Polyurethane 'A' Arm Bushings

[mbstude]

I'd swear one of our Stude vendors, (maybe in AZ) has been offering Delrin bushings for decades. Anyone else remember those?

jack vines

Still available from Russ at www.studebakerparts.com

[studejohn]

I have done the urethane bushings have a set in my car. And I’ve been in it for many years the uppers are Camaro 67 to 69 I believe they only need a slight machining to make work The bottom, I don’t recall But they were for rear Spring for something. They took a little bit more machining Never could find one that was a better match to machine. If it was all said and done, it’d be better just to have someone make them for Studebaker like they do any other vehicle I don’t have the capital to do it. 😞

[PackardV8]

FWIW, it's the uppers which always pound out. I could live with rubber in the lowers.

jack vines

[alpayed]

Hi Guys.
Here are a couple of links to the original discussions about the Polyeurethane bushes I have made.

https://forum.studebakerdriversclub.com/forum/your-studebaker-forum/tech-talk/1904113-front-end-bushing-kit-62-hawk/page2

https://forum.studebakerdriversclub.com/forum/your-studebaker-forum/tech-talk/1810388-a-arm-rubber-bushing-interchanges

To do this you need to use the steel shells from the old rubber bushes, and make new inner tubes (polished SS) a bit longer than the originals.
I purchased bushes a bit larger and machined them down. (Toyota hilux I think). The material is lousy to machine, very high speed and sharp tools. Freezing makes them better to machine.
My cars have had these now for 7 years.

Later I discovered you can purchase the material in a liquid air set state. I did make 1 mold but never proceeded with the project.


Kind regards
Allan

[bensherb]

This is what urethane bushings look like after ten years and around 80,000 miles. They get quite brittle. I made Delrin bushings for mine. I've not noticed any appreciable difference in ride quality.

[64studeavanti]

Yerolddad, check p.m.

[r1lark]

FWIW, it's the uppers which always pound out. I could live with rubber in the lowers.

jack vines

True, and the uppers are easy to replace on the car, without even disconnecting the a-arm from the kingpin.

[JoeHall]

Thank you Allan Tyler for posting here, and the two links you provided to earlier SDC Forum threads on same subject saved a ton of time for anyone digging through the archives. I just now read both of the linked threads, and they provide all the background info needed to jump into this thread today. As for finding brand X substitutes in OEM rubber, it appears the GM spec'd MOOGS (K5196) for the uppers was never solved. I ordered a set of them and checked their dimensions with a dial caliper, and could see NO WAY they'd fit Stude upper 'A' arm pivot shaft without machining down the shaft and/or boring out the ID of the bushing inner sleeve. Nor could I see how it was possible to force the .073" larger OD casing into the Studs's 'A' arm without turning down the casing and/or boring out the hole in the 'A' arm. I also with those bushings in hand, matched them with a spare 'A' arm and my hands and eyes told me the same thing the calipers told me. Yet two reputable forum members insisted they'd fitted them into their Studes without any mods whatsoever. So I am at a loss, but recently tossed 15-20 miscellaneous bushings for brand X cars that appeared to have possibilities of fitment into Studes. None I found could be fitted without machining, and I was also concerned about limitations of machining since all concerned materials were thin (walls of the bushing inner & outer sleeves, and the 'A' arm holes), except turning down the OD of the ends of the pivot pin. So I tossed them all, and not looking back.

As for Bensherb's posted pics of Polyurethane bushings from a friend's rear spring bushings in a brand X vehicle, with 80,000 miles and 10 years on them, if I could get anywhere near that longevity out of any kinda upper bushings I'd be very happy. The norm for the OEMs, using good live rubber, is about 50,000 miles. Of course some Studes are never driven 50,000 miles, and a few others reach those miles in 5 years or less. My highest recorded annual mileage was in the 56J, just shy of 30,000 in one year when I lived in SoCal. But I have slowed down a lot. For example in Oct 2020, I installed a new GPS speedometer in the 62GT, with zero miles on it, and it now shows about 16,000, four and a half years later.

As for polyurethane experience, for years I have been using the red ones on just about everything, including our family fleet of brand X vehicles, when OEM black rubber components disintegrate. My now 25 year old son's Buick comes to mind, I replaced it's front anti sway bar support pin bushings with red polyurethane ones about 9 years and over 100,000 miles ago. I recently did some other work on that car's front end, and those red bushings were still in place and looked OK. Perhaps I shoulda checked for hardness, and will next time. But in all cases where I used the red bushings (including several Stude shock bushings) I have never had one fail. So, at this point, I have much more confidence in them than any OEM black rubber, in any suspension component, in any brand car. I usually keep several spares in a bin, and buy them at FLAPS, where they're marketed as an upgrade kit for brand X anti sway bars. They are available in black and red, but I like the red ones because I can tell at a glance if I've replaced something, whether or not I can recall when or why. LOL

Thanks Again Allan for chiming in here!

