How would you do this?

[Mr T Bucket]

I have several pics saved of this type of setup, and am thinking this is the basic route I'm wanting to go for my front shocks. What I'm not sure about is the pivot area where it is attached to the frame. If you were going to build something similar to this, what would you use for that pivot joint? Meaning, what kind of bearing, or bushing, if any would you use? Would you use something like a half inch shanked bolt that would just rotate inside a well-lubed .505" (or similar sized) piece of round tube steel? Isn't that how most of the under floor T bucket brake pedal setups are done? My mount would most likely be welded on the top or bottom of my frame, and not through the side. I had thought about integrating a heim at that spot and another where the shock mounts just like in a CAD picture that George Barnes did some time back, but I think it might clutter up the look a little. However, I am not 100% against that idea. It's just that the stuff I keep wondering about that would be somewhat compact, like an oilite bronze or plastic bushing just doesn't seem like it would live very long. Short of lucking out and finding a thin caged needle bearing, I'm not coming up with many other options.

I also noticed no plan for movement where the shock is bolted to the top of the "L", unlike the heim at the axle. Is it because the rubber bushing in the end of the shock would "give" just enough for what might be a relatively small movement? I'm not really concerned about that aspect as much as I am the pivot at the frame, but figured I'd ask.

 

[Hotrod46]

Since that's my car in your picture, I'll tell you how I did it.

I used poly 4 bar end link bushings. I welded a sleeve in the frame at the pivot point. They have held up well so far.

The axle for the rocker was a 3/4" bolt that I machined the head to give a better look. I actually turned the 3/4" bolt into a 1/2" shoulder bolt. Each side was custom fit for minimal end play. A flat washer and a thin self-locking nut holds it all together.

Keep in mind that in my setup there is a 2 to 1 leverage ratio due to the length of the arm that attaches to the axle. This reduces the effectiveness and shortens the travel of the shock. If I was doing this again, I would check into adjustable shocks. Something like a QA-1.

As far as movement at the shock goes, you are correct. The rubber bushings have enough give for the small amount of movement required.

The bronze bushing in the rocker was left over from an earlier mock-up attempt. It's not needed.

Mike

 

[Corley]

Hotrod46 is right on... Think about the lever's pivot carefully. If you used a metal to metal pivot as you suggested, (bolt in tube), the tinyest bit of wear or construction clearance (slop) would surly cause a metal to metal banging (rattle) as you drive and the axle goes up and down a little bit. On the other hand, if you use a softer rubber pivot, it will cushon the lever action so much that the shock won't see any motion. If you used needle bearings, the limited motion would probably wear them out in a hurry. (They like more rotation.) (Some chain saw clutch drums use a nice little needle bearing that is pretty cheap to buy but I recommend against those.) Probably poly sleeves or the poly pivots as used by hotrod46 would be the best choiice because they wear well without lub, are tight and have little give so will transfer the motion well, shouldn't bang or rattle, don't require ugly grease for lub, and since they are fairly hard material they should transfer all of the motion from the axle to the shock well, which is what you want. JMHO

 

[Northstar T]

Since that's my car in your picture, I'll tell you how I did it.

The axle for the rocker was a 3/4" bolt that I machined the head to give a better look. I actually turned the 3/4" bolt into a 1/2" shoulder bolt. Each side was custom fit for minimal end play. A flat washer and a thin self-locking nut holds it all together.


Mike

Mike,

I love the look of that setup. nice job !!
For those wanting a similar arrangement, you might save the extra machine work of making the shoulder bolts if you stop by your local lawn mower repair shop. vertually all walk behind mowers use a shoulder bolt to hold on each wheel. they're 1/2" diameter shank with 3/8" threaded portion, have a 3/4" hex head that is quite thin and non-obtrusive. they come in a wide variety of shoulder lengths as well. about a buck fifty each.
They also use a spring steel wave washer on some, which could be usefull as an "anti rattle" devise.

Cheers,
Russ

 

[Hotrod46]

Corley brought up an important point. When I was playing around with this during the build, I found out that just about any slop in the main pivot point resulted in a lot of lost motion at the shock. You could also make some bushings out of Delrin or Teflon so that little or no lube would be required. I used the 4 bar bushings because they are easy to get if replacements are needed.

