It's time to talk about bush

[edwardbear]

I have heard on the grape vine that poly bushes wear and this can cause all sorts of noises and problems. In principle this looks like it could be easily done myself.

Is this the case or is there any specialist equipment?
Can you get complete kits of bushes or do you have to buy different sizes?

[welshpug]

yes they can wear, yes they can cause noises, even when new.

whats the application?

in most cases I would never use a Poly bush as they aren't particularly suited to the task in hand even though many do use them, a set of good quality, oem if possible, rubber bushes will do the job much better and last a very long time whilst not adding any noise vibration or harshness (NVH)

[droopsnoot]

I've seen poly bushes that have worn quite badly in a mates Scimitar, and I have a note to check the ones in the back of my car, which were only fitted because at the time I couldn't get new rubber ones.

The issue for me is that they don't work the same way as a standard metalstik bush - the poly bush isn't bonded to the central steel tube as in a metalastik bush, so it's pivoting much more easily than a rubber bush would allow. I don't know enough about suspension to know what the effect of this would be, but I imagine it will alter the handling characteristics. To a noticeable degree? No idea.

[stealthstylz]

Most people think polybushes are great because they replace knackered OEM rubber bushes and marvel at the difference.

[edwardbear]

So rubber bushes are better?

Can I buy a whole set for my car or are there different sizes for different wheels etc etc

[ferny]

For my cars rubber isn't an option as the quality is too low. Maybe replacements will last six months.

I fitted Polybush branded blue to the Herald in 2006 and just replaced them for red. Some like shock absorber ones had worn oval. The others had cracked on the outside but overall were mostly still fine internally. The only issue was bolts seizing to the insert despite regular strip downs and reassembly with anti-seize. That was more bad luck than anything as it only really at the back.

I also agree with people not acknowledging swapping worn rubber for polyurethane and declaring an amazing difference. But for Triumph cars it's the best option.

[vitesseefi]

The key here is OE quality rubber bushes...... For classic British cars at least most of the new rubber bushes are made of very inferior material which fails very quickly. Decent quality polybushes are wholly superior to those.

There is also a fair amount of variation in the quality of poly bushes. Superflex are excellent though costly. Some of the cheap ebay stuff though is even shorter lived that the repro "rubber" ones. It's a minefield.

Nick

[colnerov]

Hi, As said poly bushes turn on the sleeve whereas metalastic bushes 'squirm'. Poly bushes can start to squeak which can be annoying, metalistic even when they tear off the inner sleeve don't usually make noise until they are so bad it's usually a knock.

Colin

[MonzaPhil]

I poly-bushed our Discovery 1.5 and I can't recommend it. Ride is awful, it's noisy and handling us a bit questionable. When I can be bothered I'll fit standard rubber ones.

( It was fine before I fitted the polys. )

[DavidB]

Make your own:

www.driftworks.com/forum/threads/making-your-own-polyurethane-bushes-possible.141003/

[edwardbear]

I've had a look at power flex but the prices seem high and I don't know how many of each I need

Making my own would be awesome. Does seem so complicated. How do you know what sizes to buy?

[DavidB]

I think you mix two liquids up into a cast. They're always round so it can't be that hard.

[welshpug]

still don't know what car you have.

bushes aren't always round, also very often not on the same plane/axis so a rigid bush is not a good idea.

there are some instances where they work, roll bar bushes for example, my 205 has poly arb bushes from the factory and 28 years on they're still good.

[edwardbear]

Audi 80

[ChasR]

Sept 1, 2017 19:37:10 GMT vitesseefi said:

The key here is OE quality rubber bushes...... For classic British cars at least most of the new rubber bushes are made of very inferior material which fails very quickly. Decent quality polybushes are wholly superior to those.

There is also a fair amount of variation in the quality of poly bushes. Superflex are excellent though costly. Some of the cheap ebay stuff though is even shorter lived that the repro "rubber" ones. It's a minefield.

Nick

Best reply of the thread!

You have been in the same boat as me many times however I suspect Nick and can live to tell the tale.

There is a massive quality difference in both rubber and poly bushes. I've been in a Triumph 2.5 PI with SuperFlex/Pro throughout and it has been a spot on ride, probably the best all round chassis I've driven on an old Triumph. I've also been in some poly bushed Triumphs where the ride is crashy etc.

