Hot Rods Rotoflo shocks 2014

There have been several threads on the Rotoflo subject but non of them have info regarding success stories with replacing the elastic medium. What would be interesting is for someone who has actually disassembled a Rotoflo to tell us about it. (1) what is the volume of the elastic material for their particular model of Rotoflo? (2) did they remove the original material? If so, how? (3) is there an eccentric inside that rotates? (4) did they find a suitable replacement material? If so, what is it?

I have found some viscous silicone fluids and some silicone paste that might work in a Rotoflo. I just need to get my hands on one that we can disassemble and remove the old material so we can use it as a test mule.
Thanks in advance
Mike in Tucson

 

I just looked on google,nothing came up?

 

I have a set I would love to use on a build, so I will follow this thread with interest.

P7220092 (Medium) by k1w1rodder posted Aug 23, 2014 at 8:53 AM

 

We have 4 that appear to be NOS but they are stiff. Since we are in the middle of a build, I cant risk using one for elastic medium tests.....and getting left with 3 shocks for a 4 wheel 32. Here is a pic of our mounting. The rotoflo arms were bent to fit and the dog bone is shortened to fit. Cool looking but very difficult to find info on.

 

Thanx for the pics,they look unique.What were they used on?

 

From my searching mine are English and were used on trailers and caravans in the fifties and sixties. So not very heavy but good for a light weight bucket/modified.

 

I have a set that's complete and a set that's taken apart. I didn't take them apart, they came to me that way.

I had a machinist friend make me a special "socket" that fits the X in the back of the shock. I can't see how you could safely disassemble them without it. The housing is only aluminum, and not really that thick.

I'd guess the volume of the elastic to be about a quarter cup or less. It was mostly missing from my incomplete set. The little bit I could see is a lot like windshield pinch weld, which has been suggested as a possible replacement. I'll try to get some inside pics in the next few days.

 

Alchemy, that would be great to have more pics. Especially pics of the part that the arm rotates....I assume it is an eccentric that "squeeges" the material as it rotates. If that is true, there must be some stop somewhere. Is your disassembled shock in good enough shape to reassemble and work? IF so, I will send you some silicone material that might work so you can try it. I have been researching the viscosities of available matrials....we can get silicone fluid up to 1,000,000 cPs....really stiff. Measure the bore diameter and depth of the housing and we can calculate the volume. Also, I am confused about what the adjusting screw in the center of the rotation does....does it adjust the damping OR is it just a fill hole? Thanks

 

For those who didnt know, Rotoflo shocks were British manufacture. Probably were invented to replace Houdailles that leaked.....or were shot. Rotoflos were similar to the hydraulic lever shocks and tubular (called airplane shocks back then) shocks were just being introduced to the masses. I have never seen any info regarding how Rotoflos were sold in the USA (if they were sold here).

 

There is a tab in there that is captured in the goo, and the twisting tab in the firm goo makes the dampening. I think the screw in the middle is where they installed the goo. Not positive though.

My shocks are worn where the shaft enters the outer housing. I think I'll make some sort of bushing to get the hole back down to the proper size. But that project is a while away.

I'll try to get the pics tomorrow.

 

For those on this thread that are new to rotoflo shocks, there is some good background info on this old thread ...

http://www.jalopyjournal.com/forum/threads/rotoflo-owners-needed-here.70294/

 

Simonsez has the good oil(rubber) on these shocks.
We have 4 fitted to our 32 W and went thru a few till we found the best. Simply placing them in boiling water to soften the rubber and working them in a vice ,then repeat the process till they work smoothly worked for us. If they are loose this May or may not work.

 

Extremely interesting. I had no idea of their existence. Some information from Grace's Guide:



Better resolution on the website itself.

This seems to be more akin to the viscous dynamics found in '80s AWD exercises than rubber hysteresis. My greatest concern is about the degree of thixotropicity of the working medium, and how that changes with temperature, time, or both. I can imagine that a slightly thixotropic medium might be advantageous if it re-gels very quickly, but it would need a degree of thermal stability which I associate with the era in question only with great difficulty.

