Urethane beam bushings modification

[wythac]

I've recently had what (so far) seems to be a successful experiment in making those nasty red urethane front torsion arm bushings more forgiving, and thought I would share the idea. Like anyone else who has used them, you find that they tend to bind and make your front suspension stiff, especially on our light buggies.

The modification I describe was suggested to me by one of the brilliant guys at my local VW shop (thanks Jack). Since his time (and my money) is best spent figuring out more complicated stuff, I tried his suggestions a few weeks back and early indications are that it works like a charm. The job, along with a few other upgrades under the cowl, took me the better part of a weekend.

You will have to forgive me for not providing pictures, but suspension grease and digital cameras dont mix in my shop. It is simple enough that anyone who is interested in trying it shouldnt have trouble picturing it. Here goes;

Tools needed: Dremel tool with small thin cutting disc, drill motor with 3/16" drill, and whatever else you need to disassemble your beam.

The general idea is to create a passage for grease to move between the beam tubes and the bushings, and the bushings and the torsion arms.

Remove the bushings. Grab the dremel with the cutting disc. Starting on the non-flanged end of the bushing, carefully run a SHALLOW spiral notch in the outer casing of the bushing, from the starting point, moving toward the flanged outer end. Your spiral should make one complete orbit of the bushing. You may find that the urethane will "ball up" in the notch on the first pass. A second pass cleans that stuff out and leaves a nice, uniform depth notch if you did it right. Doesnt need to be real deep...in fact you dont want it deep at all, as the bushing might separate and fail.

Now take the drill and drill four holes at 90 degrees from each other along the run of the spiral. This will allow grease that migrates down the notch to also find it's way between the bushings. and the torsion arms.

Clean and reassemble. I took this opportunity to install 4 zerk fittings in my beam. I then "installed" what ended up being SIX big tubes of suspension grease, pressurizing the beam with grease until it was oozing past the bushings and the ends of the torsion leaves.

The suspension is dramatically more supple as a result of these changes. I am hopeful that it wont stiffen up over time, but will actually get more loose instead..I only have a few hundred miles on it since the change but it seems to be working well.

[junior55]

Suspension grease ?
Is this a petroleum grease ?

[wythac]

A Sta-Lube product, nothing exotic. Goop in a tube. A moly based grease I would imagine. I do know that the capacity of a widened warrior beam is 6 tubes of it though.

[BL3Manx]

I think instead of neoprene you mean polyurethane. Neoprene is wet suit material.

Besides that it sounds like a great idea. Maybe one of the better manufacturer/vendors will start doing it as part of the manufacturing process.

[junior55]

I was under the impression not to use petro based grease in poly
bushings ?? Not sure why ?

Although I was never impressed with the specified Pro-thane grease,,,
I always wondered what would happen with molly grease on urithane.

I was thinking of a No-Seize / molly mix perhaps...?

[Q-Dog]

I picked up several boxes of parts recently from someone who got out of VWs. In one box I found a red urethane tranny mount still in the sealed plastic bag. No idea how old the mount is but when I squeezed the mount it crumbled in my hands. I still haven't opened the package ... it's now just a bag full of red crumbs and some bolts.

I would suggest to anyone running these red urethane parts to inspect them often. Does anyone know if the manufacturers of these parts have a suggested or recommended lifespan for them?
_________________
Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[wythac]

BL3,

Yes. Polyurethane. I went kayaking this morning with my wetsuit on...Freudian slip. When I get to a real computer I will fix the title.

My first assembly of the beam used some dry graphite lube that didn't really work because it didn't stay put. I ended up with dry pockets on the bushings and one helluva stiff beam, like everyone else complains about when using these bushings.

I am going to watch this latest assembly for deterioration over this summer and disassemble it again next winter and see how it is holding up. I'll post some pictures at that time so everyone can see how it looks and what the mods look like too. I am cautiously optomistic....Drove it about 150 miles this afternoon on pavement and dirt and I have to say that for now at least, it is muuuuch better.

[PELLAND]

If you have used a petroleum based grease such as axle grease, bearing grease etc then strip down your beam remove your bushes and clean it all down.

If you dont the petroleum based grease will degrade your poly bushes....your suspension WILL fail...and if you're driving at speed when it fails then you WILL die!!

The only grease you should use with poly bushes is a synthetic silicon based grease...sometimes marketed as white sticky stuff, or Mobil1 pink stuff. I have used a ceramic based white grease...plenty of it at the build up stage and so long as the parts are in good order have not had any binding,squeaking etc. Once the poly bushes have bedded in they are self lubricating.