Northstar - Having a lathe means that sometimes I make more work for myself! Thanks for the compliment BTW.

Mike

 

[Gerry]

I have used 'engineering plastic' in a lot of places on my T, that others probably would nt, including the king pin bushes. King pins move slowly and gradually, dampers move quickly and often. I think plastic is a great material but please remember its very proned to humidity and temperature changes unlike metal (Especially teflon). For things like my damper pivots I went the old way of brass (OILIGHT) bushes, which I reamed to the correct size. In saying that I did use plastic for the damper to pivot mount points.
Gerry

 

[Corley]

Gerry, Is that really true that engineering plastic or "poly" is subject to humidity concerns? I know it changes dimensions a bit with temp, most all materials do, but I always thought it pretty much impervious to humidity, given that it is non-absorbant. I defer to your knowledge on this, but this is a huge surprise to me and something that I might have to research more to understand the mechanics of it all... (God knows I have a lot to learn...) The main concern with the oilight bearings that I had was that they will tend to attract and hold dust which then tends to cause wear, then slop, then banging and lost motion. Perhaps some o-ring seals would be good with bronze or oilight?

 

[Differen T]

I have several pics saved of this type of setup, and am thinking this is the basic route I'm wanting to go for my front shocks. What I'm not sure about is the pivot area where it is attached to the frame. If you were going to build something similar to this, what would you use for that pivot joint? Meaning, what kind of bearing, or bushing, if any would you use? Would you use something like a half inch shanked bolt that would just rotate inside a well-lubed .505" (or similar sized) piece of round tube steel? Isn't that how most of the under floor T bucket brake pedal setups are done? My mount would most likely be welded on the top or bottom of my frame, and not through the side. I had thought about integrating a heim at that spot and another where the shock mounts just like in a CAD picture that George Barnes did some time back, but I think it might clutter up the look a little. However, I am not 100% against that idea. It's just that the stuff I keep wondering about that would be somewhat compact, like an oilite bronze or plastic bushing just doesn't seem like it would live very long. Short of lucking out and finding a thin caged needle bearing, I'm not coming up with many other options.

I also noticed no plan for movement where the shock is bolted to the top of the "L", unlike the heim at the axle. Is it because the rubber bushing in the end of the shock would "give" just enough for what might be a relatively small movement? I'm not really concerned about that aspect as much as I am the pivot at the frame, but figured I'd ask.

Spherical plain bearings (the family to which Heim ends belong) are available in a round type of mounting. Weld a correctly sized ID tube into the frame and press the bearing into it using a large C clamp. They can be sealed and self lubricated if desired. RBC is a manufacturer of this type of bearing http://www.rbcbearings.com/sphericalplainbearings/selguide.htm

Al

 

[Gerry]

There are sites on the web that have all the specs for engineering plastic, I can t remember them, just do a search. There are many different types of eng plastics and the specs help to pick the one you need.
Yep Teflon is really quite bad. I initially used it for the steering column but replaced it when it started to get hot in the spring. Every weekend they got tighter and tighter.
All the bellcranks on my suspension run needle rollers but as has been pointed out they really dont like restricted movement. I am not planning to do high mileage perhaps 5000 a year so I am prepared to replace them as a maintenance thing.
If they give up in less time I will think again.

Gerry

 

[Lee_in_KC]

Hey guys, check out this stuff. This is the material that is used for the bushings that replace the needle bearings in my Jag rear-end. I got mine from CWI, but they apparently are out of business (web site gone, phone disconnected). If you could find a place that sells the stuff in rods, you could machine what you need.

 

[Gerry]

Lee
Just put that in a search engine and came up with the exact company (UK) that I got mine from. They have loads of specs on all sorts of plastic http://www.directplasticsonline.co.uk/UHMWPERod/Black/. go see
gerry

 

[Mr T Bucket]

Wow! Thank you, Thank you, Thank you everybody for all the replies.

