Teflon eyebolt bushes

Post by **Declan_Burns** » Fri Jan 02, 2009 4:10 pm

I have just been reading an article about the long time experience with the teflon eyebolt bush kit from Rolf Corbat and I found it quite interesting. It’s posted on the SMMC Swiss morris minor
club website-(in German).

http://www.morrisminor.ch/

I fitted these bushes to my Moggy over a year ago and believe me it’s not an easy job as they do not flex a millimetre! They also do not absorb any knocks to the extent that rubber or polyurethane does. They are also very expensive but are supposed to last a hell of a lot longer-that’s the reason I fitted them. According to the Swiss there are apparently approx. 50 moggies fitted with this kit and no complaints.
I can summarize the contents of the article basically as follows:

They tested rubber, polyurethane and teflon bushes under various road conditions with thermocouples mounted in the bushes to measure and record the temperature. The results are quite astonishing.
The life of the rubber bushes was 3000 … 15000km
The life of the polyurethane bushes was 15000 … 20000km
The life of the teflon bushes was > 100000km

On normal (Swiss) roads
Rubber-temperature 70 … 90°C
Polyurethane-temperature 120 … 170°C

On bumpy (Swiss) roads (didn’t know they had any!)
Rubber-temperature up to 110°C
Polyurethane-temperature up to 270°C (above limit for polybush and hence the signs of overheating and premature failure)
Under none of the above conditions did the temperature of the teflon exceed 70°C

It all sounds very scientific –that’s probably the reason they make such good watches!
Declan

Post by **alanworland** » Fri Jan 02, 2009 4:56 pm

I can understand that they may get warm but these temperatures are well out of the 'warm' zone!

Post by **bigginger** » Fri Jan 02, 2009 5:14 pm

Seconded - afraid I just don't believe those figures
a

Post by **Declan_Burns** » Fri Jan 02, 2009 6:10 pm

I'm not sure I believe the 270°C bit myself-perhaps they were doing an Alpine off road rally! Who knows?
Declan

(DEC 1964H-formerly HMP 960B)

Post by **bigginger** » Fri Jan 02, 2009 7:13 pm

Saharan off road rally with oxy/acet torches pointed at the bushes, I'd have thought

a

Post by **minor_hickup** » Fri Jan 02, 2009 8:25 pm

Sounds like advertising for an item that's unsuitable for a road car. If it has no give its transmitting a lot of stress and vibration.

Post by **les** » Fri Jan 02, 2009 9:26 pm

As above, and it must be a terribly rough ride.

Post by **Kevin** » Fri Jan 02, 2009 10:35 pm

As has been said I imagine the ride to be very harsh with those and remember that the poly bushes made by superflex were designed with Aussie roads in mind and I would have thought their road testing would be better than Swiss road testing.

Post by **les** » Fri Jan 02, 2009 10:50 pm

So remember next time you suspect you're overheating, it might just be your poly bushes!!

Post by **Kevin** » Fri Jan 02, 2009 11:19 pm

So remember next time you suspect you're overheating, it might just be your poly bushes!!

Post by **bmcecosse** » Sat Jan 03, 2009 12:41 am

I seriously doubt these temperatures too. Teflon will be far too hard and highly likely to cause cracking in the chassis legs. I won't be trying this !

Post by **MoggyTech** » Sun Jan 04, 2009 4:16 pm

Sounds like total pants to me. Those temperatures are nonsense. I think someone thought of Teflon frying pans and made up the numbers with cooking in mind.

Post by **Peetee** » Sun Jan 04, 2009 9:21 pm

do not flex a millimetre

Sounds like a short cut to chassis fractures to me.

According to the Swiss there are apparently approx. 50 moggies fitted with this kit and no complaints.

Probably race or Santa Pod sprint cars.

Post by **Stig** » Mon Jan 05, 2009 8:56 am

I fitted hard nylon bushes many years ago (poly wasn't available then) and there is a bit more noise and a harsher ride but not as bad as you might think. I'd rather have poly but couldn't be bothered to change them.

I'm sure the temperatures would be lower than any resilient bush as they're not absorbing any energy and have copper grease to lubricate them, but I'd share the scepticism of the 270C figure!

No cracking of the chassis legs after many years but it's logical to think that hard bushes will put put more strain on the metal.

I've done > 100000km with the nylon bushes but if I'd fitted poly I doubt I'd have had to change them by now. I've done way more than 20000km with poly rear spring bushes and don't feel the need to change them.

In short, poly's better IMO.

Ratbag · Post by **Ratbag** » Mon Jan 05, 2009 1:13 pm

I wonder why everyone would think those temperatures too high when the normal bushes are supposed to absorb enough energy to crack a chassis leg?

Post by **bigginger** » Mon Jan 05, 2009 3:52 pm

Yoe seriously think they get to 170 degrees - let alone 270?

Post by **bmcecosse** » Mon Jan 05, 2009 9:25 pm

It's shock loading that may help induce cracks. I seriously doubt bushes of any kind will even be slightly warm - even after a hard bashing round a rally stage!

Post by **Dean** » Mon Jan 05, 2009 9:37 pm

According to this link the melting point of polyurethane is 284 degrees F!

http://www.indianplasticportal.com/tpu.html

which at a guess is about 125 degrees c ? So makes 270 degrees c seem a tad silly.

Post by **les** » Mon Jan 05, 2009 9:39 pm

It does sound a ridiculous temperature, and surely it is, but, but, the thing is why would someone quote this if not true ,and indeed why would someone even trouble to put a probe into a bush in the first place without reason, assuming that also is true. What's going on here. Who's kidding who?

Post by **bmcecosse** » Mon Jan 05, 2009 9:40 pm

140 C - bushes will be well gone ! The whole idea is just rubish!!

Morris Minor Owners Club

Teflon eyebolt bushes

Teflon eyebolt bushes

Eyebolt bushes