Joe H

[yeroldad]

So, do you know what are the part numbers are for the Poly a arm bushings, or do I tell them I want them for my '53, which is usually a waste of time, since they haven't ever heard of a Studebaker?

[bensherb]

I agree with you Joe and have installed urethane bushings in many of my vehicles, I also prefer the red for the same reason. I only posted the pic to show that urethane too has its shortcomings and a limited life. Even so, they do tend to tighten up a suspension and improve its stability even if in some cases they last no longer than the factory rubber. Generally I prefer the stiffer Delrin bushings depending on their application and have even installed aluminum bushings for some applications; not recommended for a street car.

[JoeHall]

Hi Oldad,
Of course there's no part number that I am aware of, though, as I mentioned above, two of our members insist they installed MOOG K5196 rubber bushings (for miscellaneous GM vehicles) in their Stude upper 'A' arms with zero mods needed. Since the rubber ones are still around for those GMs, you may be able to find them in polyurethane. But if they don't fit your Stude, talk to the two guys who say they will.

As for dimensions of the ones Allan Tyler made for me, and several other Stude drivers in Australia, I am happy to provide pics and as much info as I have, but just wanted to be sure it was OK with Allan. Since it sounds like he does not plan to make anymore, at least not for the foreseen future, I feel confident he won't mind. (But if you do Allan, please speak up.) They require use of the OEM metal outer shells, and are machined exactly as they should be (including the outer shoulder) for a light thumb press into the shells (ONCE GREASED). The inner shaft slips in easily also with thumb pressure, again once greased. I dunno exactly what kinda grease it is, but Allan included 2 packets of it with mine. He also provided a red Lock Tite that felt stronger than USA red, and almost locked the 3/8" screws up as I was drawing them down and tightening them. As Allan explained, they are designed to float, instead of using the OEM's twist of the locked up rubber. I did not measure the inner pins, but took pics, and they are about .125" longer than the OEM pins, top and bottom. Allan probably can provide exact specs.

If you have not done so already, I highly recommend you peruse the two links Allan provided today, as he provided excellent pics, and sufficient details in those links, to answer most questions here today. I must admit, I installed the OEM end washers, since I liked the way they "cage" the outer edges of the bushings, but do not impede float. In looking at his pics, I see he did it several ways, probably as he was refining the product. If he says remove the OEM washers and use the ones he sent, I will do so, but next question is, is that Australian Lock Tite gonna let me get those 3/8" bolts out? LOL

[yeroldad]

Joe and Alan, Thanks for the info and the leads! I'm going to call Prothane Tuesday and see what they have to say. Maybe something has changed to make it easier to get the correct urethane bushings, or ones I can easily modify to fit. I have no problem modifying them, as long at it isn't to much of a hassle, which it seems to be fairly simple . All in all, it seems to be the way to go. My plan is to do the bushings when he snow flies in the next couple three months. Right now, I drive it several times a week, and I don't want to miss out. I'll be pulling the body off to strengthen the frame and take care of the body rust. Hoping for next winter for that.

[64V-K7]

This is what urethane bushings look like after ten years and around 80,000 miles. They get quite brittle. I made Delrin bushings for mine. I've not noticed any appreciable difference in ride quality.

At least they look a lot easier to swap out..

[JoeHall]

Yep, that’s an added benefit I forgot to mention, it will only take about 5 minutes each to change the ploys, won’t even need to remove the A arms, but will need to unload the suspension (coil springs)

[Buzzard]

Years ago I had a 1972 Hurst Olds Indy Pace Car convertible. I thought I was smarter than the engineers who developed the chassis. I replaced all the front end bushings with Energy Suspension urethane and totally destroyed the ride quality. It did however corner like it was on rails but it had a price. I learned why they used rubber from the factory
Bill

[JoeHall]

Buzzard I can identify, concern about harshness was the main reason it took me 6 years to install them. Now that I did, I only wish I'd had Allan make me half a dozen sets. Time will tell if there's any worms in the woodwork, and the 56J is an excellent Guinea pig. If anything is gonna go wrong it's more likely to happen on a 56J than any other Stude I can think of. Especially mine, with PS, AC, and a humongous radiator. Time will tell, but for now I am tickled pink.

[Buzzard]

Joe,
It is always nice to hear good news stories so I am glad you are happy. Enjoy your great ride.
Bill