Next the machining of the bushes:

Firstly...you dont want to drill holes as you dont want grease to ease throught the holes and between the beam and the poly bush. The bush should be tight in the beam and not be free to relvolve.

Secondly...you do not want to dremel grooves the way you suggest. As the suspension operates the grease will be driven up the grooves like an artisian well and the bearing will dry up.

I don't want to put a downer on alternative thinking but with all due respect to everybody involved this idea is a crock...and the use of petroleum based grease is nothing short of dangerous.

Re the poly g/box mount that crumbled in the packaging.....I would reckon that has been subjected to extremes of temperature over a sustained period which has degraded the material...poor storage I would suggest.

You should also make sure that you are buying quality products from the likes of Polybush or Superflex etc and not at the cheaper end of the market.....and consult the manufacturers re lubrication instructions.

Good luck
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[BL3Manx]

As far as dying...First off even if the polyurethane bushes spontaneously fracture into dozens of pieces when you're "driving at speed", the pieces are all still captured between the trailing arms and the beam tubes and they aren't going any where and you ain't going to die and probably won't notice anything until the pieces start working themselves inboard then the suspension will get stiff and then you might notice it, but probably not for a while until one side starts sitting lower than the other, but even so, I've seen guys that drive for years with totally frozen front suspensions and they don't even have a clue and think the ride is normal for a buggy, so no, not at all likely.

As far as the rest of it... polyurethane bushings are going to fail sooner or later whether you use petroleum based grease on them or not. The grease might just make them squeak less until they do fail. The one good thing about polyurethane bushes is that they work as well broken as in one piece. Because they're captured, they keep working and you don't know they're broke until you remove them.

The bushings the guy found which were broken still in the box probably were exposed to extreme temperatures, maybe 80 or 90 or 100 degrees Fahrenheit. We also call that a nice Spring day over here.

FWIW, an Artesian well is one that flows up out of the ground under its own pressure. On the other hand an Archimedes screw raises liquid by a screw turning inside a tubular housing.

[wythac]

Thanks for weighing in. It is possible that what you say is true. We'll see how it goes.

Direct observation is a rather reliable method of testing theories. For now, those observations indicate a dramatic improvement over the original configuration and application. I am watching the assemblies for wear and degradation...if they go south, I will see it and feel it well in advance of failure, so your fears of mayhem are, I am afraid, a bit overstated...I'll be out ten(?) bucks and half a day to swap them out.


The point of the grooves and holes are to do precisely what you suggest is a handicap...to allow the grease to move past the bushings. When dry, they bind and squeak. Graphite, food based greases, lithium, you name it, I have tried it. The binding of these assemblies has created far more profound safety and handling concerns, which have been addressed with this modification...in the near term. Might not work out in the long term.

Your comments on this topic are valuable because folks reading all this stuff can make up their own minds on what makes sense and what doesn't. I would however appreciate toning down the hyperbole... telling me I WILL die and calling this a "crock" adds nothing but antagonism and serves no useful purpose. Find another forum for that, or find a better way of saying it.

[PELLAND]

[wythac]

Like I said, those sort of comments serve no useful purpose and have no place in a reasonable discussion of ideas. Feel free to disagree, that is what a discussion forum is about, but do it in a way that moves the topic forward.

As I mentioned, I am willing to accept that what you say about grease and poly bushings may be true, although you don't indicate that you have tried it and had the bushings fail as you suggest, or posted pictures of bushings that have failed due to this sort of grease bath. These things would go a long way toward supporting what you say, and I would encourage you or anyone else with pictures or testimonials to that effect to add that information to this thread so that others can see it.

My experience so far has been different, but that may be only because of the lack of time that has elapsed, and I am aware of that. That is why I will watch and see how this goes. I still don't like these crappy things at all and would prefer ditching them altogether, I'm just not willing to drive the car around with a rock hard front end while I source better/different parts.

I have had these bushings in regular petroleum based grease for a year prior to the modification that is the subject of this post. Before that, the squeaks I had before were coming from the outside of the bushings rotating inside the tube, the binding from the inside of the bushing getting stuck on the torsion arm. When they were out for this modification I found them in the same condition as I installed them the year before. This modification only adds zerks to the beam and the grooves to the bushings, and pressurizes the beam with grease....I WANT to see the grease weeping past the bushings, just like in a stock original beam.

