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Quality rubber or poly suspension bushes


Ian Comerford

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If I can venture an opinion on poly bushes.

A lot of the longevity depends on the install.  You are putting something round and pretty much solid into a hole that is not necessarily completely round and is very much solid - eg., the spring plate bushings.  Think about it for a second.  Eventually that imperfect fit and focussed pressure will create a section of the bush that is no longer lubricated.  The inner grooves help maintain a supply of lube, but the better answer is the perfectly round bronze fitting of an ER polybronze bushing.  In addition, the ER bushing has grease nipples so you can re-lube without pulling apart.

I had maybe 8+ yrs of trouble free ER bushings.  My original poly bushes on the spring plates lasted maybe 1 yr before becoming noisy and ended up replaced with Neatrix rubber.

On my first 72 911, I had poly spring plate bushes that were silent, but they were installed by an engineer who made sure they fit and used various abrasives/burnishers/tools to ensure there was a tight fit, but everything moved freely and easily when trial assembled.

YMMV, but failed poly bushes are being used where they shouldn't be or in a way that they are not designed for, even if they are being sold that purpose IMHO.  The conclusion is that rubber may be better for many applications unless you accept the increased installation effort and the necessity to re-grease from time to time.

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Interesting observations RB. All valid points. 

Didn't @sladey have the ER polybronze ones and have some issues with them?  To be fair Mark's a beautiful freak who daily drives his car, so mileage and therefore grime ingress likely to be much higher than us high day and holiday pussies.  

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On 11/29/2018 at 12:10 PM, Northy said:

I should add - my creaking is from trailing arm bushes not a-arm. 

Actually I’m talking crap here it’s my spring plate bushings not the trailing arm ones (I.e. next to gearbox) - I’ve not changed those. 

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On 11/30/2018 at 2:18 PM, Northy said:

Interesting observations RB. All valid points. 

Didn't @sladey have the ER polybronze ones and have some issues with them?  To be fair Mark's a beautiful freak who daily drives his car, so mileage and therefore grime ingress likely to be much higher than us high day and holiday pussies.  

Beautiful freak here. ;)

Yes I installed my ER polybronze ones about 10 years ago so they have had about 100K miles on them. (still got the rears, changed the fronts)

The front ones eventually started creaking and when I took them apart they had deteriorated - skimming one part on a lathe helped to give them another year of life but about a year ago I replaced them with the rebel racing ones that don't need any greasing (https://www.rsrproducts.com/product-page/rebel-s-racing-rsr-front-bushing-set)

For the rear ones whilst I have had squeaky periods after I re-grease them they get better. The last time I struggled to get the grease in and ended up taking them apart and slathering the pink grease on there before reassembly. They've been quiet since - touch wood.

If you're driving your car every day I find the greasing to be a ball-ache. When I come to replace the rears I'll go for ones like the front (these https://www.rsrproducts.com/product-page/rebel-s-racing-rsr-rear-bushing-set) - They are allegedly thermoplastic PTFE impregnated, missus, and require no maintenance.

Greasing them is not easy - the rear ones especially - it's hard to get access in there and even harder to know for sure if the grease is going in. If you don't stay on top of it then eventually bits of it solidifies stopping any future greasing from working. This is what happened to my front ones. After speaking to Chris at Centre Gravity I now grease them with some pink grease that is like thick snot. I trust his recommendation. If I were fitting front ones again then I would recommend wrapping a bit of inner tube round them (with a drain hole) to protect them from the worst of the weather - from memory it was the rearmost front ones that were the most badly affected - they are right in the firing line of crap.

HTH

 

Mark

 

 

 

 

"high day and holiday pussies" - made me laugh!

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If the A arm poly bushes need greasing regularly, do top mount poly bushes need regular greasing as well? I was thinking of replacing my koni doughnut rubbers to polys but reading this makes me wonder if I should go back to stock rubber mounts. 

