Polyurethane bushes/grommets c",)

[reidalpine]

Anyone tried these Polyurtehane-bushes instead of the usual black rubber-parts? I tried them on a Fuego 2L.GTX some yars ago and they worked wonders in tighening up the drive.They have the advantage of full flexability but only in the designed or wanted direction, any tendecies at swaying or rolling were gone-Totally..
-I'm not especially bothered by Roffens handling as is,but if he could be persuaded to respond as the Fuego did it will certainly be worth it!

There's a few firms on-line offering these,but to my knowledge there are none specifically made for our 4...
-Anyone with the relevant info on specific measurements on rubber-grommets for (inner/outer/width etc)
Front/Rear dampers top & bottom
Front/Rear anti-swaybars Rear for F4/6)
Front A-arms upper & lower
Engine mounts R/L
+ any other parts

would it be a good idea to have all measurements catalogued and certified then send Malcolm off to see the fabricators??
If we ordered in hordes we could possibly get a cracking good price ??
-Any thoughts?-Reservations?-Better ideas? -R.

 

[Realnut4]

It's funny you ask that question. A similar idea appeared on the German forum a few days ago. Since everybody is able to buy the raw materials, the guy asking the question (www.ingo-heitel.de) has decided to produce them himself. You might want to contact him. --> ingo@r4l.de He is planning to make a few more.

 

[reidalpine]

Hallo Realnut4, Meine Deutch ist Sehr rustig! -I tried to look up this site just now,but couldn't find anything re. upgraded bushes. Advice needed. -R.

 

[Realnut4]

Sorry, that's just his private homepage. But if you send him an e-mail, I am sure he will try and answer in English. If not, I will try and translate.

The forum is that one: http://r4-forum.de/ - but German as well.

 

[reidalpine]

Yep-Got it now..I see they are discussing same topic,so it looks we're even more owners looking for both the right track & positive stability in our future (!)
-I'll mail him to see what comes out of it.
To me it seems more natural to have all measurements taken from the orig ones-which is the task that takes time & effort
as it would require a model-comparison.
With these in hand (+as many interested parties as poss.) ask a supplier to
dial in his machines and fabricate a batch for us -R.

 

[R4L]

Hello Renault 4 enthousiansts,
for short introduction: I am from southern Germany started collecting everything around the Renault 4 back in 1980 ( at the age of 14 ) - more on my homepage: www.ingo-heitel.de

To the Polyurethane topic. After it seems no Polyurethane parts are available for the Renault 4 - I discovered the possibility to cast these parts at home. For the steel covered bushes no special form is needed. The old bushers can be filled with liquid Urethane after removing the old rubber. I am planning to try the bushes of the top triangular arm of the front supension - after they seem to be the reason for a bad handling of my '67 Plein Air. If someone has some parts to fill as well let me know - the minimum material batch is for about 30 bushes.
Ingo Heitel / Germany - email: ingo@R4L.de

 

[angel]

Hello Ingo-nice to meet you again!

I have been using Vulcollan for some time, mostly to make unobtainable or expensive to buy suspension bushes, for other classic cars like old Lancias. But I have never been involved with casting it, I buy it in cylindrical bars and machine it in the lathe.
But this is a time-consuming process as opposed to casting them...So we are waiting your experience on this.
Have you tried making the lower arm tie-rod bush? This would make sense, i think it's the mosl strained bush and frequently in need of replacement.

 

[reidalpine]

Hi Ingo and Angel.. I have no knowledge as such on the physical properties of Polyurethane or PUR but how do you know this "melt" will be conform if poured into an empty crevis like a bushing? -I have only worked with various forms of silicone-rubbers and have experienced difficulties in getting a "solid block" without weaknesses due to swirling,airbubbles etc.. I'm ot trying to discourage anyone in having a go at making them in the garage or at the kitchen-table,but am a bit sceptical as to if the end-result would be uniform enough for making pairs that acts alike under stress....
-It would be interseting to know just How the stuff sets..Is it a mono-compound or 2 or 3part solution or what?
-Buying in in rods as Angel describes sound to me to rid (most of) the risk of bad moulds,but as you say it's a time consuming job,which leads me to my orig.question of getting in touch with a factory and have them fabricate to measurements.
-How about you put together a priority-list Angel? -You've already mentioned the
top triangular arm bushings,what would be next?
Hope I'm not scaring people off here-that's not my intent!-and I won't lead anyone to think I know the first thing about this PUR-stuff as such,but remembering just how totally it transformed the quality of ride on my Fuego I for one would be willing to swap for these yellow (or wahtever) -Diamonds, to be sure I got the best handling out of Roffen Anytime... Lets face it old-skool rubber-grommets are low-tech,prone to cracks,drying-out,bending and twisting in all (unwanted)angles and directions,and generally do nothing to better our ride,just masking some of the bad effects -R.