Mike, that's cool it's your car. Now I know who to ask for all the answers, LOL. Ballpark, how long are the links/heims (center to center) that connect your shackles to the "L" arms? Did you use 1/4" plate for the "L" arms? Looks too thin to be 3/8". I was thinking my ratio would be closer to 1 to 1. When you say you'd rather go with an adjustable shock, is it because you think you need more dampening for your particular front end due to the 2 to 1 ratio killing the shock movement, or just because you should be able to fine tune it?

I guess I hadn't really thought about any kind of "soft" non-metal type of bushing for the pivot. I ran across a rod end that had a replaceable/removable heim style bearing, to where I could cut the stud off and weld the outer housing to the frame, and then dress it with a housing that blended into the frame. Problem was that it was about 3 inches in diameter and that was just to big and ugly. Was pretty cool though with internal snap-rings on both sides and the inner bearing protruded out just like a sleeve. Anyway, after reading your reply, I searched around for sizes and such for 4 bar bushings and found something that I think might work for me. I had originally thought about putting the shocks on the top of the frame, like yours, but closer to level with the frame, (adjusted for clearance from the radius swing of the pivot of course), and incorporating a headlight stand or riser for the rear-most shock mount. I'm planning on using the stainless '32 style headlight stands and they are somewhat short compared to the more traditional T bucket stands, and a 2 or 2.5" little "box" for the headlight stand to sit on as well as bolt the rear eye of the shock sort of sounded good, or 2 birds type deal. I had planned on putting the pivot mount on the bottom of the frame, which would flatten the radius swing some, plus allow a more 1 to 1 ratio. Hopefully it wouldn't be too stiff, but I might be able to build-in something between 1 to 1 and 2 to 1 if anybody felt it might be better that way.

And then I figured out I may not have room to do it the way I thought. I may have to flip it all over and put the shock under the frame and the pivot on top. I have some pictures of those setups also. Otherwise, the L shaped arm may have to be T shaped or pie peace shaped in order to keep the shock up top and my headlight stand's stand project in play.

I was thinking about using the shackle plates with the stud hole in them, but got to thinking about the angle of the shackles changing, even if the stud hole is mounted near the axle shackle bolt instead of the spring shackle bolt, and how that might change the effectiveness of the shocks, albeit ever so slightly. Am I over thinking this? Short of making something that would attach using the radius rod bolt locations on the front axle batwings (like a reverse batwing) there's not many other options that would keep the whole look the way I want it.

Still kind of sorting it out now that I have a couple of the pieces on hand. Need to order some heims and do some more playing around. But the pivot bushings is one hurdle I'm over now. Thanks again!

 

[Mr T Bucket]

Also got to thinking about the idea of using a heim style bearing at that pivot spot. While I like the idea of having more of a real bearing there for the pivot action and even though the "bearing" is captured and can't really move in and out of its housing, it could still twist, right? I was thinking, and this may be hard to explain, but I wanted something more solid or rigid as far as how that arm can pivot. With a single heim style joint there, it would be just like most of our radius rods. With the rod unbolted from the axle and your hand on the axle end of the radius rod, you could move the rod up and down AND in and out towards the frame. If your radius rod had a solid bushing in place of the heim, you would only be able to move the radius rod up and down. The bushing would/should put up some resistance to being moved/swung in and out, and with the front of that L arm attached to the front end with a rod end link of some sort, there's going to be very little resistance to keeping that arm in place. In other words, the L arm could squirt off to the side as the back end twists. You could put a pair of spherical bearings at the pivot spot, so that the pivot bolt runs through both center sleeves and that would keep the L shaped arm from being able to possibly twist on a vertical axis through the pivot. Plus that gets expensive, LOL. I could possibly be over thinking this too.

 

[Mr T Bucket]

This is why I wish we could go back and edit our posts. Good tip on the lawn mower shoulder bolts. I had those in mind for a while. One of my duties at my old job many moons ago, was putting all the lawn mowers together, so I was quite familiar with those danged bolts, LOL. The cheap units had bolt on wheels and if you wanted to adjust the height of the cut, you had to unbolt the wheels and move them up or down a hole in the deck housing.