Those rebel racing a arm bushes look great. Real quality 

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1 minute ago, Busybee said:

If the A arm poly bushes need greasing regularly, do top mount poly bushes need regular greasing as well? 

Not if you have archliners I would say. In 8 years I haven’t touched my poly top mount bushes.

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12 minutes ago, Dr Rock said:

Not if you have archliners I would say. In 8 years I haven’t touched my poly top mount bushes.

So as I drive the ibs very little in the wet, crappy weather but I don’t have liners, I should be ok? Wish I hadn’t messed with my original top mounts. I mistakenly assumed the rubbers that came with the new koni inserts has to be fitted so set about taking the original rubber out of the top mounts. Doh! 

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31 minutes ago, Busybee said:

If the A arm poly bushes need greasing regularly, do top mount poly bushes need regular greasing as well? I was thinking of replacing my koni doughnut rubbers to polys but reading this makes me wonder if I should go back to stock rubber mounts. 

Those rebel racing a arm bushes look great. Real quality 

I had the monoballs from Elephant racing - there was no grease nipple on those so nowhere to grease them other than taking them apart. 

Mine deteriorated until there was slop in them  - I eventually replaced them with poly. They've been fine. To be honest this is one of the simpler things to replace. 

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Thanks. Sounds like polys might be ok in the top mounts. Do they come split for ease of fitting and what brand did you fit Doc/sladey? 

Going back to your inner tube idea to cover the a arm bushes. Surprised no one has come up with a little casing to go over these which keeps crud out and good grease in. 

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15 minutes ago, Busybee said:

Thanks. Sounds like polys might be ok in the top mounts. Do they come split for ease of fitting and what brand did you fit Doc/sladey? 

Going back to your inner tube idea to cover the a arm bushes. Surprised no one has come up with a little casing to go over these which keeps crud out and good grease in. 

Yep mine were superpro I think - picked them up second hand on here. I think they probably aren't as precise as freshly installed monoballs but they are 95% of the way there and are fit and forget. 

I think the inner tube thing is irrelevant if you're a "high day and holiday *beep*" :lol:

 

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4 minutes ago, Dr Rock said:

Blue ones I think.

 

1 minute ago, sladey said:

Yep mine were superpro I think - picked them up second hand on here. I think they probably aren't as precise as freshly installed monoballs but they are 95% of the way there and are fit and forget. 

I think the inner tube thing is irrelevant if you're a "high day and holiday *beep*" :lol:

 

If they’re good enough for you two, good enough for me 👍 Superpro it is then. Yup, big girls blouse when I look out at rainy salty roads and then at my ib. Modern stuff just doesn’t matter as much somehow 

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On 11/28/2018 at 4:11 PM, longman said:

Is there actually anything wrong with genuine Porsche bushes? Replacing 30 plus yr old bushes with new is going to make a difference anyway ... Chris at Center grav reckoned there was no real reason to change to poly 

 

On 11/28/2018 at 4:38 PM, longman said:

Just saying the genuine ones have lasted 30 plus years but the aftermarket ones are having issues at 5 yrs or less .. if and when I need any suspension bushes I think I’ll stick with The genuine ones .. 

100% agree. For a pure street car I see no reason to take on the headache of polys. Every shop I spoke to in my area recommended OEM Porsche as well fwiw. 

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  • 4 weeks later...

So you are right Northy, I just called Powerflex and the grease supplied with their bushes is a PTFE Silicone  grease which is apparently specially formulated and should NOT require re applying !

They told me that this grease cannot be obtained separately but if you ever feel the need to regressed they would gladly send you some free gratis ...........which they are doing for me because one pack of the bushes I bought from them has the grease sachet missing!

so there you are folks

 

Edited by Nerodino
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For a mostly street car OEM Porsche or some type of rubber bushing all the way. Poly are a PITA for street cars and the benefits don't outweigh the annoyances in my experience. As someone said, replacing 30+ yr old factory rubber bushings with OEM will be a huge improvement regardless.

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