rangerovers.pub
The only place for a coil spring is up Zebedee's arse.
Member
avatar
Joined: Dec 30 2015
Posts: 3286

Having just changed my (and others) radius arm bushes here's a few observations for anyone considering poly bushes.

1, The yellow Britpart ones have a reputation to wearing out and turning to dust within a few months (no idea about the black or blue ones but I suspect they will be much the same as the yellow or orange ones).

2, My car was fitted with the supposedly far superior orange poly bushes (the ones that cost about 4 times the price of genuine original bushes). They've lasted quite a long time and many miles, but although the car didn't exhibit any of the usual complaints of wandering steering, vibrations or anything like that, it has always felt like the front tyre pressures were too high over small bumps and uneven surfaces even though the ride was fine on smooth surfaces. Having now changed to standard bushes, the steering is more responsive, the ride over uneven surfaces is vastly improved and the whole car feels much smoother.

3, The poly bushes are an absolute pain to remove. It took Marty's 20 ton press, a number of different sized mandrels, hacksaws, hole cutters and just about everything else we could find short of burning them out, to remove them from the radius arms. When we finally got them out, we found that they also allow moisture to get between the bush and the arm so rather than pushing the old ones out and finding a nice clean shiny hole, the inside of the radius arms were rusted to hell. It took a rotary wire brush to clean the surface, a punch and hammer to knock the rust scale off the inside of the radius arm and emery cloth to clean them up before they were smooth enough to press the new bushes in.

So the moral of this is poly bushes should be put into the same category as coil spring conversions, don't even consider them.

Member
Joined: Sep 02 2016
Posts: 320

Absolutely agree (and I have seen this with other marques too): Generally Poly bushes are just Big on Hype but Low on Performance"....

Member
Joined: Jul 12 2016
Posts: 812

I wonder if the increased amount of retained moisture contributed to the bolt seizing inside the sleeve?

I wasn't paying enough attention to which arm was which when they came off as they got passed around for various attempts at bush removal and rust removal.

Was the one with the seized bolt also the most rusty bush hole?

Member
Joined: Jan 16 2016
Posts: 166

Thanks for the very practical tips, Richard. You are preaching to the converted about suspension bushes. I would always stick with OEM. I had bad experiences with a classic rangerover I once had and also souped up Ford escorts many years ago.
I clamped the radius arm in a Black & Decker workmate and burnt the old OEM bushes out with a propane torch in the back garden. I used an old wood chisel and I caught the blobs of burning rubber in a tray underneath. This just left the plastic outer to chisel out. The inside hole in the radius arm was bright metal.

Member
avatar
Joined: Dec 30 2015
Posts: 3286

RutlandRover wrote:

Was the one with the seized bolt also the most rusty bush hole?

No, all the bush holes were as bad as each other, all rusted to hell and full of scale that I had to carefully break out with a punch and hammer. We were a bit concerned that it would leave the hole too big for the new bushes to fit properly but they still needed a fair amount of grunt to press them in so I don't think they'll be going anywhere.

Member
Joined: Sep 14 2016
Posts: 339

Imagine an annular cutter (Rotabroach) is the tool most likely to shift stuck in poly-bushes without excessive verbal encouragement. £60 + a pop in that sort of size tho' and really need a vertical mill to be confident of alignment. Right size pilot rod ought to work but how central the hole will be after many miles is open to question. Still have to cut undersize to be safe but scraping a couple of mm or so of left over polybush tube out isn't the end of the world. 2" twisted wire cup brush would be the tool of choice for that but I've not seen them that small for years, 2 3/4" seems to be the bottom size nowadays.

Clive

Member
Joined: Nov 27 2017
Posts: 202

The problem with drilling it is as we tried with a hole saw. (Good ones I might add) is that the minute it got hot it started to melt and jamming the tool.

Marty ended up using one of his spares to save time over the weekend. The one with Richards old poly bushes is still there if anyone wants a go!

Member
avatar
Joined: Dec 30 2015
Posts: 3286

Only one of them though. I've got one of Marty's spares(with my new bushes) on the nearside and my original one on the offside after it finally succumbed to much brute force and butchery. Still had to chip the scale out of both holes before the new bushes could be pressed in though.

Oddly, they hadn't deformed much and the central hole was still in the centre. Even after pressing the central tube out the poly bits still didn't want to give up.

Member
Joined: Jul 12 2016
Posts: 812

The polybush was so seized, stretchy and tough that it managed to bend one of Marty's press tools. The tool bent, pinched around part of the polybush and was difficult to remove.

Member
avatar
Joined: Dec 30 2015
Posts: 3286

The way they started to melt as soon as they got remotely warm, I reckon a blowlamp would have been the easiest way of removing them. If only one of us had thought of bringing one, we'd have been able to light the Sunday lunch barbecue too I would think.