 

I have no idea what Ned Ludd just said!

 

I think he's talking about the goo inside the shock?

 

I just learned a new word, and also learned that both ketchup and yogurt are thixotropic......

 

Here's a pic (somebody else's) from that old thread of mine to show a little about the guts of these shocks. I'll still get to mine and take some more pics from different angles.

.

My sets are the larger variety, but they basically look like this. The main shaft is actually like a cage in the inside, and the goo flows around it's internal openings and presses against the big tab (see on round part near lower right corner) to provide dampening action.

thixotropic
thixotropic
thixotropic
thixotropic
thixotropic
thixotropic
thixotropic

 

Great info Ned , but your words are bigger than "double wheeled wheelbarrow"

 

Thanks, hadn't heard that tip before.

I bought a (cheap) pair the other day that are so loose they rattle, so I'll give that a go and see what happens.

 

Dubbelwielkruiwa in Afrikaans: not a long word as Afrikaans words go

 

Here are some pics of one of my shocks. And a pic of the rear cover removal tool I had made.

This shock is worn a little where the splined shaft comes through the outer housing. The shaft opening is slightly egged, and the fiber gasket inside has impressions worn into it. I was thinking I'd chuck the housing into a lathe and machine the shaft opening out a bit, and counterbore the fiber area, and fit a oillite bushing into the area. Not sure if we could get it a press fit, or might need some small screws from the outside to hold it in place.

I am missing the arms on this set, but found an arm made for a torsion bar by Schroeder that kinda fits. I may need to spread the tabs a little to get it on there, but at least it will be on tight.

 

I forgot to mention that one of my shocks has been only partially disassembled, and has some original goo I could dig out for testing. Can you test it Mike-in-Tucson? If so, PM me your info and I'll mail some to you.

 

From Jeff's pictures, I think we know how they work. Now, we could make a drawing of the internal rotary
part and change the output from a spline to a square drive like a Ford Houdaille shock. Orientation is not an issue since the Rotoflo shock appears to be capable of the arm rotating all the way around....no hard stops inside. One of the problems that we have had recently is that the Rotoflo levers dont always line up with the Ford parts on the other end of the dog bone.....if we could use Ford levers, the only difference would be the offset caused by how tall the shock body is.

 

OK, Alchemy has been a great help in figuring out the mystery of the Rotoflo. He supplied a sample of the material inside the shock and it appears to be a natural rubber (sometimes called India rubber). From Alchemy's pictures, the lever turns the rotor inside the shock body. The rubber goo resists the acceleration of the rotor, thus providing the damping. What we need now is to find someone who can provide a picture of a shock interior with the back removed and with the goo inside......the big question is how much goo is inside the body and if it filled the cavity completely....i.e., does the "bar" on the back cover press into the goo OR does it squeeze it around the inside perimeter of the rotor? I think we are close to figuring this out and then can formulate a rebuild plan. Somewhere we should take a census on how many Rotoflo shocks are out there....I have 4 NOS units that are on loan to a friend (and cant access them to remove the cover). Thanks, Alchemy!
Mike

 

I have always assumed they are completely full of goo.

The slotted bolt that goes inside the splined shaft has a lock-nut on it, so I figure it is like that so you can wind it in to put pressure on the goo and then tighten the lock-nut to hold it there?

 

Here are some picture that show the difference in size between the A1 and the A2.

 

Just a bump to see if we have been able to find out what the mysterious “goo” is inside these .We have some that need a full birthday rebuild. Might look at making Alchemy’s tool for disassembly.

 

It’s just unvulcanised natrual rubber .

Here’s a picture of a pair of a2 disassembled from Mike Bartlett who can rebuild them for you . They really are as simple as you thi

 

I have used Mike before for rebuilding parts when we were in USA . As we are in NZ shipping back and forward becomes an issue.
Hopefully we can scource some unvulcanised rubber here . And make the cool little tool.

 

I made a disassembly tool using a short piece of hex-bar - just file the cross in the end and put a spanner on it too undo.

It seemed to help to warm the shock up gently with a propane torch before trying to undo the backplate.