 

[angel]

Lets face it old-skool rubber-grommets are low-tech,prone to cracks,drying-out,bending and twisting in all (unwanted)angles and directions,and generally do nothing to better our ride,just masking some of the bad effects

Well, that's not exactly the case with our R4s!
If you compare "our" bushes with these of other cars, they actually have very little rubber material, and are far less prone to twisting in any unwanted direction.

They are also of the "Flexibloc" type, that is, the rubber material is vulcanized/bonded on both sleeves and it is mostly under tension (if you disconnect an upper wishbone ball joint you will see what I mean, the wishbone springs upwards under the Flexibloc bush effect). Again that's clever engineering compared to other manufacturers who only put loose rubber inserts in these points...

So our problem has not to do so much with the handling but with durability, as PU materials are much more durable and are more oil-resistant. Provided, of course, that the material is of the appropriate quality (I have experienced cheap ones for Austin Mini breaking into pieces after a five kilometer test run...).

Ingo must be talking about a process of letting liquid PU polymerize in the bushing, not melting already solidified one and pouring it in. This should be a far better process than machining a rod as it leaves a smooth outer surface, and can produce shapes difficult or impossible to make otherwise (like the anti-roll bar to chassis rubbers).

My priority list...Steering rack to track rod bush (for pre-79 cars), anti roll bar to chassis bushes, as they get oil soaked, lower wishbone tie rod bush, and perhaps some of the early "introuvable" stuff.
For the end, here is a part I made from Vulcollan rod for the Jogging, because I could not find the rubber one.

 

[simonandjuliet]

Interesting topic

Interesting thread - we watch and wait .....

Ingo - great website, excellent reference material, have you thought about translating it into English ???? (my German is VERY rusty)

 

[R4L]

Dear R4 Enthousiasts,

the casting of Polyuresthane bushes is something quite common. This Process is discribed in the popular magazine "OldtimerPraxis" and material is distributed by classic-car stores in Germany. So i think it should not be impossilble. It is recommended to mix the two components slowly to avoid bubbles and cast slowly with a medical injection ( without needle ). I will prepare some parts for the R4 front suspension the next weeks and keep you updated. Driving results might not be available before Spring 2012.
So long, Ingo

 

[reidalpine]

Hi guys-sorry for my long silence ,have been on a field-trip so only had a few sneak-views on here.. How do get Consistancy and uniformity of the "melt" and how do you know when you have achieved say 80 shores? Are the recipy to be found on the web somewhere or is it included when you buy the goo?
-My fear is to mount parts with very different properties each side giving unpredictable behaviour,but ofcourse I may be totally wrong here!

Years ago Samco used my rubber-hoses from MY Alpine to manufacture same in silicone (for the D501) most of them turned up good,but a couple they didn't manage too well,return to waterpump has an overflow-tube attached to it (to the expansion-tank)this they never could get leak-free in the joint.
Just mention it as even pro makers seems to have various degree of difficulties with all these "new" stuff
I'm looking forward to see your evaluation Ingo..
Angel-as always, solid points! -R.

 

[iMacThere4iAm]

Ingo, do you have any results from your experiments?

 

[angel]

I'm digging out this six year old thread to keep you informed on my latest progress on the poly-bush issue. I fabricated this pair of tie rod bushes by splitting a pair of worn bushes in half, machining the rubber part in 85 Shore hardness polyurethane, and reassemblying the shells.


The result seems very promising, I managed to fabricate the bush to the correct shape and dimensions, which is critical because it has to do a 3-axis movement, unlike convenional bushes.
I am going to make one more pair and fit them on two R4s in order to see how they keep up. Stay tuned :-)

 

[petak]

Interesting!