Member
Joined: Sep 14 2016
Posts: 339

Rcutler wrote:

The problem with drilling it is as we tried with a hole saw. (Good ones I might add) is that the minute it got hot it started to melt and jamming the tool.

Getting hot and nowhere for the swarf to go is always the issue when using holesaws on anything other than sheet metal and similar thin stuff. Unsurprising I suppose as thin is what they are designed for. Which hasn't stopped me sacrificing a few in the interests of "getting 'er done wiv wot I've got" despite inherent unsuitability. Really doesn't help that, most of the time there is no recourse but to run them far too fast. Mr Starrett puts a nice speed chart in the box with his. Sometimes I think I'm the only guy who has actually read one. Reading and following being slightly different matters of course.

Nice thing about Rotabroach type cutters is that they have proper arrangements for swarf extraction. I imagine the usual rules for plastic would apply. Razor sharp, run slow (so it doesn't warm up) and heavy feed for a thick chip mechanically strong enough to spiral out. Maybe done in short bites and lubricate the centre stub or maybe just push on and let the centre burnish smooth. Depends on whether it behaves like nylon or delrin.

Experimentally heating plastics is something I tend to avoid. Frequently you end up with smoky, smelly or a mess. Often all three. Which offends angainst my conceit of knowing what I'm doing.

Clive

Member
Joined: Dec 30 2015
Posts: 1359

Amateurs! lol

Member
Joined: Jul 12 2016
Posts: 812

Morat wrote:

Amateurs! lol

There was at least one polybush still in an arm when I left if you wanted to show us how it's done :P

Member
avatar
Joined: Dec 30 2015
Posts: 3286

Clive603 wrote:

Depends on whether it behaves like nylon or delrin.

Problem is it behaved more like marshmallow! Not like plastic at all, very soft and squidgy but also very tough to cut with anything.

Member
Joined: Dec 30 2015
Posts: 1359

RutlandRover wrote:

Morat wrote:

Amateurs! lol

There was at least one polybush still in an arm when I left if you wanted to show us how it's done :P

I was talking about the barbeque :)

Member
Joined: Jul 12 2016
Posts: 812

Ah, got it.

Member
Joined: Sep 14 2016
Posts: 339

Gilbertd wrote:

Clive603 wrote:

Depends on whether it behaves like nylon or delrin.

Problem is it behaved more like marshmallow! Not like plastic at all, very soft and squidgy but also very tough to cut with anything.

Urg. Sharp Rotabroach will shift that sort of stuff but big issue is controlling the feed through rate. With the slow spiral on the flutes its going to want to pull straight through in about a turn or two. if it does that the big issue becomes whether or not you have the power to make a complete rotation at the end and snap the whole mess of swarf off. Alternative is a controlled low rate feed which will nibble it out in little balls. Which does work with rubber but you have to get the rate of feed right otherwise it squishes in under the cutter which takes occasional big bites. Not the sort of thing that's easily done in the ordinary garage workshop. With rubber best answer is to freeze it and hit it fast before it cottons on to whats going on. Even if freezing works for ploy bushes a complete radius arm will need an industrial freezer!

If its that soft a Forstener bit might work. Cut will have to be in thin slices so you still have the issue of controlling feed. The edge might hold it back enough so things can be controlled. Lubricant will help. Synthetic cutting oil would be best but normal folks don't have that sort of stuff about the place. WD40 spray should work adequately.

Clive

Member
avatar
Joined: Jan 05 2016
Posts: 869

...next time I'll bring the blow torch. Can't argue if its a liquid. And we'd have had the BBQ going one way or another ;)

Member
Joined: Dec 29 2016
Posts: 198

We had exactly the same experience with the Blue Polybushes in our P38. They weren't BritPart ones, they were the genuine Polybush ones that came with a sticker saying "Revolutionise your ride" which I now look at and can't help but laugh.

I keep telling people on the Facebook groups not to use them and post the below but none of them ever listen.

We fitted the real Polybushes to a P38. The blue ones. They were off within 12 months and replaced with genuine as they were dangerous.
The ones we fitted to ours were made by Polybush and were the blue comfort ones. They came with a sticker that said "revolutionise your ride" - that's laughable.
We fitted these as Polybush themselves advised that the orange ones can make the ride hard. After a year (8k miles) the car developed a lethal wobble when on uneven roads.
When we put the car on the ramp and had a look the front radius arm bushes were slack and moving around in the radius arm. The vibration on the car felt like the axle was ready to come off when hitting pot holes.
We removed them all and binned them and fitted genuine ones 5 years ago now and the difference is amazing.
I wouldn't waste my money on them for anything now. I know I'm not alone in my thoughts either.

Member
avatar
Joined: Dec 30 2015
Posts: 3286

As Britpart don't make orange ones but Polybush do, I assume the ones on mine were Polybush. They've lasted and the car didn't feel too bad, it's just that now I'm on genuine rubber ones, I realise just how much better it can be.