Sidenote, I was mowing my yard some years back when one of my wheels came off the adjuster. Got down and the nut had disappeared. I was kind of mad cause I was really wanting to get the yard finished, but believe it or not, I found the nut some 10 or 15 feet back. Lucky that night, I was.

 

[Gerry]

Hi
I may be corrected here but I have always been told that the fasteners for things like lawn mowers etc were not of a good quality as they do not have the stress levels of a road going vehicle. The ones I have bought could be cut with a good pair of pliers. IMHO
Gerry

 

[Northstar T]

Hi
I may be corrected here but I have always been told that the fasteners for things like lawn mowers etc were not of a good quality as they do not have the stress levels of a road going vehicle. The ones I have bought could be cut with a good pair of pliers. IMHO
Gerry

cheep equipment uses cheep parts. that's true for most products. Toro Wheel bolts, for example, are of very good quality, wile MTD, AYP, and some others..... not so much.
With the shoulder of the bolt being supported in the frame, and right next to the pivot arm, even a cheep one would sufice IMO. but always better to use the good stuff when possible.
.
I like your thought process on this, Mr T Bucket. good to see people using their noggin before picking up a wrench.

Russ

 

[Hotrod46]

Sorry it's taken me so long to reply to your questions, Mr T Bucket. I've been busy for the last few days.

The arms are 1/4" thick. I was concerned as to whether they would hold up, but have been doing fine for several thousand miles.

I would use the adjustable shocks to gain more dampening. You are correct. The 2 to 1 ratio in my setup reduces it's effectiveness. The dampening is fine until you get on a washboard type of road. You get some bounce that takes the shocks a few cycles to get under control. With a 1 to 1 ratio, that shouldn't be a problem.

I don't have the exact length on the links, but I can get that for you. They are made from a male and female 3/8" heim joint screwed together.

One other type of pivot bushing you might consider is the bonded rubber bushings like the ones that are used in the control arms on independent suspensions. They are available in several sizes and will last for tens of thousands of cycles. They would work because the shock arms don't move more than a few degrees. In fact, that type of movement is exactly what they were designed for.

Mike

 

[PotvinGuy]

Hey Mr. T, have you selected a shock yet? I am designing a similar setup for my T, and am looking at the QA1 DR3855B, a short adjustable unit. QA1 has many other lengths, strokes and choice of poly bushing or rod end bearing mounts. You can add springs to the shocks also. My design has an arm connected to the bottom of the axle, pivoting under the frame, then thru the frame to the shocks on top, which will be parallel to the frame.

 

[Mr T Bucket]

Potvvinguy, yes, I've selected the shocks. Actually have them already. 10" Chrome from Speedway if I recall. One of the reasons I'm wanting to go this direction as far as the shock setup, is I want the look of a cleaner front end without the shocks sticking up vertical. And I don't have space for the vertical shocks either, LOL. Don't really even have room for friction shocks, but but if I'm going to go to the trouble of integrating a shock setup on my T, I want the hydraulic route. I know people have had mostly good luck with the frictions, but I just want to go this way instead.

The bushings I ordered from Amazon on Sunday???? showed up yesterday via UPS. Not sure how so quick, but they're here. Need to order some links and stuff and play around in the garage. Was thinking about ordering a brake master cylinder pedal setup at the same time so that's why I hadn't ordered some of the shock pieces, but don't believe I've got the room, so since I'm going to have to fab up half the brake stuff, I might as well save the dough for right now. Gotta get the other stuff ordered though so I have it on hand to figure some stuff out.

MIke, thanks again for the info. Don't bust your hump on getting the link length for me. I'll get it figured out. Was already figuring make and female 3/8" links, but was waiting like I said on possibly ordering some other stuff at the same time.

Might flip it like I said similar to this quick pic from my garage but with shocks parallel to the frame and of course a much more streamlined L bracket than the blocky cardboard. Though if I double layered the cardboard and sandwiched a steel plate between the layers.....

 

[Northstar T]

is the bound and rebound the same rate on the shocks you're using? the way you have the linkage pictured you'll be reversing the action of the shock ya know.
just a thought,
Russ