SuperFlex are one of the few companies who actually test their bushes before they sell them on which is where the costs come in ; they will load them and see how they move etc. Many others like a brand beginning with P will make a bush that looks fine and then let the customers be the test subjects but go with a lifetime warranty. After all, how many classic car owners actually drive their cars? Most are concerned about 'low mileage' and 'originialty' over the car actually driving in a straight line.

This is why making your own is not as easy as it sounds.

I tend to do this TBH and in the long run I've been saving cash and more importantly, time.
-If the original bushes last well go genuine or an upgrade of the genuine bush (E46 M3 bushes on an E46 6 pot for example. Even OE brands are very hit and miss including some big names; I've had Lemforder bushes die within a year on an Alfa 147. AutoLusso were not surprised and were practically laughing at me when I queried this. Yes they are expensive but buy cheap and buy twice along with your time ; I these days don't have much of that ; I want to spanner on the fun stuff, not stuff that always breaks again and again.

-Go with a decent Poly bush manufacturer, especially if the original bushes are known for having a flaw. Some local outfits do deliver great results SuperPro and SuperFlex have impressed me time and time again and give better than rubber ride quality? Why? the Arms are free to move and Chris and SuperPro don't just generically spec shore ratings across the board.

Here are a couple of videos:



This shows that not all bushes despite being the same type are equal

[darrenh]

my gripe with polysushes (powerflex superflex and flo-flex i have used) is that they change the actual mechanical joint as colnerov mentioned. not always for the best in my experience

i've also tried poly exhaust hangers (powerflex) and they stress fractured very easily, they literally "tore" along one side. i also had another on the backbox which deformed from heat (imagine pushing your finger into play dough) which is ludicrous as it was at the coolest part of the system and by basic design suspending something that gets ffin hot

have to agree vitess and chasR, the only time i use them now is when there is simply no other product available, or the ones that are are terrible quality

[DavidB]

I've bought motor factor bushes in the past.
I may as well get some dough and bake (delicious) pastry bushes in the oven and use them. They are utter rubbish. Are they even rubber?

A previous owner put polybushes on the front wishbones on my Astra - they're not great.

[ChasR]

Sept 4, 2017 14:18:47 GMT darrenh said:

my gripe with polysushes (powerflex superflex and flo-flex i have used) is that they change the actual mechanical joint as colnerov mentioned. not always for the best in my experience

i've also tried poly exhaust hangers (powerflex) and they stress fractured very easily, they literally "tore" along one side. i also had another on the backbox which deformed from heat (imagine pushing your finger into play dough) which is ludicrous as it was at the coolest part of the system and by basic design suspending something that gets ffin hot

have to agree vitess and chasR, the only time i use them now is when there is simply no other product available, or the ones that are are terrible quality

When I saw the test subjects were the customers it was PowerFlex I was referring to. As an example the E46 subframe bushes have changed twice in their production due to issues early on. Oddly enough while they are now proven the price of them has gone up to SuperFlex/Pro levels... I went with the latter as I've used them before.

Sept 4, 2017 19:05:13 GMT DavidB said:

I've bought motor factor bushes in the past.
I may as well get some dough and bake (delicious) pastry bushes in the oven and use them. They are utter rubbish. Are they even rubber?

Pirelli F1 quality you know are Motor Factor bushes .

[kevins]

My experince is much the same.

On the tr7V8, I have used superpro bushes on the inner control arm, steering colmn and gearchange linkage, all original weak spots and they seem to work very well. on the other hand the oem V8 rubber bushes on the rear still look like new after 20 years as well.

On the old series Landrover I Used Britpart poly bushes on the spring eye bushes, they lasted much better than the pattern rubber parts available, apparently still OK now 5 years later, the rubber ones were so bad they were failing every MOT. Can't really comment on ride as it was always pretty awful.

On the minor I am using rubber bushes, after 2 years of being pushed no further than the end of the drive and back they already have surface cracks, no one seems to do OEM quality ones so we may have to go to poly.

At the moment I am thinking about what to do with our MX5 when I change the bent subframe, I'll probably stick to oem rubber but they seem very expensive hoepfullly some won't be worn.