I'm going to run it and watch it, as I said, and I will post pictures and comments at the end of the season, or earlier if this stuff falls apart and I have to fix it. For now it is working great....hammered it on some dirt roads last weekend with better performance than any other configuration I have tried thus far.

[slalombuggy]

I just fit some poly bushings in a 4" narrowed beam I'm building for my next project. They barely fit in the beam let alone getting the arms in. What I did was sand down the outside of the bushings with a 3M plastic disk made for cleaning engine mating surfaces. They are yellow or green and have hundred of bristles on them so they don't clog. I fit each bushing to a particular place and only sanded enough so that the arm moved freely but the bushing doesn't spin in the tube. For lube I will be applying a liberal coating of silicone base brake grease sold by Raybestos. It is inert and won't attack rubber or poly.

brad

[wythac]

When mine come out again I am going to find a cylinder hone for a lawnmower engine and hone the tubes on my warrior beam. They seem smooth on the inside as far as I can stick a finger in there, but that doesnt necessarily mean that they are smooth as far as the bushing goes in or in a perfect circle either.

[PELLAND]

Perhaps here lies the problem. Just like bearing sets the bush should not be free to revolve in the beam. It should be held tight and the arms free to rotate in the bush....the bush reduces the friction and protects the housing from wear....just like the spigot bush for the starter motor in the bell housing. If the bush is free to rotate then if the arm binds on the bush then the wear is transferred to the housing, or in this case the beam. In real terms the polyurethane will wear through before the metal in the beam. However any lateral or fore-aft movement imposed from the suspension/steering transmitted through a loose of worn bush will be enough to elongate the holes in the end of the beam. Your solution is aiding the bush to rotate in the beam which is not ideal irrespective of what grease you use......Slalombuggy has got it spot on.

I have to ask why, if you hate these "crappy" bushes and you've gone to all this trouble to modify them, did you not install a set of needle bearings...heavy duty if required for your application?

As far as your other comments are concerned I dont have any testamonials or pictures of failed bushes to show you. All I have is forty years of building customers' engines and chassis for both race, (mainly Formula Vee but some off-road) and road cars. The worst case I've seen is polyurethane transmission mounts covered in grease, apparently to preserve them, mushroom into a sqidgy mess inside 12 months.

Cheers
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[wythac]

I have found needle bearings to be made of unobtainium or they would be in use. These assemblies are a poor substitute for the original...what I am trying to do is see if these modifications can make these substitutions a more viable option, as it seems that they are unfortunately the most common solution, though not the best. I agree with you that installation of these is simpler, but, they are inferior to the original design, as many things are that are not designed by the original engineers of these cars. We may be smart, but not a lot of us have ever been hired by Ferdinand Porsche to design car parts.

I have only stated that the mods are to allow grease to move past the bushing, not to allow them to move. I put marks on each of them outside the tube, and so far, haven't noticed them moving. Neither have I noticed them squeaking. Honing won't be to allow movement but to make sure that the inside of the beam is truly round and not likely to create a stiction point on a torsion arm inside the bushing as it collapses inward. I like slalombuggys idea for roughing the outsides. Should have done that too. Next time.

"All this trouble"? How much time do you think I needed to do this? Answer is less than 5 minutes for all four bushings. Not rocket science. The beam was already apart and the front end of the car disassembled as part of a larger project.

As I have already pointed out, I did not find any "squidginess" with this set of bushings after the same twelve months in goo that you say turned yours to pudding. That doesn't mean that won't happen to mine eventually, only that so far, it hasn't. Perhaps the difference is the added exposure to oxygen and/or UV, or mfg source material.

Your roads will be safe from my menace; My car isn't a Schwimminwagen, so no Atlantic crossings for me. I'll bet the saltwater is hard on these things too.......

[slalombuggy]

I forgot to say that I used a 1.5 inch flapper wheel on a die gringer to home inside the tube to get rid of the seam and also where it is welded around the shock towers is pinched from the welding. Opening that up made a huge difference.

brad

[wythac]

That's a cheaper tool and useful for more than beam tubes and mower engines, thanks, I'll try that when I disassemble and inspect.

[BL3Manx]

[wythac]

Thanks BL3, I'll give those guys a call and see who their source for those is. I would like to have an alternative set up with parts on my bench before I disassemble again, in case I decide this experiment is just that and not a solution. I'm going to poke around for some of the recommended mfgs of the bushings too...I bought the current set long enough ago I can't remember who made them, but I'll bet their name starts with a capital "E".

Priot to this mod, I'd been looking for German ones to no avail.....no NOS stuff left of course.