia. I called the U.S. supplier, multiple times, who also called the Australia office. Come to find out, OME/ARB has no listing for the 1986 and older Isuzu Troopers for applicable Torsion Bars or rear shocks. I was incredulous!
I'm a bit hard headed. I had very good specs as verified by both the 1986 AND 1988 Isuzu Trooper factory manuals I now have. Apparently, Troopers morphed somewhat in their suspensions in '87,for a completed changeover in '88. The kit I received is a replacement for '88 to '91 Troopers. The kit I received applied to the rear springs and front shocks only on the '86 Troopers as far as I can personally verify. I don't have specs on the other years or models. Thus my original post question.
I went back to the OME/ARB International application guide I found on the web. I have to say that OME/ARB did a very good job in spec'ing their COMPONENTS. There is a wealth of information in that guide. So much so that some things that OME/ARB weren't aware of started coming to light.
As some of you older folks who shopped for auto parts know, BOOKS used to be available to source and cross reference parts. Perhaps some of you, like me, have had to find that oddball part for a less than usual application from time to time, and pored over numbers and PICTURES of parts and found something that worked, sometimes fabulously. I've been there, still am.
Note 2: If you have good info, chances are, if you search hard enough, you WILL find something that works OK at least, or even very well. Not necessarily from the original source either.
I spec'd a torsion bar that was not for my application but was an almost exact fit by the numbers. It had 40 splines in the correct diameter, a slightly larger cross section in the body of the bar, that I wanted, and was short of the factory overall length by 1mm. That's 1/2 of a mm on each end or roughly .020", smaller than a good points gap for those who remember such things. Who cares it's a mm short. In the same way I found a set of rear shocks, correct end layout, opened and closed lengths, and dampening. The only thing I couldn't find out, even after calling the aforementioned folks and receiving a reply, finally, from ARB Australia's engineering dept. was the actual spring rate. That was going to be a seat of the pants answer after everything was put back together. By dimensions though it should work.
It does. With no warranty or return available because these were a non-application installation, I ordered the parts anyway and finally got them installed in mid Sept. after months of delays. The truck rides well but handles great! It rides flat in a tight turn at speed, takes undulations, (like speed bumps) very well, and is a bit sharp on rutted roads. Of course all of these are my opinions, and my wife's, and I am pleased with it. Although it is not a true ARB start to finish engineered-for- that-particular-vehicle assembly, it is still ARB quality parts and that is what I think is it's strong point. They are robust.
If anyone can possibly use this information to upgrade their P'up, then by all means use it. As for the parts I used on my 1986 Isuzu Trooper, (All part #'s OME/ARB), here they are:
Torsion Bars- originally for Ford/Mazda P/N 303005 1 PC. ( comes as a set of 2 torsion bars)
Front Shocks- originally GM-Colorado P/N 60031 2 PCS. (sport shock)
Rear Springs- Isuzu Trooper pre'92 P/N CS028R 2 PCS.
Spring Bush Kit- Isuzu Trooper P/N OMESB90 2 PCS.
Rear Shocks- GM/Isuzu P/N 60032 2 PCS. (sport Shock)
As a note, you will need longer spring U-bolts as the OME spring pack in taller by 3/4". I bought mine at a chain auto parts store. OEM diameter is 7/16" but the spring plates on my Trooper accepted the 1/2" diameter U-bolts I bought. The U-bolts will need INSIDE dimensions of 2 7/8" wide and 7" long. Mine were in the Dorman HELP! section, P/N 35617 .
I modified a set of universal lift shackles sourced from the same store type. Multiple brands were the same dimensions nominally, 1 1/2" wide, 1/4" thick, about 10" long with 3 sets of holes per piece. I cut off the excess length. The 18mm coarse thread bolts I used were sourced from an industrial supply house like Granger, etc. Bolt/Pin hole center dimensions should be taken from the OEM shackles to retain the original spacing/ ride height if wanted or needed. Remember the warning about driveline angle adjustment that is mandatory to prevent parts failures in the driveline at 1" above OEM ride height.
I sure hope this helps someone. I am still amazed that I got absolutely zero steering from the manufacturer or their vendor about the even possible compatibility of these parts to a non-specific application. I gave them all my dimensions, data, you name it, and I couldn't even get a spring rate from them. Good thing the research and development was done years ago on these parts. I'm not sure anyone capable is on watch these days that could accomplish that mission.
Happy Thanksgiving 2017. God's Blessings to one and all. Chris

89rebelpup
Regular Member
Posts: 33
Joined: Sat Apr 23, 2016 3:46 pm
Location: Georgia
Isuzu vehicle(s): 1989 Standard cab swb 2.3l (carb)

Re: Suspension similarities

Postby 89rebelpup » Tue Nov 28, 2017 6:10 am

Chris,
Your detailed post here was probably more enjoyable to read at 6:15am for me, taking only a few minutes, than it was for you during the weeks and month of obvious disappointment, confusion and frustration.
But due to your own learned knowledge, confidence and resourceful determination, all of which are fading character traits in our modern society remaining only in us older fellas, it ended well. Like "they" say who doesn't like a happy ending?!
I think there is fewer and fewer of us that can appreciate the irony in these instances when an otherwise well planned and expected smooth process start not going well. That WHEN not IF one doesn't give up but instead sets their mind, efforts and resourced to work at reaching a certain goal or end result, even if it takes seemingly "forever", that end result or product is so much more valuable to the soul.
The experience found in the journey is at least equal to the pleasure or reward of one reaching the destination if not even more so! Funny also how afterwards we begin searching for our next "problem" to solve or situation that someone else needs our now seasoned advice on a subject!
But anyways.. thanks for sharing your dilemma complete to its end and keeping the "will do" spirit alive!

Richard

2zuzus
Regular Member
Posts: 31
Joined: Thu Nov 16, 2017 5:36 pm
Location: N.J. U.S.A.
Isuzu vehicle(s): P'up Friendly Trooper Owner

Re: Suspension similarities

Postby 2zuzus » Thu Dec 14, 2017 3:07 pm

Hello Richard,
Thank you for the kind words and moral support! I was out of town 'til yesterday, 12/13, and am just now seeing your post. I apologize for the delay in response.
I have to agree with everything you have written. And yes, I am on another "Are you kidding me?" project, as you predicted. (No, I'm not kidding. HaHa!) It's a turbo problem on a 2.2 diesel, and it is turning into another can of worms, of course. I'll be posting my findings on that one as I conclude it. Best Regards, Chris.


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